/**
 * @author mrdoob / http://mrdoob.com/
 */

THREE.OBJLoader = ( function () {

	// o object_name | g group_name
	var object_pattern           = /^[og]\s*(.+)?/;
	// mtllib file_reference
	var material_library_pattern = /^mtllib /;
	// usemtl material_name
	var material_use_pattern     = /^usemtl /;

	function ParserState() {

		var state = {
			objects  : [],
			object   : {},

			vertices : [],
			normals  : [],
			uvs      : [],

			materialLibraries : [],

			startObject: function ( name, fromDeclaration ) {

				// If the current object (initial from reset) is not from a g/o declaration in the parsed
				// file. We need to use it for the first parsed g/o to keep things in sync.
				if ( this.object && this.object.fromDeclaration === false ) {

					this.object.name = name;
					this.object.fromDeclaration = ( fromDeclaration !== false );
					return;

				}

				var previousMaterial = ( this.object && typeof this.object.currentMaterial === 'function' ? this.object.currentMaterial() : undefined );

				if ( this.object && typeof this.object._finalize === 'function' ) {

					this.object._finalize( true );

				}

				this.object = {
					name : name || '',
					fromDeclaration : ( fromDeclaration !== false ),

					geometry : {
						vertices : [],
						normals  : [],
						uvs      : []
					},
					materials : [],
					smooth : true,

					startMaterial: function ( name, libraries ) {

						var previous = this._finalize( false );

						// New usemtl declaration overwrites an inherited material, except if faces were declared
						// after the material, then it must be preserved for proper MultiMaterial continuation.
						if ( previous && ( previous.inherited || previous.groupCount <= 0 ) ) {

							this.materials.splice( previous.index, 1 );

						}

						var material = {
							index      : this.materials.length,
							name       : name || '',
							mtllib     : ( Array.isArray( libraries ) && libraries.length > 0 ? libraries[ libraries.length - 1 ] : '' ),
							smooth     : ( previous !== undefined ? previous.smooth : this.smooth ),
							groupStart : ( previous !== undefined ? previous.groupEnd : 0 ),
							groupEnd   : -1,
							groupCount : -1,
							inherited  : false,

							clone: function ( index ) {
								var cloned = {
									index      : ( typeof index === 'number' ? index : this.index ),
									name       : this.name,
									mtllib     : this.mtllib,
									smooth     : this.smooth,
									groupStart : 0,
									groupEnd   : -1,
									groupCount : -1,
									inherited  : false
								};
								cloned.clone = this.clone.bind(cloned);
								return cloned;
							}
						};

						this.materials.push( material );

						return material;

					},

					currentMaterial: function () {

						if ( this.materials.length > 0 ) {
							return this.materials[ this.materials.length - 1 ];
						}

						return undefined;

					},

					_finalize: function ( end ) {

						var lastMultiMaterial = this.currentMaterial();
						if ( lastMultiMaterial && lastMultiMaterial.groupEnd === -1 ) {

							lastMultiMaterial.groupEnd = this.geometry.vertices.length / 3;
							lastMultiMaterial.groupCount = lastMultiMaterial.groupEnd - lastMultiMaterial.groupStart;
							lastMultiMaterial.inherited = false;

						}

						// Ignore objects tail materials if no face declarations followed them before a new o/g started.
						if ( end && this.materials.length > 1 ) {

							for ( var mi = this.materials.length - 1; mi >= 0; mi-- ) {
								if ( this.materials[ mi ].groupCount <= 0 ) {
									this.materials.splice( mi, 1 );
								}
							}

						}

						// Guarantee at least one empty material, this makes the creation later more straight forward.
						if ( end && this.materials.length === 0 ) {

							this.materials.push({
								name   : '',
								smooth : this.smooth
							});

						}

						return lastMultiMaterial;

					}
				};

				// Inherit previous objects material.
				// Spec tells us that a declared material must be set to all objects until a new material is declared.
				// If a usemtl declaration is encountered while this new object is being parsed, it will
				// overwrite the inherited material. Exception being that there was already face declarations
				// to the inherited material, then it will be preserved for proper MultiMaterial continuation.

				if ( previousMaterial && previousMaterial.name && typeof previousMaterial.clone === 'function' ) {

					var declared = previousMaterial.clone( 0 );
					declared.inherited = true;
					this.object.materials.push( declared );

				}

				this.objects.push( this.object );

			},

			finalize: function () {

				if ( this.object && typeof this.object._finalize === 'function' ) {

					this.object._finalize( true );

				}

			},

			parseVertexIndex: function ( value, len ) {

				var index = parseInt( value, 10 );
				return ( index >= 0 ? index - 1 : index + len / 3 ) * 3;

			},

			parseNormalIndex: function ( value, len ) {

				var index = parseInt( value, 10 );
				return ( index >= 0 ? index - 1 : index + len / 3 ) * 3;

			},

			parseUVIndex: function ( value, len ) {

				var index = parseInt( value, 10 );
				return ( index >= 0 ? index - 1 : index + len / 2 ) * 2;

			},

			addVertex: function ( a, b, c ) {

				var src = this.vertices;
				var dst = this.object.geometry.vertices;

				dst.push( src[ a + 0 ], src[ a + 1 ], src[ a + 2 ] );
				dst.push( src[ b + 0 ], src[ b + 1 ], src[ b + 2 ] );
				dst.push( src[ c + 0 ], src[ c + 1 ], src[ c + 2 ] );

			},

			addVertexLine: function ( a ) {

				var src = this.vertices;
				var dst = this.object.geometry.vertices;

				dst.push( src[ a + 0 ], src[ a + 1 ], src[ a + 2 ] );

			},

			addNormal: function ( a, b, c ) {

				var src = this.normals;
				var dst = this.object.geometry.normals;

				dst.push( src[ a + 0 ], src[ a + 1 ], src[ a + 2 ] );
				dst.push( src[ b + 0 ], src[ b + 1 ], src[ b + 2 ] );
				dst.push( src[ c + 0 ], src[ c + 1 ], src[ c + 2 ] );

			},

			addUV: function ( a, b, c ) {

				var src = this.uvs;
				var dst = this.object.geometry.uvs;

				dst.push( src[ a + 0 ], src[ a + 1 ] );
				dst.push( src[ b + 0 ], src[ b + 1 ] );
				dst.push( src[ c + 0 ], src[ c + 1 ] );

			},

			addUVLine: function ( a ) {

				var src = this.uvs;
				var dst = this.object.geometry.uvs;

				dst.push( src[ a + 0 ], src[ a + 1 ] );

			},

			addFace: function ( a, b, c, ua, ub, uc, na, nb, nc ) {

				var vLen = this.vertices.length;

				var ia = this.parseVertexIndex( a, vLen );
				var ib = this.parseVertexIndex( b, vLen );
				var ic = this.parseVertexIndex( c, vLen );

				this.addVertex( ia, ib, ic );

				if ( ua !== undefined ) {

					var uvLen = this.uvs.length;

					ia = this.parseUVIndex( ua, uvLen );
					ib = this.parseUVIndex( ub, uvLen );
					ic = this.parseUVIndex( uc, uvLen );

					this.addUV( ia, ib, ic );

				}

				if ( na !== undefined ) {

					// Normals are many times the same. If so, skip function call and parseInt.
					var nLen = this.normals.length;
					ia = this.parseNormalIndex( na, nLen );

					ib = na === nb ? ia : this.parseNormalIndex( nb, nLen );
					ic = na === nc ? ia : this.parseNormalIndex( nc, nLen );

					this.addNormal( ia, ib, ic );

				}

			},

			addLineGeometry: function ( vertices, uvs ) {

				this.object.geometry.type = 'Line';

				var vLen = this.vertices.length;
				var uvLen = this.uvs.length;

				for ( var vi = 0, l = vertices.length; vi < l; vi ++ ) {

					this.addVertexLine( this.parseVertexIndex( vertices[ vi ], vLen ) );

				}

				for ( var uvi = 0, l = uvs.length; uvi < l; uvi ++ ) {

					this.addUVLine( this.parseUVIndex( uvs[ uvi ], uvLen ) );

				}

			}

		};

		state.startObject( '', false );

		return state;

	}

	//

	function OBJLoader( manager ) {

		this.manager = ( manager !== undefined ) ? manager : THREE.DefaultLoadingManager;

		this.materials = null;

	};

	OBJLoader.prototype = {

		constructor: OBJLoader,

		load: function ( url, onLoad, onProgress, onError ) {

			var scope = this;

			var loader = new THREE.FileLoader( scope.manager );
			loader.setPath( this.path );
			loader.load( url, function ( text ) {

				onLoad( scope.parse( text ) );

			}, onProgress, onError );

		},

		setPath: function ( value ) {

			this.path = value;

		},

		setMaterials: function ( materials ) {

			this.materials = materials;

			return this;

		},

		parse: function ( text ) {

			console.time( 'OBJLoader' );

			var state = new ParserState();

			if ( text.indexOf( '\r\n' ) !== - 1 ) {

				// This is faster than String.split with regex that splits on both
				text = text.replace( /\r\n/g, '\n' );

			}

			if ( text.indexOf( '\\\n' ) !== - 1) {

				// join lines separated by a line continuation character (\)
				text = text.replace( /\\\n/g, '' );

			}

			var lines = text.split( '\n' );
			var line = '', lineFirstChar = '';
			var lineLength = 0;
			var result = [];

			// Faster to just trim left side of the line. Use if available.
			var trimLeft = ( typeof ''.trimLeft === 'function' );

			for ( var i = 0, l = lines.length; i < l; i ++ ) {

				line = lines[ i ];

				line = trimLeft ? line.trimLeft() : line.trim();

				lineLength = line.length;

				if ( lineLength === 0 ) continue;

				lineFirstChar = line.charAt( 0 );

				// @todo invoke passed in handler if any
				if ( lineFirstChar === '#' ) continue;

				if ( lineFirstChar === 'v' ) {

					var data = line.split( /\s+/ );

					switch ( data[ 0 ] ) {

						case 'v':
							state.vertices.push(
								parseFloat( data[ 1 ] ),
								parseFloat( data[ 2 ] ),
								parseFloat( data[ 3 ] )
							);
							break;
						case 'vn':
							state.normals.push(
								parseFloat( data[ 1 ] ),
								parseFloat( data[ 2 ] ),
								parseFloat( data[ 3 ] )
							);
							break;
						case 'vt':
							state.uvs.push(
								parseFloat( data[ 1 ] ),
								parseFloat( data[ 2 ] )
							);
							break;
					}

				} else if ( lineFirstChar === 'f' ) {

					var lineData = line.substr( 1 ).trim();
					var vertexData = lineData.split( /\s+/ );
					var faceVertices = [];

					// Parse the face vertex data into an easy to work with format

					for ( var j = 0, jl = vertexData.length; j < jl; j ++ ) {

						var vertex = vertexData[ j ];

						if ( vertex.length > 0 ) {

							var vertexParts = vertex.split( '/' );
							faceVertices.push( vertexParts );

						}

					}

					// Draw an edge between the first vertex and all subsequent vertices to form an n-gon

					var v1 = faceVertices[ 0 ];

					for ( var j = 1, jl = faceVertices.length - 1; j < jl; j ++ ) {

						var v2 = faceVertices[ j ];
						var v3 = faceVertices[ j + 1 ];

						state.addFace(
							v1[ 0 ], v2[ 0 ], v3[ 0 ],
							v1[ 1 ], v2[ 1 ], v3[ 1 ],
							v1[ 2 ], v2[ 2 ], v3[ 2 ]
						);

					}

				} else if ( lineFirstChar === 'l' ) {

					var lineParts = line.substring( 1 ).trim().split( " " );
					var lineVertices = [], lineUVs = [];

					if ( line.indexOf( "/" ) === - 1 ) {

						lineVertices = lineParts;

					} else {

						for ( var li = 0, llen = lineParts.length; li < llen; li ++ ) {

							var parts = lineParts[ li ].split( "/" );

							if ( parts[ 0 ] !== "" ) lineVertices.push( parts[ 0 ] );
							if ( parts[ 1 ] !== "" ) lineUVs.push( parts[ 1 ] );

						}

					}
					state.addLineGeometry( lineVertices, lineUVs );

				} else if ( ( result = object_pattern.exec( line ) ) !== null ) {

					// o object_name
					// or
					// g group_name

					// WORKAROUND: https://bugs.chromium.org/p/v8/issues/detail?id=2869
					// var name = result[ 0 ].substr( 1 ).trim();
					var name = ( " " + result[ 0 ].substr( 1 ).trim() ).substr( 1 );

					state.startObject( name );

				} else if ( material_use_pattern.test( line ) ) {

					// material

					state.object.startMaterial( line.substring( 7 ).trim(), state.materialLibraries );

				} else if ( material_library_pattern.test( line ) ) {

					// mtl file

					state.materialLibraries.push( line.substring( 7 ).trim() );

				} else if ( lineFirstChar === 's' ) {

					result = line.split( ' ' );

					// smooth shading

					// @todo Handle files that have varying smooth values for a set of faces inside one geometry,
					// but does not define a usemtl for each face set.
					// This should be detected and a dummy material created (later MultiMaterial and geometry groups).
					// This requires some care to not create extra material on each smooth value for "normal" obj files.
					// where explicit usemtl defines geometry groups.
					// Example asset: examples/models/obj/cerberus/Cerberus.obj

					/*
					 * http://paulbourke.net/dataformats/obj/
					 * or
					 * http://www.cs.utah.edu/~boulos/cs3505/obj_spec.pdf
					 *
					 * From chapter "Grouping" Syntax explanation "s group_number":
					 * "group_number is the smoothing group number. To turn off smoothing groups, use a value of 0 or off.
					 * Polygonal elements use group numbers to put elements in different smoothing groups. For free-form
					 * surfaces, smoothing groups are either turned on or off; there is no difference between values greater
					 * than 0."
					 */
					if ( result.length > 1 ) {

						var value = result[ 1 ].trim().toLowerCase();
						state.object.smooth = ( value !== '0' && value !== 'off' );

					} else {

						// ZBrush can produce "s" lines #11707
						state.object.smooth = true;

					}
					var material = state.object.currentMaterial();
					if ( material ) material.smooth = state.object.smooth;

				} else {

					// Handle null terminated files without exception
					if ( line === '\0' ) continue;

					throw new Error( "Unexpected line: '" + line  + "'" );

				}

			}

			state.finalize();

			var container = new THREE.Group();
			container.materialLibraries = [].concat( state.materialLibraries );

			for ( var i = 0, l = state.objects.length; i < l; i ++ ) {

				var object = state.objects[ i ];
				var geometry = object.geometry;
				var materials = object.materials;
				var isLine = ( geometry.type === 'Line' );

				// Skip o/g line declarations that did not follow with any faces
				if ( geometry.vertices.length === 0 ) continue;

				var buffergeometry = new THREE.BufferGeometry();

				buffergeometry.addAttribute( 'position', new THREE.BufferAttribute( new Float32Array( geometry.vertices ), 3 ) );

				if ( geometry.normals.length > 0 ) {

					buffergeometry.addAttribute( 'normal', new THREE.BufferAttribute( new Float32Array( geometry.normals ), 3 ) );

				} else {

					buffergeometry.computeVertexNormals();

				}

				if ( geometry.uvs.length > 0 ) {

					buffergeometry.addAttribute( 'uv', new THREE.BufferAttribute( new Float32Array( geometry.uvs ), 2 ) );

				}

				// Create materials

				var createdMaterials = [];

				for ( var mi = 0, miLen = materials.length; mi < miLen ; mi++ ) {

					var sourceMaterial = materials[ mi ];
					var material = undefined;

					if ( this.materials !== null ) {

						material = this.materials.create( sourceMaterial.name );

						// mtl etc. loaders probably can't create line materials correctly, copy properties to a line material.
						if ( isLine && material && ! ( material instanceof THREE.LineBasicMaterial ) ) {

							var materialLine = new THREE.LineBasicMaterial();
							materialLine.copy( material );
							material = materialLine;

						}

					}

					if ( ! material ) {

						material = ( ! isLine ? new THREE.MeshPhongMaterial() : new THREE.LineBasicMaterial() );
						material.name = sourceMaterial.name;

					}

					material.flatShading = sourceMaterial.smooth ? false : true;

					createdMaterials.push(material);

				}

				// Create mesh

				var mesh;

				if ( createdMaterials.length > 1 ) {

					for ( var mi = 0, miLen = materials.length; mi < miLen ; mi++ ) {

						var sourceMaterial = materials[ mi ];
						buffergeometry.addGroup( sourceMaterial.groupStart, sourceMaterial.groupCount, mi );

					}

					mesh = ( ! isLine ? new THREE.Mesh( buffergeometry, createdMaterials ) : new THREE.LineSegments( buffergeometry, createdMaterials ) );

				} else {

					mesh = ( ! isLine ? new THREE.Mesh( buffergeometry, createdMaterials[ 0 ] ) : new THREE.LineSegments( buffergeometry, createdMaterials[ 0 ] ) );
				}

				mesh.name = object.name;

				container.add( mesh );

			}

			console.timeEnd( 'OBJLoader' );

			return container;

		}

	};

	return OBJLoader;

} )();