/*
 * 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.client.render.model;


import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;
import java.util.function.Function;
import java.util.stream.IntStream;

import javax.annotation.Nullable;

import com.google.common.base.Strings;

import net.minecraft.block.BlockState;
import net.minecraft.client.renderer.model.BakedQuad;
import net.minecraft.client.renderer.block.model.IBakedModel;
import net.minecraft.client.renderer.block.model.ItemCameraTransforms;
import net.minecraft.client.renderer.block.model.ItemOverrideList;
import net.minecraft.client.renderer.texture.TextureAtlasSprite;
import net.minecraft.client.renderer.vertex.VertexFormat;
import net.minecraft.util.Direction;
import net.minecraft.util.ResourceLocation;
import net.minecraft.util.math.MathHelper;
import net.minecraft.util.math.Vec3d;
import net.minecraftforge.client.model.pipeline.UnpackedBakedQuad;
import net.minecraftforge.common.property.IExtendedBlockState;

import appeng.decorative.solid.BlockQuartzGlass;
import appeng.decorative.solid.GlassState;


class GlassBakedModel implements IBakedModel
{

	private static final byte[][][] OFFSETS = generateOffsets();

	// Alternating textures based on position
	static final ResourceLocation TEXTURE_A = new ResourceLocation( "appliedenergistics2:blocks/glass/quartz_glass_a" );
	static final ResourceLocation TEXTURE_B = new ResourceLocation( "appliedenergistics2:blocks/glass/quartz_glass_b" );
	static final ResourceLocation TEXTURE_C = new ResourceLocation( "appliedenergistics2:blocks/glass/quartz_glass_c" );
	static final ResourceLocation TEXTURE_D = new ResourceLocation( "appliedenergistics2:blocks/glass/quartz_glass_d" );

	// Frame texture
	static final ResourceLocation[] TEXTURES_FRAME = generateTexturesFrame();

	// Generates the required textures for the frame
	private static ResourceLocation[] generateTexturesFrame()
	{
		return IntStream.range( 1, 16 )
				.mapToObj( Integer::toBinaryString )
				.map( s -> Strings.padStart( s, 4, '0' ) )
				.map( s -> new ResourceLocation( "appliedenergistics2:blocks/glass/quartz_glass_frame" + s ) )
				.toArray( ResourceLocation[]::new );
	}

	private final TextureAtlasSprite[] glassTextures;

	private final TextureAtlasSprite[] frameTextures;

	private final VertexFormat vertexFormat;

	public GlassBakedModel( VertexFormat format, Function<ResourceLocation, TextureAtlasSprite> bakedTextureGetter )
	{
		this.glassTextures = new TextureAtlasSprite[] {
				bakedTextureGetter.apply( TEXTURE_A ),
				bakedTextureGetter.apply( TEXTURE_B ),
				bakedTextureGetter.apply( TEXTURE_C ),
				bakedTextureGetter.apply( TEXTURE_D )
		};

		this.vertexFormat = format;

		// The first frame texture would be empty, so we simply leave it set to null here
		this.frameTextures = new TextureAtlasSprite[16];
		for( int i = 0; i < TEXTURES_FRAME.length; i++ )
		{
			this.frameTextures[1 + i] = bakedTextureGetter.apply( TEXTURES_FRAME[i] );
		}
	}

	@Override
	public List<BakedQuad> getQuads( @Nullable BlockState state, @Nullable Direction side, long rand )
	{
		if( !( state instanceof IExtendedBlockState ) || side == null )
		{
			return Collections.emptyList();
		}

		final IExtendedBlockState extState = (IExtendedBlockState) state;
		final GlassState glassState = extState.getValue( BlockQuartzGlass.GLASS_STATE );

		if( glassState == null )
		{
			return Collections.emptyList();
		}

		final int cx = Math.abs( glassState.getX() % 10 );
		final int cy = Math.abs( glassState.getY() % 10 );
		final int cz = Math.abs( glassState.getZ() % 10 );

		int u = OFFSETS[cx][cy][cz] % 4;
		int v = OFFSETS[9 - cx][9 - cy][9 - cz] % 4;

		int texIdx = Math.abs( ( OFFSETS[cx][cy][cz] + ( glassState.getX() + glassState.getY() + glassState.getZ() ) ) % 4 );

		if( texIdx < 2 )
		{
			u /= 2;
			v /= 2;
		}

		final TextureAtlasSprite glassTexture = this.glassTextures[texIdx];

		// Render the glass side
		final List<BakedQuad> quads = new ArrayList<>( 5 ); // At most 5

		final List<Vec3d> corners = RenderHelper.getFaceCorners( side );
		quads.add( this.createQuad( side, corners, glassTexture, u, v ) );

		/*
		 * This needs some explanation:
		 * The bit-field contains 4-bits, one for each direction that a frame may be drawn.
		 * Converted to a number, the bit-field is then used as an index into the list of
		 * frame textures, which have been created in such a way that their filenames
		 * indicate, in which directions they contain borders.
		 * i.e. bitmask = 0101 means a border should be drawn up and down (in terms of u,v space).
		 * Converted to a number, this bitmask is 5. So the texture at index 5 is used.
		 * That texture had "0101" in its filename to indicate this.
		 */
		final int edgeBitmask = makeBitmask( glassState, side );
		final TextureAtlasSprite sideSprite = this.frameTextures[edgeBitmask];

		if( sideSprite != null )
		{
			quads.add( this.createQuad( side, corners, sideSprite, 0, 0 ) );
		}

		return quads;
	}

	/**
	 * Creates the bitmask that indicates, in which directions (in terms of u,v space) a border should be drawn.
	 */
	private static int makeBitmask( GlassState state, Direction side )
	{
		switch( side )
		{
			case DOWN:
				return makeBitmask( state, Direction.SOUTH, Direction.EAST, Direction.NORTH, Direction.WEST );
			case UP:
				return makeBitmask( state, Direction.SOUTH, Direction.WEST, Direction.NORTH, Direction.EAST );
			case NORTH:
				return makeBitmask( state, Direction.UP, Direction.WEST, Direction.DOWN, Direction.EAST );
			case SOUTH:
				return makeBitmask( state, Direction.UP, Direction.EAST, Direction.DOWN, Direction.WEST );
			case WEST:
				return makeBitmask( state, Direction.UP, Direction.SOUTH, Direction.DOWN, Direction.NORTH );
			case EAST:
				return makeBitmask( state, Direction.UP, Direction.NORTH, Direction.DOWN, Direction.SOUTH );
			default:
				throw new IllegalArgumentException( "Unsupported side!" );
		}
	}

	private static int makeBitmask( GlassState state, Direction up, Direction right, Direction down, Direction left )
	{

		int bitmask = 0;

		if( !state.isFlushWith( up ) )
		{
			bitmask |= 1;
		}
		if( !state.isFlushWith( right ) )
		{
			bitmask |= 2;
		}
		if( !state.isFlushWith( down ) )
		{
			bitmask |= 4;
		}
		if( !state.isFlushWith( left ) )
		{
			bitmask |= 8;
		}
		return bitmask;
	}

	private BakedQuad createQuad( Direction side, List<Vec3d> corners, TextureAtlasSprite sprite, float uOffset, float vOffset )
	{
		return this.createQuad( side, corners.get( 0 ), corners.get( 1 ), corners.get( 2 ), corners.get( 3 ), sprite, uOffset, vOffset );
	}

	private BakedQuad createQuad( Direction side, Vec3d c1, Vec3d c2, Vec3d c3, Vec3d c4, TextureAtlasSprite sprite, float uOffset, float vOffset )
	{
		Vec3d normal = new Vec3d( side.getDirectionVec() );

		// Apply the u,v shift.
		// This mirrors the logic from OffsetIcon from 1.7
		float u1 = MathHelper.clamp( 0 - uOffset, 0, 16 );
		float u2 = MathHelper.clamp( 16 - uOffset, 0, 16 );
		float v1 = MathHelper.clamp( 0 - vOffset, 0, 16 );
		float v2 = MathHelper.clamp( 16 - vOffset, 0, 16 );

		UnpackedBakedQuad.Builder builder = new UnpackedBakedQuad.Builder( this.vertexFormat );
		builder.setTexture( sprite );
		this.putVertex( builder, normal, c1.x, c1.y, c1.z, sprite, u1, v1 );
		this.putVertex( builder, normal, c2.x, c2.y, c2.z, sprite, u1, v2 );
		this.putVertex( builder, normal, c3.x, c3.y, c3.z, sprite, u2, v2 );
		this.putVertex( builder, normal, c4.x, c4.y, c4.z, sprite, u2, v1 );
		return builder.build();
	}

	/*
	 * This method is as complicated as it is, because the order in which we push data into the vertexbuffer actually
	 * has to be precisely the order
	 * in which the vertex elements had been declared in the vertex format.
	 */
	private void putVertex( UnpackedBakedQuad.Builder builder, Vec3d normal, double x, double y, double z, TextureAtlasSprite sprite, float u, float v )
	{
		for( int e = 0; e < this.vertexFormat.getElementCount(); e++ )
		{
			switch( this.vertexFormat.getElement( e ).getUsage() )
			{
				case POSITION:
					builder.put( e, (float) x, (float) y, (float) z, 1.0f );
					break;
				case COLOR:
					builder.put( e, 1.0f, 1.0f, 1.0f, 1.0f );
					break;
				case UV:
					if( this.vertexFormat.getElement( e ).getIndex() == 0 )
					{
						u = sprite.getInterpolatedU( u );
						v = sprite.getInterpolatedV( v );
						builder.put( e, u, v, 0f, 1f );
						break;
					}
				case NORMAL:
					builder.put( e, (float) normal.x, (float) normal.y, (float) normal.z, 0f );
					break;
				default:
					builder.put( e );
					break;
			}
		}
	}

	@Override
	public ItemOverrideList getOverrides()
	{
		return ItemOverrideList.NONE;
	}

	@Override
	public boolean isAmbientOcclusion()
	{
		return false;
	}

	@Override
	public boolean isGui3d()
	{
		return false;
	}

	@Override
	public boolean isBuiltInRenderer()
	{
		return false;
	}

	@Override
	public TextureAtlasSprite getParticleTexture()
	{
		return this.frameTextures[this.frameTextures.length - 1];
	}

	@Override
	public ItemCameraTransforms getItemCameraTransforms()
	{
		return ItemCameraTransforms.DEFAULT;
	}

	private static byte[][][] generateOffsets()
	{
		final Random r = new Random( 924 );
		final byte[][][] offset = new byte[10][10][10];

		for( int x = 0; x < 10; x++ )
		{
			for( int y = 0; y < 10; y++ )
			{
				r.nextBytes( offset[x][y] );
			}
		}

		return offset;
	}
}