/*
 * This file is part of Applied Energistics 2.
 * Copyright (c) 2013 - 2014, AlgorithmX2, All rights reserved.
 *
 * Applied Energistics 2 is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Applied Energistics 2 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Applied Energistics 2.  If not, see <http://www.gnu.org/licenses/lgpl>.
 */

package appeng.worldgen;


import java.util.Collection;
import java.util.Random;
import java.util.concurrent.Callable;

import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.world.World;
import net.minecraft.world.chunk.IChunkProvider;

import cpw.mods.fml.common.IWorldGenerator;

import appeng.api.features.IWorldGen.WorldGenType;
import appeng.core.AEConfig;
import appeng.core.WorldSettings;
import appeng.core.features.registries.WorldGenRegistry;
import appeng.hooks.TickHandler;
import appeng.util.Platform;
import appeng.worldgen.meteorite.ChunkOnly;

final public class MeteoriteWorldGen implements IWorldGenerator
{
	@Override
	public void generate(Random r, int chunkX, int chunkZ, World w, IChunkProvider chunkGenerator, IChunkProvider chunkProvider)
	{
		if ( WorldGenRegistry.INSTANCE.isWorldGenEnabled( WorldGenType.Meteorites, w ) )
		{
			// add new meteorites?
			if ( r.nextFloat() < AEConfig.instance.meteoriteSpawnChance )
			{
				int x = r.nextInt( 16 ) + (chunkX << 4);
				int z = r.nextInt( 16 ) + (chunkZ << 4);

				int depth = 180 + r.nextInt( 20 );
				TickHandler.INSTANCE.addCallable( w, new MeteoriteSpawn( x, depth, z, w ) );
			}
			else
				TickHandler.INSTANCE.addCallable( w, new MeteoriteSpawn( chunkX << 4, 128, chunkZ << 4, w ) );
		}
		else
			WorldSettings.getInstance().getCompass().updateArea( w, chunkX, chunkZ );
	}

	class MeteoriteSpawn implements Callable
	{

		final int x;
		final int z;
		final World w;
		final int depth;

		public MeteoriteSpawn(int x, int depth, int z, World w) {
			this.x = x;
			this.z = z;
			this.w = w;
			this.depth = depth;
		}

		@Override
		public Object call() throws Exception
		{
			int chunkX = this.x >> 4;
			int chunkZ = this.z >> 4;

			double minSqDist = Double.MAX_VALUE;

			// near by meteorites!
			for (NBTTagCompound data : MeteoriteWorldGen.this.getNearByMeteorites( this.w, chunkX, chunkZ ))
			{
				MeteoritePlacer mp = new MeteoritePlacer();
				mp.spawnMeteorite( new ChunkOnly( this.w, chunkX, chunkZ ), data );

				minSqDist = Math.min( minSqDist, mp.getSqDistance( this.x, this.z ) );
			}

			boolean isCluster = (minSqDist < 30 * 30) && Platform.getRandomFloat() < AEConfig.instance.meteoriteClusterChance;

			if ( minSqDist > AEConfig.instance.minMeteoriteDistanceSq || isCluster )
				MeteoriteWorldGen.this.tryMeteorite( this.w, this.depth, this.x, this.z );

			WorldSettings.getInstance().setGenerated( this.w.provider.dimensionId, chunkX, chunkZ );
			WorldSettings.getInstance().getCompass().updateArea( this.w, chunkX, chunkZ );

			return null;
		}
	}

	private boolean tryMeteorite(World w, int depth, int x, int z)
	{
		for (int tries = 0; tries < 20; tries++)
		{
			MeteoritePlacer mp = new MeteoritePlacer();

			if ( mp.spawnMeteorite( new ChunkOnly( w, x >> 4, z >> 4 ), x, depth, z ) )
			{
				int px = x >> 4;
				int pz = z >> 4;

				for (int cx = px - 6; cx < px + 6; cx++)
					for (int cz = pz - 6; cz < pz + 6; cz++)
					{
						if ( w.getChunkProvider().chunkExists( cx, cz ) )
						{
							if ( px == cx && pz == cz )
								continue;

							if ( WorldSettings.getInstance().hasGenerated( w.provider.dimensionId, cx, cz ) )
							{
								MeteoritePlacer mp2 = new MeteoritePlacer();
								mp2.spawnMeteorite( new ChunkOnly( w, cx, cz ), mp.getSettings() );
							}
						}
					}

				return true;
			}

			depth -= 15;
			if ( depth < 40 )
				return false;
		}

		return false;
	}

	private Collection<NBTTagCompound> getNearByMeteorites(World w, int chunkX, int chunkZ)
	{
		return WorldSettings.getInstance().getNearByMeteorites( w.provider.dimensionId, chunkX, chunkZ );
	}

}