Discord thread shutdown, last Autosave singlethreaded (#2318)

* Bring Incas into the main game
(also changes slinger withdraw ability to inheritable)

* Update Nations.json

* Discord thread is now a timer and gets notified to shut down
Solved truncated Autosaves: Made it singlethreaded within shutdown.

Co-authored-by: Yair Morgenstern <yairm210@hotmail.com>

core/src/com/unciv/UncivGame.kt

@@ -24,7 +24,8 @@ import kotlin.concurrent.thread
 class UncivGame(
         val version: String,
         private val crashReportSender: CrashReportSender? = null,
-        val exitEvent: (()->Unit)? = null
+        val exitEvent: (()->Unit)? = null,
+        val cancelDiscordEvent: (()->Unit)? = null
 ) : Game() {
     // we need this secondary constructor because Java code for iOS can't handle Kotlin lambda parameters
     constructor(version: String) : this(version, null)
@@ -177,10 +178,19 @@ class UncivGame(
     }
 
     override fun dispose() {
-        if (::gameInfo.isInitialized) {
-            GameSaver().autoSave(gameInfo)
+        cancelDiscordEvent?.invoke()
+        if (::gameInfo.isInitialized){
+            GameSaver().autoSaveSingleThreaded(gameInfo)      // NO new thread
             settings.save()
         }
+
+        // Log still running threads (should be only this one and "DestroyJavaVM")
+        val numThreads = Thread.activeCount()
+        val threadList = Array<Thread>(numThreads) { _ -> Thread() }
+        Thread.enumerate(threadList)
+        threadList.filter { it !== Thread.currentThread() && it.name != "DestroyJavaVM"}.forEach {
+            println ("    Thread ${it.name} still running in UncivGame.dispose().")
+        }
     }
 
     companion object {

core/src/com/unciv/logic/GameSaver.kt

@@ -80,25 +80,26 @@ class GameSaver {
         // On the other hand if we alter the game data while it's being serialized we could get a concurrent modification exception.
         // So what we do is we clone all the game data and serialize the clone.
         val gameInfoClone = gameInfo.clone()
-        thread(name="Autosave") {
-            saveGame(gameInfoClone, "Autosave")
-
-            // keep auto-saves for the last 10 turns for debugging purposes
-            val newAutosaveFilename = saveFilesFolder + File.separator + "Autosave-${gameInfo.currentPlayer}-${gameInfoClone.turns}"
-            getSave("Autosave").copyTo(Gdx.files.local(newAutosaveFilename))
-
-            fun getAutosaves(): List<String> { return getSaves().filter { it.startsWith("Autosave") } }
-            while(getAutosaves().size>10){
-                val saveToDelete = getAutosaves().minBy { getSave(it).lastModified() }!!
-                deleteSave(saveToDelete)
-            }
-
+        thread(name = "Autosave") {
+            autoSaveSingleThreaded(gameInfoClone)
             // do this on main thread
             Gdx.app.postRunnable {
                 postRunnable()
             }
         }
+    }
+    fun autoSaveSingleThreaded (gameInfo: GameInfo) {
+        saveGame(gameInfo, "Autosave")
 
+        // keep auto-saves for the last 10 turns for debugging purposes
+        val newAutosaveFilename = saveFilesFolder + File.separator + "Autosave-${gameInfo.currentPlayer}-${gameInfo.turns}"
+        getSave("Autosave").copyTo(Gdx.files.local(newAutosaveFilename))
+
+        fun getAutosaves(): List<String> { return getSaves().filter { it.startsWith("Autosave") } }
+        while(getAutosaves().size>10){
+            val saveToDelete = getAutosaves().minBy { getSave(it).lastModified() }!!
+            deleteSave(saveToDelete)
+        }
     }
 
     /**

desktop/src/com/unciv/app/desktop/DesktopLauncher.kt

@@ -11,11 +11,14 @@ import com.badlogic.gdx.tools.texturepacker.TexturePacker
 import com.unciv.UncivGame
 import com.unciv.models.translations.tr
 import java.io.File
-import kotlin.concurrent.thread
+import java.util.*
+import kotlin.concurrent.timer
 import kotlin.system.exitProcess
 
 
 internal object DesktopLauncher {
+    private var discordTimer: Timer? = null
+
     @JvmStatic
     fun main(arg: Array<String>) {
 
@@ -27,9 +30,9 @@ internal object DesktopLauncher {
         config.title = "Unciv"
         config.useHDPI = true
 
-        val versionFromJar = DesktopLauncher.javaClass.`package`.specificationVersion
+        val versionFromJar = DesktopLauncher.javaClass.`package`.specificationVersion ?: "Desktop"
 
-        val game = UncivGame(if (versionFromJar != null) versionFromJar else "Desktop", null){exitProcess(0)}
+        val game = UncivGame ( versionFromJar, null, { exitProcess(0) }, { discordTimer?.cancel() } )
 
         if(!RaspberryPiDetector.isRaspberryPi()) // No discord RPC for Raspberry Pi, see https://github.com/yairm210/Unciv/issues/1624
             tryActivateDiscord(game)
@@ -71,27 +74,23 @@ internal object DesktopLauncher {
     }
 
     private fun tryActivateDiscord(game: UncivGame) {
-
         try {
             val handlers = DiscordEventHandlers()
             DiscordRPC.INSTANCE.Discord_Initialize("647066573147996161", handlers, true, null)
 
             Runtime.getRuntime().addShutdownHook(Thread { DiscordRPC.INSTANCE.Discord_Shutdown() })
 
-            thread {
-                while (true) {
-                    try {
-                        updateRpc(game)
-                    }catch (ex:Exception){}
-                    Thread.sleep(1000)
-                }
+            discordTimer = timer(name = "Discord", daemon = true, period = 1000) {
+                try {
+                    updateRpc(game)
+                } catch (ex:Exception){}
             }
         } catch (ex: Exception) {
-            print("Could not initialize Discord")
+            println("Could not initialize Discord")
         }
     }
 
-    fun updateRpc(game: UncivGame) {
+    private fun updateRpc(game: UncivGame) {
         if(!game.isInitialized) return
         val presence = DiscordRichPresence()
         val currentPlayerCiv = game.gameInfo.getCurrentPlayerCivilization()