OfflinePlayer PersistentDataContainers (#63)

* add methods for getting OfflinePlayer PDCs

* add editOfflinePDC inline function

idofront-nms/src/main/kotlin/com/mineinabyss/idofront/nms/nbt/OfflinePDC.kt

@@ -0,0 +1,58 @@
+package com.mineinabyss.idofront.nms.nbt
+
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.nbt.NbtIo
+import org.bukkit.Bukkit
+import org.bukkit.OfflinePlayer
+import org.bukkit.craftbukkit.v1_20_R1.CraftServer
+import java.io.File
+import java.nio.file.Files
+import java.util.*
+
+/**
+ * Gets the PlayerData from file for this UUID.
+ */
+fun UUID.getOfflinePlayerData(): CompoundTag? = (Bukkit.getServer() as CraftServer).server.playerDataStorage.getPlayerData(this.toString())
+
+/**
+ * Gets a copy of the WrappedPDC for this OfflinePlayer.
+ * Care should be taken to ensure that the player is not online when this is called.
+ */
+fun OfflinePlayer.getOfflinePDC() : WrappedPDC? {
+    if (isOnline) return null
+    val baseTag = uniqueId.getOfflinePlayerData()?.getCompound("BukkitValues") ?: return null
+    return WrappedPDC(baseTag)
+}
+
+/**
+ * Saves the given WrappedPDC to the OfflinePlayer's PlayerData file.
+ * Care should be taken to ensure that the player is not online when this is called.
+ * @return true if successful, false otherwise.
+ */
+fun OfflinePlayer.saveOfflinePDC(pdc: WrappedPDC): Boolean {
+    if (isOnline) return false
+    val worldNBTStorage = (Bukkit.getServer() as CraftServer).server.playerDataStorage
+    val tempFile = File(worldNBTStorage.playerDir, "$uniqueId.dat.tmp")
+    val playerFile = File(worldNBTStorage.playerDir, "$uniqueId.dat")
+
+    val mainPDc = uniqueId.getOfflinePlayerData() ?: return false
+    mainPDc.put("BukkitValues", pdc.compoundTag) ?: return false
+    runCatching {
+        Files.newOutputStream(tempFile.toPath()).use { outStream ->
+            NbtIo.writeCompressed(mainPDc, outStream)
+            if (playerFile.exists() && !playerFile.delete()) Bukkit.getLogger().severe("Failed to delete player file $uniqueId")
+            if (!tempFile.renameTo(playerFile)) Bukkit.getLogger().severe("Failed to rename player file $uniqueId")
+        }
+    }.onFailure {
+        Bukkit.getLogger().severe("Failed to save player file $uniqueId")
+        it.printStackTrace()
+        return false
+    }
+    return true
+}
+
+inline fun OfflinePlayer.editOfflinePDC(apply: WrappedPDC.() -> Unit): Boolean {
+    val pdc = getOfflinePDC() ?: return false
+    apply(pdc)
+    return saveOfflinePDC(pdc)
+}

idofront-nms/src/main/kotlin/com/mineinabyss/idofront/nms/nbt/WrappedPDC.kt

@@ -66,7 +66,7 @@ class WrappedPDC(
         }
     }
 
-    override fun readFromBytes(bytes: ByteArray?, clear: Boolean) {
+    override fun readFromBytes(bytes: ByteArray, clear: Boolean) {
         if (clear) compoundTag.tags.clear()
         DataInputStream(ByteArrayInputStream(bytes)).use { dataInput ->
             val compound = NbtIo.read(dataInput)