feat(rust): chat titles on the leaderboard (module-rust phase 17, M19)

Each leaderboard row carries `titles: [{ text, color }]` from a phase-17
module: the chat titles the player holds now. Drawn as chips under the
name, in the operator's colour with black or white ink chosen by WCAG
contrast (the website's rule). Absent from an older module, so the field
defaults to empty and nothing is drawn.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

app/src/main/java/com/runicgateway/app/data/api/dto/RustDto.kt

@@ -176,6 +176,20 @@ data class RustLeaderboardRowDto(
     val structures: Int = 0,
     val playtimeSec: Long = 0,
     val lastSeen: String? = null,
+    /**
+     * The chat titles this player holds now (module-rust phase 17, M19) — the
+     * ones the game shows in chat, after the server's mode. They rank the
+     * CURRENT wipe whichever wipe the board is showing. Absent from an older
+     * module, which is why it defaults to empty: nothing is drawn.
+     */
+    val titles: List<RustTitleDto> = emptyList(),
+)
+
+/** One chat title: its text, and the operator's `#rrggbb` colour for it. */
+@Serializable
+data class RustTitleDto(
+    val text: String = "",
+    val color: String = "",
 )
 
 /** `GET /public/rust/servers/{id}/wipes` — every wipe this server has had, newest first. */

app/src/main/java/com/runicgateway/app/ui/rust/RustFormat.kt

@@ -175,3 +175,31 @@ fun shortSteamId(steamId: String?): String {
  */
 fun playerLabel(name: String?, steamId: String?): String =
     name?.takeIf { it.isNotBlank() } ?: shortSteamId(steamId)
+
+/**
+ * A chat title's `#rrggbb` colour as opaque ARGB, or null for anything else —
+ * a title with a colour this build cannot read is drawn in the theme's own chip
+ * colours rather than guessed at (M19).
+ */
+fun titleArgb(hex: String?): Long? {
+    val m = Regex("^#([0-9a-fA-F]{6})$").find(hex.orEmpty()) ?: return null
+    return 0xFF000000L or m.groupValues[1].toLong(16)
+}
+
+/**
+ * Whether a title chip of this colour needs DARK ink — the same rule as the
+ * website's `contrastInk`: black or white, whichever has the higher WCAG
+ * contrast. The colour is the operator's, chosen for a dark game chat, and the
+ * app draws in the reader's theme, so the colour becomes the chip and the ink is
+ * picked for it.
+ */
+fun titleInkIsDark(argb: Long): Boolean {
+    fun linear(channel: Long): Double {
+        val v = channel / 255.0
+        return if (v <= 0.03928) v / 12.92 else Math.pow((v + 0.055) / 1.055, 2.4)
+    }
+    val l = 0.2126 * linear((argb shr 16) and 0xFF) +
+        0.7152 * linear((argb shr 8) and 0xFF) +
+        0.0722 * linear(argb and 0xFF)
+    return (l + 0.05) / 0.05 >= 1.05 / (l + 0.05)
+}

app/src/main/java/com/runicgateway/app/ui/rust/RustServerScreen.kt

@@ -3,10 +3,13 @@
  */
 package com.runicgateway.app.ui.rust
 
+import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.horizontalScroll
 import androidx.compose.foundation.layout.Arrangement
 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.fillMaxSize
@@ -15,6 +18,7 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.FilterChip
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.ScrollableTabRow
@@ -25,6 +29,8 @@ import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.alpha
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
@@ -38,6 +44,7 @@ import com.runicgateway.app.data.api.dto.RustEventListDto
 import com.runicgateway.app.data.api.dto.RustLeaderboardRowDto
 import com.runicgateway.app.data.api.dto.RustOnlineDto
 import com.runicgateway.app.data.api.dto.RustServerDto
+import com.runicgateway.app.data.api.dto.RustTitleDto
 import com.runicgateway.app.data.api.dto.RustWipeDto
 import com.runicgateway.app.ui.ErrorKind
 import com.runicgateway.app.ui.PollWhileResumed
@@ -392,6 +399,7 @@ private val RUST_COLUMNS = listOf(
     RustColumn(R.string.rust_col_played, RustSort.PLAYTIME) { playtime(it.playtimeSec) },
 )
 
+@OptIn(ExperimentalLayoutApi::class)
 @Composable
 private fun LeaderboardPanel(
     state: UiState<List<RustLeaderboardRowDto>>,
@@ -452,13 +460,25 @@ private fun LeaderboardPanel(
                         // Five numeric columns beside an equal-weight name column
                         // left "Brannock" touching its own kill count, which the
                         // walk read as one field.
-                        Text(
-                            text = playerLabel(row.name, row.steamId),
-                            style = MaterialTheme.typography.bodyMedium,
-                            maxLines = 1,
-                            overflow = TextOverflow.Ellipsis,
-                            modifier = Modifier.weight(NAME_WEIGHT).padding(end = 8.dp),
-                        )
+                        Column(Modifier.weight(NAME_WEIGHT).padding(end = 8.dp)) {
+                            Text(
+                                text = playerLabel(row.name, row.steamId),
+                                style = MaterialTheme.typography.bodyMedium,
+                                maxLines = 1,
+                                overflow = TextOverflow.Ellipsis,
+                            )
+                            // M19: the chat titles this player holds now, under the
+                            // name — the column is too narrow to put them beside it.
+                            if (row.titles.isNotEmpty()) {
+                                FlowRow(
+                                    Modifier.padding(top = 2.dp),
+                                    horizontalArrangement = Arrangement.spacedBy(4.dp),
+                                    verticalArrangement = Arrangement.spacedBy(2.dp),
+                                ) {
+                                    row.titles.forEach { title -> TitleChip(title) }
+                                }
+                            }
+                        }
                         RUST_COLUMNS.forEach { column ->
                             Text(
                                 text = column.value(row),
@@ -475,6 +495,33 @@ private fun LeaderboardPanel(
     }
 }
 
+/**
+ * One chat title (M19): the operator's colour as the chip, and black or white
+ * ink chosen for it, as the website draws it. A colour this build cannot read
+ * falls back to the theme's own chip colours.
+ */
+@Composable
+private fun TitleChip(title: RustTitleDto) {
+    val argb = titleArgb(title.color)
+    val background = argb?.let { Color(it) } ?: MaterialTheme.colorScheme.secondaryContainer
+    val ink = when {
+        argb == null -> MaterialTheme.colorScheme.onSecondaryContainer
+        titleInkIsDark(argb) -> Color.Black
+        else -> Color.White
+    }
+    Text(
+        text = title.text,
+        style = MaterialTheme.typography.labelSmall,
+        color = ink,
+        maxLines = 1,
+        overflow = TextOverflow.Ellipsis,
+        modifier = Modifier
+            .clip(RoundedCornerShape(50))
+            .background(background)
+            .padding(horizontal = 6.dp, vertical = 1.dp),
+    )
+}
+
 // ── Online ────────────────────────────────────────────────────────────────
 
 @Composable

app/src/test/java/com/runicgateway/app/ui/rust/RustDtoTest.kt

@@ -4,6 +4,7 @@
 package com.runicgateway.app.ui.rust
 
 import com.runicgateway.app.data.api.dto.RustEventDto
+import com.runicgateway.app.data.api.dto.RustLeaderboardDto
 import com.runicgateway.app.data.api.dto.RustServerListDto
 import kotlinx.serialization.json.Json
 import org.junit.Assert.assertEquals
@@ -121,4 +122,28 @@ class RustDtoTest {
         assertNull(b.nextWipe)
         assertNull(c.nextWipe)
     }
+
+    @Test
+    fun `a leaderboard row carries its chat titles, and an older module's carries none`() {
+        // M19. The shape is module-rust's `listLeaderboard`: `titles` on every
+        // row, empty for a player with none; absent altogether from a module
+        // older than phase 17, which must decode to empty rather than fail.
+        val board = json.decodeFromString<RustLeaderboardDto>(
+            """
+            {"leaderboard":[
+              {"steamId":"1","name":"Brannock","kills":12,"deaths":3,"npcKills":0,"structures":0,"playtimeSec":3600,
+               "titles":[{"text":"Top Killer","color":"#ff8800"},{"text":"Regular","color":"#00aa55"}]},
+              {"steamId":"2","name":"Wren","kills":1,"deaths":0,"npcKills":0,"structures":0,"playtimeSec":60,"titles":[]}
+            ]}
+            """.trimIndent(),
+        )
+        assertEquals(listOf("Top Killer", "Regular"), board.leaderboard[0].titles.map { it.text })
+        assertEquals("#ff8800", board.leaderboard[0].titles[0].color)
+        assertTrue(board.leaderboard[1].titles.isEmpty())
+
+        val older = json.decodeFromString<RustLeaderboardDto>(
+            """{"leaderboard":[{"steamId":"1","name":"Brannock","kills":12}]}""",
+        )
+        assertTrue(older.leaderboard.single().titles.isEmpty())
+    }
 }

app/src/test/java/com/runicgateway/app/ui/rust/RustFormatTest.kt

@@ -4,6 +4,7 @@
 package com.runicgateway.app.ui.rust
 
 import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
 import org.junit.Assert.assertNull
 import org.junit.Assert.assertTrue
 import org.junit.Test
@@ -153,4 +154,19 @@ class RustFormatTest {
         assertNull(nextWipeWhen(null, now, utc, uk))
         assertNull(nextWipeWhen("soon", now, utc, uk))
     }
+
+    @Test
+    fun `a title colour is read only as #rrggbb, and its ink is whichever reads`() {
+        assertEquals(0xFFFFAA55L, titleArgb("#ffaa55"))
+        assertEquals(0xFFFFAA55L, titleArgb("#FFAA55"))
+        assertNull(titleArgb("red"))
+        assertNull(titleArgb(null))
+
+        // The same four the website's contrastInk test asserts, so the two
+        // clients draw a title the same way.
+        assertTrue(titleInkIsDark(titleArgb("#ffff00")!!))
+        assertTrue(titleInkIsDark(titleArgb("#ffaa55")!!))
+        assertTrue(titleInkIsDark(titleArgb("#ff0000")!!))
+        assertFalse(titleInkIsDark(titleArgb("#1a1a8c")!!))
+    }
 }