From 74cfda9854805a50dea1f507970c810693d2138f Mon Sep 17 00:00:00 2001
From: SomeTroglodyte <63000004+SomeTroglodyte@users.noreply.github.com>
Date: Sun, 29 Oct 2023 18:00:34 +0100
Subject: [PATCH] Tighten RulesetValidator for Terrain (#10355)

* Tighten RulesetValidator for Terrain

* Fix unintended indentation (say that fast repeatedly)
---
 .../ruleset/validation/RulesetValidator.kt    | 20 ++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/core/src/com/unciv/models/ruleset/validation/RulesetValidator.kt b/core/src/com/unciv/models/ruleset/validation/RulesetValidator.kt
index 45299a7c8d..99f9c76bc4 100644
--- a/core/src/com/unciv/models/ruleset/validation/RulesetValidator.kt
+++ b/core/src/com/unciv/models/ruleset/validation/RulesetValidator.kt
@@ -328,9 +328,23 @@ class RulesetValidator(val ruleset: Ruleset) {
         if (ruleset.terrains.values.none { it.type == TerrainType.Land && !it.impassable })
             lines += "No passable land terrains exist!"
         for (terrain in ruleset.terrains.values) {
-            for (baseTerrain in terrain.occursOn)
-                if (!ruleset.terrains.containsKey(baseTerrain))
-                    lines += "${terrain.name} occurs on terrain $baseTerrain which does not exist!"
+            for (baseTerrainName in terrain.occursOn) {
+                val baseTerrain = ruleset.terrains[baseTerrainName]
+                if (baseTerrain == null)
+                    lines += "${terrain.name} occurs on terrain $baseTerrainName which does not exist!"
+                else if (baseTerrain.type == TerrainType.NaturalWonder)
+                    lines.add("${terrain.name} occurs on natural wonder $baseTerrainName: Unsupported.", RulesetErrorSeverity.WarningOptionsOnly)
+            }
+            if (terrain.type == TerrainType.NaturalWonder) {
+                if (terrain.turnsInto == null)
+                    lines += "Natural Wonder ${terrain.name} is missing the turnsInto attribute!"
+                val baseTerrain = ruleset.terrains[terrain.turnsInto]
+                if (baseTerrain == null)
+                    lines += "${terrain.name} turns into terrain ${terrain.turnsInto} which does not exist!"
+                else if (!baseTerrain.type.isBaseTerrain)
+                    // See https://github.com/hackedpassword/Z2/blob/main/HybridTileTech.md for a clever exploit
+                    lines.add("${terrain.name} turns into terrain ${terrain.turnsInto} which is not a base terrain!", RulesetErrorSeverity.Warning)
+            }
             uniqueValidator.checkUniques(terrain, lines, rulesetSpecific, tryFixUnknownUniques)
         }
     }