package net.tylermurphy.Minecraft.Util;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import net.tylermurphy.Minecraft.Chunk.Chunk;
import net.tylermurphy.Minecraft.Scene.World;
import org.joml.Vector2i;

public class ChunkLoader {
	
	private static final ArrayList<Vector2i> keys_to_be_removed = new ArrayList<>();

	private static final HashMap<String, Data> loaded_regions = new HashMap<>();
	
	public static void run() {
		try {
			int cx,cz;
			cx = (int) ((World.player.getTransform().getGlobalPosition().x)/16);
			cz = (int) ((World.player.getTransform().getGlobalPosition().z)/16);
			keys_to_be_removed.clear();
			for(Chunk c : World.getChunks()) {
				if(c.gridX < cx-World.renderDistance || c.gridX > cx+World.renderDistance || c.gridZ < cz-World.renderDistance || c.gridZ > cz+World.renderDistance) {
					
					int x = c.gridX; int z = c.gridZ;
					int regionX = x > 0 ? x / 16 : (x - 16) / 16;
					int regionZ = z > 0 ? z / 16 : (z - 16) / 16;
					Data region = loaded_regions.get(getRegionKey(regionX,regionZ));
					byte[] data = ResourceManager.flattenArray(c.cubes);
					region.BYTE_ARRAYS.put(getChunkKey(x,z), data);
					loaded_regions.put(getRegionKey(regionX,regionZ), region);
					
					if(c.renderable() != null)
						c.renderable().getMesh().delete();
					c.deleteRenderable();
					if(c.transparentRenderable() != null)
						c.transparentRenderable().getMesh().delete();
					c.deleteTransparentRenderable();
					c.cubes = null;
					keys_to_be_removed.add(new Vector2i(c.gridX, c.gridZ));
				}
			}
			for(Vector2i pos : keys_to_be_removed) {
				World.removeChunk(pos.x, pos.y);
			}
			for(int x=cx-World.renderDistance; x<cx+World.renderDistance;x++) {
				for(int z=cz-World.renderDistance; z<cz+World.renderDistance;z++) {
					if(World.getChunkUnsafe(x, z) != null) continue;

					Chunk chunk = loadChunk(x, z);
					chunk.initialize();
					World.addChunk(chunk);
					update(x+1,z);
					update(x-1,z);
					update(x,z+1);
					update(x,z-1);
				}
			}
		}catch(Exception e) {
			e.printStackTrace();
		}
	}
	
	public static void save() {
		for(Chunk c : World.getChunks()) {
			int x = c.gridX; int z = c.gridZ;
			int regionX = x > 0 ? x / 16 : (x - 16) / 16;
			int regionZ = z > 0 ? z / 16 : (z - 16) / 16;
			Data region = loaded_regions.get(getRegionKey(regionX,regionZ));
			byte[] data = ResourceManager.flattenArray(c.cubes);
			region.BYTE_ARRAYS.put(getChunkKey(x,z), data);
			loaded_regions.put(getRegionKey(regionX,regionZ), region);
		}
		for(Map.Entry<String, Data> entry : loaded_regions.entrySet()) {
			ResourceManager.saveObject("region/", entry.getKey(), entry.getValue());
		}
	}

	private static void update(int x, int z) {
		Chunk c = World.getChunkUnsafe(x, z);
		if(c != null) c.updateMesh();
	}
	
	private static Chunk loadChunk(int gridX, int gridZ) {
		int regionX = gridX > 0 ? gridX / 16 : (gridX - 16) / 16;
		int regionZ = gridZ > 0 ? gridZ / 16 : (gridZ - 16) / 16;
		Data region;
		if(!loaded_regions.containsKey(getRegionKey(regionX,regionZ))) {
			Object reg = ResourceManager.loadObject("region/", getRegionKey(regionX,regionZ));
			if(reg == null) region = new Data();
			else region = (Data)reg;
			loaded_regions.put(getRegionKey(regionX,regionZ), region);
		} else region = loaded_regions.get(getRegionKey(regionX,regionZ));
		if(region.BYTE_ARRAYS.containsKey(getChunkKey(gridX,gridZ))) {
			byte[] data = region.BYTE_ARRAYS.get(getChunkKey(gridX,gridZ));
			Chunk chunk = new Chunk(gridX,gridZ,true);
			chunk.cubes = ResourceManager.expandArray(data);
			return chunk;
		} else {
			return new Chunk(gridX,gridZ,true);
		}
	}
	
	public static String getRegionKey(int regionX, int regionZ) {
		return regionX+"x"+regionZ+"z.region";
	}
	
	public static String getChunkKey(int gridX, int gridZ) {
		return gridX+"x"+gridZ+"z";
	}
}