app/src/main/java/org/prolibertate/games/ui/GameSetupScreen.kt

@@ -58,6 +58,7 @@ import org.prolibertate.games.game.pirates.PiratesLevel
 import org.prolibertate.games.game.pirates.PiratesOptions
 import org.prolibertate.games.game.president.PresidentOptions
 import org.prolibertate.games.game.catan.CatanOptions
+import org.prolibertate.games.game.catan.CatanRuleSet
 import org.prolibertate.games.game.sequence.SequenceOptions
 import org.prolibertate.games.game.tayu.TayuLevel
 import org.prolibertate.games.game.tayu.TayuOptions
@@ -334,9 +335,55 @@ fun teamForSeat(gameId: String, seat: Int, seatCount: Int): Int = when (gameId)
     else -> seat
 }
 
+/** The targets the setup screen offers for a Katan rule set. */
+internal fun catanPointsChoices(ruleSet: CatanRuleSet): List<Int> = when (ruleSet) {
+    // Five is a short game for trying things out; ten is the published target.
+    CatanRuleSet.BASE -> listOf(5, 8, 10, 12)
+    // Cities & Knights is played to thirteen, which is also why it runs longer.
+    CatanRuleSet.CITIES_AND_KNIGHTS -> listOf(8, 10, 13, 15)
+}
+
+/** The published target for a rule set. */
+internal fun catanDefaultPoints(ruleSet: CatanRuleSet): Int = when (ruleSet) {
+    CatanRuleSet.BASE -> 10
+    CatanRuleSet.CITIES_AND_KNIGHTS -> 13
+}
+
+/**
+ * [options] switched to [ruleSet]. The target moves to the new rule set's own
+ * default unless the one already chosen is on its menu too.
+ */
+internal fun catanSwitchRules(options: CatanOptions, ruleSet: CatanRuleSet): CatanOptions =
+    options.copy(
+        ruleSet = ruleSet,
+        pointsToWin = options.pointsToWin.takeIf { it in catanPointsChoices(ruleSet) && it != catanDefaultPoints(options.ruleSet) }
+            ?: catanDefaultPoints(ruleSet),
+    )
+
+private fun catanRuleSetName(ruleSet: CatanRuleSet): String = when (ruleSet) {
+    CatanRuleSet.BASE -> "Base game"
+    CatanRuleSet.CITIES_AND_KNIGHTS -> "Cities & Knights"
+}
+
+private fun catanRuleSetBlurb(ruleSet: CatanRuleSet): String = when (ruleSet) {
+    CatanRuleSet.BASE ->
+        "Settle the island, trade, and play development cards. Longest Road and Largest Army score."
+    CatanRuleSet.CITIES_AND_KNIGHTS ->
+        "Cities make commodities, knights hold off the barbarians, and improvements earn progress " +
+            "cards and metropolises. No development cards; the robber sleeps until the first attack."
+}
+
 @Composable
 private fun CatanOptionsEditor(options: CatanOptions, onChange: (CatanOptions) -> Unit) {
     Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+        ChipRow(
+            label = "Rules",
+            values = CatanRuleSet.entries,
+            selected = options.ruleSet,
+            display = ::catanRuleSetName,
+            onSelect = { onChange(catanSwitchRules(options, it)) },
+        )
+        Text(catanRuleSetBlurb(options.ruleSet), style = MaterialTheme.typography.bodySmall)
         ChipRow(
             label = "Players",
             values = listOf(3, 4),
@@ -346,8 +393,7 @@ private fun CatanOptionsEditor(options: CatanOptions, onChange: (CatanOptions) -
         )
         ChipRow(
             label = "Game to",
-            // Five is a short game for trying things out; ten is the published target.
+            values = catanPointsChoices(options.ruleSet),
-            values = listOf(5, 8, 10, 12),
             selected = options.pointsToWin,
             display = { "$it points" },
             onSelect = { onChange(options.copy(pointsToWin = it)) },

app/src/main/java/org/prolibertate/games/ui/game/catan/CatanBoardView.kt

@@ -14,6 +14,7 @@ import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.Path
+import androidx.compose.ui.graphics.PathEffect
 import androidx.compose.ui.graphics.StrokeCap
 import androidx.compose.ui.graphics.drawscope.DrawScope
 import androidx.compose.ui.graphics.drawscope.Stroke
@@ -58,6 +59,8 @@ fun CatanBoardView(
     style: CatanStyle = LocalCatanStyle.current,
     /** Hexes to light up as having produced on the latest roll. */
     rolledHexes: Set<Int> = emptySet(),
+    /** Cities & Knights: the knight whose menu is open or that is about to move. */
+    selectedKnight: Int? = null,
 ) {
     val measurer = rememberTextMeasurer()
     var size by remember { mutableStateOf(IntSize.Zero) }
@@ -86,8 +89,8 @@ fun CatanBoardView(
                     val at = Pt(tap.x, tap.y)
                     val reach = board.radius * style.tapReach
                     when {
-                        targets.vertices.isNotEmpty() ->
+                        targets.tappableVertices.isNotEmpty() ->
-                            board.nearestVertex(at, reach, targets.vertices)?.let { vertexTap(it) }
+                            board.nearestVertex(at, reach, targets.tappableVertices)?.let { vertexTap(it) }
 
                         targets.edges.isNotEmpty() ->
                             board.nearestEdge(at, reach, targets.edges)?.let { edgeTap(it) }
@@ -105,10 +108,15 @@ fun CatanBoardView(
         drawHexes(state, board, style, measurer)
         drawRolled(rolledHexes, board, style)
         drawRobber(state, board, style)
+        drawMerchant(state, board, style, measurer)
         drawRoads(state, board, style)
         drawEdgeTargets(targets, board, style)
         drawBuildings(state, board, style)
-        drawVertexTargets(targets, selectedVertex, board, style)
+        drawWalls(state, board, style)
+        drawMetropolises(state, board, style)
+        drawKnights(state, board, style)
+        drawKnightTargets(targets, board, style)
+        drawVertexTargets(targets, selectedVertex ?: selectedKnight, board, style)
         drawHexTargets(targets, board, style)
     }
 }
@@ -185,6 +193,10 @@ private fun DrawScope.drawToken(
 }
 
 private fun DrawScope.drawRobber(state: CatanState, board: BoardLayout, style: CatanStyle) {
+    // In Cities & Knights the robber sleeps, drawn faintly, until the barbarians first land.
+    val asleep = state.ck?.attacked == false
+    val tint = if (asleep) style.robber.copy(alpha = 0.3f) else style.robber
+    val rim = Color.White.copy(alpha = if (asleep) 0.25f else 0.7f)
     val hex = board.hexCenter(state.robber)
     // Beside the number token rather than on it, so the number stays readable.
     val x = hex.x + board.radius * 0.5f
@@ -197,11 +209,11 @@ private fun DrawScope.drawRobber(state: CatanState, board: BoardLayout, style: C
         lineTo(x + s * 0.55f, y + s * 0.9f)
         close()
     }
-    drawPath(pawn, color = style.robber)
+    drawPath(pawn, color = tint)
-    drawCircle(color = style.robber, radius = s * 0.38f, center = Offset(x, y - s * 0.42f))
+    drawCircle(color = tint, radius = s * 0.38f, center = Offset(x, y - s * 0.42f))
-    drawPath(pawn, color = Color.White.copy(alpha = 0.7f), style = Stroke(width = s * 0.07f))
+    drawPath(pawn, color = rim, style = Stroke(width = s * 0.07f))
     drawCircle(
-        color = Color.White.copy(alpha = 0.7f),
+        color = rim,
         radius = s * 0.38f,
         center = Offset(x, y - s * 0.42f),
         style = Stroke(width = s * 0.07f),
@@ -409,6 +421,131 @@ private fun cityPath(at: Pt, s: Float): Path = Path().apply {
     close()
 }
 
+// ---------------------------------------------------------------------------
+// Cities & Knights pieces
+// ---------------------------------------------------------------------------
+
+/** A dashed wall round each walled city, crenellated by the dashes. */
+private fun DrawScope.drawWalls(state: CatanState, board: BoardLayout, style: CatanStyle) {
+    val walls = state.ck?.walls ?: return
+    for (vertex in walls) {
+        val at = board.vertex(vertex).offset()
+        val radius = board.radius * style.citySize * 1.25f
+        val dash = PathEffect.dashPathEffect(floatArrayOf(radius * 0.38f, radius * 0.22f))
+        drawCircle(
+            color = style.pieceOutline,
+            radius = radius,
+            center = at,
+            style = Stroke(width = board.radius * 0.13f, pathEffect = dash),
+        )
+        drawCircle(
+            color = style.wall,
+            radius = radius,
+            center = at,
+            style = Stroke(width = board.radius * 0.09f, pathEffect = dash),
+        )
+    }
+}
+
+/** A pennant in the track's colour flying over a city that carries its metropolis. */
+private fun DrawScope.drawMetropolises(state: CatanState, board: BoardLayout, style: CatanStyle) {
+    val metropolises = state.ck?.metropolises ?: return
+    for ((track, at) in metropolises) {
+        val base = board.vertex(at.vertex)
+        val unit = board.radius * style.citySize
+        val poleTop = Pt(base.x + unit * 0.9f, base.y - unit * 2.0f)
+        val poleBottom = Pt(base.x + unit * 0.9f, base.y - unit * 0.4f)
+        drawLine(
+            color = style.pieceOutline,
+            start = poleBottom.offset(),
+            end = poleTop.offset(),
+            strokeWidth = board.radius * 0.05f,
+        )
+        val flag = Path().apply {
+            moveTo(poleTop.x, poleTop.y)
+            lineTo(poleTop.x + unit * 1.1f, poleTop.y + unit * 0.35f)
+            lineTo(poleTop.x, poleTop.y + unit * 0.7f)
+            close()
+        }
+        drawPath(flag, color = style.track.getValue(track))
+        drawPath(flag, color = style.pieceOutline, style = Stroke(width = board.radius * 0.035f))
+    }
+}
+
+/**
+ * Each knight is a shield in its owner's colour, marked with one, two or three
+ * dots for its strength. A sleeping knight is drawn faded; an awake one has a
+ * bright rim.
+ */
+private fun DrawScope.drawKnights(state: CatanState, board: BoardLayout, style: CatanStyle) {
+    val knights = state.ck?.knights ?: return
+    for (knight in knights) {
+        val at = board.vertex(knight.vertex)
+        val s = board.radius * style.knightSize
+        val seat = style.seats[knight.owner % style.seats.size]
+        val path = shieldPath(at, s)
+        if (knight.active) {
+            drawPath(path, color = style.knightReady, style = Stroke(width = s * 0.55f))
+        }
+        drawPath(path, color = if (knight.active) seat else seat.copy(alpha = 0.55f))
+        drawPath(path, color = style.pieceOutline, style = Stroke(width = s * 0.16f))
+        val pip = s * 0.14f
+        val gap = pip * 2.8f
+        val startX = at.x - gap * (knight.level - 1) / 2f
+        for (i in 0 until knight.level) {
+            drawCircle(
+                color = style.pieceOutline,
+                radius = pip,
+                center = Offset(startX + i * gap, at.y - s * 0.05f),
+            )
+        }
+    }
+}
+
+private fun shieldPath(at: Pt, s: Float): Path = Path().apply {
+    moveTo(at.x - s * 0.8f, at.y - s)
+    lineTo(at.x + s * 0.8f, at.y - s)
+    lineTo(at.x + s * 0.8f, at.y + s * 0.1f)
+    quadraticBezierTo(at.x + s * 0.8f, at.y + s * 0.9f, at.x, at.y + s * 1.25f)
+    quadraticBezierTo(at.x - s * 0.8f, at.y + s * 0.9f, at.x - s * 0.8f, at.y + s * 0.1f)
+    close()
+}
+
+/** A ring round each of the player's knights that can do something now. */
+private fun DrawScope.drawKnightTargets(targets: BoardTargets, board: BoardLayout, style: CatanStyle) {
+    for (vertex in targets.knights) {
+        drawCircle(
+            color = style.target,
+            radius = board.radius * style.knightSize * 1.9f,
+            center = board.vertex(vertex).offset(),
+            style = Stroke(width = board.radius * 0.07f),
+        )
+    }
+}
+
+/** The merchant: a coin in its controller's colour, beside the hex it sits on. */
+private fun DrawScope.drawMerchant(
+    state: CatanState,
+    board: BoardLayout,
+    style: CatanStyle,
+    measurer: TextMeasurer,
+) {
+    val merchant = state.ck?.merchant ?: return
+    val hex = board.hexCenter(merchant.hex)
+    val at = Pt(hex.x - board.radius * 0.5f, hex.y + board.radius * 0.3f)
+    val r = board.radius * 0.2f
+    drawCircle(color = style.seats[merchant.seat % style.seats.size], radius = r, center = at.offset())
+    drawCircle(color = style.pieceOutline, radius = r, center = at.offset(), style = Stroke(width = r * 0.3f))
+    drawCentered(
+        measurer = measurer,
+        text = "M",
+        at = at,
+        fontPx = r * 1.3f,
+        color = style.pieceOutline,
+        weight = FontWeight.ExtraBold,
+    )
+}
+
 // ---------------------------------------------------------------------------
 // Tap targets
 // ---------------------------------------------------------------------------

app/src/main/java/org/prolibertate/games/ui/game/catan/CatanCkDialogs.kt

@@ -0,0 +1,728 @@
+package org.prolibertate.games.ui.game.catan
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ExperimentalLayoutApi
+import androidx.compose.foundation.layout.FlowRow
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Button
+import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import org.prolibertate.games.game.catan.ActivateKnight
+import org.prolibertate.games.game.catan.BuyImprovement
+import org.prolibertate.games.game.catan.CatanCk
+import org.prolibertate.games.game.catan.CatanMove
+import org.prolibertate.games.game.catan.CatanState
+import org.prolibertate.games.game.catan.ChaseRobber
+import org.prolibertate.games.game.catan.DropProgress
+import org.prolibertate.games.game.catan.GoodsBankTrade
+import org.prolibertate.games.game.catan.Good
+import org.prolibertate.games.game.catan.GoodsOffer
+import org.prolibertate.games.game.catan.IMPROVEMENT_MAX
+import org.prolibertate.games.game.catan.MoveKnight
+import org.prolibertate.games.game.catan.OfferGoods
+import org.prolibertate.games.game.catan.PickDeck
+import org.prolibertate.games.game.catan.PlayProgress
+import org.prolibertate.games.game.catan.ProgressCard
+import org.prolibertate.games.game.catan.ProgressType
+import org.prolibertate.games.game.catan.PromoteKnight
+import org.prolibertate.games.game.catan.SpyTake
+import org.prolibertate.games.game.catan.TakeAqueduct
+import org.prolibertate.games.game.catan.Track
+
+/*
+ * The Cities & Knights dialogs. Like the base game's, each is a stateless
+ * composable apart from the choice it is helping the player make, and what is
+ * allowed is always asked of the engine's legal list through CatanInteraction.
+ */
+
+// ---------------------------------------------------------------------------
+// Shared pieces
+// ---------------------------------------------------------------------------
+
+/** A card tile with a minus and a plus, for choosing how many of a good. */
+@Composable
+private fun GoodCounter(good: Good, count: Int, max: Int, onChange: (Int) -> Unit) {
+    Column(horizontalAlignment = Alignment.CenterHorizontally, verticalArrangement = Arrangement.spacedBy(4.dp)) {
+        GoodTile(good, count, enabled = max > 0 || count > 0)
+        Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
+            OutlinedButton(
+                onClick = { onChange(count - 1) },
+                enabled = count > 0,
+                contentPadding = PaddingValues(0.dp),
+                modifier = Modifier.width(34.dp).height(32.dp),
+            ) { Text("−") }
+            OutlinedButton(
+                onClick = { onChange(count + 1) },
+                enabled = count < max,
+                contentPadding = PaddingValues(0.dp),
+                modifier = Modifier.width(34.dp).height(32.dp),
+            ) { Text("+") }
+        }
+    }
+}
+
+private fun Map<Good, Int>.asGoods(): List<Good> = Good.entries.flatMap { g -> List(this[g] ?: 0) { g } }
+
+/** A row of the three track colours, used for decks and improvements. */
+@Composable
+private fun TrackChip(track: Track, style: CatanStyle = LocalCatanStyle.current) {
+    Box(
+        modifier = Modifier
+            .size(14.dp)
+            .clip(RoundedCornerShape(3.dp))
+            .background(style.track.getValue(track)),
+    )
+}
+
+// ---------------------------------------------------------------------------
+// Choosing cards to give up
+// ---------------------------------------------------------------------------
+
+/**
+ * Pick exactly [quota] cards out of [held] — to discard on a seven or a saboteur,
+ * or to hand over for a wedding or a commercial harbour. Not dismissable: the
+ * game is waiting on it. [allowed] is the engine's structural check, so the
+ * confirm button only lights when the move would be accepted.
+ */
+@OptIn(ExperimentalLayoutApi::class)
+@Composable
+fun CatanGoodsPickDialog(
+    title: String,
+    intro: String,
+    held: Map<Good, Int>,
+    quota: Int,
+    confirmLabel: String,
+    selectable: (Good) -> Boolean,
+    allowed: (List<Good>) -> Boolean,
+    onConfirm: (List<Good>) -> Unit,
+) {
+    var picked by remember { mutableStateOf(emptyMap<Good, Int>()) }
+    val selection = picked.asGoods()
+    AlertDialog(
+        onDismissRequest = {},
+        title = { Text(title) },
+        text = {
+            Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
+                Text("$intro (${selection.size} of $quota chosen).")
+                FlowRow(
+                    horizontalArrangement = Arrangement.spacedBy(8.dp),
+                    verticalArrangement = Arrangement.spacedBy(8.dp),
+                ) {
+                    Good.entries.forEach { good ->
+                        val have = held[good] ?: 0
+                        if (have > 0 && selectable(good)) {
+                            GoodCounter(
+                                good = good,
+                                count = picked[good] ?: 0,
+                                max = if (selection.size < quota) have else (picked[good] ?: 0),
+                                onChange = { n -> picked = picked + (good to n.coerceIn(0, have)) },
+                            )
+                        }
+                    }
+                }
+            }
+        },
+        confirmButton = {
+            Button(onClick = { onConfirm(selection) }, enabled = allowed(selection)) { Text(confirmLabel) }
+        },
+    )
+}
+
+// ---------------------------------------------------------------------------
+// City improvements
+// ---------------------------------------------------------------------------
+
+/** The three improvement tracks: where the player stands, what the next level costs, and what it earns. */
+@Composable
+fun CatanImproveDialog(
+    state: CatanState,
+    seat: Int,
+    legal: List<CatanMove>,
+    onBuy: (BuyImprovement) -> Unit,
+    onCancel: () -> Unit,
+) {
+    val ck = state.ck ?: return
+    val buyable = CatanInteraction.improvable(legal)
+    AlertDialog(
+        onDismissRequest = onCancel,
+        title = { Text(CatanText.IMPROVE) },
+        text = {
+            Column(
+                modifier = Modifier.heightIn(max = 460.dp).verticalScroll(rememberScrollState()),
+                verticalArrangement = Arrangement.spacedBy(14.dp),
+            ) {
+                Track.entries.forEach { track ->
+                    val level = CatanCk.improvement(state, seat, track)
+                    val have = ck.commodities[seat][track.commodity] ?: 0
+                    Column(verticalArrangement = Arrangement.spacedBy(4.dp)) {
+                        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(6.dp)) {
+                            TrackChip(track)
+                            Text(CatanText.track(track), fontWeight = FontWeight.Bold)
+                            Text("level $level of $IMPROVEMENT_MAX", style = MaterialTheme.typography.labelMedium)
+                        }
+                        Text(CatanText.trackPower(track), style = MaterialTheme.typography.bodySmall)
+                        if (level >= IMPROVEMENT_MAX) {
+                            Text("Fully built.", style = MaterialTheme.typography.bodySmall)
+                        } else {
+                            val cost = CatanCk.improvementCost(state, seat, track)
+                            Button(onClick = { onBuy(BuyImprovement(track)) }, enabled = track in buyable) {
+                                Text(
+                                    "${CatanCk.improvementName(track, level + 1)}: $cost " +
+                                        "${CatanText.good(Good.of(track.commodity))} (you hold $have)",
+                                )
+                            }
+                            if (level + 1 == org.prolibertate.games.game.catan.METROPOLIS_LEVEL ||
+                                level + 1 == IMPROVEMENT_MAX
+                            ) {
+                                Text(
+                                    if (level + 1 == IMPROVEMENT_MAX) {
+                                        "Level five takes a metropolis from a seat still on four."
+                                    } else {
+                                        "Level four earns the first metropolis in this track: two more points."
+                                    },
+                                    style = MaterialTheme.typography.labelSmall,
+                                )
+                            }
+                        }
+                    }
+                }
+            }
+        },
+        confirmButton = {},
+        dismissButton = { TextButton(onClick = onCancel) { Text("Close") } },
+    )
+}
+
+// ---------------------------------------------------------------------------
+// Progress cards
+// ---------------------------------------------------------------------------
+
+/**
+ * The player's progress cards. A card with nothing to decide plays at once; one
+ * that names a seat, a card or dice asks for it in a second step; one that
+ * needs a tap on the board closes the dialog and arms the board (see [ArmedCard]).
+ */
+@OptIn(ExperimentalLayoutApi::class)
+@Composable
+fun CatanProgressDialog(
+    hand: List<ProgressInHand>,
+    seats: CatanSeats,
+    onPlay: (CatanMove) -> Unit,
+    onArm: (ArmedCard) -> Unit,
+    onCancel: () -> Unit,
+) {
+    var chosen by remember { mutableStateOf<ProgressInHand?>(null) }
+    var target by remember { mutableStateOf<Int?>(null) }
+    var yellow by remember { mutableStateOf(1) }
+    var red by remember { mutableStateOf(1) }
+    val entry = chosen
+
+    AlertDialog(
+        onDismissRequest = onCancel,
+        title = { Text(entry?.let { CatanText.progress(it.card.kind) } ?: "Progress cards") },
+        text = {
+            Column(
+                modifier = Modifier.heightIn(max = 440.dp).verticalScroll(rememberScrollState()),
+                verticalArrangement = Arrangement.spacedBy(10.dp),
+            ) {
+                if (entry == null) {
+                    if (hand.isEmpty()) Text("You hold no progress cards.")
+                    hand.forEach { card ->
+                        ProgressRow(card) { picked ->
+                            val kind = picked.card.kind
+                            when {
+                                kind in CatanInteraction.BOARD_CARDS -> onArm(ArmedCard(kind, picked.plays))
+                                picked.plays.size == 1 && picked.plays[0].isBare() -> onPlay(picked.plays[0])
+                                else -> {
+                                    chosen = picked
+                                    target = null
+                                }
+                            }
+                        }
+                    }
+                } else {
+                    Text(CatanText.progressHelp(entry.card.kind), style = MaterialTheme.typography.bodySmall)
+                    val kind = entry.card.kind
+                    val plays = entry.plays
+                    when {
+                        kind == ProgressType.ALCHEMIST -> {
+                            Text("Production die (yellow)", fontWeight = FontWeight.Bold)
+                            DiePicker(yellow) { yellow = it }
+                            Text("Progress die (red)", fontWeight = FontWeight.Bold)
+                            DiePicker(red) { red = it }
+                        }
+
+                        kind == ProgressType.DESERTER || kind == ProgressType.SPY -> {
+                            Text("Choose a player:", fontWeight = FontWeight.Bold)
+                            plays.mapNotNull { it.target }.distinct().forEach { seat ->
+                                OutlinedButton(
+                                    onClick = { plays.firstOrNull { it.target == seat }?.let(onPlay) },
+                                    modifier = Modifier.fillMaxWidth(),
+                                ) { Text(seats.label(seat)) }
+                            }
+                        }
+
+                        kind == ProgressType.MASTER_MERCHANT -> {
+                            Text("Choose a player with more points:", fontWeight = FontWeight.Bold)
+                            Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                                plays.mapNotNull { it.target }.distinct().forEach { seat ->
+                                    if (target == seat) {
+                                        FilledTonalButton(onClick = { target = seat }) { Text(seats.label(seat)) }
+                                    } else {
+                                        OutlinedButton(onClick = { target = seat }) { Text(seats.label(seat)) }
+                                    }
+                                }
+                            }
+                            val seat = target
+                            if (seat != null) {
+                                Text("Take:", fontWeight = FontWeight.Bold)
+                                plays.filter { it.target == seat }.forEach { play ->
+                                    OutlinedButton(
+                                        onClick = { onPlay(play) },
+                                        modifier = Modifier.fillMaxWidth(),
+                                    ) { Text(CatanText.goods(play.goods.orEmpty())) }
+                                }
+                            }
+                        }
+
+                        else -> {
+                            val label = when (kind) {
+                                ProgressType.COMMERCIAL_HARBOR -> "Offer which resource?"
+                                ProgressType.MERCHANT_FLEET -> "Trade which card two for one?"
+                                ProgressType.RESOURCE_MONOPOLY -> "Name a resource:"
+                                else -> "Name a commodity:"
+                            }
+                            Text(label, fontWeight = FontWeight.Bold)
+                            FlowRow(
+                                horizontalArrangement = Arrangement.spacedBy(8.dp),
+                                verticalArrangement = Arrangement.spacedBy(8.dp),
+                            ) {
+                                plays.mapNotNull { it.good }.distinct().forEach { good ->
+                                    GoodTile(
+                                        good = good,
+                                        count = 0,
+                                        onClick = { plays.firstOrNull { it.good == good }?.let(onPlay) },
+                                    )
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        },
+        confirmButton = {
+            if (entry != null && entry.card.kind == ProgressType.ALCHEMIST) {
+                val play = entry.plays.firstOrNull { it.dice == listOf(yellow, red) }
+                Button(onClick = { play?.let(onPlay) }, enabled = play != null) { Text("Play") }
+            }
+        },
+        dismissButton = {
+            TextButton(
+                onClick = {
+                    if (entry == null) {
+                        onCancel()
+                    } else {
+                        chosen = null
+                        target = null
+                    }
+                },
+            ) { Text(if (entry == null) CatanText.CANCEL else "Back") }
+        },
+    )
+}
+
+private fun PlayProgress.isBare(): Boolean =
+    target == null && vertex == null && edge == null && hexA == null && hexB == null &&
+        good == null && dice == null && goods == null
+
+@Composable
+private fun DiePicker(selected: Int, onPick: (Int) -> Unit) {
+    Row(horizontalArrangement = Arrangement.spacedBy(6.dp)) {
+        (1..6).forEach { n ->
+            if (n == selected) {
+                FilledTonalButton(
+                    onClick = { onPick(n) },
+                    contentPadding = PaddingValues(0.dp),
+                    modifier = Modifier.size(40.dp),
+                ) { Text("$n") }
+            } else {
+                OutlinedButton(
+                    onClick = { onPick(n) },
+                    contentPadding = PaddingValues(0.dp),
+                    modifier = Modifier.size(40.dp),
+                ) { Text("$n") }
+            }
+        }
+    }
+}
+
+@Composable
+private fun ProgressRow(entry: ProgressInHand, onChoose: (ProgressInHand) -> Unit) {
+    val kind = entry.card.kind
+    Row(
+        modifier = Modifier.fillMaxWidth(),
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        TrackChip(kind.track)
+        Column(modifier = Modifier.weight(1f)) {
+            Text(CatanText.progress(kind), fontWeight = FontWeight.Bold)
+            Text(CatanText.progressHelp(kind), style = MaterialTheme.typography.bodySmall)
+        }
+        if (entry.playable) {
+            Button(onClick = { onChoose(entry) }) { Text("Play") }
+        } else {
+            Text("Not now", style = MaterialTheme.typography.labelSmall)
+        }
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Knights
+// ---------------------------------------------------------------------------
+
+/** What the knight on one crossing can do: wake, promote, move, chase the robber. */
+@Composable
+fun CatanKnightDialog(
+    state: CatanState,
+    vertex: Int,
+    actions: List<CatanMove>,
+    onDo: (CatanMove) -> Unit,
+    onMove: (Int) -> Unit,
+    onCancel: () -> Unit,
+) {
+    val knight = state.ck?.knights?.firstOrNull { it.vertex == vertex }
+    AlertDialog(
+        onDismissRequest = onCancel,
+        title = { Text(knight?.let { CatanText.knightName(it.level) } ?: "Knight") },
+        text = {
+            Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                if (knight != null) {
+                    val mood = when {
+                        !knight.active -> "Asleep. Waking it costs ${CatanText.ACTIVATE_COST}."
+                        knight.activatedTurn == state.turnNumber -> "Awake, but it woke this turn and cannot act yet."
+                        else -> "Awake and ready. It counts against the barbarians."
+                    }
+                    Text(mood, style = MaterialTheme.typography.bodySmall)
+                }
+                actions.forEach { move ->
+                    when (move) {
+                        is ActivateKnight ->
+                            Button(onClick = { onDo(move) }, modifier = Modifier.fillMaxWidth()) {
+                                Text("Wake (${CatanText.ACTIVATE_COST})")
+                            }
+
+                        is PromoteKnight ->
+                            Button(onClick = { onDo(move) }, modifier = Modifier.fillMaxWidth()) {
+                                Text("Promote (${CatanText.KNIGHT_COST})")
+                            }
+
+                        is MoveKnight ->
+                            OutlinedButton(onClick = { onMove(move.from) }, modifier = Modifier.fillMaxWidth()) {
+                                Text("Move along your roads")
+                            }
+
+                        is ChaseRobber ->
+                            OutlinedButton(onClick = { onDo(move) }, modifier = Modifier.fillMaxWidth()) {
+                                Text("Chase away the robber")
+                            }
+
+                        else -> Unit
+                    }
+                }
+                if (actions.isEmpty()) Text("Nothing to do with it right now.")
+            }
+        },
+        confirmButton = {},
+        dismissButton = { TextButton(onClick = onCancel) { Text("Close") } },
+    )
+}
+
+// ---------------------------------------------------------------------------
+// Chores that are answered in a dialog
+// ---------------------------------------------------------------------------
+
+/** Choose a colour of progress deck to draw from. */
+@Composable
+fun CatanPickDeckDialog(legal: List<CatanMove>, onPick: (PickDeck) -> Unit) {
+    val open = legal.filterIsInstance<PickDeck>()
+    AlertDialog(
+        onDismissRequest = {},
+        title = { Text("Draw a progress card") },
+        text = {
+            Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                Text("Catan held. You tied for the strongest defence, so choose any deck.")
+                open.forEach { pick ->
+                    Button(onClick = { onPick(pick) }, modifier = Modifier.fillMaxWidth()) {
+                        TrackChip(pick.track)
+                        Text("  ${CatanText.track(pick.track)}")
+                    }
+                }
+            }
+        },
+        confirmButton = {},
+    )
+}
+
+/** The hand is over its limit: give one progress card back. */
+@Composable
+fun CatanDropProgressDialog(hand: List<ProgressCard>, onDrop: (DropProgress) -> Unit) {
+    AlertDialog(
+        onDismissRequest = {},
+        title = { Text("Too many progress cards") },
+        text = {
+            Column(
+                modifier = Modifier.heightIn(max = 380.dp).verticalScroll(rememberScrollState()),
+                verticalArrangement = Arrangement.spacedBy(8.dp),
+            ) {
+                Text("You may keep four. Choose one to give back.")
+                hand.forEach { card ->
+                    OutlinedButton(onClick = { onDrop(DropProgress(card.id)) }, modifier = Modifier.fillMaxWidth()) {
+                        TrackChip(card.kind.track)
+                        Text("  ${CatanText.progress(card.kind)}")
+                    }
+                }
+            }
+        },
+        confirmButton = {},
+    )
+}
+
+/** The aqueduct pays: take any one resource. */
+@OptIn(ExperimentalLayoutApi::class)
+@Composable
+fun CatanAqueductDialog(legal: List<CatanMove>, onTake: (TakeAqueduct) -> Unit) {
+    AlertDialog(
+        onDismissRequest = {},
+        title = { Text("Aqueduct") },
+        text = {
+            Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
+                Text("The dice paid you nothing. Take any resource.")
+                FlowRow(
+                    horizontalArrangement = Arrangement.spacedBy(8.dp),
+                    verticalArrangement = Arrangement.spacedBy(8.dp),
+                ) {
+                    legal.filterIsInstance<TakeAqueduct>().forEach { take ->
+                        ResourceTile(resource = take.resource, count = 1, onClick = { onTake(take) })
+                    }
+                }
+            }
+        },
+        confirmButton = {},
+    )
+}
+
+/** A spy: these are the progress cards the other player holds; take one. */
+@Composable
+fun CatanSpyDialog(cards: List<ProgressCard>, legal: List<CatanMove>, onTake: (SpyTake) -> Unit) {
+    AlertDialog(
+        onDismissRequest = {},
+        title = { Text("Spy") },
+        text = {
+            Column(
+                modifier = Modifier.heightIn(max = 380.dp).verticalScroll(rememberScrollState()),
+                verticalArrangement = Arrangement.spacedBy(8.dp),
+            ) {
+                Text("Choose a card to take.")
+                cards.forEach { card ->
+                    val take = SpyTake(card.id)
+                    OutlinedButton(
+                        onClick = { onTake(take) },
+                        enabled = take in legal,
+                        modifier = Modifier.fillMaxWidth(),
+                    ) {
+                        TrackChip(card.kind.track)
+                        Text("  ${CatanText.progress(card.kind)}")
+                    }
+                }
+            }
+        },
+        confirmButton = {},
+    )
+}
+
+// ---------------------------------------------------------------------------
+// Trading in goods
+// ---------------------------------------------------------------------------
+
+private enum class GoodsTab { BANK, PLAYER }
+
+/**
+ * Trade with the bank at the best ratio each card has, or offer cards —
+ * commodities included — to one other player.
+ */
+@OptIn(ExperimentalLayoutApi::class)
+@Composable
+fun CatanGoodsTradeDialog(
+    state: CatanState,
+    seat: Int,
+    seats: CatanSeats,
+    legal: List<CatanMove>,
+    onBank: (GoodsBankTrade) -> Unit,
+    onOffer: (OfferGoods) -> Unit,
+    onCancel: () -> Unit,
+) {
+    var tab by remember { mutableStateOf(GoodsTab.BANK) }
+    var bankGive by remember { mutableStateOf<Good?>(null) }
+    var partner by remember { mutableStateOf<Int?>(null) }
+    var give by remember { mutableStateOf(emptyMap<Good, Int>()) }
+    var get by remember { mutableStateOf(emptyMap<Good, Int>()) }
+    val held = CatanCk.goodsOf(state, seat)
+
+    AlertDialog(
+        onDismissRequest = onCancel,
+        title = { Text(CatanText.TRADE) },
+        text = {
+            Column(
+                modifier = Modifier.heightIn(max = 460.dp).verticalScroll(rememberScrollState()),
+                verticalArrangement = Arrangement.spacedBy(12.dp),
+            ) {
+                Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                    GoodsTabButton(CatanText.TRADE_WITH_BANK, tab == GoodsTab.BANK) { tab = GoodsTab.BANK }
+                    GoodsTabButton(CatanText.TRADE_WITH_PLAYER, tab == GoodsTab.PLAYER) { tab = GoodsTab.PLAYER }
+                }
+                if (tab == GoodsTab.BANK) {
+                    val trades = CatanInteraction.goodsBankTrades(legal)
+                    if (trades.isEmpty()) {
+                        Text("You do not hold enough of any one card to trade with the bank.")
+                    } else {
+                        Text("Give:", fontWeight = FontWeight.Bold)
+                        FlowRow(
+                            horizontalArrangement = Arrangement.spacedBy(8.dp),
+                            verticalArrangement = Arrangement.spacedBy(8.dp),
+                        ) {
+                            trades.keys.forEach { good ->
+                                val ratio = CatanCk.bankRatio(state, seat, good)
+                                Column(horizontalAlignment = Alignment.CenterHorizontally) {
+                                    GoodTile(good, ratio, selected = bankGive == good, onClick = { bankGive = good })
+                                    Text("$ratio : 1", style = MaterialTheme.typography.labelSmall)
+                                }
+                            }
+                        }
+                        val chosen = bankGive
+                        if (chosen != null && chosen in trades) {
+                            Text("Get one:", fontWeight = FontWeight.Bold)
+                            FlowRow(
+                                horizontalArrangement = Arrangement.spacedBy(8.dp),
+                                verticalArrangement = Arrangement.spacedBy(8.dp),
+                            ) {
+                                trades.getValue(chosen).forEach { good ->
+                                    GoodTile(good, 1, onClick = { onBank(GoodsBankTrade(chosen, good)) })
+                                }
+                            }
+                        }
+                    }
+                } else {
+                    Text("Offer to:", fontWeight = FontWeight.Bold)
+                    Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                        (0 until state.playerCount).filter { it != seat }.forEach { other ->
+                            GoodsTabButton(seats.label(other), partner == other) { partner = other }
+                        }
+                    }
+                    Text(CatanText.YOU_GIVE, fontWeight = FontWeight.Bold)
+                    GoodCounters(give, { held[it] ?: 0 }) { give = it }
+                    Text(CatanText.YOU_GET, fontWeight = FontWeight.Bold)
+                    GoodCounters(get, { 9 }) { get = it }
+                }
+            }
+        },
+        confirmButton = {
+            if (tab == GoodsTab.PLAYER) {
+                val to = partner
+                val giveCards = give.asGoods()
+                val getCards = get.asGoods()
+                val allowed = to != null && CatanInteraction.goodsOfferAllowed(state, seat, to, giveCards, getCards)
+                Button(
+                    onClick = { if (to != null) onOffer(OfferGoods(to, giveCards, getCards)) },
+                    enabled = allowed,
+                ) { Text(CatanText.SEND_OFFER) }
+            }
+        },
+        dismissButton = { TextButton(onClick = onCancel) { Text(CatanText.CANCEL) } },
+    )
+}
+
+@OptIn(ExperimentalLayoutApi::class)
+@Composable
+private fun GoodCounters(counts: Map<Good, Int>, limit: (Good) -> Int, onChange: (Map<Good, Int>) -> Unit) {
+    FlowRow(
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+        verticalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        Good.entries.forEach { good ->
+            GoodCounter(
+                good = good,
+                count = counts[good] ?: 0,
+                max = limit(good),
+                onChange = { n -> onChange(counts + (good to n.coerceIn(0, limit(good)))) },
+            )
+        }
+    }
+}
+
+@Composable
+private fun GoodsTabButton(label: String, selected: Boolean, onClick: () -> Unit) {
+    if (selected) {
+        FilledTonalButton(onClick = onClick) { Text(label) }
+    } else {
+        OutlinedButton(onClick = onClick) { Text(label) }
+    }
+}
+
+/** Another player has offered the local player a trade in goods. */
+@Composable
+fun CatanGoodsTradeResponseDialog(
+    offer: GoodsOffer,
+    seats: CatanSeats,
+    canAccept: Boolean,
+    onAccept: () -> Unit,
+    onDecline: () -> Unit,
+) {
+    AlertDialog(
+        onDismissRequest = {},
+        title = { Text("Trade offer") },
+        text = {
+            Column(verticalArrangement = Arrangement.spacedBy(6.dp)) {
+                Text(
+                    "${seats.label(offer.by)} offers ${CatanText.goods(offer.give)} to you " +
+                        "for ${CatanText.goods(offer.get)}",
+                )
+                if (!canAccept) {
+                    Text(
+                        "You cannot accept this: one side no longer holds the cards.",
+                        style = MaterialTheme.typography.bodySmall,
+                    )
+                }
+            }
+        },
+        confirmButton = { Button(onClick = onAccept, enabled = canAccept) { Text(CatanText.ACCEPT) } },
+        dismissButton = { TextButton(onClick = onDecline) { Text(CatanText.DECLINE) } },
+    )
+}

app/src/main/java/org/prolibertate/games/ui/game/catan/CatanInteraction.kt

@@ -1,43 +1,93 @@
 package org.prolibertate.games.ui.game.catan
 
 import org.prolibertate.games.game.catan.AcceptTrade
+import org.prolibertate.games.game.catan.ActivateKnight
 import org.prolibertate.games.game.catan.BuildCity
 import org.prolibertate.games.game.catan.BuildRoad
 import org.prolibertate.games.game.catan.BuildSettlement
+import org.prolibertate.games.game.catan.BuildWall
 import org.prolibertate.games.game.catan.BuyDevCard
+import org.prolibertate.games.game.catan.BuyImprovement
 import org.prolibertate.games.game.catan.CatanBoard
 import org.prolibertate.games.game.catan.CatanMove
 import org.prolibertate.games.game.catan.CatanPhase
 import org.prolibertate.games.game.catan.CatanRules
 import org.prolibertate.games.game.catan.CatanState
+import org.prolibertate.games.game.catan.ChaseRobber
+import org.prolibertate.games.game.catan.Chore
 import org.prolibertate.games.game.catan.DeclineTrade
 import org.prolibertate.games.game.catan.DevCard
 import org.prolibertate.games.game.catan.DevCardType
 import org.prolibertate.games.game.catan.Discard
 import org.prolibertate.games.game.catan.EndFreeRoads
+import org.prolibertate.games.game.catan.EndSmith
 import org.prolibertate.games.game.catan.EndTurn
+import org.prolibertate.games.game.catan.GoodsBankTrade
+import org.prolibertate.games.game.catan.Good
 import org.prolibertate.games.game.catan.HexCoord
+import org.prolibertate.games.game.catan.HireKnight
 import org.prolibertate.games.game.catan.MaritimeTrade
+import org.prolibertate.games.game.catan.MoveKnight
 import org.prolibertate.games.game.catan.MoveRobber
+import org.prolibertate.games.game.catan.OfferGoods
 import org.prolibertate.games.game.catan.OfferTrade
+import org.prolibertate.games.game.catan.PillageCity
+import org.prolibertate.games.game.catan.PlaceKnight
+import org.prolibertate.games.game.catan.PlaceMetropolis
 import org.prolibertate.games.game.catan.PlayKnight
 import org.prolibertate.games.game.catan.PlayMonopoly
+import org.prolibertate.games.game.catan.PlayProgress
 import org.prolibertate.games.game.catan.PlayRoadBuilding
 import org.prolibertate.games.game.catan.PlayYearOfPlenty
+import org.prolibertate.games.game.catan.ProgressCard
+import org.prolibertate.games.game.catan.ProgressType
+import org.prolibertate.games.game.catan.PromoteKnight
+import org.prolibertate.games.game.catan.RelocateKnight
+import org.prolibertate.games.game.catan.RemoveKnight
 import org.prolibertate.games.game.catan.Resource
 import org.prolibertate.games.game.catan.RollDice
 import org.prolibertate.games.game.catan.SetupPlace
+import org.prolibertate.games.game.catan.Track
 
-/** What a player can ask to build by tapping the board. */
+/**
-enum class BuildKind { ROAD, SETTLEMENT, CITY }
+ * What a player can ask to build by tapping the board. Wall and Knight exist
+ * only in Cities & Knights; the base game's build menu lists the first three.
+ */
+enum class BuildKind {
+    ROAD, SETTLEMENT, CITY, WALL, KNIGHT;
 
-/** The parts of the board the player may tap right now. Everything else is inert. */
+    companion object {
+        val BASE: List<BuildKind> = listOf(ROAD, SETTLEMENT, CITY)
+    }
+}
+
+/**
+ * The parts of the board the player may tap right now. Everything else is inert.
+ * [knights] are crossings holding one of the player's own knights that can do
+ * something this turn: tapping one opens its menu.
+ */
 data class BoardTargets(
     val vertices: Set<Int> = emptySet(),
     val edges: Set<Int> = emptySet(),
     val hexes: Set<Int> = emptySet(),
+    val knights: Set<Int> = emptySet(),
 ) {
-    val isEmpty: Boolean get() = vertices.isEmpty() && edges.isEmpty() && hexes.isEmpty()
+    val isEmpty: Boolean get() = vertices.isEmpty() && edges.isEmpty() && hexes.isEmpty() && knights.isEmpty()
+
+    /** Every crossing a tap can land on. */
+    val tappableVertices: Set<Int> get() = vertices + knights
+}
+
+/**
+ * A progress card that is waiting for a tap on the board: [plays] are every play
+ * of it the engine accepts, and the player's tap picks one. [firstHex] is the
+ * first of the two hexes an Inventor swaps, once tapped.
+ */
+data class ArmedCard(val kind: ProgressType, val plays: List<PlayProgress>, val firstHex: Int? = null)
+
+/** One progress card in the local player's hand, and the plays the engine allows for it. */
+data class ProgressInHand(val card: ProgressCard, val plays: List<PlayProgress>) {
+    val playable: Boolean get() = plays.isNotEmpty()
 }
 
 /** What a tap on the board amounts to. */
@@ -53,6 +103,12 @@ sealed interface TapOutcome {
 
     /** The robber's hex has more than one possible victim: ask which. */
     data class PickRobberVictim(val hex: HexCoord, val victims: List<Int>) : TapOutcome
+
+    /** One of the player's own knights was tapped: open its menu. */
+    data class PickKnight(val vertex: Int) : TapOutcome
+
+    /** An Inventor's first hex was tapped; the second completes the swap. */
+    data class PickFirstHex(val hex: Int) : TapOutcome
 }
 
 /**
@@ -85,6 +141,8 @@ object CatanInteraction {
         legal: List<CatanMove>,
         building: BuildKind?,
         setupVertex: Int?,
+        movingKnight: Int? = null,
+        armed: ArmedCard? = null,
     ): BoardTargets {
         val setup = legal.filterIsInstance<SetupPlace>()
         if (setup.isNotEmpty()) {
@@ -100,9 +158,21 @@ object CatanInteraction {
             return BoardTargets(hexes = robber.mapNotNull { CatanBoard.hexIndex[it.hex] }.toSet())
         }
 
+        // Cities & Knights: answers to a queued chore are taps on the board.
+        val chore = choreVertices(legal)
+        if (chore.isNotEmpty()) return BoardTargets(vertices = chore)
+
         val roads = legal.filterIsInstance<BuildRoad>().map { it.edge }.toSet()
         if (state.phase == CatanPhase.FREE_ROADS) return BoardTargets(edges = roads)
 
+        if (armed != null) return armedTargets(armed)
+
+        if (movingKnight != null) {
+            return BoardTargets(
+                vertices = legal.filterIsInstance<MoveKnight>().filter { it.from == movingKnight }.map { it.to }.toSet(),
+            )
+        }
+
         return when (building) {
             BuildKind.ROAD -> BoardTargets(edges = roads)
             BuildKind.SETTLEMENT ->
@@ -111,15 +181,148 @@ object CatanInteraction {
             BuildKind.CITY ->
                 BoardTargets(vertices = legal.filterIsInstance<BuildCity>().map { it.vertex }.toSet())
 
-            null -> BoardTargets()
+            BuildKind.WALL ->
+                BoardTargets(vertices = legal.filterIsInstance<BuildWall>().map { it.vertex }.toSet())
+
+            BuildKind.KNIGHT ->
+                BoardTargets(vertices = legal.filterIsInstance<HireKnight>().map { it.vertex }.toSet())
+
+            null -> BoardTargets(knights = knightsWithActions(legal))
         }
     }
 
+    /** The crossings a queued chore is asking the player to tap, from the legal list. */
+    private fun choreVertices(legal: List<CatanMove>): Set<Int> = buildSet {
+        legal.forEach { move ->
+            when (move) {
+                is PillageCity -> add(move.vertex)
+                is PlaceMetropolis -> add(move.vertex)
+                is RelocateKnight -> add(move.to)
+                is RemoveKnight -> add(move.vertex)
+                is PlaceKnight -> add(move.vertex)
+                else -> Unit
+            }
+        }
+        // A Smith's promotions are knights to tap, while the chore is open.
+        if (legal.any { it is EndSmith }) {
+            legal.filterIsInstance<PromoteKnight>().forEach { add(it.vertex) }
+        }
+    }
+
+    private fun choreMove(legal: List<CatanMove>, vertex: Int): CatanMove? = legal.firstOrNull { move ->
+        when (move) {
+            is PillageCity -> move.vertex == vertex
+            is PlaceMetropolis -> move.vertex == vertex
+            is RelocateKnight -> move.to == vertex
+            is RemoveKnight -> move.vertex == vertex
+            is PlaceKnight -> move.vertex == vertex
+            is PromoteKnight -> legal.any { it is EndSmith } && move.vertex == vertex
+            else -> false
+        }
+    }
+
+    // --- Cities & Knights: knights ---------------------------------------------
+
+    /** Crossings of the player's knights that have an action available. */
+    fun knightsWithActions(legal: List<CatanMove>): Set<Int> = buildSet {
+        legal.forEach { move ->
+            when (move) {
+                is ActivateKnight -> add(move.vertex)
+                is MoveKnight -> add(move.from)
+                is ChaseRobber -> add(move.vertex)
+                is PromoteKnight -> if (legal.none { it is EndSmith }) add(move.vertex)
+                else -> Unit
+            }
+        }
+    }
+
+    /** What the knight on [vertex] can do right now, in the order its menu lists them. */
+    fun knightActions(legal: List<CatanMove>, vertex: Int): List<CatanMove> =
+        legal.filter { move ->
+            when (move) {
+                is ActivateKnight -> move.vertex == vertex
+                is PromoteKnight -> move.vertex == vertex && legal.none { it is EndSmith }
+                is ChaseRobber -> move.vertex == vertex
+                else -> false
+            }
+        } + listOfNotNull(legal.firstOrNull { it is MoveKnight && it.from == vertex })
+
+    fun canEndSmith(legal: List<CatanMove>): Boolean = legal.any { it is EndSmith }
+
+    // --- Cities & Knights: progress cards --------------------------------------
+
+    /** [seat]'s progress cards, each with the plays the engine currently allows. */
+    fun progressHand(state: CatanState, seat: Int, legal: List<CatanMove>): List<ProgressInHand> =
+        state.ck?.progressHands?.getOrNull(seat).orEmpty().map { card ->
+            ProgressInHand(card, legal.filterIsInstance<PlayProgress>().filter { it.card == card.id })
+        }.sortedWith(compareBy({ it.card.kind.track.ordinal }, { it.card.kind.ordinal }, { it.card.id }))
+
+    /** The cards that are played by tapping the board, not by choosing in a dialog. */
+    val BOARD_CARDS: Set<ProgressType> = setOf(
+        ProgressType.ENGINEER, ProgressType.MEDICINE, ProgressType.MERCHANT,
+        ProgressType.DIPLOMAT, ProgressType.INTRIGUE, ProgressType.INVENTOR,
+    )
+
+    private fun armedTargets(armed: ArmedCard): BoardTargets = when (armed.kind) {
+        ProgressType.ENGINEER, ProgressType.MEDICINE, ProgressType.INTRIGUE ->
+            BoardTargets(vertices = armed.plays.mapNotNull { it.vertex }.toSet())
+
+        ProgressType.DIPLOMAT -> BoardTargets(edges = armed.plays.mapNotNull { it.edge }.toSet())
+
+        ProgressType.MERCHANT -> BoardTargets(hexes = armed.plays.mapNotNull { it.hexA }.toSet())
+
+        ProgressType.INVENTOR -> {
+            val first = armed.firstHex
+            val all = armed.plays.flatMap { listOfNotNull(it.hexA, it.hexB) }.toSet()
+            if (first == null) {
+                BoardTargets(hexes = all)
+            } else {
+                BoardTargets(
+                    hexes = armed.plays
+                        .filter { it.hexA == first || it.hexB == first }
+                        .flatMap { listOfNotNull(it.hexA, it.hexB) }
+                        .filter { it != first }
+                        .toSet(),
+                )
+            }
+        }
+
+        else -> BoardTargets()
+    }
+
+    /** The improvement tracks the player can buy a level of right now. */
+    fun improvable(legal: List<CatanMove>): Set<Track> =
+        legal.filterIsInstance<BuyImprovement>().map { it.track }.toSet()
+
+    // --- Cities & Knights: goods ----------------------------------------------
+
+    /** Bank trades on offer in Cities & Knights: what can be given, and for what. */
+    fun goodsBankTrades(legal: List<CatanMove>): Map<Good, List<Good>> =
+        legal.filterIsInstance<GoodsBankTrade>()
+            .groupBy({ it.give }, { it.get })
+            .mapValues { (_, gets) -> gets.sortedBy { it.ordinal } }
+            .toSortedMap(compareBy<Good> { it.ordinal })
+
+    fun goodsOfferAllowed(
+        state: CatanState,
+        seat: Int,
+        to: Int,
+        give: List<Good>,
+        get: List<Good>,
+    ): Boolean = give.isNotEmpty() && get.isNotEmpty() &&
+        CatanRules.isLegalMove(state, seat, OfferGoods(to, give, get))
+
+    /** The chore at the front of the queue, if the table is waiting on one. */
+    fun chore(state: CatanState): Chore? =
+        if (state.phase == CatanPhase.CHORE) state.ck?.chores?.firstOrNull() else null
+
     fun onVertexTap(
         vertex: Int,
         legal: List<CatanMove>,
         building: BuildKind?,
         setupVertex: Int?,
+        movingKnight: Int? = null,
+        armed: ArmedCard? = null,
     ): TapOutcome {
         val setup = legal.filterIsInstance<SetupPlace>()
         if (setup.isNotEmpty()) {
@@ -131,10 +334,27 @@ object CatanInteraction {
                 TapOutcome.Ignored
             }
         }
+        choreMove(legal, vertex)?.let { return TapOutcome.Submit(it) }
+
+        if (armed != null) {
+            val play = armed.plays.firstOrNull { it.vertex == vertex } ?: return TapOutcome.Ignored
+            return if (play in legal) TapOutcome.Submit(play) else TapOutcome.Ignored
+        }
+        if (movingKnight != null) {
+            val move = MoveKnight(movingKnight, vertex)
+            return if (move in legal) TapOutcome.Submit(move) else TapOutcome.Ignored
+        }
+
         val move: CatanMove = when (building) {
             BuildKind.SETTLEMENT -> BuildSettlement(vertex)
             BuildKind.CITY -> BuildCity(vertex)
-            else -> return TapOutcome.Ignored
+            BuildKind.WALL -> BuildWall(vertex)
+            BuildKind.KNIGHT -> HireKnight(vertex)
+            else -> return if (building == null && vertex in knightsWithActions(legal)) {
+                TapOutcome.PickKnight(vertex)
+            } else {
+                TapOutcome.Ignored
+            }
         }
         return if (move in legal) TapOutcome.Submit(move) else TapOutcome.Ignored
     }
@@ -144,12 +364,17 @@ object CatanInteraction {
         legal: List<CatanMove>,
         building: BuildKind?,
         setupVertex: Int?,
+        armed: ArmedCard? = null,
     ): TapOutcome {
         if (legal.any { it is SetupPlace }) {
             if (setupVertex == null) return TapOutcome.Ignored
             val move = SetupPlace(setupVertex, edge)
             return if (move in legal) TapOutcome.Submit(move) else TapOutcome.Ignored
         }
+        if (armed != null) {
+            val play = armed.plays.firstOrNull { it.edge == edge } ?: return TapOutcome.Ignored
+            return if (play in legal) TapOutcome.Submit(play) else TapOutcome.Ignored
+        }
         // Free roads need no build mode; a paid road does.
         val canBuild = building == BuildKind.ROAD || legal.any { it is EndFreeRoads }
         if (!canBuild) return TapOutcome.Ignored
@@ -157,7 +382,8 @@ object CatanInteraction {
         return if (move in legal) TapOutcome.Submit(move) else TapOutcome.Ignored
     }
 
-    fun onHexTap(hex: Int, legal: List<CatanMove>): TapOutcome {
+    fun onHexTap(hex: Int, legal: List<CatanMove>, armed: ArmedCard? = null): TapOutcome {
+        if (armed != null) return onArmedHexTap(hex, legal, armed)
         val coord = CatanBoard.HEXES.getOrNull(hex) ?: return TapOutcome.Ignored
         val moves = legal.filterIsInstance<MoveRobber>().filter { it.hex == coord }
         return when {
@@ -167,6 +393,22 @@ object CatanInteraction {
         }
     }
 
+    private fun onArmedHexTap(hex: Int, legal: List<CatanMove>, armed: ArmedCard): TapOutcome {
+        if (armed.kind == ProgressType.INVENTOR) {
+            val first = armed.firstHex ?: return if (hex in armedTargets(armed).hexes) {
+                TapOutcome.PickFirstHex(hex)
+            } else {
+                TapOutcome.Ignored
+            }
+            val play = armed.plays.firstOrNull {
+                (it.hexA == first && it.hexB == hex) || (it.hexA == hex && it.hexB == first)
+            } ?: return TapOutcome.Ignored
+            return if (play in legal) TapOutcome.Submit(play) else TapOutcome.Ignored
+        }
+        val play = armed.plays.firstOrNull { it.hexA == hex } ?: return TapOutcome.Ignored
+        return if (play in legal) TapOutcome.Submit(play) else TapOutcome.Ignored
+    }
+
     // --- Action bar ------------------------------------------------------------
 
     fun canRoll(legal: List<CatanMove>): Boolean = legal.any { it is RollDice }
@@ -200,6 +442,8 @@ object CatanInteraction {
         if (legal.any { it is BuildRoad }) add(BuildKind.ROAD)
         if (legal.any { it is BuildSettlement }) add(BuildKind.SETTLEMENT)
         if (legal.any { it is BuildCity }) add(BuildKind.CITY)
+        if (legal.any { it is BuildWall }) add(BuildKind.WALL)
+        if (legal.any { it is HireKnight }) add(BuildKind.KNIGHT)
     }
 
     fun tradeResponses(legal: List<CatanMove>): Pair<Boolean, Boolean> =

app/src/main/java/org/prolibertate/games/ui/game/catan/CatanPanels.kt

@@ -40,10 +40,15 @@ import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import org.prolibertate.games.game.catan.BuildingType
+import org.prolibertate.games.game.catan.CatanCk
 import org.prolibertate.games.game.catan.CatanPhase
 import org.prolibertate.games.game.catan.CatanRules
 import org.prolibertate.games.game.catan.CatanState
+import org.prolibertate.games.game.catan.EventFace
+import org.prolibertate.games.game.catan.Good
 import org.prolibertate.games.game.catan.Resource
+import org.prolibertate.games.game.catan.Track
 
 /*
  * Stateless building blocks for the Katan screen.
@@ -102,7 +107,52 @@ fun ResourceTile(
     }
 }
 
-/** The local player's cards: one tile per resource, in a row that wraps. */
+/**
+ * One card type — a resource or a commodity — as a coloured tile with its count.
+ * Cities & Knights hands, discards and trades use this so commodities look the
+ * same everywhere.
+ */
+@Composable
+fun GoodTile(
+    good: Good,
+    count: Int,
+    modifier: Modifier = Modifier,
+    selected: Boolean = false,
+    enabled: Boolean = true,
+    style: CatanStyle = LocalCatanStyle.current,
+    onClick: (() -> Unit)? = null,
+) {
+    val resource = good.resource
+    if (resource != null) {
+        ResourceTile(resource, count, modifier, selected, enabled, style, onClick)
+        return
+    }
+    val commodity = good.commodity!!
+    val shape = RoundedCornerShape(10.dp)
+    val ink = style.commodityInk.getValue(commodity)
+    Column(
+        modifier = modifier
+            .defaultMinSize(minWidth = 56.dp)
+            .clip(shape)
+            .background(style.commodity.getValue(commodity).copy(alpha = if (enabled) 1f else 0.4f))
+            .border(
+                width = if (selected) 3.dp else 1.dp,
+                color = if (selected) Color.White else Color(0x33000000),
+                shape = shape,
+            )
+            .then(if (onClick != null && enabled) Modifier.clickable { onClick() } else Modifier)
+            .padding(horizontal = 6.dp, vertical = 6.dp),
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Text(text = count.toString(), color = ink, fontWeight = FontWeight.Bold, fontSize = 20.sp)
+        Text(text = CatanText.good(good), color = ink, fontSize = 11.sp, maxLines = 1)
+    }
+}
+
+/**
+ * The local player's cards: one tile per resource, and in Cities & Knights one
+ * per commodity as well, in a row that wraps.
+ */
 @OptIn(ExperimentalLayoutApi::class)
 @Composable
 fun CatanHand(
@@ -115,10 +165,15 @@ fun CatanHand(
         horizontalArrangement = Arrangement.spacedBy(6.dp),
         verticalArrangement = Arrangement.spacedBy(6.dp),
     ) {
+        if (state.isCk) {
+            val held = CatanCk.goodsOf(state, seat)
+            Good.entries.forEach { good -> GoodTile(good, held[good] ?: 0) }
+        } else {
             Resource.entries.forEach { resource ->
                 ResourceTile(resource, state.resources[seat][resource] ?: 0)
             }
         }
+    }
 }
 
 // ---------------------------------------------------------------------------
@@ -175,6 +230,41 @@ fun CatanPlayerCard(
             CardLine(seats.label(seat), MaterialTheme.typography.labelLarge, FontWeight.Bold)
         }
         CardLine("$points VP", MaterialTheme.typography.titleMedium, FontWeight.Bold)
+        val ck = state.ck
+        if (ck != null) {
+            val cards = CatanCk.goodsCount(state, seat)
+            val strength = CatanCk.strength(state, seat)
+            if (compact) {
+                CardLine("$cards cards · ⚔$strength", MaterialTheme.typography.bodySmall)
+            } else {
+                CardLine("$cards cards · ${ck.progressCounts[seat]} progress", MaterialTheme.typography.bodySmall)
+                CardLine(
+                    "Knights ${CatanCk.knightsOf(state, seat).size} (strength $strength) · " +
+                        "Road ${CatanRules.longestRoadFor(state, seat)}",
+                    MaterialTheme.typography.bodySmall,
+                )
+            }
+            // Trade, politics, science: the three improvement levels.
+            CardLine(
+                Track.entries.joinToString(" ") { "${it.name.first()}${CatanCk.improvement(state, seat, it)}" },
+                MaterialTheme.typography.bodySmall,
+                color = Color.Unspecified,
+            )
+            val ckAwards = buildList {
+                if (state.longestRoadOwner == seat) add(if (compact) "Road" else "Longest road")
+                ck.metropolises.forEach { (track, at) ->
+                    if (at.seat == seat) add(if (compact) track.name.first().toString() else "${CatanText.track(track)} metropolis")
+                }
+                if (ck.merchant?.seat == seat) add("Merchant")
+            }
+            CardLine(
+                text = ckAwards.joinToString(" · ").ifEmpty { BLANK },
+                style = MaterialTheme.typography.labelSmall,
+                weight = FontWeight.Bold,
+                color = MaterialTheme.colorScheme.primary,
+            )
+            return@Column
+        }
         if (compact) {
             CardLine("${state.resourceCount(seat)} cards", MaterialTheme.typography.bodySmall)
         } else {
@@ -226,21 +316,36 @@ private fun CardLine(
 // Dice
 // ---------------------------------------------------------------------------
 
-/** The two dice as last rolled, with their total. Blank until the first roll. */
+/**
+ * The two dice as last rolled, with their total. Blank until the first roll. In
+ * Cities & Knights the dice are yellow and red (the red one decides progress
+ * cards) and a third, the event die, shows a ship or a coloured city gate.
+ */
 @Composable
-fun CatanDice(dice: List<Int>, modifier: Modifier = Modifier) {
+fun CatanDice(
+    dice: List<Int>,
+    modifier: Modifier = Modifier,
+    ck: Boolean = false,
+    event: EventFace? = null,
+    style: CatanStyle = LocalCatanStyle.current,
+) {
     Row(
         modifier = modifier,
         verticalAlignment = Alignment.CenterVertically,
         horizontalArrangement = Arrangement.spacedBy(6.dp),
     ) {
         val shown = if (dice.size == 2) dice else listOf(null, null)
-        shown.forEach { value ->
+        shown.forEachIndexed { index, value ->
+            val face = when {
+                !ck -> Color.White
+                index == 0 -> Color(0xFFFFF176)
+                else -> Color(0xFFEF9A9A)
+            }
             Box(
                 modifier = Modifier
                     .size(36.dp)
                     .clip(RoundedCornerShape(8.dp))
-                    .background(Color.White)
+                    .background(face)
                     .border(1.dp, Color(0x55000000), RoundedCornerShape(8.dp)),
                 contentAlignment = Alignment.Center,
             ) {
@@ -253,6 +358,31 @@ fun CatanDice(dice: List<Int>, modifier: Modifier = Modifier) {
                 )
             }
         }
+        if (ck) {
+            val gate = when (event) {
+                EventFace.TRADE -> style.track.getValue(Track.TRADE)
+                EventFace.POLITICS -> style.track.getValue(Track.POLITICS)
+                EventFace.SCIENCE -> style.track.getValue(Track.SCIENCE)
+                EventFace.SHIP -> style.barbarian
+                null -> Color(0x33000000)
+            }
+            Box(
+                modifier = Modifier
+                    .size(width = 52.dp, height = 36.dp)
+                    .clip(RoundedCornerShape(8.dp))
+                    .background(gate)
+                    .border(1.dp, Color(0x55000000), RoundedCornerShape(8.dp)),
+                contentAlignment = Alignment.Center,
+            ) {
+                Text(
+                    text = if (event == EventFace.SHIP) "⛵ Ship" else CatanText.event(event),
+                    color = if (event == EventFace.TRADE) Color(0xFF1C1B1F) else Color.White,
+                    fontWeight = FontWeight.Bold,
+                    fontSize = 11.sp,
+                    maxLines = 1,
+                )
+            }
+        }
         // Always drawn ("= –" before the first roll) so the row never changes width.
         Text(
             text = if (dice.size == 2) "= ${dice.sum()}" else "= –",
@@ -262,6 +392,48 @@ fun CatanDice(dice: List<Int>, modifier: Modifier = Modifier) {
     }
 }
 
+/**
+ * Cities & Knights: how close the barbarians are, and how the cities on the
+ * island compare with the knights standing ready. **Fixed height**, like every
+ * other strip around the board.
+ */
+@Composable
+fun CatanBarbarians(state: CatanState, modifier: Modifier = Modifier, style: CatanStyle = LocalCatanStyle.current) {
+    val ck = state.ck ?: return
+    val cities = state.buildings.count { it?.type == BuildingType.CITY }
+    val defence = (0 until state.playerCount).sumOf { CatanCk.strength(state, it) }
+    Row(
+        modifier = modifier.fillMaxWidth().height(24.dp),
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(6.dp),
+    ) {
+        Text("⛵", fontSize = 14.sp)
+        Row(horizontalArrangement = Arrangement.spacedBy(2.dp), modifier = Modifier.weight(1f)) {
+            // The ship starts seven steps out and lands when the last box fills.
+            val sailed = BARBARIAN_STEPS_DISPLAY - ck.barbarians
+            for (i in 0 until BARBARIAN_STEPS_DISPLAY) {
+                Box(
+                    modifier = Modifier
+                        .weight(1f)
+                        .height(10.dp)
+                        .clip(RoundedCornerShape(3.dp))
+                        .background(if (i < sailed) style.barbarian else Color(0x33000000)),
+                )
+            }
+        }
+        val verdict = if (defence >= cities) "holds" else "falls"
+        Text(
+            text = "${CatanText.barbarianSteps(ck.barbarians)} · knights $defence v. $cities cities ($verdict)",
+            style = MaterialTheme.typography.labelSmall,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+        )
+    }
+}
+
+/** Steps shown on the barbarian strip: the engine's seven. */
+private const val BARBARIAN_STEPS_DISPLAY = org.prolibertate.games.game.catan.BARBARIAN_STEPS
+
 // ---------------------------------------------------------------------------
 // Actions
 // ---------------------------------------------------------------------------
@@ -278,6 +450,14 @@ data class CatanActions(
     val canEndFreeRoads: Boolean = false,
     /** A setup settlement is chosen and a different one may still be picked. */
     val canRepickSetup: Boolean = false,
+    /** Which kinds the Build menu lists: three in the base game, five in Cities & Knights. */
+    val buildKinds: List<BuildKind> = BuildKind.BASE,
+    /** Cities & Knights: the table plays the expansion, so the bar shows its buttons instead. */
+    val ck: Boolean = false,
+    val canImprove: Boolean = false,
+    val canPlayProgress: Boolean = false,
+    val progressCount: Int = 0,
+    val canEndSmith: Boolean = false,
 )
 
 /**
@@ -305,6 +485,9 @@ fun CatanActionBar(
     modifier: Modifier = Modifier,
     /** Small screens: fold Road / Settlement / City into one "Build" button with a menu. */
     compact: Boolean = false,
+    onImprove: () -> Unit = {},
+    onProgress: () -> Unit = {},
+    onEndSmith: () -> Unit = {},
 ) {
     Column(modifier = modifier.fillMaxWidth(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
         Row(
@@ -315,6 +498,7 @@ fun CatanActionBar(
             if (actions.canRoll) Button(onClick = onRoll) { Text(CatanText.ROLL) }
             if (actions.canRepickSetup) OutlinedButton(onClick = onRepickSetup) { Text(CatanText.CANCEL) }
             if (actions.canEndFreeRoads) Button(onClick = onEndFreeRoads) { Text(CatanText.STOP_ROADS) }
+            if (actions.canEndSmith) Button(onClick = onEndSmith) { Text(CatanText.STOP_SMITH) }
             if (actions.canEndTurn) Button(onClick = onEndTurn) { Text(CatanText.END_TURN) }
         }
 
@@ -323,19 +507,28 @@ fun CatanActionBar(
             horizontalArrangement = Arrangement.spacedBy(8.dp),
             verticalArrangement = Arrangement.spacedBy(8.dp),
         ) {
-            if (compact) {
+            if (compact || actions.ck) {
                 BuildMenuButton(actions, onBuild)
             } else {
                 BuildButton(BuildKind.ROAD, CatanText.ROAD, CatanText.ROAD_COST, actions, onBuild)
                 BuildButton(BuildKind.SETTLEMENT, CatanText.SETTLEMENT, CatanText.SETTLEMENT_COST, actions, onBuild)
                 BuildButton(BuildKind.CITY, CatanText.CITY, CatanText.CITY_COST, actions, onBuild)
             }
+            if (actions.ck) {
+                OutlinedButton(onClick = onImprove, enabled = actions.canImprove) {
+                    LabelWithCost(CatanText.IMPROVE, CatanText.NO_COST)
+                }
+                OutlinedButton(onClick = onProgress, enabled = actions.canPlayProgress) {
+                    LabelWithCost(CatanText.CARDS_BUTTON, "${actions.progressCount} held")
+                }
+            } else {
                 OutlinedButton(onClick = onBuyCard, enabled = actions.canBuyCard) {
                     LabelWithCost(CatanText.BUY_CARD, CatanText.DEV_COST)
                 }
                 OutlinedButton(onClick = onPlayCard, enabled = actions.canPlayCard) {
                     LabelWithCost(CatanText.PLAY_CARD, CatanText.NO_COST)
                 }
+            }
             OutlinedButton(onClick = onTrade, enabled = actions.canTrade) {
                 LabelWithCost(CatanText.TRADE, CatanText.NO_COST)
             }
@@ -384,7 +577,7 @@ private fun BuildMenuButton(actions: CatanActions, onBuild: (BuildKind?) -> Unit
             OutlinedButton(onClick = { open = true }, enabled = anyEnabled) { label() }
         }
         DropdownMenu(expanded = open, onDismissRequest = { open = false }) {
-            for (kind in BuildKind.entries) {
+            for (kind in actions.buildKinds) {
                 DropdownMenuItem(
                     text = { LabelWithCost(buildLabel(kind), buildCost(kind)) },
                     enabled = kind in actions.canBuild,
@@ -402,12 +595,16 @@ private fun buildLabel(kind: BuildKind): String = when (kind) {
     BuildKind.ROAD -> CatanText.ROAD
     BuildKind.SETTLEMENT -> CatanText.SETTLEMENT
     BuildKind.CITY -> CatanText.CITY
+    BuildKind.WALL -> CatanText.WALL
+    BuildKind.KNIGHT -> CatanText.KNIGHT
 }
 
 private fun buildCost(kind: BuildKind): String = when (kind) {
     BuildKind.ROAD -> CatanText.ROAD_COST
     BuildKind.SETTLEMENT -> CatanText.SETTLEMENT_COST
     BuildKind.CITY -> CatanText.CITY_COST
+    BuildKind.WALL -> CatanText.WALL_COST
+    BuildKind.KNIGHT -> CatanText.KNIGHT_COST
 }
 
 @Composable

app/src/main/java/org/prolibertate/games/ui/game/catan/CatanScreen.kt

@@ -28,17 +28,29 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import org.prolibertate.games.game.catan.AcceptTrade
+import org.prolibertate.games.game.catan.AqueductChore
 import org.prolibertate.games.game.catan.BuyDevCard
+import org.prolibertate.games.game.catan.CatanCk
 import org.prolibertate.games.game.catan.CatanMove
 import org.prolibertate.games.game.catan.CatanPhase
 import org.prolibertate.games.game.catan.CatanRules
 import org.prolibertate.games.game.catan.CatanState
 import org.prolibertate.games.game.catan.DeclineTrade
+import org.prolibertate.games.game.catan.DiscardChore
+import org.prolibertate.games.game.catan.DiscardGoods
+import org.prolibertate.games.game.catan.DropProgress
+import org.prolibertate.games.game.catan.DropProgressChore
 import org.prolibertate.games.game.catan.EndFreeRoads
+import org.prolibertate.games.game.catan.EndSmith
 import org.prolibertate.games.game.catan.EndTurn
+import org.prolibertate.games.game.catan.GiveChore
+import org.prolibertate.games.game.catan.GiveGoods
+import org.prolibertate.games.game.catan.MoveKnight
 import org.prolibertate.games.game.catan.MoveRobber
+import org.prolibertate.games.game.catan.PickDeckChore
 import org.prolibertate.games.game.catan.RollDice
 import org.prolibertate.games.game.catan.SetupPlace
+import org.prolibertate.games.game.catan.SpyChore
 import org.prolibertate.games.net.MatchController
 import org.prolibertate.games.ui.ScreenScaffold
 
@@ -84,6 +96,13 @@ fun CatanScreen(
     var showTrade by remember { mutableStateOf(false) }
     var confirmingEnd by remember { mutableStateOf(false) }
     var resultDismissed by remember { mutableStateOf(false) }
+    // Cities & Knights: the knight whose menu is open, the one about to move,
+    // a progress card waiting for a tap on the board, and the two list dialogs.
+    var knightMenu by remember { mutableStateOf<Int?>(null) }
+    var movingKnight by remember { mutableStateOf<Int?>(null) }
+    var armed by remember { mutableStateOf<ArmedCard?>(null) }
+    var showImprove by remember { mutableStateOf(false) }
+    var showProgress by remember { mutableStateOf(false) }
 
     val dark = isSystemInDarkTheme()
     val style = remember(dark) { catanStyle(dark) }
@@ -97,10 +116,18 @@ fun CatanScreen(
         if (setupVertex != null && legal.none { it is SetupPlace && it.vertex == setupVertex }) {
             setupVertex = null
         }
+        if (movingKnight != null && legal.none { it is MoveKnight && it.from == movingKnight }) movingKnight = null
+        if (knightMenu != null && CatanInteraction.knightActions(legal, knightMenu!!).isEmpty()) knightMenu = null
+        armed?.let { card -> if (card.plays.none { it in legal }) armed = null }
         if (legal.isEmpty()) {
             showCards = false
             showTrade = false
             victimChoice = null
+            showImprove = false
+            showProgress = false
+            knightMenu = null
+            movingKnight = null
+            armed = null
         }
     }
 
@@ -111,6 +138,11 @@ fun CatanScreen(
         victimChoice = null
         showCards = false
         showTrade = false
+        showImprove = false
+        showProgress = false
+        knightMenu = null
+        movingKnight = null
+        armed = null
     }
 
     val endGameAction: @Composable () -> Unit = {
@@ -127,10 +159,17 @@ fun CatanScreen(
         return
     }
 
-    val targets = CatanInteraction.targets(current, legal, building, setupVertex)
+    val targets = CatanInteraction.targets(current, legal, building, setupVertex, movingKnight, armed)
     val devHand = CatanInteraction.devHand(current, localSeat, legal)
+    val progressHand = CatanInteraction.progressHand(current, localSeat, legal)
     val playing = current.phase == CatanPhase.PLAYING && legal.isNotEmpty()
     val actions = CatanActions(
+        buildKinds = if (current.isCk) BuildKind.entries else BuildKind.BASE,
+        ck = current.isCk,
+        canImprove = CatanInteraction.improvable(legal).isNotEmpty(),
+        canPlayProgress = progressHand.any { it.playable },
+        progressCount = progressHand.size,
+        canEndSmith = CatanInteraction.canEndSmith(legal),
         canRoll = CatanInteraction.canRoll(legal),
         canBuild = CatanInteraction.canBuild(legal),
         building = building,
@@ -142,7 +181,14 @@ fun CatanScreen(
         canRepickSetup = setupVertex != null,
     )
     val rolledHexes = CatanInteraction.rolledHexes(current)
-    val prompt = CatanText.prompt(current, seats, setupVertexChosen = setupVertex != null, building = building)
+    val prompt = CatanText.prompt(
+        current,
+        seats,
+        setupVertexChosen = setupVertex != null,
+        building = building,
+        movingKnight = movingKnight != null,
+        armed = armed?.kind,
+    )
 
     val handle: (TapOutcome) -> Unit = { outcome ->
         when (outcome) {
@@ -150,6 +196,8 @@ fun CatanScreen(
             is TapOutcome.Submit -> submit(outcome.move)
             is TapOutcome.PickSetupVertex -> setupVertex = outcome.vertex
             is TapOutcome.PickRobberVictim -> victimChoice = outcome
+            is TapOutcome.PickKnight -> knightMenu = outcome.vertex
+            is TapOutcome.PickFirstHex -> armed = armed?.copy(firstHex = outcome.hex)
         }
     }
 
@@ -170,12 +218,15 @@ fun CatanScreen(
                         state = current,
                         targets = targets,
                         selectedVertex = setupVertex,
-                        onVertexTap = { handle(CatanInteraction.onVertexTap(it, legal, building, setupVertex)) },
+                        onVertexTap = {
-                        onEdgeTap = { handle(CatanInteraction.onEdgeTap(it, legal, building, setupVertex)) },
+                            handle(CatanInteraction.onVertexTap(it, legal, building, setupVertex, movingKnight, armed))
-                        onHexTap = { handle(CatanInteraction.onHexTap(it, legal)) },
+                        },
+                        onEdgeTap = { handle(CatanInteraction.onEdgeTap(it, legal, building, setupVertex, armed)) },
+                        onHexTap = { handle(CatanInteraction.onHexTap(it, legal, armed)) },
                         modifier = boardModifier,
                         style = style,
                         rolledHexes = rolledHexes,
+                        selectedKnight = movingKnight ?: knightMenu,
                     )
                 }
                 val players: @Composable (Boolean) -> Unit = { grid ->
@@ -200,6 +251,9 @@ fun CatanScreen(
                             },
                             onRepickSetup = { setupVertex = null },
                             compact = compactBuild,
+                            onImprove = { showImprove = true },
+                            onProgress = { showProgress = true },
+                            onEndSmith = { legal.firstOrNull { m -> m is EndSmith }?.let(submit) },
                         )
                     }
                 }
@@ -214,6 +268,7 @@ fun CatanScreen(
                             verticalArrangement = Arrangement.spacedBy(8.dp),
                         ) {
                             players(true)
+                            if (current.isCk) CatanBarbarians(current, style = style)
                             promptRow()
                             handAndActions()
                             CatanLog(current, Modifier.fillMaxWidth().height(120.dp))
@@ -222,6 +277,7 @@ fun CatanScreen(
                 } else {
                     Column(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
                         players(false)
+                        if (current.isCk) CatanBarbarians(current, style = style)
                         promptRow()
                         Box(Modifier.weight(1f).fillMaxWidth(), contentAlignment = Alignment.Center) {
                             board(Modifier)
@@ -243,6 +299,21 @@ fun CatanScreen(
                 showCards = showCards,
                 showTrade = showTrade,
                 devHand = devHand,
+                knightMenu = knightMenu,
+                showImprove = showImprove,
+                showProgress = showProgress,
+                progressHand = progressHand,
+                onMoveKnight = { from ->
+                    knightMenu = null
+                    movingKnight = from
+                },
+                onArmCard = { card ->
+                    showProgress = false
+                    armed = card
+                },
+                onCancelKnight = { knightMenu = null },
+                onCancelImprove = { showImprove = false },
+                onCancelProgress = { showProgress = false },
                 onExit = onExit,
                 onSubmit = submit,
                 onStay = controller::dismissAbandoned,
@@ -315,7 +386,7 @@ private fun PromptRow(prompt: String, notice: String?, state: CatanState) {
             overflow = TextOverflow.Ellipsis,
             modifier = Modifier.weight(1f),
         )
-        CatanDice(state.lastDice)
+        CatanDice(state.lastDice, ck = state.isCk, event = state.ck?.eventDie)
     }
 }
 
@@ -337,6 +408,15 @@ private fun CatanDialogHost(
     showCards: Boolean,
     showTrade: Boolean,
     devHand: List<DevCardInHand>,
+    knightMenu: Int?,
+    showImprove: Boolean,
+    showProgress: Boolean,
+    progressHand: List<ProgressInHand>,
+    onMoveKnight: (Int) -> Unit,
+    onArmCard: (ArmedCard) -> Unit,
+    onCancelKnight: () -> Unit,
+    onCancelImprove: () -> Unit,
+    onCancelProgress: () -> Unit,
     onExit: () -> Unit,
     onSubmit: (CatanMove) -> Unit,
     onStay: () -> Unit,
@@ -347,6 +427,7 @@ private fun CatanDialogHost(
     onCancelTrade: () -> Unit,
 ) {
     val offer = state.pendingTrade
+    val goodsOffer = state.ck?.goodsOffer
     when {
         abandoned != null -> CatanAbandonedDialog(abandoned, onExit, onStay)
 
@@ -363,6 +444,18 @@ private fun CatanDialogHost(
                 onSubmit = onSubmit,
             )
 
+        state.phase == CatanPhase.CHORE && CatanRules.currentSeat(state) == localSeat ->
+            ChoreDialog(state, localSeat, legal, onSubmit)
+
+        state.phase == CatanPhase.TRADE_PENDING && goodsOffer != null && goodsOffer.to == localSeat ->
+            CatanGoodsTradeResponseDialog(
+                offer = goodsOffer,
+                seats = seats,
+                canAccept = CatanInteraction.tradeResponses(legal).first,
+                onAccept = { onSubmit(AcceptTrade) },
+                onDecline = { onSubmit(DeclineTrade) },
+            )
+
         state.phase == CatanPhase.TRADE_PENDING && offer != null && offer.to == localSeat ->
             CatanTradeResponseDialog(
                 offer = offer,
@@ -380,8 +473,47 @@ private fun CatanDialogHost(
                 onCancel = onCancelVictim,
             )
 
+        knightMenu != null ->
+            CatanKnightDialog(
+                state = state,
+                vertex = knightMenu,
+                actions = CatanInteraction.knightActions(legal, knightMenu),
+                onDo = onSubmit,
+                onMove = onMoveKnight,
+                onCancel = onCancelKnight,
+            )
+
+        showImprove ->
+            CatanImproveDialog(
+                state = state,
+                seat = localSeat,
+                legal = legal,
+                onBuy = onSubmit,
+                onCancel = onCancelImprove,
+            )
+
+        showProgress ->
+            CatanProgressDialog(
+                hand = progressHand,
+                seats = seats,
+                onPlay = onSubmit,
+                onArm = onArmCard,
+                onCancel = onCancelProgress,
+            )
+
         showCards -> CatanPlayCardDialog(devHand, onPlay = onSubmit, onCancel = onCancelCards)
 
+        showTrade && state.isCk ->
+            CatanGoodsTradeDialog(
+                state = state,
+                seat = localSeat,
+                seats = seats,
+                legal = legal,
+                onBank = onSubmit,
+                onOffer = onSubmit,
+                onCancel = onCancelTrade,
+            )
+
         showTrade ->
             CatanTradeDialog(
                 state = state,
@@ -394,3 +526,61 @@ private fun CatanDialogHost(
             )
     }
 }
+
+/**
+ * The dialog for the chore at the front of the queue, when it is the local
+ * player's. Chores that are answered by tapping the board (a city to lose, a
+ * metropolis site, a knight to place) have no dialog: the prompt line tells the
+ * player what to tap.
+ */
+@Composable
+private fun ChoreDialog(
+    state: CatanState,
+    localSeat: Int,
+    legal: List<CatanMove>,
+    onSubmit: (CatanMove) -> Unit,
+) {
+    val ck = state.ck ?: return
+    val check: (List<org.prolibertate.games.game.catan.Good>, (List<org.prolibertate.games.game.catan.Good>) -> CatanMove) -> Boolean =
+        { cards, make -> CatanRules.isLegalMove(state, localSeat, make(cards)) }
+    when (val chore = ck.chores.firstOrNull()) {
+        is DiscardChore -> {
+            val quota = minOf(chore.count, CatanCk.goodsCount(state, localSeat))
+            CatanGoodsPickDialog(
+                title = "Discard $quota cards",
+                intro = "Choose $quota cards to give up",
+                held = CatanCk.goodsOf(state, localSeat),
+                quota = quota,
+                confirmLabel = "Discard",
+                selectable = { true },
+                allowed = { check(it, ::DiscardGoods) },
+                onConfirm = { onSubmit(DiscardGoods(it)) },
+            )
+        }
+
+        is GiveChore -> {
+            val pool = CatanCk.goodsOf(state, localSeat).filterKeys { !chore.commoditiesOnly || it.isCommodity }
+            val quota = minOf(chore.count, pool.values.sum())
+            CatanGoodsPickDialog(
+                title = "Hand over $quota ${if (quota == 1) "card" else "cards"}",
+                intro = if (chore.commoditiesOnly) "Choose a commodity to give" else "Choose which cards to give",
+                held = pool,
+                quota = quota,
+                confirmLabel = "Give",
+                selectable = { !chore.commoditiesOnly || it.isCommodity },
+                allowed = { check(it, ::GiveGoods) },
+                onConfirm = { onSubmit(GiveGoods(it)) },
+            )
+        }
+
+        is PickDeckChore -> CatanPickDeckDialog(legal) { onSubmit(it) }
+
+        is DropProgressChore -> CatanDropProgressDialog(ck.progressHands[localSeat]) { onSubmit(it) }
+
+        is AqueductChore -> CatanAqueductDialog(legal) { onSubmit(it) }
+
+        is SpyChore -> CatanSpyDialog(ck.progressHands[chore.target], legal) { onSubmit(it) }
+
+        else -> Unit
+    }
+}

app/src/main/java/org/prolibertate/games/ui/game/catan/CatanStyle.kt

@@ -3,8 +3,10 @@ package org.prolibertate.games.ui.game.catan
 import androidx.compose.runtime.Immutable
 import androidx.compose.runtime.staticCompositionLocalOf
 import androidx.compose.ui.graphics.Color
+import org.prolibertate.games.game.catan.Commodity
 import org.prolibertate.games.game.catan.Resource
 import org.prolibertate.games.game.catan.Terrain
+import org.prolibertate.games.game.catan.Track
 
 /**
  * Every visual decision for the Katan screen, in one place.
@@ -46,6 +48,19 @@ data class CatanStyle(
     val resource: Map<Resource, Color>,
     val resourceInk: Color,
 
+    // --- Cities & Knights ---------------------------------------------------
+    /** Commodity cards: cloth, coin and paper. */
+    val commodity: Map<Commodity, Color> = LightCommodities,
+    /** Ink on a commodity tile (paper is pale, so it is not white). */
+    val commodityInk: Map<Commodity, Color> = LightCommodityInk,
+    /** The colour of each improvement track, its city gate, its deck and its metropolis. */
+    val track: Map<Track, Color> = LightTracks,
+    /** Wall round a city, and the barbarian strip. */
+    val wall: Color = Color(0xFF5D4037),
+    val barbarian: Color = Color(0xFFB71C1C),
+    /** A knight that is awake and ready to act. */
+    val knightReady: Color = Color(0xFFFFEB3B),
+
     // --- Players ------------------------------------------------------------
     /** One colour per seat, in seat order. Roads, settlements, cities, player strip. */
     val seats: List<Color>,
@@ -72,6 +87,25 @@ data class CatanStyle(
     val tapReach: Float = 0.55f,
     val tokenText: Float = 0.34f,
     val portText: Float = 0.27f,
+    val knightSize: Float = 0.30f,
+)
+
+private val LightCommodities = mapOf(
+    Commodity.CLOTH to Color(0xFF7E57C2),
+    Commodity.COIN to Color(0xFFF9A825),
+    Commodity.PAPER to Color(0xFFECEFF1),
+)
+
+private val LightCommodityInk = mapOf(
+    Commodity.CLOTH to Color(0xFFFFFFFF),
+    Commodity.COIN to Color(0xFF3E2723),
+    Commodity.PAPER to Color(0xFF263238),
+)
+
+private val LightTracks = mapOf(
+    Track.TRADE to Color(0xFFF2C300),
+    Track.POLITICS to Color(0xFF1E6FD9),
+    Track.SCIENCE to Color(0xFF2E9E4F),
 )
 
 /** The light palette, which is also the reference for the dark one. */

app/src/main/java/org/prolibertate/games/ui/game/catan/CatanText.kt

@@ -1,12 +1,29 @@
 package org.prolibertate.games.ui.game.catan
 
+import org.prolibertate.games.game.catan.AqueductChore
+import org.prolibertate.games.game.catan.CatanCk
 import org.prolibertate.games.game.catan.CatanPhase
 import org.prolibertate.games.game.catan.CatanRules
 import org.prolibertate.games.game.catan.CatanState
 import org.prolibertate.games.game.catan.DevCardType
+import org.prolibertate.games.game.catan.DiscardChore
+import org.prolibertate.games.game.catan.DropProgressChore
+import org.prolibertate.games.game.catan.EventFace
+import org.prolibertate.games.game.catan.GiveChore
+import org.prolibertate.games.game.catan.Good
+import org.prolibertate.games.game.catan.MetropolisChore
+import org.prolibertate.games.game.catan.PickDeckChore
+import org.prolibertate.games.game.catan.PillageChore
+import org.prolibertate.games.game.catan.PlaceKnightChore
 import org.prolibertate.games.game.catan.Port
+import org.prolibertate.games.game.catan.ProgressType
+import org.prolibertate.games.game.catan.RelocateChore
+import org.prolibertate.games.game.catan.RemoveKnightChore
 import org.prolibertate.games.game.catan.Resource
+import org.prolibertate.games.game.catan.SmithChore
+import org.prolibertate.games.game.catan.SpyChore
 import org.prolibertate.games.game.catan.Terrain
+import org.prolibertate.games.game.catan.Track
 
 /**
  * Who is who at the table, for wording. [names] may be empty or short — a
@@ -136,7 +153,12 @@ object CatanText {
         seats: CatanSeats,
         setupVertexChosen: Boolean,
         building: BuildKind?,
+        /** Cities & Knights: a knight has been picked to move, and its destination is awaited. */
+        movingKnight: Boolean = false,
+        /** Cities & Knights: a progress card is waiting for a tap on the board. */
+        armed: ProgressType? = null,
     ): String {
+        if (state.isCk) return ckPrompt(state, seats, setupVertexChosen, building, movingKnight, armed)
         val me = seats.me
         val onClock = CatanRules.currentSeat(state)
         val mine = onClock == me
@@ -218,4 +240,208 @@ object CatanText {
         val winner = state.winner ?: return "Game over"
         return if (winner == seats.me) "You won!" else "${seats.label(winner)} won"
     }
+
+    // --- Cities & Knights ----------------------------------------------------
+
+    fun good(good: Good): String = when (good) {
+        Good.LUMBER -> "Lumber"
+        Good.BRICK -> "Brick"
+        Good.WOOL -> "Wool"
+        Good.GRAIN -> "Grain"
+        Good.ORE -> "Ore"
+        Good.CLOTH -> "Cloth"
+        Good.COIN -> "Coin"
+        Good.PAPER -> "Paper"
+    }
+
+    /** "2 Lumber + 1 Cloth" for a flat list of goods. */
+    fun goods(cards: List<Good>): String =
+        cards.groupingBy { it }.eachCount().entries
+            .sortedBy { it.key.ordinal }
+            .joinToString(" + ") { (g, n) -> "$n ${good(g)}" }
+            .ifEmpty { "nothing" }
+
+    fun track(track: Track): String = when (track) {
+        Track.TRADE -> "Trade"
+        Track.POLITICS -> "Politics"
+        Track.SCIENCE -> "Science"
+    }
+
+    /** What the third level of a track gives, for the improvement dialog. */
+    fun trackPower(track: Track): String = when (track) {
+        Track.TRADE -> "From level 3, trade commodities with the bank two for one."
+        Track.POLITICS -> "From level 3, knights can be promoted to mighty."
+        Track.SCIENCE -> "From level 3, when the dice pay you nothing, take any resource."
+    }
+
+    fun knightName(level: Int): String = when (level) {
+        1 -> "Basic knight"
+        2 -> "Strong knight"
+        else -> "Mighty knight"
+    }
+
+    fun event(face: EventFace?): String = when (face) {
+        null -> "–"
+        EventFace.SHIP -> "Ship"
+        EventFace.TRADE -> "Trade"
+        EventFace.POLITICS -> "Politics"
+        EventFace.SCIENCE -> "Science"
+    }
+
+    fun progress(kind: ProgressType): String = CatanCk.progressName(kind)
+
+    fun progressHelp(kind: ProgressType): String = when (kind) {
+        ProgressType.ALCHEMIST -> "Before rolling, choose what the two number dice show."
+        ProgressType.CRANE -> "Your next city improvement costs one commodity less."
+        ProgressType.ENGINEER -> "Raise a wall round one of your cities for free."
+        ProgressType.INVENTOR -> "Swap two number tokens (not 2, 6, 8 or 12)."
+        ProgressType.IRRIGATION -> "Take 2 grain for each fields hex beside your settlements and cities."
+        ProgressType.MEDICINE -> "Upgrade a settlement to a city for 2 ore and 1 grain."
+        ProgressType.MINING -> "Take 2 ore for each mountains hex beside your settlements and cities."
+        ProgressType.PRINTER -> "One victory point."
+        ProgressType.ROAD_BUILDING -> "Build two roads for free."
+        ProgressType.SMITH -> "Promote up to two of your knights one level for free."
+        ProgressType.BISHOP -> "Move the robber and take a card from every player beside its new hex."
+        ProgressType.CONSTITUTION -> "One victory point."
+        ProgressType.DESERTER -> "Another player removes a knight; you place a free one of the same strength."
+        ProgressType.DIPLOMAT -> "Remove an open road. If it was yours, build it again anywhere for free."
+        ProgressType.INTRIGUE -> "Drive an opponent's knight off a crossing beside one of your roads."
+        ProgressType.SABOTEUR -> "Every player with as many points as you or more discards half their cards."
+        ProgressType.SPY -> "Look at another player's progress cards and take one."
+        ProgressType.WARLORD -> "Wake all your knights without paying grain."
+        ProgressType.WEDDING -> "Every player with more points gives you 2 cards."
+        ProgressType.COMMERCIAL_HARBOR -> "Offer a resource to each player; each swaps it for a commodity."
+        ProgressType.MASTER_MERCHANT -> "Take 2 cards from a player with more points."
+        ProgressType.MERCHANT -> "Put the merchant beside your settlement: trade that resource 2:1 and score a point."
+        ProgressType.MERCHANT_FLEET -> "This turn, trade one chosen card type with the bank two for one."
+        ProgressType.RESOURCE_MONOPOLY -> "Name a resource. Every other player gives you 2 of it."
+        ProgressType.TRADE_MONOPOLY -> "Name a commodity. Every other player gives you 1 of it."
+    }
+
+    const val IMPROVE = "Improve"
+    const val KNIGHTS = "Knights"
+    const val CARDS_BUTTON = "Progress"
+    const val WALL = "Wall"
+    const val KNIGHT = "Knight"
+    const val STOP_SMITH = "Done promoting"
+
+    val KNIGHT_COST: String get() = cost(CatanCk.KNIGHT_COST)
+    val ACTIVATE_COST: String get() = cost(CatanCk.ACTIVATE_COST)
+    val WALL_COST: String get() = cost(CatanCk.WALL_COST)
+
+    private fun ckPrompt(
+        state: CatanState,
+        seats: CatanSeats,
+        setupVertexChosen: Boolean,
+        building: BuildKind?,
+        movingKnight: Boolean,
+        armed: ProgressType?,
+    ): String {
+        val me = seats.me
+        val onClock = CatanRules.currentSeat(state)
+        val mine = onClock == me
+        val turn = seats.label(state.turn)
+        val ck = state.ck!!
+
+        return when (state.phase) {
+            CatanPhase.GAME_OVER -> {
+                val winner = state.winner
+                if (winner == null) "The game is over." else "${seats.label(winner)} won the game."
+            }
+
+            CatanPhase.SETUP_FIRST, CatanPhase.SETUP_SECOND -> when {
+                !mine -> "${seats.label(onClock ?: state.turn)} is placing a settlement and a road…"
+                setupVertexChosen -> "Now tap the road to place beside that settlement."
+                state.phase == CatanPhase.SETUP_SECOND ->
+                    "Place your second piece: it is a city, and earns resources from the hexes around it."
+
+                else -> "Place a settlement, then a road."
+            }
+
+            CatanPhase.AWAIT_ROLL -> when {
+                !mine -> "$turn is rolling…"
+                armed != null -> armedPrompt(armed)
+                movingKnight -> "Tap where the knight should go."
+                else -> "Your turn. Roll the dice, or wake knights and play progress cards first."
+            }
+
+            CatanPhase.ROBBER -> when {
+                !mine -> "$turn is moving the robber…"
+                ck.bishop -> "The bishop: tap a hex. Everyone beside it pays you a card."
+                else -> "Move the robber. Tap a hex."
+            }
+
+            CatanPhase.PLAYING -> when {
+                !mine -> "$turn is playing…"
+                armed != null -> armedPrompt(armed)
+                movingKnight -> "Tap where the knight should go."
+                building == BuildKind.ROAD -> "Tap an edge to build a road."
+                building == BuildKind.SETTLEMENT -> "Tap an empty crossing to build a settlement."
+                building == BuildKind.CITY -> "Tap one of your settlements to upgrade it."
+                building == BuildKind.WALL -> "Tap one of your cities to raise a wall."
+                building == BuildKind.KNIGHT -> "Tap an empty crossing at the end of your road to hire a knight."
+                else -> "Your turn. Build, improve, trade, or end the turn. Tap a knight to use it."
+            }
+
+            CatanPhase.FREE_ROADS ->
+                if (mine) {
+                    "Place ${state.pendingFreeRoads} free " +
+                        if (state.pendingFreeRoads == 1) "road." else "roads."
+                } else {
+                    "$turn is placing free roads…"
+                }
+
+            CatanPhase.TRADE_PENDING -> {
+                val offer = ck.goodsOffer
+                when {
+                    offer == null -> "Waiting for a reply…"
+                    offer.to == me -> "${seats.label(offer.by)} offers you a trade."
+                    offer.by == me -> "Waiting for ${seats.label(offer.to)} to answer your offer…"
+                    else -> "${seats.label(offer.by)} has offered ${seats.label(offer.to)} a trade."
+                }
+            }
+
+            CatanPhase.DISCARDING -> "Discarding…"
+
+            CatanPhase.CHORE -> {
+                val chore = ck.chores.firstOrNull()
+                val who = seats.label(chore?.seat ?: state.turn)
+                if (chore == null || chore.seat != me) {
+                    when (chore) {
+                        is PillageChore -> "The barbarians have landed. $who must give up a city."
+                        is DiscardChore -> "$who must discard ${chore.count} cards."
+                        else -> "Waiting for $who…"
+                    }
+                } else {
+                    when (chore) {
+                        is DiscardChore -> "Discard ${chore.count} cards."
+                        is GiveChore -> "Give ${chore.count} card${if (chore.count == 1) "" else "s"} to ${seats.lower(chore.to)}."
+                        is PillageChore -> "The barbarians won. Tap a city of yours to give up."
+                        is PickDeckChore -> "Choose a progress deck to draw from."
+                        is DropProgressChore -> "You hold too many progress cards. Give one back."
+                        is MetropolisChore -> "Tap the city that will bear the ${track(chore.track).lowercase()} metropolis."
+                        is AqueductChore -> "Your aqueduct pays. Take any resource."
+                        is RelocateChore -> "Your knight was driven off. Tap where it goes."
+                        is RemoveKnightChore -> "Tap one of your knights to remove."
+                        is PlaceKnightChore -> "Tap where your free ${knightName(chore.level).lowercase()} stands."
+                        is SpyChore -> "Choose a progress card to take."
+                        is SmithChore -> "Tap a knight to promote (${chore.left} left), or stop."
+                    }
+                }
+            }
+        }
+    }
+
+    private fun armedPrompt(kind: ProgressType): String = when (kind) {
+        ProgressType.ENGINEER -> "Engineer: tap a city to wall."
+        ProgressType.MEDICINE -> "Medicine: tap a settlement to upgrade."
+        ProgressType.MERCHANT -> "Merchant: tap a hex beside one of your buildings."
+        ProgressType.DIPLOMAT -> "Diplomat: tap an open road to remove."
+        ProgressType.INTRIGUE -> "Intrigue: tap an enemy knight beside your road."
+        ProgressType.INVENTOR -> "Inventor: tap two hexes to swap their tokens."
+        else -> "Tap the board."
+    }
+
+    /** "6 steps away", "1 step away" for the barbarian ship. */
+    fun barbarianSteps(steps: Int): String = "$steps ${if (steps == 1) "step" else "steps"} away"
 }

app/src/test/java/org/prolibertate/games/ui/game/catan/CatanCkInteractionTest.kt

@@ -0,0 +1,264 @@
+package org.prolibertate.games.ui.game.catan
+
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import org.prolibertate.games.game.GameCatalog
+import org.prolibertate.games.game.catan.AcceptTrade
+import org.prolibertate.games.game.catan.ActivateKnight
+import org.prolibertate.games.game.catan.BuildCity
+import org.prolibertate.games.game.catan.BuildRoad
+import org.prolibertate.games.game.catan.BuildSettlement
+import org.prolibertate.games.game.catan.BuildWall
+import org.prolibertate.games.game.catan.BuyImprovement
+import org.prolibertate.games.game.catan.CatanAi
+import org.prolibertate.games.game.catan.CatanBoard
+import org.prolibertate.games.game.catan.CatanMove
+import org.prolibertate.games.game.catan.CatanOptions
+import org.prolibertate.games.game.catan.CatanPhase
+import org.prolibertate.games.game.catan.CatanRuleSet
+import org.prolibertate.games.game.catan.CatanRules
+import org.prolibertate.games.game.catan.CatanState
+import org.prolibertate.games.game.catan.ChaseRobber
+import org.prolibertate.games.game.catan.DeclineTrade
+import org.prolibertate.games.game.catan.DiscardGoods
+import org.prolibertate.games.game.catan.DropProgress
+import org.prolibertate.games.game.catan.EndFreeRoads
+import org.prolibertate.games.game.catan.EndSmith
+import org.prolibertate.games.game.catan.EndTurn
+import org.prolibertate.games.game.catan.GiveGoods
+import org.prolibertate.games.game.catan.GoodsBankTrade
+import org.prolibertate.games.game.catan.HireKnight
+import org.prolibertate.games.game.catan.MoveKnight
+import org.prolibertate.games.game.catan.MoveRobber
+import org.prolibertate.games.game.catan.OfferGoods
+import org.prolibertate.games.game.catan.PickDeck
+import org.prolibertate.games.game.catan.PillageCity
+import org.prolibertate.games.game.catan.PlaceKnight
+import org.prolibertate.games.game.catan.PlaceMetropolis
+import org.prolibertate.games.game.catan.PlayProgress
+import org.prolibertate.games.game.catan.PromoteKnight
+import org.prolibertate.games.game.catan.RelocateKnight
+import org.prolibertate.games.game.catan.RemoveKnight
+import org.prolibertate.games.game.catan.RollDice
+import org.prolibertate.games.game.catan.SetupPlace
+import org.prolibertate.games.game.catan.SpyTake
+import org.prolibertate.games.game.catan.TakeAqueduct
+import org.prolibertate.games.game.engine.PlayerKind
+import org.prolibertate.games.game.engine.PlayerSlot
+import org.prolibertate.games.game.engine.TableConfig
+
+/**
+ * Cities & Knights has no device in this test suite, so the screen's logic is
+ * checked another way: engines play whole games, and at every position the
+ * player on the clock is treated as the local one. For every move the engine says
+ * is legal, [CatanInteraction] (and the dialogs' own filters) must offer a way to
+ * make it — a tap, a button or a dialog choice. A legal move that no control can
+ * produce would be a stuck game on a real phone.
+ */
+class CatanCkInteractionTest {
+
+    private val json = Json { encodeDefaults = true }
+
+    private fun config(players: Int, seed: Long) = TableConfig(
+        gameId = GameCatalog.CATAN,
+        seats = (0 until players).map { PlayerSlot(seat = it, name = "P$it", kind = PlayerKind.AI, team = it) },
+        optionsJson = json.encodeToString(
+            CatanOptions(players, pointsToWin = 13, ruleSet = CatanRuleSet.CITIES_AND_KNIGHTS),
+        ),
+        seed = seed,
+    )
+
+    /** How a move reaches the engine from the screen, or null if nothing can produce it. */
+    private fun reachable(state: CatanState, legal: List<CatanMove>, move: CatanMove): String? {
+        fun tapVertex(vertex: Int, building: BuildKind? = null, moving: Int? = null, armed: ArmedCard? = null): TapOutcome =
+            CatanInteraction.onVertexTap(vertex, legal, building, null, moving, armed)
+
+        return when (move) {
+            is SetupPlace -> {
+                val vertex = CatanInteraction.targets(state, legal, null, null).vertices
+                val edges = CatanInteraction.targets(state, legal, null, move.vertex).edges
+                "setup".takeIf {
+                    move.vertex in vertex && move.edge in edges &&
+                        CatanInteraction.onVertexTap(move.vertex, legal, null, null) is TapOutcome.PickSetupVertex &&
+                        CatanInteraction.onEdgeTap(move.edge, legal, null, move.vertex) == TapOutcome.Submit(move)
+                }
+            }
+
+            is BuildRoad -> {
+                val targets = CatanInteraction.targets(state, legal, BuildKind.ROAD, null)
+                "road".takeIf {
+                    move.edge in targets.edges &&
+                        CatanInteraction.onEdgeTap(move.edge, legal, BuildKind.ROAD, null) == TapOutcome.Submit(move)
+                }
+            }
+
+            is BuildSettlement -> viaBuild(state, legal, BuildKind.SETTLEMENT, move.vertex, move)
+            is BuildCity -> viaBuild(state, legal, BuildKind.CITY, move.vertex, move)
+            is BuildWall -> viaBuild(state, legal, BuildKind.WALL, move.vertex, move)
+            is HireKnight -> viaBuild(state, legal, BuildKind.KNIGHT, move.vertex, move)
+
+            is MoveRobber -> {
+                val hex = CatanBoard.hexIndex.getValue(move.hex)
+                val targets = CatanInteraction.targets(state, legal, null, null)
+                val tap = CatanInteraction.onHexTap(hex, legal)
+                "robber".takeIf {
+                    hex in targets.hexes &&
+                        (tap == TapOutcome.Submit(move) || (tap is TapOutcome.PickRobberVictim && move.victim in tap.victims))
+                }
+            }
+
+            is MoveKnight -> {
+                val targets = CatanInteraction.targets(state, legal, null, null, movingKnight = move.from)
+                "moveKnight".takeIf {
+                    move.to in targets.vertices && tapVertex(move.to, moving = move.from) == TapOutcome.Submit(move) &&
+                        move.from in CatanInteraction.targets(state, legal, null, null).knights &&
+                        CatanInteraction.knightActions(legal, move.from).any { it is MoveKnight }
+                }
+            }
+
+            is ActivateKnight, is ChaseRobber, is PromoteKnight -> {
+                val vertex = when (move) {
+                    is ActivateKnight -> move.vertex
+                    is ChaseRobber -> move.vertex
+                    else -> (move as PromoteKnight).vertex
+                }
+                val smith = legal.any { it is EndSmith }
+                if (move is PromoteKnight && smith) {
+                    val targets = CatanInteraction.targets(state, legal, null, null)
+                    "smith".takeIf {
+                        vertex in targets.vertices && tapVertex(vertex) == TapOutcome.Submit(move)
+                    }
+                } else {
+                    val targets = CatanInteraction.targets(state, legal, null, null)
+                    "knightMenu".takeIf {
+                        vertex in targets.knights && tapVertex(vertex) == TapOutcome.PickKnight(vertex) &&
+                            move in CatanInteraction.knightActions(legal, vertex)
+                    }
+                }
+            }
+
+            is PillageCity -> viaChore(state, legal, move.vertex, move)
+            is PlaceMetropolis -> viaChore(state, legal, move.vertex, move)
+            is RelocateKnight -> viaChore(state, legal, move.to, move)
+            is RemoveKnight -> viaChore(state, legal, move.vertex, move)
+            is PlaceKnight -> viaChore(state, legal, move.vertex, move)
+
+            is PlayProgress -> viaCard(state, legal, move)
+
+            is BuyImprovement -> "improve".takeIf { move.track in CatanInteraction.improvable(legal) }
+
+            is GoodsBankTrade ->
+                "bankTrade".takeIf { move.get in CatanInteraction.goodsBankTrades(legal)[move.give].orEmpty() }
+
+            RollDice(), is RollDice -> "roll".takeIf { CatanInteraction.canRoll(legal) }
+            EndTurn -> "endTurn".takeIf { CatanInteraction.canEndTurn(legal) }
+            EndFreeRoads -> "endRoads".takeIf { CatanInteraction.canEndFreeRoads(legal) }
+            EndSmith -> "endSmith".takeIf { CatanInteraction.canEndSmith(legal) }
+            AcceptTrade, DeclineTrade -> "tradeReply".takeIf { CatanInteraction.tradeResponses(legal) != (false to false) }
+
+            // Answered in a dialog that offers exactly the moves in the legal list.
+            is PickDeck, is DropProgress, is TakeAqueduct, is SpyTake -> "choreDialog"
+
+            // Structural: the discard and give dialogs build these and ask the engine.
+            is DiscardGoods, is GiveGoods -> "goodsDialog"
+            is OfferGoods -> "tradeDialog"
+
+            else -> null
+        }
+    }
+
+    private fun viaBuild(state: CatanState, legal: List<CatanMove>, kind: BuildKind, vertex: Int, move: CatanMove): String? {
+        val targets = CatanInteraction.targets(state, legal, kind, null)
+        return "build $kind".takeIf {
+            vertex in targets.vertices &&
+                CatanInteraction.onVertexTap(vertex, legal, kind, null) == TapOutcome.Submit(move) &&
+                kind in CatanInteraction.canBuild(legal)
+        }
+    }
+
+    private fun viaChore(state: CatanState, legal: List<CatanMove>, vertex: Int, move: CatanMove): String? {
+        val targets = CatanInteraction.targets(state, legal, null, null)
+        return "chore".takeIf {
+            vertex in targets.vertices &&
+                CatanInteraction.onVertexTap(vertex, legal, null, null) == TapOutcome.Submit(move)
+        }
+    }
+
+    private fun viaCard(state: CatanState, legal: List<CatanMove>, move: PlayProgress): String? {
+        val seat = CatanRules.currentSeat(state) ?: return null
+        val entry = CatanInteraction.progressHand(state, seat, legal).firstOrNull { it.card.id == move.card }
+            ?: return null
+        val kind = entry.card.kind
+        if (move !in entry.plays) return null
+        if (kind !in CatanInteraction.BOARD_CARDS) return "cardDialog"
+
+        val armed = ArmedCard(kind, entry.plays)
+        val targets = CatanInteraction.targets(state, legal, null, null, armed = armed)
+        return when (kind) {
+            org.prolibertate.games.game.catan.ProgressType.DIPLOMAT ->
+                "armed".takeIf {
+                    move.edge in targets.edges &&
+                        CatanInteraction.onEdgeTap(move.edge!!, legal, null, null, armed) == TapOutcome.Submit(move)
+                }
+
+            org.prolibertate.games.game.catan.ProgressType.MERCHANT ->
+                "armed".takeIf {
+                    move.hexA in targets.hexes &&
+                        CatanInteraction.onHexTap(move.hexA!!, legal, armed) == TapOutcome.Submit(move)
+                }
+
+            org.prolibertate.games.game.catan.ProgressType.INVENTOR -> {
+                val first = CatanInteraction.onHexTap(move.hexA!!, legal, armed)
+                if (first != TapOutcome.PickFirstHex(move.hexA!!)) return null
+                val second = armed.copy(firstHex = move.hexA)
+                val partners = CatanInteraction.targets(state, legal, null, null, armed = second).hexes
+                "armed".takeIf {
+                    move.hexB in partners &&
+                        CatanInteraction.onHexTap(move.hexB!!, legal, second) == TapOutcome.Submit(move)
+                }
+            }
+
+            else ->
+                "armed".takeIf {
+                    move.vertex in targets.vertices &&
+                        CatanInteraction.onVertexTap(move.vertex!!, legal, null, null, null, armed) == TapOutcome.Submit(move)
+                }
+        }
+    }
+
+    private fun playAndCheck(players: Int, seed: Long): Map<String, Int> {
+        val ai = CatanAi()
+        var state = CatanRules.initialState(config(players, seed))
+        val seen = mutableMapOf<String, Int>()
+        var moves = 0
+        while (!CatanRules.isFinished(state) && moves++ < 20_000) {
+            val seat = CatanRules.currentSeat(state) ?: break
+            val legal = CatanRules.legalMoves(state, seat)
+            for (move in legal) {
+                val how = reachable(state, legal, move)
+                assertTrue(
+                    "seed $seed: no control produces $move in ${state.phase} " +
+                        "(chore ${state.ck?.chores?.firstOrNull()}); log tail: ${state.log.takeLast(3)}",
+                    how != null,
+                )
+                seen.merge(how!!, 1, Int::plus)
+            }
+            state = CatanRules.applyMove(state, seat, ai.chooseMove(state, seat, legal))
+        }
+        return seen
+    }
+
+    @Test
+    fun `every legal move in a full game has a control that produces it`() {
+        val total = mutableMapOf<String, Int>()
+        listOf(3 to 21L, 4 to 22L, 3 to 23L, 4 to 24L).forEach { (players, seed) ->
+            playAndCheck(players, seed).forEach { (k, v) -> total.merge(k, v, Int::plus) }
+        }
+        println("CK UI coverage: ${total.toSortedMap()}")
+        // The ways the screen builds, moves and answers all got exercised.
+        listOf("setup", "road", "build SETTLEMENT", "build CITY", "knightMenu", "improve", "bankTrade", "roll", "endTurn")
+            .forEach { assertTrue("never exercised: $it in $total", (total[it] ?: 0) > 0) }
+    }
+}

app/src/test/java/org/prolibertate/games/ui/game/catan/CatanCkTextTest.kt

@@ -0,0 +1,75 @@
+package org.prolibertate.games.ui.game.catan
+
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import org.prolibertate.games.game.GameCatalog
+import org.prolibertate.games.game.catan.CatanAi
+import org.prolibertate.games.game.catan.CatanOptions
+import org.prolibertate.games.game.catan.CatanRuleSet
+import org.prolibertate.games.game.catan.CatanRules
+import org.prolibertate.games.game.catan.ProgressType
+import org.prolibertate.games.game.engine.PlayerKind
+import org.prolibertate.games.game.engine.PlayerSlot
+import org.prolibertate.games.game.engine.TableConfig
+import org.prolibertate.games.ui.catanDefaultPoints
+import org.prolibertate.games.ui.catanPointsChoices
+import org.prolibertate.games.ui.catanSwitchRules
+
+class CatanCkTextTest {
+
+    private val json = Json { encodeDefaults = true }
+
+    @Test
+    fun `every position of a Cities and Knights game has a prompt for every seat`() {
+        val config = TableConfig(
+            gameId = GameCatalog.CATAN,
+            seats = (0 until 3).map { PlayerSlot(seat = it, name = "P$it", kind = PlayerKind.AI, team = it) },
+            optionsJson = json.encodeToString(
+                CatanOptions(3, 13, CatanRuleSet.CITIES_AND_KNIGHTS),
+            ),
+            seed = 31L,
+        )
+        var state = CatanRules.initialState(config)
+        val ai = CatanAi()
+        var moves = 0
+        while (!CatanRules.isFinished(state) && moves++ < 20_000) {
+            for (me in 0 until 3) {
+                val seats = CatanSeats(me, listOf("A", "B", "C"))
+                val text = CatanText.prompt(state, seats, setupVertexChosen = false, building = null)
+                assertTrue("blank prompt in ${state.phase} for seat $me", text.isNotBlank())
+            }
+            val seat = CatanRules.currentSeat(state) ?: break
+            state = CatanRules.applyMove(state, seat, ai.chooseMove(state, seat, CatanRules.legalMoves(state, seat)))
+        }
+    }
+
+    @Test
+    fun `every progress card has a name and a description`() {
+        ProgressType.entries.forEach {
+            assertTrue(CatanText.progress(it).isNotBlank())
+            assertTrue("no help for $it", CatanText.progressHelp(it).length > 10)
+        }
+    }
+
+    @Test
+    fun `the setup screen offers each rule set its own targets and switches sensibly`() {
+        assertEquals(listOf(5, 8, 10, 12), catanPointsChoices(CatanRuleSet.BASE))
+        assertEquals(listOf(8, 10, 13, 15), catanPointsChoices(CatanRuleSet.CITIES_AND_KNIGHTS))
+        assertEquals(10, catanDefaultPoints(CatanRuleSet.BASE))
+        assertEquals(13, catanDefaultPoints(CatanRuleSet.CITIES_AND_KNIGHTS))
+
+        val base = CatanOptions()
+        val ck = catanSwitchRules(base, CatanRuleSet.CITIES_AND_KNIGHTS)
+        assertEquals(CatanRuleSet.CITIES_AND_KNIGHTS, ck.ruleSet)
+        assertEquals("the published target for the new rules", 13, ck.pointsToWin)
+        assertEquals(10, catanSwitchRules(ck, CatanRuleSet.BASE).pointsToWin)
+
+        // A short game picked on purpose is kept when both menus have it.
+        val short = catanSwitchRules(base.copy(pointsToWin = 8), CatanRuleSet.CITIES_AND_KNIGHTS)
+        assertEquals(8, short.pointsToWin)
+        assertEquals(3, ck.playerCount)
+    }
+}