package appeng.worldgen;

import appeng.api.AEApi;
import appeng.api.definitions.IBlocks;
import appeng.core.AEConfig;
import appeng.worldgen.meteorite.IMeteoriteWorld;
import appeng.worldgen.meteorite.StandardWorld;
import net.minecraft.block.Block;
import net.minecraft.block.Blocks;
import net.minecraft.util.math.BlockPos;
import net.minecraft.world.IWorldReader;

import javax.annotation.Nullable;
import java.util.HashSet;
import java.util.Set;

/**
 * Makes decisions about spawning meteorites in the world.
 */
public class MeteoriteSpawner {

    private final Set<Block> validSpawn = new HashSet<>();
    private final Set<Block> invalidSpawn = new HashSet<>();

    public MeteoriteSpawner()
    {
        final IBlocks blocks = AEApi.instance().definitions().blocks();

        this.validSpawn.add( Blocks.STONE );
        this.validSpawn.add( Blocks.COBBLESTONE );
        this.validSpawn.add( Blocks.GRASS );
        this.validSpawn.add( Blocks.SAND );
        this.validSpawn.add( Blocks.DIRT );
        this.validSpawn.add( Blocks.GRAVEL );
        this.validSpawn.add( Blocks.NETHERRACK );
        this.validSpawn.add( Blocks.IRON_ORE );
        this.validSpawn.add( Blocks.GOLD_ORE );
        this.validSpawn.add( Blocks.DIAMOND_ORE );
        this.validSpawn.add( Blocks.REDSTONE_ORE );
        this.validSpawn.add( Blocks.ICE );
        this.validSpawn.add( Blocks.SNOW );

        this.invalidSpawn.add( blocks.skyStoneBlock().block() );
        this.invalidSpawn.add( Blocks.IRON_DOOR );
        this.invalidSpawn.add( Blocks.IRON_BARS );
        this.invalidSpawn.add( Blocks.OAK_DOOR );
        this.invalidSpawn.add( Blocks.ACACIA_DOOR );
        this.invalidSpawn.add( Blocks.BIRCH_DOOR );
        this.invalidSpawn.add( Blocks.DARK_OAK_DOOR );
        this.invalidSpawn.add( Blocks.JUNGLE_DOOR );
        this.invalidSpawn.add( Blocks.SPRUCE_DOOR );
        this.invalidSpawn.add( Blocks.BRICKS );
        this.invalidSpawn.add( Blocks.CLAY );
        this.invalidSpawn.add( Blocks.WATER );
    }

    public PlacedMeteoriteSettings trySpawnMeteoriteAtSuitableHeight(IWorldReader world, int x, int y, int z) {

        for( int tries = 0; tries < 20; tries++ )
        {
            PlacedMeteoriteSettings spawned = trySpawnMeteorite(world, new BlockPos(x, y, z));
            if (spawned != null) {
                return spawned;
            }

            y -= 15;
            if( y < 40 )
            {
                return null;
            }
        }

        return null;
    }

    @Nullable
    public PlacedMeteoriteSettings trySpawnMeteorite(IWorldReader world, BlockPos pos )
    {
        Block blk = world.getBlockState(pos).getBlock();
        if( !this.validSpawn.contains( blk ) )
        {
            return null; // must spawn on a valid block..
        }

        double meteoriteSize = ( Math.random() * 6.0 ) + 2;
        double realCrater = meteoriteSize * 2 + 5;
        boolean lava = Math.random() > 0.9;

        if (!areSurroundingsSuitable(world, pos)) {
            return null;
        }

        // we can spawn here!
        int skyMode = countBlockWithSkyLight(world, pos);

        boolean solid = !isAirBelowSpawnPoint(world, pos);

        if( !solid )
        {
            skyMode = 0;
        }

        return new PlacedMeteoriteSettings(pos, blk.getRegistryName(), lava, skyMode, meteoriteSize, realCrater);
    }

    private static boolean isAirBelowSpawnPoint(IWorldReader w, BlockPos pos) {
        BlockPos.Mutable testPos = new BlockPos.Mutable(pos);
        for( int j = pos.getY() - 15; j < pos.getY() - 1; j++ )
        {
            testPos.setY(j);
            if( w.isAirBlock(testPos) )
            {
                return true;
            }
        }
        return false;
    }

    private int countBlockWithSkyLight(IWorldReader w, BlockPos pos) {
        int skyMode = 0;

        BlockPos.Mutable testPos = new BlockPos.Mutable();
        for( int i = pos.getX() - 15; i < pos.getX() + 15; i++ )
        {
            testPos.setX(i);
            for( int j = pos.getY() - 15; j < pos.getY() + 11; j++ )
            {
                testPos.setY(j);
                for( int k = pos.getZ() - 15; k < pos.getZ() + 15; k++ )
                {
                    testPos.setZ(k);
                    if( w.canBlockSeeSky( testPos ) )
                    {
                        skyMode++;
                    }
                }
            }
        }
        return skyMode;
    }

    private boolean areSurroundingsSuitable(IWorldReader w, BlockPos pos) {
        int realValidBlocks = 0;

        BlockPos.Mutable testPos = new BlockPos.Mutable();
        for( int i = pos.getX() - 6; i < pos.getX() + 6; i++ )
        {
            testPos.setX(i);
            for( int j = pos.getY() - 6; j < pos.getY() + 6; j++ )
            {
                testPos.setY(j);
                for( int k = pos.getZ() - 6; k < pos.getZ() + 6; k++ )
                {
                    testPos.setZ(k);
                    Block testBlk = w.getBlockState(testPos).getBlock();
                    if( this.validSpawn.contains( testBlk ) )
                    {
                        realValidBlocks++;
                    }
                }
            }
        }

        int validBlocks = 0;
        for( int i = pos.getX() - 15; i < pos.getX() + 15; i++ )
        {
            testPos.setX(i);
            for( int j = pos.getY() - 15; j < pos.getY() + 15; j++ )
            {
                testPos.setY(j);
                for( int k = pos.getZ() - 15; k < pos.getZ() + 15; k++ )
                {
                    testPos.setZ(k);
                    Block testBlk = w.getBlockState( testPos ).getBlock();
                    if( this.invalidSpawn.contains( testBlk ) )
                    {
                        return false;
                    }
                    if( this.validSpawn.contains( testBlk ) )
                    {
                        validBlocks++;
                    }
                }
            }
        }

        final int minBlocks = 200;
        return validBlocks > minBlocks && realValidBlocks > 80;
    }

}