Filter only affordable transactions

Resolves:
https://github.com/joffrey-bion/seven-wonders/issues/81

2 files changed, 42 insertions, 6 deletions

diff --git a/sw-engine/src/main/kotlin/org/luxons/sevenwonders/engine/cards/Requirements.kt b/sw-engine/src/main/kotlin/org/luxons/sevenwonders/engine/cards/Requirements.kt
index 1d03aa76..4872f44f 100644
--- a/sw-engine/src/main/kotlin/org/luxons/sevenwonders/engine/cards/Requirements.kt
+++ b/sw-engine/src/main/kotlin/org/luxons/sevenwonders/engine/cards/Requirements.kt
@@ -6,6 +6,8 @@ import org.luxons.sevenwonders.engine.boards.Board
 import org.luxons.sevenwonders.engine.resources.*
 import org.luxons.sevenwonders.model.resources.ResourceTransactions
 import org.luxons.sevenwonders.model.resources.bestPrice
+import org.luxons.sevenwonders.model.resources.noTransactionOptions
+import org.luxons.sevenwonders.model.resources.totalPrice
 
 @Serializable
 data class Requirements internal constructor(
@@ -36,15 +38,16 @@ data class Requirements internal constructor(
     }
 
     private fun satisfactionWithPotentialHelp(player: Player): RequirementsSatisfaction {
-        val options = transactionOptions(resources, player)
-        val minPrice = options.bestPrice + gold
-        if (options.isEmpty()) {
+        val allOptions = transactionOptions(resources, player)
+        if (allOptions.isEmpty()) {
             return RequirementsSatisfaction.unavailableResources()
         }
-        if (player.board.gold < minPrice) {
-            return RequirementsSatisfaction.missingGoldForResources(minPrice, options)
+        val minPrice = allOptions.bestPrice + gold
+        if (minPrice > player.board.gold) {
+            return RequirementsSatisfaction.missingGoldForResources(minPrice, noTransactionOptions())
         }
-        return RequirementsSatisfaction.metWithHelp(minPrice, options)
+        val availableOptions = allOptions.filter { it.totalPrice + gold <= player.board.gold }
+        return RequirementsSatisfaction.metWithHelp(minPrice, availableOptions)
     }
 
     /**
diff --git a/sw-engine/src/test/kotlin/org/luxons/sevenwonders/engine/cards/RequirementsTest.kt b/sw-engine/src/test/kotlin/org/luxons/sevenwonders/engine/cards/RequirementsTest.kt
index 36dc8ed1..20100537 100644
--- a/sw-engine/src/test/kotlin/org/luxons/sevenwonders/engine/cards/RequirementsTest.kt
+++ b/sw-engine/src/test/kotlin/org/luxons/sevenwonders/engine/cards/RequirementsTest.kt
@@ -128,6 +128,39 @@ class RequirementsTest {
     }
 
     @Theory
+    fun allTransactionOptionsAreValid(
+        initialResource: ResourceType,
+        boughtResource: ResourceType,
+        requiredResource: ResourceType,
+    ) {
+        assumeTrue(initialResource != requiredResource)
+
+        val requirements = createRequirements(requiredResource)
+
+        val board = testBoard(initialResource, 1)
+        board.tradingRules.setCost(boughtResource, Provider.RIGHT_PLAYER, 1)
+
+        val leftNeighbourBoard = testBoard(initialResource, 0)
+        leftNeighbourBoard.publicProduction.addFixedResource(boughtResource, 1)
+
+        val rightNeighbourBoard = testBoard(initialResource, 0)
+        rightNeighbourBoard.publicProduction.addFixedResource(boughtResource, 1)
+
+        val table = Table(listOf(leftNeighbourBoard, board, rightNeighbourBoard))
+        val player = SimplePlayer(0, table)
+
+        val satisfaction = requirements.assess(player)
+        if (satisfaction.satisfied) {
+            satisfaction.transactionOptions.forEach {
+                assertTrue(
+                    requirements.areMetWithHelpBy(board, it),
+                    "all transaction options should be valid, but this is not: $it"
+                )
+            }
+        }
+    }
+
+    @Theory
     fun pay_boughtResource(initialResource: ResourceType, requiredResource: ResourceType) {
         assumeTrue(initialResource != requiredResource)