Fix ex-aequo ranks

When 2 players are ex-aequo, the rank of the next player is
still supposed to take into account the 2 players in front
of thim. So if 2 players are 2nd ex-aequo, the next guy is
supposed to be 4th, not 3rd.

2 files changed, 68 insertions, 8 deletions

diff --git a/sw-common-model/src/commonMain/kotlin/org/luxons/sevenwonders/model/score/Score.kt b/sw-common-model/src/commonMain/kotlin/org/luxons/sevenwonders/model/score/Score.kt
index 36d0857f..9b0c5fb6 100644
--- a/sw-common-model/src/commonMain/kotlin/org/luxons/sevenwonders/model/score/Score.kt
+++ b/sw-common-model/src/commonMain/kotlin/org/luxons/sevenwonders/model/score/Score.kt
@@ -4,18 +4,16 @@ import kotlinx.serialization.Serializable
 
 @Serializable
 data class ScoreBoard(val scores: List<PlayerScore>) {
+    init {
+        require(scores.sortedDescending() == scores) { "Scores must be sorted highest-to-lowest" }
+    }
 
     @OptIn(ExperimentalStdlibApi::class)
     val ranks: List<Int>
-        get() = buildList {
-            var r = 1
+        get() = buildList<Int> {
             add(1)
-            for (i in 1..scores.lastIndex) {
-                if (scores[i] < scores[i - 1]) {
-                    add(++r)
-                } else {
-                    add(r)
-                }
+            scores.zipWithNext { prev, current -> current.compareTo(prev) == 0 }.forEach { exAequoWithPrev ->
+                add(if (exAequoWithPrev) last() else size + 1)
             }
         }
 }
diff --git a/sw-common-model/src/commonTest/kotlin/org/luxons/sevenwonders/model/score/ScoreBoardTest.kt b/sw-common-model/src/commonTest/kotlin/org/luxons/sevenwonders/model/score/ScoreBoardTest.kt
new file mode 100644
index 00000000..0e3d904b
--- /dev/null
+++ b/sw-common-model/src/commonTest/kotlin/org/luxons/sevenwonders/model/score/ScoreBoardTest.kt
@@ -0,0 +1,62 @@
+package org.luxons.sevenwonders.model.score
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class ScoreBoardTest {
+
+    @Test
+    fun ranks_simpleOrder() {
+        val playerScores = listOf(
+            PlayerScore(1, 4, mapOf(ScoreCategory.CIVIL to 2, ScoreCategory.GOLD to 1)),
+            PlayerScore(2, 4, mapOf(ScoreCategory.CIVIL to 5, ScoreCategory.GOLD to 1)),
+            PlayerScore(3, 4, mapOf(ScoreCategory.SCIENCE to 4, ScoreCategory.GOLD to 1)),
+        )
+        val sortedScores = playerScores.sortedDescending()
+        val scoreBoard = ScoreBoard(sortedScores)
+        assertEquals(listOf(2, 3, 1), sortedScores.map { it.playerIndex })
+        assertEquals(listOf(1, 2, 3), scoreBoard.ranks)
+    }
+
+    @Test
+    fun ranks_tiesBrokenByGoldPoints() {
+        val playerScores = listOf(
+            PlayerScore(1, 4, mapOf(ScoreCategory.CIVIL to 2, ScoreCategory.GOLD to 1)),
+            PlayerScore(2, 9, mapOf(ScoreCategory.CIVIL to 5, ScoreCategory.GOLD to 3)),
+            PlayerScore(3, 4, mapOf(ScoreCategory.SCIENCE to 4, ScoreCategory.GOLD to 1)),
+            PlayerScore(4, 4, mapOf(ScoreCategory.SCIENCE to 7, ScoreCategory.GOLD to 1)),
+        )
+        val sortedScores = playerScores.sortedDescending()
+        val scoreBoard = ScoreBoard(sortedScores)
+        assertEquals(listOf(2, 4, 3, 1), sortedScores.map { it.playerIndex })
+        assertEquals(listOf(1, 2, 3, 4), scoreBoard.ranks)
+    }
+
+    @Test
+    fun ranks_tiesBrokenByGoldAmount() {
+        val playerScores = listOf(
+            PlayerScore(1, 4, mapOf(ScoreCategory.CIVIL to 2, ScoreCategory.GOLD to 1)),
+            PlayerScore(2, 6, mapOf(ScoreCategory.CIVIL to 5, ScoreCategory.GOLD to 2)),
+            PlayerScore(3, 4, mapOf(ScoreCategory.SCIENCE to 12, ScoreCategory.GOLD to 1)),
+            PlayerScore(4, 8, mapOf(ScoreCategory.SCIENCE to 5, ScoreCategory.GOLD to 2)),
+        )
+        val sortedScores = playerScores.sortedDescending()
+        val scoreBoard = ScoreBoard(sortedScores)
+        assertEquals(listOf(3, 4, 2, 1), sortedScores.map { it.playerIndex })
+        assertEquals(listOf(1, 2, 3, 4), scoreBoard.ranks)
+    }
+
+    @Test
+    fun ranks_actualTie() {
+        val playerScores = listOf(
+            PlayerScore(1, 4, mapOf(ScoreCategory.CIVIL to 2, ScoreCategory.GOLD to 1)),
+            PlayerScore(2, 6, mapOf(ScoreCategory.CIVIL to 5, ScoreCategory.GOLD to 2)),
+            PlayerScore(3, 4, mapOf(ScoreCategory.SCIENCE to 12, ScoreCategory.GOLD to 1)),
+            PlayerScore(4, 6, mapOf(ScoreCategory.SCIENCE to 5, ScoreCategory.GOLD to 2)),
+        )
+        val sortedScores = playerScores.sortedDescending()
+        val scoreBoard = ScoreBoard(sortedScores)
+        assertEquals(listOf(3, 2, 4, 1), sortedScores.map { it.playerIndex })
+        assertEquals(listOf(1, 2, 2, 4), scoreBoard.ranks)
+    }
+}