/**
 * @author zz85 / http://www.lab4games.net/zz85/blog
 *
 * Creates extruded geometry from a path shape.
 *
 * parameters = {
 *
 *  curveSegments: <int>, // number of points on the curves
 *  steps: <int>, // number of points for z-side extrusions / used for subdividing segements of extrude spline too
 *  amount: <int>, // Depth to extrude the shape
 *
 *  bevelEnabled: <bool>, // turn on bevel
 *  bevelThickness: <float>, // how deep into the original shape bevel goes
 *  bevelSize: <float>, // how far from shape outline is bevel
 *  bevelSegments: <int>, // number of bevel layers
 *
 *  extrudePath: <THREE.CurvePath> // 3d spline path to extrude shape along. (creates Frames if .frames aren't defined)
 *  frames: <THREE.TubeGeometry.FrenetFrames> // containing arrays of tangents, normals, binormals
 *
 *  material: <int> // material index for front and back faces
 *  extrudeMaterial: <int> // material index for extrusion and beveled faces
 *  uvGenerator: <Object> // object that provides UV generator functions
 *
 * }
 **/

THREE.ExtrudeGeometry = function ( shapes, options ) {

	if ( typeof( shapes ) === "undefined" ) {
		shapes = [];
		return;
	}

	THREE.Geometry.call( this );

	this.type = 'ExtrudeGeometry';

	shapes = shapes instanceof Array ? shapes : [ shapes ];

	this.addShapeList( shapes, options );

	this.computeFaceNormals();

	// can't really use automatic vertex normals
	// as then front and back sides get smoothed too
	// should do separate smoothing just for sides

	//this.computeVertexNormals();

	//console.log( "took", ( Date.now() - startTime ) );

};

THREE.ExtrudeGeometry.prototype = Object.create( THREE.Geometry.prototype );
THREE.ExtrudeGeometry.prototype.constructor = THREE.ExtrudeGeometry;

THREE.ExtrudeGeometry.prototype.addShapeList = function ( shapes, options ) {
	var sl = shapes.length;

	for ( var s = 0; s < sl; s ++ ) {
		var shape = shapes[ s ];
		this.addShape( shape, options );
	}
};

THREE.ExtrudeGeometry.prototype.addShape = function ( shape, options ) {

	var amount = options.amount !== undefined ? options.amount : 100;

	var bevelThickness = options.bevelThickness !== undefined ? options.bevelThickness : 6; // 10
	var bevelSize = options.bevelSize !== undefined ? options.bevelSize : bevelThickness - 2; // 8
	var bevelSegments = options.bevelSegments !== undefined ? options.bevelSegments : 3;

	var bevelEnabled = options.bevelEnabled !== undefined ? options.bevelEnabled : true; // false

	var curveSegments = options.curveSegments !== undefined ? options.curveSegments : 12;

	var steps = options.steps !== undefined ? options.steps : 1;

	var extrudePath = options.extrudePath;
	var extrudePts, extrudeByPath = false;

	var material = options.material;
	var extrudeMaterial = options.extrudeMaterial;

	// Use default WorldUVGenerator if no UV generators are specified.
	var uvgen = options.UVGenerator !== undefined ? options.UVGenerator : THREE.ExtrudeGeometry.WorldUVGenerator;

	var splineTube, binormal, normal, position2;
	if ( extrudePath ) {

		extrudePts = extrudePath.getSpacedPoints( steps );

		extrudeByPath = true;
		bevelEnabled = false; // bevels not supported for path extrusion

		// SETUP TNB variables

		// Reuse TNB from TubeGeomtry for now.
		// TODO1 - have a .isClosed in spline?

		splineTube = options.frames !== undefined ? options.frames : new THREE.TubeGeometry.FrenetFrames(extrudePath, steps, false);

		// console.log(splineTube, 'splineTube', splineTube.normals.length, 'steps', steps, 'extrudePts', extrudePts.length);

		binormal = new THREE.Vector3();
		normal = new THREE.Vector3();
		position2 = new THREE.Vector3();

	}

	// Safeguards if bevels are not enabled

	if ( ! bevelEnabled ) {

		bevelSegments = 0;
		bevelThickness = 0;
		bevelSize = 0;

	}

	// Variables initalization

	var ahole, h, hl; // looping of holes
	var scope = this;

	var shapesOffset = this.vertices.length;

	var shapePoints = shape.extractPoints( curveSegments );

	var vertices = shapePoints.shape;
	var holes = shapePoints.holes;

	var reverse = ! THREE.Shape.Utils.isClockWise( vertices ) ;

	if ( reverse ) {

		vertices = vertices.reverse();

		// Maybe we should also check if holes are in the opposite direction, just to be safe ...

		for ( h = 0, hl = holes.length; h < hl; h ++ ) {

			ahole = holes[ h ];

			if ( THREE.Shape.Utils.isClockWise( ahole ) ) {

				holes[ h ] = ahole.reverse();

			}

		}

		reverse = false; // If vertices are in order now, we shouldn't need to worry about them again (hopefully)!

	}


	var faces = THREE.Shape.Utils.triangulateShape ( vertices, holes );

	/* Vertices */

	var contour = vertices; // vertices has all points but contour has only points of circumference

	for ( h = 0, hl = holes.length; h < hl; h ++ ) {

		ahole = holes[ h ];

		vertices = vertices.concat( ahole );

	}


	function scalePt2 ( pt, vec, size ) {

		if ( ! vec ) THREE.error( "THREE.ExtrudeGeometry: vec does not exist" );

		return vec.clone().multiplyScalar( size ).add( pt );

	}

	var b, bs, t, z,
		vert, vlen = vertices.length,
		face, flen = faces.length;


	// Find directions for point movement


	function getBevelVec( inPt, inPrev, inNext ) {

		var EPSILON = 0.0000000001;
		
		// computes for inPt the corresponding point inPt' on a new contour
		//   shiftet by 1 unit (length of normalized vector) to the left
		// if we walk along contour clockwise, this new contour is outside the old one
		//
		// inPt' is the intersection of the two lines parallel to the two
		//  adjacent edges of inPt at a distance of 1 unit on the left side.
		
		var v_trans_x, v_trans_y, shrink_by = 1;		// resulting translation vector for inPt

		// good reading for geometry algorithms (here: line-line intersection)
		// http://geomalgorithms.com/a05-_intersect-1.html

		var v_prev_x = inPt.x - inPrev.x, v_prev_y = inPt.y - inPrev.y;
		var v_next_x = inNext.x - inPt.x, v_next_y = inNext.y - inPt.y;
		
		var v_prev_lensq = ( v_prev_x * v_prev_x + v_prev_y * v_prev_y );
		
		// check for colinear edges
		var colinear0 = ( v_prev_x * v_next_y - v_prev_y * v_next_x );
		
		if ( Math.abs( colinear0 ) > EPSILON ) {		// not colinear
			
			// length of vectors for normalizing
	
			var v_prev_len = Math.sqrt( v_prev_lensq );
			var v_next_len = Math.sqrt( v_next_x * v_next_x + v_next_y * v_next_y );
			
			// shift adjacent points by unit vectors to the left
	
			var ptPrevShift_x = ( inPrev.x - v_prev_y / v_prev_len );
			var ptPrevShift_y = ( inPrev.y + v_prev_x / v_prev_len );
			
			var ptNextShift_x = ( inNext.x - v_next_y / v_next_len );
			var ptNextShift_y = ( inNext.y + v_next_x / v_next_len );
	
			// scaling factor for v_prev to intersection point
	
			var sf = (  ( ptNextShift_x - ptPrevShift_x ) * v_next_y -
						( ptNextShift_y - ptPrevShift_y ) * v_next_x    ) /
					  ( v_prev_x * v_next_y - v_prev_y * v_next_x );
	
			// vector from inPt to intersection point
	
			v_trans_x = ( ptPrevShift_x + v_prev_x * sf - inPt.x );
			v_trans_y = ( ptPrevShift_y + v_prev_y * sf - inPt.y );
	
			// Don't normalize!, otherwise sharp corners become ugly
			//  but prevent crazy spikes
			var v_trans_lensq = ( v_trans_x * v_trans_x + v_trans_y * v_trans_y )
			if ( v_trans_lensq <= 2 ) {
				return	new THREE.Vector2( v_trans_x, v_trans_y );
			} else {
				shrink_by = Math.sqrt( v_trans_lensq / 2 );
			}
			
		} else {		// handle special case of colinear edges

			var direction_eq = false;		// assumes: opposite
			if ( v_prev_x > EPSILON ) {
				if ( v_next_x > EPSILON ) { direction_eq = true; }
			} else {
				if ( v_prev_x < - EPSILON ) {
					if ( v_next_x < - EPSILON ) { direction_eq = true; }
				} else {
					if ( Math.sign(v_prev_y) == Math.sign(v_next_y) ) { direction_eq = true; }
				}
			}

			if ( direction_eq ) {
				// console.log("Warning: lines are a straight sequence");
				v_trans_x = - v_prev_y;
				v_trans_y =  v_prev_x;
				shrink_by = Math.sqrt( v_prev_lensq );
			} else {
				// console.log("Warning: lines are a straight spike");
				v_trans_x = v_prev_x;
				v_trans_y = v_prev_y;
				shrink_by = Math.sqrt( v_prev_lensq / 2 );
			}

		}

		return	new THREE.Vector2( v_trans_x / shrink_by, v_trans_y / shrink_by );

	}


	var contourMovements = [];

	for ( var i = 0, il = contour.length, j = il - 1, k = i + 1; i < il; i ++, j ++, k ++ ) {

		if ( j === il ) j = 0;
		if ( k === il ) k = 0;

		//  (j)---(i)---(k)
		// console.log('i,j,k', i, j , k)

		contourMovements[ i ] = getBevelVec( contour[ i ], contour[ j ], contour[ k ] );

	}

	var holesMovements = [], oneHoleMovements, verticesMovements = contourMovements.concat();

	for ( h = 0, hl = holes.length; h < hl; h ++ ) {

		ahole = holes[ h ];

		oneHoleMovements = [];

		for ( i = 0, il = ahole.length, j = il - 1, k = i + 1; i < il; i ++, j ++, k ++ ) {

			if ( j === il ) j = 0;
			if ( k === il ) k = 0;

			//  (j)---(i)---(k)
			oneHoleMovements[ i ] = getBevelVec( ahole[ i ], ahole[ j ], ahole[ k ] );

		}

		holesMovements.push( oneHoleMovements );
		verticesMovements = verticesMovements.concat( oneHoleMovements );

	}


	// Loop bevelSegments, 1 for the front, 1 for the back

	for ( b = 0; b < bevelSegments; b ++ ) {
	//for ( b = bevelSegments; b > 0; b -- ) {

		t = b / bevelSegments;
		z = bevelThickness * ( 1 - t );

		//z = bevelThickness * t;
		bs = bevelSize * ( Math.sin ( t * Math.PI / 2 ) ) ; // curved
		//bs = bevelSize * t ; // linear

		// contract shape

		for ( i = 0, il = contour.length; i < il; i ++ ) {

			vert = scalePt2( contour[ i ], contourMovements[ i ], bs );

			v( vert.x, vert.y,  - z );

		}

		// expand holes

		for ( h = 0, hl = holes.length; h < hl; h ++ ) {

			ahole = holes[ h ];
			oneHoleMovements = holesMovements[ h ];

			for ( i = 0, il = ahole.length; i < il; i ++ ) {

				vert = scalePt2( ahole[ i ], oneHoleMovements[ i ], bs );

				v( vert.x, vert.y,  - z );

			}

		}

	}

	bs = bevelSize;

	// Back facing vertices

	for ( i = 0; i < vlen; i ++ ) {

		vert = bevelEnabled ? scalePt2( vertices[ i ], verticesMovements[ i ], bs ) : vertices[ i ];

		if ( ! extrudeByPath ) {

			v( vert.x, vert.y, 0 );

		} else {

			// v( vert.x, vert.y + extrudePts[ 0 ].y, extrudePts[ 0 ].x );

			normal.copy( splineTube.normals[0] ).multiplyScalar(vert.x);
			binormal.copy( splineTube.binormals[0] ).multiplyScalar(vert.y);

			position2.copy( extrudePts[0] ).add(normal).add(binormal);

			v( position2.x, position2.y, position2.z );

		}

	}

	// Add stepped vertices...
	// Including front facing vertices

	var s;

	for ( s = 1; s <= steps; s ++ ) {

		for ( i = 0; i < vlen; i ++ ) {

			vert = bevelEnabled ? scalePt2( vertices[ i ], verticesMovements[ i ], bs ) : vertices[ i ];

			if ( ! extrudeByPath ) {

				v( vert.x, vert.y, amount / steps * s );

			} else {

				// v( vert.x, vert.y + extrudePts[ s - 1 ].y, extrudePts[ s - 1 ].x );

				normal.copy( splineTube.normals[s] ).multiplyScalar( vert.x );
				binormal.copy( splineTube.binormals[s] ).multiplyScalar( vert.y );

				position2.copy( extrudePts[s] ).add( normal ).add( binormal );

				v( position2.x, position2.y, position2.z );

			}

		}

	}


	// Add bevel segments planes

	//for ( b = 1; b <= bevelSegments; b ++ ) {
	for ( b = bevelSegments - 1; b >= 0; b -- ) {

		t = b / bevelSegments;
		z = bevelThickness * ( 1 - t );
		//bs = bevelSize * ( 1-Math.sin ( ( 1 - t ) * Math.PI/2 ) );
		bs = bevelSize * Math.sin ( t * Math.PI / 2 ) ;

		// contract shape

		for ( i = 0, il = contour.length; i < il; i ++ ) {

			vert = scalePt2( contour[ i ], contourMovements[ i ], bs );
			v( vert.x, vert.y,  amount + z );

		}

		// expand holes

		for ( h = 0, hl = holes.length; h < hl; h ++ ) {

			ahole = holes[ h ];
			oneHoleMovements = holesMovements[ h ];

			for ( i = 0, il = ahole.length; i < il; i ++ ) {

				vert = scalePt2( ahole[ i ], oneHoleMovements[ i ], bs );

				if ( ! extrudeByPath ) {

					v( vert.x, vert.y,  amount + z );

				} else {

					v( vert.x, vert.y + extrudePts[ steps - 1 ].y, extrudePts[ steps - 1 ].x + z );

				}

			}

		}

	}

	/* Faces */

	// Top and bottom faces

	buildLidFaces();

	// Sides faces

	buildSideFaces();


	/////  Internal functions

	function buildLidFaces() {

		if ( bevelEnabled ) {

			var layer = 0 ; // steps + 1
			var offset = vlen * layer;

			// Bottom faces

			for ( i = 0; i < flen; i ++ ) {

				face = faces[ i ];
				f3( face[ 2 ] + offset, face[ 1 ] + offset, face[ 0 ] + offset );

			}

			layer = steps + bevelSegments * 2;
			offset = vlen * layer;

			// Top faces

			for ( i = 0; i < flen; i ++ ) {

				face = faces[ i ];
				f3( face[ 0 ] + offset, face[ 1 ] + offset, face[ 2 ] + offset );

			}

		} else {

			// Bottom faces

			for ( i = 0; i < flen; i ++ ) {

				face = faces[ i ];
				f3( face[ 2 ], face[ 1 ], face[ 0 ] );

			}

			// Top faces

			for ( i = 0; i < flen; i ++ ) {

				face = faces[ i ];
				f3( face[ 0 ] + vlen * steps, face[ 1 ] + vlen * steps, face[ 2 ] + vlen * steps );

			}
		}

	}

	// Create faces for the z-sides of the shape

	function buildSideFaces() {

		var layeroffset = 0;
		sidewalls( contour, layeroffset );
		layeroffset += contour.length;

		for ( h = 0, hl = holes.length; h < hl; h ++ ) {

			ahole = holes[ h ];
			sidewalls( ahole, layeroffset );

			//, true
			layeroffset += ahole.length;

		}

	}

	function sidewalls( contour, layeroffset ) {

		var j, k;
		i = contour.length;

		while ( -- i >= 0 ) {

			j = i;
			k = i - 1;
			if ( k < 0 ) k = contour.length - 1;

			//console.log('b', i,j, i-1, k,vertices.length);

			var s = 0, sl = steps  + bevelSegments * 2;

			for ( s = 0; s < sl; s ++ ) {

				var slen1 = vlen * s;
				var slen2 = vlen * ( s + 1 );

				var a = layeroffset + j + slen1,
					b = layeroffset + k + slen1,
					c = layeroffset + k + slen2,
					d = layeroffset + j + slen2;

				f4( a, b, c, d, contour, s, sl, j, k );

			}
		}

	}


	function v( x, y, z ) {

		scope.vertices.push( new THREE.Vector3( x, y, z ) );

	}

	function f3( a, b, c ) {

		a += shapesOffset;
		b += shapesOffset;
		c += shapesOffset;

		// normal, color, material
		scope.faces.push( new THREE.Face3( a, b, c, null, null, material ) );

		var uvs = uvgen.generateTopUV( scope, a, b, c );

		scope.faceVertexUvs[ 0 ].push( uvs );

	}

	function f4( a, b, c, d, wallContour, stepIndex, stepsLength, contourIndex1, contourIndex2 ) {

		a += shapesOffset;
		b += shapesOffset;
		c += shapesOffset;
		d += shapesOffset;

		scope.faces.push( new THREE.Face3( a, b, d, null, null, extrudeMaterial ) );
		scope.faces.push( new THREE.Face3( b, c, d, null, null, extrudeMaterial ) );

		var uvs = uvgen.generateSideWallUV( scope, a, b, c, d );

		scope.faceVertexUvs[ 0 ].push( [ uvs[ 0 ], uvs[ 1 ], uvs[ 3 ] ] );
		scope.faceVertexUvs[ 0 ].push( [ uvs[ 1 ], uvs[ 2 ], uvs[ 3 ] ] );

	}

};

THREE.ExtrudeGeometry.WorldUVGenerator = {

	generateTopUV: function ( geometry, indexA, indexB, indexC ) {

		var vertices = geometry.vertices;

		var a = vertices[ indexA ];
		var b = vertices[ indexB ];
		var c = vertices[ indexC ];

		return [
			new THREE.Vector2( a.x, a.y ),
			new THREE.Vector2( b.x, b.y ),
			new THREE.Vector2( c.x, c.y )
		];

	},

	generateSideWallUV: function ( geometry, indexA, indexB, indexC, indexD ) {

		var vertices = geometry.vertices;

		var a = vertices[ indexA ];
		var b = vertices[ indexB ];
		var c = vertices[ indexC ];
		var d = vertices[ indexD ];

		if ( Math.abs( a.y - b.y ) < 0.01 ) {
			return [
				new THREE.Vector2( a.x, 1 - a.z ),
				new THREE.Vector2( b.x, 1 - b.z ),
				new THREE.Vector2( c.x, 1 - c.z ),
				new THREE.Vector2( d.x, 1 - d.z )
			];
		} else {
			return [
				new THREE.Vector2( a.y, 1 - a.z ),
				new THREE.Vector2( b.y, 1 - b.z ),
				new THREE.Vector2( c.y, 1 - c.z ),
				new THREE.Vector2( d.y, 1 - d.z )
			];
		}
	}
};