feat: add selector and using by event listener

Author: sysnote8main

src/main/kotlin/be4rjp/sclat/map/MapEventListener.kt

@@ -2,12 +2,17 @@ package be4rjp.sclat.map
 
 import be4rjp.sclat.match.MatchEndEvent
 import be4rjp.sclat.match.MatchStartEvent
+import be4rjp.sclat.world.BukkitWorldAPI
 import org.bukkit.event.Listener
 import org.bukkit.event.server.ServerLoadEvent
 
 object MapEventListener : Listener {
+    var currentMapName: String = ""
+    var nextMapName: String = ""
+
     fun onServerStart(event: ServerLoadEvent) {
         // todo: load 2 maps
+        nextMap()
     }
 
     fun onMatchStart(event: MatchStartEvent) {
@@ -17,5 +22,17 @@ object MapEventListener : Listener {
     fun onMatchEnd(event: MatchEndEvent) {
         // unload map without saving and mark as not using
         // load different map for future match
+        BukkitWorldAPI.unloadWorld(currentMapName, false) ?: false
+        nextMap()
+    }
+
+    fun nextMap() {
+        currentMapName = nextMapName
+        nextMapName = MapSelector.selectRandomMap()
+        BukkitWorldAPI.loadWorld(nextMapName)
+        if (currentMapName == "") {
+            currentMapName = MapSelector.selectRandomMap()
+            BukkitWorldAPI.loadWorld(currentMapName)
+        }
     }
 }

src/main/kotlin/be4rjp/sclat/map/MapSelector.kt

@@ -0,0 +1,37 @@
+package be4rjp.sclat.map
+
+/**
+ * Selector for match maps. It manages the maps and their usage status.
+ */
+object MapSelector {
+    private val maps: MutableSet<String> = mutableSetOf()
+    private val usingMaps: MutableSet<String> = mutableSetOf()
+
+    fun addMap(mapName: String) {
+        maps.add(mapName)
+    }
+
+    fun removeMap(mapName: String) {
+        maps.remove(mapName)
+    }
+
+    fun getAllMaps(): Set<String> = maps.toSet()
+
+    /**
+     * get random map and mark its using.
+     *
+     * @return the name of the selected map, or null if no maps are available
+     */
+    fun selectRandomMap(): String {
+        if (maps.isEmpty()) throw RuntimeException("No maps available.")
+        return maps.filter { s -> !usingMaps.contains(s) }.random().also { markUsed(it) }
+    }
+
+    fun markUsed(mapName: String) {
+        usingMaps.add(mapName)
+    }
+
+    fun markUnused(mapName: String) {
+        usingMaps.remove(mapName)
+    }
+}