From a6f8f578609e558a846debd07c5c4c700c937532 Mon Sep 17 00:00:00 2001
From: SomeTroglodyte <63000004+SomeTroglodyte@users.noreply.github.com>
Date: Mon, 24 Apr 2023 13:56:10 +0200
Subject: [PATCH] Avoid first contact alerts for dead City-States (#9269)

* Avoid first contact alerts for dead City-States

* Clearer simpler (hopefully) updateOurTiles
---
 .../transients/CivInfoTransientCache.kt       | 21 ++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/core/src/com/unciv/logic/civilization/transients/CivInfoTransientCache.kt b/core/src/com/unciv/logic/civilization/transients/CivInfoTransientCache.kt
index fc5ce73f36..657c839b4e 100644
--- a/core/src/com/unciv/logic/civilization/transients/CivInfoTransientCache.kt
+++ b/core/src/com/unciv/logic/civilization/transients/CivInfoTransientCache.kt
@@ -143,19 +143,26 @@ class CivInfoTransientCache(val civInfo: Civilization) {
     /** Our tiles update pretty infrequently - most 'viewable tile' changes are due to unit movements,
      * which means we can store this separately and use it 'as is' so we don't need to find the neighboring tiles every time
      * a unit moves */
-    fun updateOurTiles(){
-        val newOurTilesAndNeighboring = HashSet<Tile>()
-        val ownedTiles = civInfo.cities.asSequence().flatMap { it.getTiles() }
-        newOurTilesAndNeighboring.addAll(ownedTiles)
-        val neighboringUnownedTiles = ownedTiles.flatMap { tile -> tile.neighbors.filter { it.getOwner() != civInfo } }
-        newOurTilesAndNeighboring.addAll(neighboringUnownedTiles)
-        ourTilesAndNeighboringTiles = newOurTilesAndNeighboring
+    fun updateOurTiles() {
+        ourTilesAndNeighboringTiles = civInfo.cities.asSequence()
+            .flatMap { it.getTiles() } // our owned tiles, still distinct
+            .flatMap { sequenceOf(it) + it.neighbors }
+            // now we got a mix of owned, unowned and competitor-owned tiles, and **duplicates**
+            // but Sequence.toSet is just as good at making them distinct as any other operation
+            .toSet()
 
         updateViewableTiles()
         updateCivResources()
     }
 
     private fun setNewViewableTiles() {
+        if (civInfo.isDefeated()) {
+            // Avoid meeting dead city states when entering a tile owned by their former ally (#9245)
+            // In that case ourTilesAndNeighboringTiles and getCivUnits will be empty, but the for
+            // loop getKnownCivs/getAllyCiv would add tiles.
+            civInfo.viewableTiles = emptySet()
+            return
+        }
 
         // while spectating all map is visible
         if (civInfo.isSpectator() || DebugUtils.VISIBLE_MAP) {