/**
 * @author WestLangley / http://github.com/WestLangley
 *
 */

THREE.LineSegmentsGeometry = function () {

	THREE.InstancedBufferGeometry.call( this );

	this.type = 'LineSegmentsGeometry';

	var positions = [ - 1, 2, 0, 1, 2, 0, - 1, 1, 0, 1, 1, 0, - 1, 0, 0, 1, 0, 0, - 1, - 1, 0, 1, - 1, 0 ];
	var uvs = [ - 1, 2, 1, 2, - 1, 1, 1, 1, - 1, - 1, 1, - 1, - 1, - 2, 1, - 2 ];
	var index = [ 0, 2, 1, 2, 3, 1, 2, 4, 3, 4, 5, 3, 4, 6, 5, 6, 7, 5 ];

	this.setIndex( index );
	this.setAttribute( 'position', new THREE.Float32BufferAttribute( positions, 3 ) );
	this.setAttribute( 'uv', new THREE.Float32BufferAttribute( uvs, 2 ) );

};

THREE.LineSegmentsGeometry.prototype = Object.assign( Object.create( THREE.InstancedBufferGeometry.prototype ), {

	constructor: THREE.LineSegmentsGeometry,

	isLineSegmentsGeometry: true,

	applyMatrix: function ( matrix ) {

		var start = this.attributes.instanceStart;
		var end = this.attributes.instanceEnd;

		if ( start !== undefined ) {

			matrix.applyToBufferAttribute( start );

			matrix.applyToBufferAttribute( end );

			start.data.needsUpdate = true;

		}

		if ( this.boundingBox !== null ) {

			this.computeBoundingBox();

		}

		if ( this.boundingSphere !== null ) {

			this.computeBoundingSphere();

		}

		return this;

	},

	setPositions: function ( array ) {

		var lineSegments;

		if ( array instanceof Float32Array ) {

			lineSegments = array;

		} else if ( Array.isArray( array ) ) {

			lineSegments = new Float32Array( array );

		}

		var instanceBuffer = new THREE.InstancedInterleavedBuffer( lineSegments, 6, 1 ); // xyz, xyz

		this.setAttribute( 'instanceStart', new THREE.InterleavedBufferAttribute( instanceBuffer, 3, 0 ) ); // xyz
		this.setAttribute( 'instanceEnd', new THREE.InterleavedBufferAttribute( instanceBuffer, 3, 3 ) ); // xyz

		//

		this.computeBoundingBox();
		this.computeBoundingSphere();

		return this;

	},

	setColors: function ( array ) {

		var colors;

		if ( array instanceof Float32Array ) {

			colors = array;

		} else if ( Array.isArray( array ) ) {

			colors = new Float32Array( array );

		}

		var instanceColorBuffer = new THREE.InstancedInterleavedBuffer( colors, 6, 1 ); // rgb, rgb

		this.setAttribute( 'instanceColorStart', new THREE.InterleavedBufferAttribute( instanceColorBuffer, 3, 0 ) ); // rgb
		this.setAttribute( 'instanceColorEnd', new THREE.InterleavedBufferAttribute( instanceColorBuffer, 3, 3 ) ); // rgb

		return this;

	},

	fromWireframeGeometry: function ( geometry ) {

		this.setPositions( geometry.attributes.position.array );

		return this;

	},

	fromEdgesGeometry: function ( geometry ) {

		this.setPositions( geometry.attributes.position.array );

		return this;

	},

	fromMesh: function ( mesh ) {

		this.fromWireframeGeometry( new THREE.WireframeGeometry( mesh.geometry ) );

		// set colors, maybe

		return this;

	},

	fromLineSegements: function ( lineSegments ) {

		var geometry = lineSegments.geometry;

		if ( geometry.isGeometry ) {

			this.setPositions( geometry.vertices );

		} else if ( geometry.isBufferGeometry ) {

			this.setPositions( geometry.position.array ); // assumes non-indexed

		}

		// set colors, maybe

		return this;

	},

	computeBoundingBox: function () {

		var box = new THREE.Box3();

		return function computeBoundingBox() {

			if ( this.boundingBox === null ) {

				this.boundingBox = new THREE.Box3();

			}

			var start = this.attributes.instanceStart;
			var end = this.attributes.instanceEnd;

			if ( start !== undefined && end !== undefined ) {

				this.boundingBox.setFromBufferAttribute( start );

				box.setFromBufferAttribute( end );

				this.boundingBox.union( box );

			}

		};

	}(),

	computeBoundingSphere: function () {

		var vector = new THREE.Vector3();

		return function computeBoundingSphere() {

			if ( this.boundingSphere === null ) {

				this.boundingSphere = new THREE.Sphere();

			}

			if ( this.boundingBox === null ) {

				this.computeBoundingBox();

			}

			var start = this.attributes.instanceStart;
			var end = this.attributes.instanceEnd;

			if ( start !== undefined && end !== undefined ) {

				var center = this.boundingSphere.center;

				this.boundingBox.getCenter( center );

				var maxRadiusSq = 0;

				for ( var i = 0, il = start.count; i < il; i ++ ) {

					vector.fromBufferAttribute( start, i );
					maxRadiusSq = Math.max( maxRadiusSq, center.distanceToSquared( vector ) );

					vector.fromBufferAttribute( end, i );
					maxRadiusSq = Math.max( maxRadiusSq, center.distanceToSquared( vector ) );

				}

				this.boundingSphere.radius = Math.sqrt( maxRadiusSq );

				if ( isNaN( this.boundingSphere.radius ) ) {

					console.error( 'THREE.LineSegmentsGeometry.computeBoundingSphere(): Computed radius is NaN. The instanced position data is likely to have NaN values.', this );

				}

			}

		};

	}(),

	toJSON: function () {

		// todo

	},

	clone: function () {

		// todo

	},

	copy: function ( /* source */ ) {

		// todo

		return this;

	}

} );


/**
 * @author WestLangley / http://github.com/WestLangley
 *
 */

THREE.LineSegments2 = function ( geometry, material ) {

	THREE.Mesh.call( this );

	this.type = 'LineSegments2';

	this.geometry = geometry !== undefined ? geometry : new THREE.LineSegmentsGeometry();
	this.material = material !== undefined ? material : new THREE.LineMaterial( { color: Math.random() * 0xffffff } );

};

THREE.LineSegments2.prototype = Object.assign( Object.create( THREE.Mesh.prototype ), {

	constructor: THREE.LineSegments2,

	isLineSegments2: true,

	computeLineDistances: ( function () { // for backwards-compatability, but could be a method of LineSegmentsGeometry...

		var start = new THREE.Vector3();
		var end = new THREE.Vector3();

		return function computeLineDistances() {

			var geometry = this.geometry;

			var instanceStart = geometry.attributes.instanceStart;
			var instanceEnd = geometry.attributes.instanceEnd;
			var lineDistances = new Float32Array( 2 * instanceStart.data.count );

			for ( var i = 0, j = 0, l = instanceStart.data.count; i < l; i ++, j += 2 ) {

				start.fromBufferAttribute( instanceStart, i );
				end.fromBufferAttribute( instanceEnd, i );

				lineDistances[ j ] = ( j === 0 ) ? 0 : lineDistances[ j - 1 ];
				lineDistances[ j + 1 ] = lineDistances[ j ] + start.distanceTo( end );

			}

			var instanceDistanceBuffer = new THREE.InstancedInterleavedBuffer( lineDistances, 2, 1 ); // d0, d1

			geometry.setAttribute( 'instanceDistanceStart', new THREE.InterleavedBufferAttribute( instanceDistanceBuffer, 1, 0 ) ); // d0
			geometry.setAttribute( 'instanceDistanceEnd', new THREE.InterleavedBufferAttribute( instanceDistanceBuffer, 1, 1 ) ); // d1

			return this;

		};

	}() ),

	copy: function ( /* source */ ) {

		// todo

		return this;

	}

} );


/**
 * @author WestLangley / http://github.com/WestLangley
 *
 * parameters = {
 *  color: <hex>,
 *  linewidth: <float>,
 *  dashed: <boolean>,
 *  dashScale: <float>,
 *  dashSize: <float>,
 *  gapSize: <float>,
 *  resolution: <Vector2>, // to be set by renderer
 * }
 */

THREE.UniformsLib.line = {

	linewidth: { value: 1 },
	resolution: { value: new THREE.Vector2( 1, 1 ) },
	dashScale: { value: 1 },
	dashSize: { value: 1 },
	gapSize: { value: 1 } // todo FIX - maybe change to totalSize

};

THREE.ShaderLib[ 'line' ] = {

	uniforms: THREE.UniformsUtils.merge( [
		THREE.UniformsLib.common,
		THREE.UniformsLib.fog,
		THREE.UniformsLib.line
	] ),

	vertexShader:
		`
		#include <common>
		#include <color_pars_vertex>
		#include <fog_pars_vertex>
		#include <logdepthbuf_pars_vertex>
		#include <clipping_planes_pars_vertex>

		uniform float linewidth;
		uniform vec2 resolution;

		attribute vec3 instanceStart;
		attribute vec3 instanceEnd;

		attribute vec3 instanceColorStart;
		attribute vec3 instanceColorEnd;

		varying vec2 vUv;

		#ifdef USE_DASH

			uniform float dashScale;
			attribute float instanceDistanceStart;
			attribute float instanceDistanceEnd;
			varying float vLineDistance;

		#endif

		void trimSegment( const in vec4 start, inout vec4 end ) {

			// trim end segment so it terminates between the camera plane and the near plane

			// conservative estimate of the near plane
			float a = projectionMatrix[ 2 ][ 2 ]; // 3nd entry in 3th column
			float b = projectionMatrix[ 3 ][ 2 ]; // 3nd entry in 4th column
			float nearEstimate = - 0.5 * b / a;

			float alpha = ( nearEstimate - start.z ) / ( end.z - start.z );

			end.xyz = mix( start.xyz, end.xyz, alpha );

		}

		void main() {

			#ifdef USE_COLOR

				vColor.xyz = ( position.y < 0.5 ) ? instanceColorStart : instanceColorEnd;

			#endif

			#ifdef USE_DASH

				vLineDistance = ( position.y < 0.5 ) ? dashScale * instanceDistanceStart : dashScale * instanceDistanceEnd;

			#endif

			float aspect = resolution.x / resolution.y;

			vUv = uv;

			// camera space
			vec4 start = modelViewMatrix * vec4( instanceStart, 1.0 );
			vec4 end = modelViewMatrix * vec4( instanceEnd, 1.0 );

			// special case for perspective projection, and segments that terminate either in, or behind, the camera plane
			// clearly the gpu firmware has a way of addressing this issue when projecting into ndc space
			// but we need to perform ndc-space calculations in the shader, so we must address this issue directly
			// perhaps there is a more elegant solution -- WestLangley

			bool perspective = ( projectionMatrix[ 2 ][ 3 ] == - 1.0 ); // 4th entry in the 3rd column

			if ( perspective ) {

				if ( start.z < 0.0 && end.z >= 0.0 ) {

					trimSegment( start, end );

				} else if ( end.z < 0.0 && start.z >= 0.0 ) {

					trimSegment( end, start );

				}

			}

			// clip space
			vec4 clipStart = projectionMatrix * start;
			vec4 clipEnd = projectionMatrix * end;

			// ndc space
			vec2 ndcStart = clipStart.xy / clipStart.w;
			vec2 ndcEnd = clipEnd.xy / clipEnd.w;

			// direction
			vec2 dir = ndcEnd - ndcStart;

			// account for clip-space aspect ratio
			dir.x *= aspect;
			dir = normalize( dir );

			// perpendicular to dir
			vec2 offset = vec2( dir.y, - dir.x );

			// undo aspect ratio adjustment
			dir.x /= aspect;
			offset.x /= aspect;

			// sign flip
			if ( position.x < 0.0 ) offset *= - 1.0;

			// endcaps
			if ( position.y < 0.0 ) {

				offset += - dir;

			} else if ( position.y > 1.0 ) {

				offset += dir;

			}

			// adjust for linewidth
			offset *= linewidth;

			// adjust for clip-space to screen-space conversion // maybe resolution should be based on viewport ...
			offset /= resolution.y;

			// select end
			vec4 clip = ( position.y < 0.5 ) ? clipStart : clipEnd;

			// back to clip space
			offset *= clip.w;

			clip.xy += offset;

			gl_Position = clip;

			vec4 mvPosition = ( position.y < 0.5 ) ? start : end; // this is an approximation

			#include <logdepthbuf_vertex>
			#include <clipping_planes_vertex>
			#include <fog_vertex>

		}
		`,

	fragmentShader:
		`
		uniform vec3 diffuse;
		uniform float opacity;

		#ifdef USE_DASH

			uniform float dashSize;
			uniform float gapSize;

		#endif

		varying float vLineDistance;

		#include <common>
		#include <color_pars_fragment>
		#include <fog_pars_fragment>
		#include <logdepthbuf_pars_fragment>
		#include <clipping_planes_pars_fragment>

		varying vec2 vUv;

		void main() {

			#include <clipping_planes_fragment>

			#ifdef USE_DASH

				if ( vUv.y < - 1.0 || vUv.y > 1.0 ) discard; // discard endcaps

				if ( mod( vLineDistance, dashSize + gapSize ) > dashSize ) discard; // todo - FIX

			#endif

			if ( abs( vUv.y ) > 1.0 ) {

				float a = vUv.x;
				float b = ( vUv.y > 0.0 ) ? vUv.y - 1.0 : vUv.y + 1.0;
				float len2 = a * a + b * b;

				if ( len2 > 1.0 ) discard;

			}

			vec4 diffuseColor = vec4( diffuse, opacity );

			#include <logdepthbuf_fragment>
			#include <color_fragment>

			gl_FragColor = vec4( diffuseColor.rgb, diffuseColor.a );

			#include <premultiplied_alpha_fragment>
			#include <tonemapping_fragment>
			#include <encodings_fragment>
			#include <fog_fragment>

		}
		`
};

THREE.LineMaterial = function ( parameters ) {

	THREE.ShaderMaterial.call( this, {

		type: 'LineMaterial',

		uniforms: THREE.UniformsUtils.clone( THREE.ShaderLib[ 'line' ].uniforms ),

		vertexShader: THREE.ShaderLib[ 'line' ].vertexShader,
		fragmentShader: THREE.ShaderLib[ 'line' ].fragmentShader

	} );

	this.dashed = false;

	Object.defineProperties( this, {

		color: {

			enumerable: true,

			get: function () {

				return this.uniforms.diffuse.value;

			},

			set: function ( value ) {

				this.uniforms.diffuse.value = value;

			}

		},

		linewidth: {

			enumerable: true,

			get: function () {

				return this.uniforms.linewidth.value;

			},

			set: function ( value ) {

				this.uniforms.linewidth.value = value;

			}

		},

		dashScale: {

			enumerable: true,

			get: function () {

				return this.uniforms.dashScale.value;

			},

			set: function ( value ) {

				this.uniforms.dashScale.value = value;

			}

		},

		dashSize: {

			enumerable: true,

			get: function () {

				return this.uniforms.dashSize.value;

			},

			set: function ( value ) {

				this.uniforms.dashSize.value = value;

			}

		},

		gapSize: {

			enumerable: true,

			get: function () {

				return this.uniforms.gapSize.value;

			},

			set: function ( value ) {

				this.uniforms.gapSize.value = value;

			}

		},

		resolution: {

			enumerable: true,

			get: function () {

				return this.uniforms.resolution.value;

			},

			set: function ( value ) {

				this.uniforms.resolution.value.copy( value );

			}

		}

	} );

	this.setValues( parameters );

};

THREE.LineMaterial.prototype = Object.create( THREE.ShaderMaterial.prototype );
THREE.LineMaterial.prototype.constructor = THREE.LineMaterial;

THREE.LineMaterial.prototype.isLineMaterial = true;

THREE.LineMaterial.prototype.copy = function ( source ) {

	THREE.ShaderMaterial.prototype.copy.call( this, source );

	this.color.copy( source.color );

	this.linewidth = source.linewidth;

	this.resolution = source.resolution;

	// todo

	return this;

};



/**
 * @author WestLangley / http://github.com/WestLangley
 *
 */

THREE.LineGeometry = function () {

	THREE.LineSegmentsGeometry.call( this );

	this.type = 'LineGeometry';

};

THREE.LineGeometry.prototype = Object.assign( Object.create( THREE.LineSegmentsGeometry.prototype ), {

	constructor: THREE.LineGeometry,

	isLineGeometry: true,

	setPositions: function ( array ) {

		// converts [ x1, y1, z1,  x2, y2, z2, ... ] to pairs format

		var length = array.length - 3;
		var points = new Float32Array( 2 * length );

		for ( var i = 0; i < length; i += 3 ) {

			points[ 2 * i ] = array[ i ];
			points[ 2 * i + 1 ] = array[ i + 1 ];
			points[ 2 * i + 2 ] = array[ i + 2 ];

			points[ 2 * i + 3 ] = array[ i + 3 ];
			points[ 2 * i + 4 ] = array[ i + 4 ];
			points[ 2 * i + 5 ] = array[ i + 5 ];

		}

		THREE.LineSegmentsGeometry.prototype.setPositions.call( this, points );

		return this;

	},

	setColors: function ( array ) {

		// converts [ r1, g1, b1,  r2, g2, b2, ... ] to pairs format

		var length = array.length - 3;
		var colors = new Float32Array( 2 * length );

		for ( var i = 0; i < length; i += 3 ) {

			colors[ 2 * i ] = array[ i ];
			colors[ 2 * i + 1 ] = array[ i + 1 ];
			colors[ 2 * i + 2 ] = array[ i + 2 ];

			colors[ 2 * i + 3 ] = array[ i + 3 ];
			colors[ 2 * i + 4 ] = array[ i + 4 ];
			colors[ 2 * i + 5 ] = array[ i + 5 ];

		}

		THREE.LineSegmentsGeometry.prototype.setColors.call( this, colors );

		return this;

	},

	fromLine: function ( line ) {

		var geometry = line.geometry;

		if ( geometry.isGeometry ) {

			this.setPositions( geometry.vertices );

		} else if ( geometry.isBufferGeometry ) {

			this.setPositions( geometry.position.array ); // assumes non-indexed

		}

		// set colors, maybe

		return this;

	},

	copy: function ( /* source */ ) {

		// todo

		return this;

	}

} );


/**
 * @author WestLangley / http://github.com/WestLangley
 *
 */

THREE.Line2 = function ( geometry, material ) {

	THREE.LineSegments2.call( this );

	this.type = 'Line2';

	this.geometry = geometry !== undefined ? geometry : new THREE.LineGeometry();
	this.material = material !== undefined ? material : new THREE.LineMaterial( { color: Math.random() * 0xffffff } );

};

THREE.Line2.prototype = Object.assign( Object.create( THREE.LineSegments2.prototype ), {

	constructor: THREE.Line2,

	isLine2: true,

	copy: function ( /* source */ ) {

		// todo

		return this;

	}

} );