import {
	BufferGeometry,
	Color,
	Data3DTexture,
	FileLoader,
	Float32BufferAttribute,
	Loader,
	LinearFilter,
	Mesh,
	MeshStandardMaterial,
	NearestFilter,
	RedFormat,
	SRGBColorSpace
} from 'three';

/**
 * A loader for the VOX format.
 *
 * ```js
 * const loader = new VOXLoader();
 * const chunks = await loader.loadAsync( 'models/vox/monu10.vox' );
 *
 * for ( let i = 0; i < chunks.length; i ++ ) {
 *
 * 	const chunk = chunks[ i ];
 * 	const mesh = new VOXMesh( chunk );
 * 	mesh.scale.setScalar( 0.0015 );
 * 	scene.add( mesh );
 *
 * }
 * ```
 * @augments Loader
 * @three_import import { VOXLoader } from 'three/addons/loaders/VOXLoader.js';
 */
class VOXLoader extends Loader {

	/**
	 * Starts loading from the given URL and passes the loaded VOX asset
	 * to the `onLoad()` callback.
	 *
	 * @param {string} url - The path/URL of the file to be loaded. This can also be a data URI.
	 * @param {function(Array<Object>)} onLoad - Executed when the loading process has been finished.
	 * @param {onProgressCallback} onProgress - Executed while the loading is in progress.
	 * @param {onErrorCallback} onError - Executed when errors occur.
	 */
	load( url, onLoad, onProgress, onError ) {

		const scope = this;

		const loader = new FileLoader( scope.manager );
		loader.setPath( scope.path );
		loader.setResponseType( 'arraybuffer' );
		loader.setRequestHeader( scope.requestHeader );
		loader.load( url, function ( buffer ) {

			try {

				onLoad( scope.parse( buffer ) );

			} catch ( e ) {

				if ( onError ) {

					onError( e );

				} else {

					console.error( e );

				}

				scope.manager.itemError( url );

			}

		}, onProgress, onError );

	}

	/**
	 * Parses the given VOX data and returns the resulting chunks.
	 *
	 * @param {ArrayBuffer} buffer - The raw VOX data as an array buffer.
	 * @return {Array<Object>} The parsed chunks.
	 */
	parse( buffer ) {

		const data = new DataView( buffer );

		const id = data.getUint32( 0, true );
		const version = data.getUint32( 4, true );

		if ( id !== 542658390 ) {

			console.error( 'THREE.VOXLoader: Invalid VOX file.' );
			return;

		}

		if ( version !== 150 ) {

			console.error( 'THREE.VOXLoader: Invalid VOX file. Unsupported version:', version );
			return;

		}

		const DEFAULT_PALETTE = [
			0x00000000, 0xffffffff, 0xffccffff, 0xff99ffff, 0xff66ffff, 0xff33ffff, 0xff00ffff, 0xffffccff,
			0xffccccff, 0xff99ccff, 0xff66ccff, 0xff33ccff, 0xff00ccff, 0xffff99ff, 0xffcc99ff, 0xff9999ff,
			0xff6699ff, 0xff3399ff, 0xff0099ff, 0xffff66ff, 0xffcc66ff, 0xff9966ff, 0xff6666ff, 0xff3366ff,
			0xff0066ff, 0xffff33ff, 0xffcc33ff, 0xff9933ff, 0xff6633ff, 0xff3333ff, 0xff0033ff, 0xffff00ff,
			0xffcc00ff, 0xff9900ff, 0xff6600ff, 0xff3300ff, 0xff0000ff, 0xffffffcc, 0xffccffcc, 0xff99ffcc,
			0xff66ffcc, 0xff33ffcc, 0xff00ffcc, 0xffffcccc, 0xffcccccc, 0xff99cccc, 0xff66cccc, 0xff33cccc,
			0xff00cccc, 0xffff99cc, 0xffcc99cc, 0xff9999cc, 0xff6699cc, 0xff3399cc, 0xff0099cc, 0xffff66cc,
			0xffcc66cc, 0xff9966cc, 0xff6666cc, 0xff3366cc, 0xff0066cc, 0xffff33cc, 0xffcc33cc, 0xff9933cc,
			0xff6633cc, 0xff3333cc, 0xff0033cc, 0xffff00cc, 0xffcc00cc, 0xff9900cc, 0xff6600cc, 0xff3300cc,
			0xff0000cc, 0xffffff99, 0xffccff99, 0xff99ff99, 0xff66ff99, 0xff33ff99, 0xff00ff99, 0xffffcc99,
			0xffcccc99, 0xff99cc99, 0xff66cc99, 0xff33cc99, 0xff00cc99, 0xffff9999, 0xffcc9999, 0xff999999,
			0xff669999, 0xff339999, 0xff009999, 0xffff6699, 0xffcc6699, 0xff996699, 0xff666699, 0xff336699,
			0xff006699, 0xffff3399, 0xffcc3399, 0xff993399, 0xff663399, 0xff333399, 0xff003399, 0xffff0099,
			0xffcc0099, 0xff990099, 0xff660099, 0xff330099, 0xff000099, 0xffffff66, 0xffccff66, 0xff99ff66,
			0xff66ff66, 0xff33ff66, 0xff00ff66, 0xffffcc66, 0xffcccc66, 0xff99cc66, 0xff66cc66, 0xff33cc66,
			0xff00cc66, 0xffff9966, 0xffcc9966, 0xff999966, 0xff669966, 0xff339966, 0xff009966, 0xffff6666,
			0xffcc6666, 0xff996666, 0xff666666, 0xff336666, 0xff006666, 0xffff3366, 0xffcc3366, 0xff993366,
			0xff663366, 0xff333366, 0xff003366, 0xffff0066, 0xffcc0066, 0xff990066, 0xff660066, 0xff330066,
			0xff000066, 0xffffff33, 0xffccff33, 0xff99ff33, 0xff66ff33, 0xff33ff33, 0xff00ff33, 0xffffcc33,
			0xffcccc33, 0xff99cc33, 0xff66cc33, 0xff33cc33, 0xff00cc33, 0xffff9933, 0xffcc9933, 0xff999933,
			0xff669933, 0xff339933, 0xff009933, 0xffff6633, 0xffcc6633, 0xff996633, 0xff666633, 0xff336633,
			0xff006633, 0xffff3333, 0xffcc3333, 0xff993333, 0xff663333, 0xff333333, 0xff003333, 0xffff0033,
			0xffcc0033, 0xff990033, 0xff660033, 0xff330033, 0xff000033, 0xffffff00, 0xffccff00, 0xff99ff00,
			0xff66ff00, 0xff33ff00, 0xff00ff00, 0xffffcc00, 0xffcccc00, 0xff99cc00, 0xff66cc00, 0xff33cc00,
			0xff00cc00, 0xffff9900, 0xffcc9900, 0xff999900, 0xff669900, 0xff339900, 0xff009900, 0xffff6600,
			0xffcc6600, 0xff996600, 0xff666600, 0xff336600, 0xff006600, 0xffff3300, 0xffcc3300, 0xff993300,
			0xff663300, 0xff333300, 0xff003300, 0xffff0000, 0xffcc0000, 0xff990000, 0xff660000, 0xff330000,
			0xff0000ee, 0xff0000dd, 0xff0000bb, 0xff0000aa, 0xff000088, 0xff000077, 0xff000055, 0xff000044,
			0xff000022, 0xff000011, 0xff00ee00, 0xff00dd00, 0xff00bb00, 0xff00aa00, 0xff008800, 0xff007700,
			0xff005500, 0xff004400, 0xff002200, 0xff001100, 0xffee0000, 0xffdd0000, 0xffbb0000, 0xffaa0000,
			0xff880000, 0xff770000, 0xff550000, 0xff440000, 0xff220000, 0xff110000, 0xffeeeeee, 0xffdddddd,
			0xffbbbbbb, 0xffaaaaaa, 0xff888888, 0xff777777, 0xff555555, 0xff444444, 0xff222222, 0xff111111
		];

		let i = 8;

		let chunk;
		const chunks = [];

		while ( i < data.byteLength ) {

			let id = '';

			for ( let j = 0; j < 4; j ++ ) {

				id += String.fromCharCode( data.getUint8( i ++ ) );

			}

			const chunkSize = data.getUint32( i, true ); i += 4;
			i += 4; // childChunks

			if ( id === 'SIZE' ) {

				const x = data.getUint32( i, true ); i += 4;
				const y = data.getUint32( i, true ); i += 4;
				const z = data.getUint32( i, true ); i += 4;

				chunk = {
					palette: DEFAULT_PALETTE,
					size: { x: x, y: y, z: z },
				};

				chunks.push( chunk );

				i += chunkSize - ( 3 * 4 );

			} else if ( id === 'XYZI' ) {

				const numVoxels = data.getUint32( i, true ); i += 4;
				chunk.data = new Uint8Array( buffer, i, numVoxels * 4 );

				i += numVoxels * 4;

			} else if ( id === 'RGBA' ) {

				const palette = [ 0 ];

				for ( let j = 0; j < 256; j ++ ) {

					palette[ j + 1 ] = data.getUint32( i, true ); i += 4;

				}

				chunk.palette = palette;

			} else {

				// console.log( id, chunkSize, childChunks );

				i += chunkSize;

			}

		}

		return chunks;

	}

}

/**
 * A VOX mesh.
 *
 * Instances of this class are created from the loaded chunks of {@link VOXLoader}.
 *
 * @augments Mesh
 */
class VOXMesh extends Mesh {

	/**
	 * Constructs a new VOX mesh.
	 *
	 * @param {Object} chunk - A VOX chunk loaded via {@link VOXLoader}.
	 */
	constructor( chunk ) {

		const data = chunk.data;
		const size = chunk.size;
		const palette = chunk.palette;

		//

		const vertices = [];
		const colors = [];

		const nx = [ 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0, 1 ];
		const px = [ 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0 ];
		const py = [ 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1 ];
		const ny = [ 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0 ];
		const nz = [ 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0 ];
		const pz = [ 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 1 ];

		const _color = new Color();

		function add( tile, x, y, z, r, g, b ) {

			x -= size.x / 2;
			y -= size.z / 2;
			z += size.y / 2;

			for ( let i = 0; i < 18; i += 3 ) {

				_color.setRGB( r, g, b, SRGBColorSpace );

				vertices.push( tile[ i + 0 ] + x, tile[ i + 1 ] + y, tile[ i + 2 ] + z );
				colors.push( _color.r, _color.g, _color.b );

			}

		}

		// Store data in a volume for sampling

		const offsety = size.x;
		const offsetz = size.x * size.y;

		const array = new Uint8Array( size.x * size.y * size.z );

		for ( let j = 0; j < data.length; j += 4 ) {

			const x = data[ j + 0 ];
			const y = data[ j + 1 ];
			const z = data[ j + 2 ];

			const index = x + ( y * offsety ) + ( z * offsetz );

			array[ index ] = 255;

		}

		// Construct geometry

		let hasColors = false;

		for ( let j = 0; j < data.length; j += 4 ) {

			const x = data[ j + 0 ];
			const y = data[ j + 1 ];
			const z = data[ j + 2 ];
			const c = data[ j + 3 ];

			const hex = palette[ c ];
			const r = ( hex >> 0 & 0xff ) / 0xff;
			const g = ( hex >> 8 & 0xff ) / 0xff;
			const b = ( hex >> 16 & 0xff ) / 0xff;

			if ( r > 0 || g > 0 || b > 0 ) hasColors = true;

			const index = x + ( y * offsety ) + ( z * offsetz );

			if ( array[ index + 1 ] === 0 || x === size.x - 1 ) add( px, x, z, - y, r, g, b );
			if ( array[ index - 1 ] === 0 || x === 0 ) add( nx, x, z, - y, r, g, b );
			if ( array[ index + offsety ] === 0 || y === size.y - 1 ) add( ny, x, z, - y, r, g, b );
			if ( array[ index - offsety ] === 0 || y === 0 ) add( py, x, z, - y, r, g, b );
			if ( array[ index + offsetz ] === 0 || z === size.z - 1 ) add( pz, x, z, - y, r, g, b );
			if ( array[ index - offsetz ] === 0 || z === 0 ) add( nz, x, z, - y, r, g, b );

		}

		const geometry = new BufferGeometry();
		geometry.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
		geometry.computeVertexNormals();

		const material = new MeshStandardMaterial();

		if ( hasColors ) {

			geometry.setAttribute( 'color', new Float32BufferAttribute( colors, 3 ) );
			material.vertexColors = true;

		}

		super( geometry, material );

	}

}

/**
 * A VOX 3D texture.
 *
 * Instances of this class are created from the loaded chunks of {@link VOXLoader}.
 *
 * @augments Data3DTexture
 */
class VOXData3DTexture extends Data3DTexture {

	/**
	 * Constructs a new VOX 3D texture.
	 *
	 * @param {Object} chunk - A VOX chunk loaded via {@link VOXLoader}.
	 */
	constructor( chunk ) {

		const data = chunk.data;
		const size = chunk.size;

		const offsety = size.x;
		const offsetz = size.x * size.y;

		const array = new Uint8Array( size.x * size.y * size.z );

		for ( let j = 0; j < data.length; j += 4 ) {

			const x = data[ j + 0 ];
			const y = data[ j + 1 ];
			const z = data[ j + 2 ];

			const index = x + ( y * offsety ) + ( z * offsetz );

			array[ index ] = 255;

		}

		super( array, size.x, size.y, size.z );

		this.format = RedFormat;
		this.minFilter = NearestFilter;
		this.magFilter = LinearFilter;
		this.unpackAlignment = 1;
		this.needsUpdate = true;

	}

}

export { VOXLoader, VOXMesh, VOXData3DTexture };
