package de.blablubbabc.test2;

import java.util.LinkedHashMap;
import java.util.Map;

import org.apache.commons.lang.Validate;
import org.bukkit.Bukkit;
import org.bukkit.Chunk;
import org.bukkit.Location;
import org.bukkit.World;
import org.bukkit.block.Block;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.world.ChunkLoadEvent;
import org.bukkit.event.world.ChunkUnloadEvent;
import org.bukkit.plugin.java.JavaPlugin;

public class Test extends JavaPlugin implements Listener {

	private final Map<ChunkCoords, Long> recentlyUnloaded = new LinkedHashMap<>();

	@Override
	public void onEnable() {
		Bukkit.getPluginManager().registerEvents(this, this);
	}

	@Override
	public void onDisable() {
	}

	@EventHandler(priority = EventPriority.MONITOR)
	void onChunkLoad(ChunkLoadEvent event) {
		Chunk chunk = event.getChunk();
		Long unloadedTime = recentlyUnloaded.get(new ChunkCoords(chunk));
		if (unloadedTime != null) {
			long reloadDelay = System.currentTimeMillis() - unloadedTime;
			getLogger().warning("  Detected recently (" + reloadDelay + "ms) unloaded chunk getting reloaded: " + chunk.getX() + "," + chunk.getZ());
			Thread.dumpStack();
		}
	}

	@EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
	void onChunkUnload(ChunkUnloadEvent event) {
		Chunk chunk = event.getChunk();
		ChunkCoords coord = new ChunkCoords(chunk);
		Long time = System.currentTimeMillis();
		recentlyUnloaded.put(coord, time);
		Bukkit.getScheduler().runTaskLater(this, () -> {
			recentlyUnloaded.remove(coord, time);
		}, 100L); // 5 seconds
	}

	/**
	 * Stores positional information about a chunk, like its world and coordinates.
	 */
	public static final class ChunkCoords {

		private final String worldName;
		private final int chunkX;
		private final int chunkZ;

		public ChunkCoords(String worldName, int chunkX, int chunkZ) {
			Validate.notNull(worldName, "World name is null!");
			this.worldName = worldName;
			this.chunkX = chunkX;
			this.chunkZ = chunkZ;
		}

		public ChunkCoords(Chunk chunk) {
			Validate.notNull(chunk, "Chunk is null!");
			this.worldName = chunk.getWorld().getName();
			this.chunkX = chunk.getX();
			this.chunkZ = chunk.getZ();
		}

		public ChunkCoords(Location location) {
			Validate.notNull(location, "Location is null!");
			World world = location.getWorld();
			Validate.notNull(world);
			this.worldName = world.getName();
			this.chunkX = convertBlockCoord(location.getBlockX());
			this.chunkZ = convertBlockCoord(location.getBlockZ());
		}

		public ChunkCoords(Block block) {
			Validate.notNull(block, "Block is null!");
			World world = block.getWorld();
			Validate.notNull(world);
			this.worldName = world.getName();
			this.chunkX = convertBlockCoord(block.getX());
			this.chunkZ = convertBlockCoord(block.getZ());
		}

		/**
		 * Gets the chunk's world name.
		 *
		 * @return the chunk's world name
		 */
		public String getWorldName() {
			return worldName;
		}

		/**
		 * Gets the chunk's x-coordinate
		 *
		 * @return the chunk's x-coordinate
		 */
		public int getChunkX() {
			return chunkX;
		}

		/**
		 * Gets the chunk's z-coordinate
		 *
		 * @return the chunk's z-coordinate
		 */
		public int getChunkZ() {
			return chunkZ;
		}

		public boolean isChunkLoaded() {
			World world = Bukkit.getServer().getWorld(worldName);
			if (world != null) {
				return world.isChunkLoaded(chunkX, chunkZ);
			}
			return false;
		}

		public boolean isSameChunk(Chunk chunk) {
			if (chunk == null) return false;
			return chunk.getX() == chunkX && chunk.getZ() == chunkZ && chunk.getWorld().getName().equals(worldName);
		}

		@Override
		public String toString() {
			return getClass().getName()
					+ "[worldName=" + worldName
					+ ",chunkX=" + chunkX
					+ ",chunkZ=" + chunkZ + "]";
		}

		@Override
		public int hashCode() {
			final int prime = 31;
			int result = 1;
			result = prime * result + chunkX;
			result = prime * result + chunkZ;
			result = prime * result + worldName.hashCode();
			return result;
		}

		@Override
		public boolean equals(Object obj) {
			if (this == obj) return true;
			if (obj == null) return false;
			if (this.getClass() != obj.getClass()) return false;
			ChunkCoords other = (ChunkCoords) obj;
			if (chunkX != other.chunkX) return false;
			if (chunkZ != other.chunkZ) return false;
			if (!worldName.equals(other.worldName)) return false;
			return true;
		}

		public static int convertBlockCoord(int blockCoord) {
			return blockCoord >> 4;
		}

		public static ChunkCoords fromBlockPos(String worldName, int blockX, int blockZ) {
			return new ChunkCoords(worldName, convertBlockCoord(blockX), convertBlockCoord(blockZ));
		}
	}
}