import {
	AnimationClip,
	BufferGeometry,
	FileLoader,
	Float32BufferAttribute,
	Loader,
	Vector3
} from 'three';

const _normalData = [
	[ - 0.525731, 0.000000, 0.850651 ], [ - 0.442863, 0.238856, 0.864188 ],
	[ - 0.295242, 0.000000, 0.955423 ], [ - 0.309017, 0.500000, 0.809017 ],
	[ - 0.162460, 0.262866, 0.951056 ], [ 0.000000, 0.000000, 1.000000 ],
	[ 0.000000, 0.850651, 0.525731 ], [ - 0.147621, 0.716567, 0.681718 ],
	[ 0.147621, 0.716567, 0.681718 ], [ 0.000000, 0.525731, 0.850651 ],
	[ 0.309017, 0.500000, 0.809017 ], [ 0.525731, 0.000000, 0.850651 ],
	[ 0.295242, 0.000000, 0.955423 ], [ 0.442863, 0.238856, 0.864188 ],
	[ 0.162460, 0.262866, 0.951056 ], [ - 0.681718, 0.147621, 0.716567 ],
	[ - 0.809017, 0.309017, 0.500000 ], [ - 0.587785, 0.425325, 0.688191 ],
	[ - 0.850651, 0.525731, 0.000000 ], [ - 0.864188, 0.442863, 0.238856 ],
	[ - 0.716567, 0.681718, 0.147621 ], [ - 0.688191, 0.587785, 0.425325 ],
	[ - 0.500000, 0.809017, 0.309017 ], [ - 0.238856, 0.864188, 0.442863 ],
	[ - 0.425325, 0.688191, 0.587785 ], [ - 0.716567, 0.681718, - 0.147621 ],
	[ - 0.500000, 0.809017, - 0.309017 ], [ - 0.525731, 0.850651, 0.000000 ],
	[ 0.000000, 0.850651, - 0.525731 ], [ - 0.238856, 0.864188, - 0.442863 ],
	[ 0.000000, 0.955423, - 0.295242 ], [ - 0.262866, 0.951056, - 0.162460 ],
	[ 0.000000, 1.000000, 0.000000 ], [ 0.000000, 0.955423, 0.295242 ],
	[ - 0.262866, 0.951056, 0.162460 ], [ 0.238856, 0.864188, 0.442863 ],
	[ 0.262866, 0.951056, 0.162460 ], [ 0.500000, 0.809017, 0.309017 ],
	[ 0.238856, 0.864188, - 0.442863 ], [ 0.262866, 0.951056, - 0.162460 ],
	[ 0.500000, 0.809017, - 0.309017 ], [ 0.850651, 0.525731, 0.000000 ],
	[ 0.716567, 0.681718, 0.147621 ], [ 0.716567, 0.681718, - 0.147621 ],
	[ 0.525731, 0.850651, 0.000000 ], [ 0.425325, 0.688191, 0.587785 ],
	[ 0.864188, 0.442863, 0.238856 ], [ 0.688191, 0.587785, 0.425325 ],
	[ 0.809017, 0.309017, 0.500000 ], [ 0.681718, 0.147621, 0.716567 ],
	[ 0.587785, 0.425325, 0.688191 ], [ 0.955423, 0.295242, 0.000000 ],
	[ 1.000000, 0.000000, 0.000000 ], [ 0.951056, 0.162460, 0.262866 ],
	[ 0.850651, - 0.525731, 0.000000 ], [ 0.955423, - 0.295242, 0.000000 ],
	[ 0.864188, - 0.442863, 0.238856 ], [ 0.951056, - 0.162460, 0.262866 ],
	[ 0.809017, - 0.309017, 0.500000 ], [ 0.681718, - 0.147621, 0.716567 ],
	[ 0.850651, 0.000000, 0.525731 ], [ 0.864188, 0.442863, - 0.238856 ],
	[ 0.809017, 0.309017, - 0.500000 ], [ 0.951056, 0.162460, - 0.262866 ],
	[ 0.525731, 0.000000, - 0.850651 ], [ 0.681718, 0.147621, - 0.716567 ],
	[ 0.681718, - 0.147621, - 0.716567 ], [ 0.850651, 0.000000, - 0.525731 ],
	[ 0.809017, - 0.309017, - 0.500000 ], [ 0.864188, - 0.442863, - 0.238856 ],
	[ 0.951056, - 0.162460, - 0.262866 ], [ 0.147621, 0.716567, - 0.681718 ],
	[ 0.309017, 0.500000, - 0.809017 ], [ 0.425325, 0.688191, - 0.587785 ],
	[ 0.442863, 0.238856, - 0.864188 ], [ 0.587785, 0.425325, - 0.688191 ],
	[ 0.688191, 0.587785, - 0.425325 ], [ - 0.147621, 0.716567, - 0.681718 ],
	[ - 0.309017, 0.500000, - 0.809017 ], [ 0.000000, 0.525731, - 0.850651 ],
	[ - 0.525731, 0.000000, - 0.850651 ], [ - 0.442863, 0.238856, - 0.864188 ],
	[ - 0.295242, 0.000000, - 0.955423 ], [ - 0.162460, 0.262866, - 0.951056 ],
	[ 0.000000, 0.000000, - 1.000000 ], [ 0.295242, 0.000000, - 0.955423 ],
	[ 0.162460, 0.262866, - 0.951056 ], [ - 0.442863, - 0.238856, - 0.864188 ],
	[ - 0.309017, - 0.500000, - 0.809017 ], [ - 0.162460, - 0.262866, - 0.951056 ],
	[ 0.000000, - 0.850651, - 0.525731 ], [ - 0.147621, - 0.716567, - 0.681718 ],
	[ 0.147621, - 0.716567, - 0.681718 ], [ 0.000000, - 0.525731, - 0.850651 ],
	[ 0.309017, - 0.500000, - 0.809017 ], [ 0.442863, - 0.238856, - 0.864188 ],
	[ 0.162460, - 0.262866, - 0.951056 ], [ 0.238856, - 0.864188, - 0.442863 ],
	[ 0.500000, - 0.809017, - 0.309017 ], [ 0.425325, - 0.688191, - 0.587785 ],
	[ 0.716567, - 0.681718, - 0.147621 ], [ 0.688191, - 0.587785, - 0.425325 ],
	[ 0.587785, - 0.425325, - 0.688191 ], [ 0.000000, - 0.955423, - 0.295242 ],
	[ 0.000000, - 1.000000, 0.000000 ], [ 0.262866, - 0.951056, - 0.162460 ],
	[ 0.000000, - 0.850651, 0.525731 ], [ 0.000000, - 0.955423, 0.295242 ],
	[ 0.238856, - 0.864188, 0.442863 ], [ 0.262866, - 0.951056, 0.162460 ],
	[ 0.500000, - 0.809017, 0.309017 ], [ 0.716567, - 0.681718, 0.147621 ],
	[ 0.525731, - 0.850651, 0.000000 ], [ - 0.238856, - 0.864188, - 0.442863 ],
	[ - 0.500000, - 0.809017, - 0.309017 ], [ - 0.262866, - 0.951056, - 0.162460 ],
	[ - 0.850651, - 0.525731, 0.000000 ], [ - 0.716567, - 0.681718, - 0.147621 ],
	[ - 0.716567, - 0.681718, 0.147621 ], [ - 0.525731, - 0.850651, 0.000000 ],
	[ - 0.500000, - 0.809017, 0.309017 ], [ - 0.238856, - 0.864188, 0.442863 ],
	[ - 0.262866, - 0.951056, 0.162460 ], [ - 0.864188, - 0.442863, 0.238856 ],
	[ - 0.809017, - 0.309017, 0.500000 ], [ - 0.688191, - 0.587785, 0.425325 ],
	[ - 0.681718, - 0.147621, 0.716567 ], [ - 0.442863, - 0.238856, 0.864188 ],
	[ - 0.587785, - 0.425325, 0.688191 ], [ - 0.309017, - 0.500000, 0.809017 ],
	[ - 0.147621, - 0.716567, 0.681718 ], [ - 0.425325, - 0.688191, 0.587785 ],
	[ - 0.162460, - 0.262866, 0.951056 ], [ 0.442863, - 0.238856, 0.864188 ],
	[ 0.162460, - 0.262866, 0.951056 ], [ 0.309017, - 0.500000, 0.809017 ],
	[ 0.147621, - 0.716567, 0.681718 ], [ 0.000000, - 0.525731, 0.850651 ],
	[ 0.425325, - 0.688191, 0.587785 ], [ 0.587785, - 0.425325, 0.688191 ],
	[ 0.688191, - 0.587785, 0.425325 ], [ - 0.955423, 0.295242, 0.000000 ],
	[ - 0.951056, 0.162460, 0.262866 ], [ - 1.000000, 0.000000, 0.000000 ],
	[ - 0.850651, 0.000000, 0.525731 ], [ - 0.955423, - 0.295242, 0.000000 ],
	[ - 0.951056, - 0.162460, 0.262866 ], [ - 0.864188, 0.442863, - 0.238856 ],
	[ - 0.951056, 0.162460, - 0.262866 ], [ - 0.809017, 0.309017, - 0.500000 ],
	[ - 0.864188, - 0.442863, - 0.238856 ], [ - 0.951056, - 0.162460, - 0.262866 ],
	[ - 0.809017, - 0.309017, - 0.500000 ], [ - 0.681718, 0.147621, - 0.716567 ],
	[ - 0.681718, - 0.147621, - 0.716567 ], [ - 0.850651, 0.000000, - 0.525731 ],
	[ - 0.688191, 0.587785, - 0.425325 ], [ - 0.587785, 0.425325, - 0.688191 ],
	[ - 0.425325, 0.688191, - 0.587785 ], [ - 0.425325, - 0.688191, - 0.587785 ],
	[ - 0.587785, - 0.425325, - 0.688191 ], [ - 0.688191, - 0.587785, - 0.425325 ]
];

class MD2Loader extends Loader {

	constructor( manager ) {

		super( manager );

	}

	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.setWithCredentials( scope.withCredentials );
		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 );

	}

	parse( buffer ) {

		const data = new DataView( buffer );

		// http://tfc.duke.free.fr/coding/md2-specs-en.html

		const header = {};
		const headerNames = [
			'ident', 'version',
			'skinwidth', 'skinheight',
			'framesize',
			'num_skins', 'num_vertices', 'num_st', 'num_tris', 'num_glcmds', 'num_frames',
			'offset_skins', 'offset_st', 'offset_tris', 'offset_frames', 'offset_glcmds', 'offset_end'
		];

		for ( let i = 0; i < headerNames.length; i ++ ) {

			header[ headerNames[ i ] ] = data.getInt32( i * 4, true );

		}

		if ( header.ident !== 844121161 || header.version !== 8 ) {

			console.error( 'Not a valid MD2 file' );
			return;

		}

		if ( header.offset_end !== data.byteLength ) {

			console.error( 'Corrupted MD2 file' );
			return;

		}

		//

		const geometry = new BufferGeometry();

		// uvs

		const uvsTemp = [];
		let offset = header.offset_st;

		for ( let i = 0, l = header.num_st; i < l; i ++ ) {

			const u = data.getInt16( offset + 0, true );
			const v = data.getInt16( offset + 2, true );

			uvsTemp.push( u / header.skinwidth, 1 - ( v / header.skinheight ) );

			offset += 4;

		}

		// triangles

		offset = header.offset_tris;

		const vertexIndices = [];
		const uvIndices = [];

		for ( let i = 0, l = header.num_tris; i < l; i ++ ) {

			vertexIndices.push(
				data.getUint16( offset + 0, true ),
				data.getUint16( offset + 2, true ),
				data.getUint16( offset + 4, true )
			);

			uvIndices.push(
				data.getUint16( offset + 6, true ),
				data.getUint16( offset + 8, true ),
				data.getUint16( offset + 10, true )
			);

			offset += 12;

		}

		// frames

		const translation = new Vector3();
		const scale = new Vector3();

		const frames = [];

		offset = header.offset_frames;

		for ( let i = 0, l = header.num_frames; i < l; i ++ ) {

			scale.set(
				data.getFloat32( offset + 0, true ),
				data.getFloat32( offset + 4, true ),
				data.getFloat32( offset + 8, true )
			);

			translation.set(
				data.getFloat32( offset + 12, true ),
				data.getFloat32( offset + 16, true ),
				data.getFloat32( offset + 20, true )
			);

			offset += 24;

			const string = [];

			for ( let j = 0; j < 16; j ++ ) {

				const character = data.getUint8( offset + j, true );
				if ( character === 0 ) break;

				string[ j ] = character;

			}

			const frame = {
				name: String.fromCharCode.apply( null, string ),
				vertices: [],
				normals: []
			};

			offset += 16;

			for ( let j = 0; j < header.num_vertices; j ++ ) {

				let x = data.getUint8( offset ++, true );
				let y = data.getUint8( offset ++, true );
				let z = data.getUint8( offset ++, true );
				const n = _normalData[ data.getUint8( offset ++, true ) ];

				x = x * scale.x + translation.x;
				y = y * scale.y + translation.y;
				z = z * scale.z + translation.z;

				frame.vertices.push( x, z, y ); // convert to Y-up
				frame.normals.push( n[ 0 ], n[ 2 ], n[ 1 ] ); // convert to Y-up

			}

			frames.push( frame );

		}

		// static

		const positions = [];
		const normals = [];
		const uvs = [];

		const verticesTemp = frames[ 0 ].vertices;
		const normalsTemp = frames[ 0 ].normals;

		for ( let i = 0, l = vertexIndices.length; i < l; i ++ ) {

			const vertexIndex = vertexIndices[ i ];
			let stride = vertexIndex * 3;

			//

			const x = verticesTemp[ stride ];
			const y = verticesTemp[ stride + 1 ];
			const z = verticesTemp[ stride + 2 ];

			positions.push( x, y, z );

			//

			const nx = normalsTemp[ stride ];
			const ny = normalsTemp[ stride + 1 ];
			const nz = normalsTemp[ stride + 2 ];

			normals.push( nx, ny, nz );

			//

			const uvIndex = uvIndices[ i ];
			stride = uvIndex * 2;

			const u = uvsTemp[ stride ];
			const v = uvsTemp[ stride + 1 ];

			uvs.push( u, v );

		}

		geometry.setAttribute( 'position', new Float32BufferAttribute( positions, 3 ) );
		geometry.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );
		geometry.setAttribute( 'uv', new Float32BufferAttribute( uvs, 2 ) );

		// animation

		const morphPositions = [];
		const morphNormals = [];

		for ( let i = 0, l = frames.length; i < l; i ++ ) {

			const frame = frames[ i ];
			const attributeName = frame.name;

			if ( frame.vertices.length > 0 ) {

				const positions = [];

				for ( let j = 0, jl = vertexIndices.length; j < jl; j ++ ) {

					const vertexIndex = vertexIndices[ j ];
					const stride = vertexIndex * 3;

					const x = frame.vertices[ stride ];
					const y = frame.vertices[ stride + 1 ];
					const z = frame.vertices[ stride + 2 ];

					positions.push( x, y, z );

				}

				const positionAttribute = new Float32BufferAttribute( positions, 3 );
				positionAttribute.name = attributeName;

				morphPositions.push( positionAttribute );

			}

			if ( frame.normals.length > 0 ) {

				const normals = [];

				for ( let j = 0, jl = vertexIndices.length; j < jl; j ++ ) {

					const vertexIndex = vertexIndices[ j ];
					const stride = vertexIndex * 3;

					const nx = frame.normals[ stride ];
					const ny = frame.normals[ stride + 1 ];
					const nz = frame.normals[ stride + 2 ];

					normals.push( nx, ny, nz );

				}

				const normalAttribute = new Float32BufferAttribute( normals, 3 );
				normalAttribute.name = attributeName;

				morphNormals.push( normalAttribute );

			}

		}

		geometry.morphAttributes.position = morphPositions;
		geometry.morphAttributes.normal = morphNormals;
		geometry.morphTargetsRelative = false;

		geometry.animations = AnimationClip.CreateClipsFromMorphTargetSequences( frames, 10 );

		return geometry;

	}

}

export { MD2Loader };