/**
 * parameters = {
 *  color: <hex>,
 *  lineWidth: <float>,
 *  dashed: <boolean>,
 *  dashScale: <float>,
 *  dashSize: <float>,
 *  dashOffset: <float>,
 *  gapSize: <float>,
 *  resolution: <Vector2>, // to be set by renderer
 * }
 */

import {
	ShaderLib,
	ShaderMaterial,
	UniformsLib,
	UniformsUtils,
	Vector2,
    Color
} from '../build/three.module.js';


UniformsLib.line = {
/* 
	worldUnits: { value: 1 },
	lineWidth: { value: 1 },
	resolution: { value: new Vector2( 1, 1 ) },
	dashOffset: { value: 0 },
	dashScale: { value: 1 },
	dashSize: { value: 1 },
	gapSize: { value: 1 } // todo FIX - maybe change to totalSize
 */
    worldUnits: { value: 1 },
	lineWidth: { value: 1 },
	resolution: { value: new Vector2( 1, 1 ) },
    viewportOffset: { value: new Vector2(0, 0 ) }, //left, top    
    devicePixelRatio:{ value:window.devicePixelRatio},
	dashScale: { value: 1 },
	dashSize: { value: 1 },
	dashOffset: { value: 0 },
	gapSize: { value: 1 }, 
	opacity: { value: 1 },
     
    backColor:     {type:'v3',   value: new Color("#ddd")},
    clipDistance :          { type: 'f', 	value:  4}, //消失距离
    occlusionDistance :     { type: 'f', 	value:  1 }, //变为backColor距离
    maxClipFactor :         { type: 'f', 	value:  1 },  //0-1
    
    
    
    depthTexture:{ value: null },
    nearPlane:{value: 0.1},
    farPlane:{value: 100000},

};

ShaderLib[ 'line' ] = {

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

	vertexShader:
	/* glsl */`
		#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;
        uniform float devicePixelRatio;  //add
        
        
		attribute vec3 instanceStart;
		attribute vec3 instanceEnd;

		attribute vec3 instanceColorStart;
		attribute vec3 instanceColorEnd;

		#ifdef WORLD_UNITS

			varying vec4 worldPos;
			varying vec3 worldStart;
			varying vec3 worldEnd;

			#ifdef USE_DASH

				varying vec2 vUv;

			#endif

		#else

			varying vec2 vUv;

		#endif

		#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;
				vUv = uv;

			#endif

			float aspect = resolution.x / resolution.y;

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

			#ifdef WORLD_UNITS

				worldStart = start.xyz;
				worldEnd = end.xyz;

			#else

				vUv = uv;

			#endif

			// 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
			vec3 ndcStart = clipStart.xyz / clipStart.w;
			vec3 ndcEnd = clipEnd.xyz / clipEnd.w;

			// direction
			vec2 dir = ndcEnd.xy - ndcStart.xy;

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

			#ifdef WORLD_UNITS

				// get the offset direction as perpendicular to the view vector
				vec3 worldDir = normalize( end.xyz - start.xyz );
				vec3 offset;
				if ( position.y < 0.5 ) {

					offset = normalize( cross( start.xyz, worldDir ) );

				} else {

					offset = normalize( cross( end.xyz, worldDir ) );

				}

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

				float forwardOffset = dot( worldDir, vec3( 0.0, 0.0, 1.0 ) );

				// don't extend the line if we're rendering dashes because we
				// won't be rendering the endcaps
				#ifndef USE_DASH

					// extend the line bounds to encompass  endcaps
					start.xyz += - worldDir * lineWidth * 0.5;
					end.xyz += worldDir * lineWidth * 0.5;

					// shift the position of the quad so it hugs the forward edge of the line
					offset.xy -= dir * forwardOffset;
					offset.z += 0.5;

				#endif

				// endcaps
				if ( position.y > 1.0 || position.y < 0.0 ) {

					offset.xy += dir * 2.0 * forwardOffset;

				}

				// adjust for lineWidth
				offset *= lineWidth * 0.5;

				// set the world position
				worldPos = ( position.y < 0.5 ) ? start : end;
				worldPos.xyz += offset;

				// project the worldpos
				vec4 clip = projectionMatrix * worldPos;

				// shift the depth of the projected points so the line
				// segments overlap neatly
				vec3 clipPose = ( position.y < 0.5 ) ? ndcStart : ndcEnd;
				clip.z = clipPose.z * clip.w;

			#else

				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 * devicePixelRatio;

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

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

				clip.xy += offset;

			#endif

			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:
	/* glsl */`
		uniform vec3 diffuse;
		uniform float opacity;
		uniform float lineWidth;
        uniform vec3 backColor;
        uniform float occlusionDistance;
        uniform float clipDistance;
        uniform float maxClipFactor;
		#ifdef USE_DASH

			uniform float dashOffset;
			uniform float dashSize;
			uniform float gapSize;

		#endif


        //加
        #if defined(GL_EXT_frag_depth) && defined(useDepth)    
            uniform sampler2D depthTexture;
            uniform float nearPlane;
            uniform float farPlane; 
            uniform vec2 resolution;
            uniform vec2 viewportOffset;
        #endif



		varying float vLineDistance;

		#ifdef WORLD_UNITS

			varying vec4 worldPos;
			varying vec3 worldStart;
			varying vec3 worldEnd;

			#ifdef USE_DASH

				varying vec2 vUv;

			#endif

		#else

			varying vec2 vUv;

		#endif

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


        #if defined(GL_EXT_frag_depth) && defined(useDepth)  
            float convertToLinear(float zValue)
            {
                float z = zValue * 2.0 - 1.0;
                return (2.0 * nearPlane * farPlane) / (farPlane + nearPlane - z * (farPlane - nearPlane));
            }
        #endif



		vec2 closestLineToLine(vec3 p1, vec3 p2, vec3 p3, vec3 p4) {

			float mua;
			float mub;

			vec3 p13 = p1 - p3;
			vec3 p43 = p4 - p3;

			vec3 p21 = p2 - p1;

			float d1343 = dot( p13, p43 );
			float d4321 = dot( p43, p21 );
			float d1321 = dot( p13, p21 );
			float d4343 = dot( p43, p43 );
			float d2121 = dot( p21, p21 );

			float denom = d2121 * d4343 - d4321 * d4321;

			float numer = d1343 * d4321 - d1321 * d4343;

			mua = numer / denom;
			mua = clamp( mua, 0.0, 1.0 );
			mub = ( d1343 + d4321 * ( mua ) ) / d4343;
			mub = clamp( mub, 0.0, 1.0 );

			return vec2( mua, mub );

		}

		void main() {

			#include <clipping_planes_fragment>

			/*#ifdef USE_DASH

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

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

			#endif*/
            
			#ifdef USE_DASH

				if ( vUv.y < - 1.0 || vUv.y > 1.0 ) discard; // discard endcaps
                
                
                bool unvisible = mod( vLineDistance + dashOffset, dashSize + gapSize ) > dashSize;
                //加
                #ifdef DASH_with_depth
                    
                #else  
                    if (unvisible) discard; // todo - FIX
                #endif
			#endif
            

			float alpha = opacity;

			#ifdef WORLD_UNITS

				// Find the closest points on the view ray and the line segment
				vec3 rayEnd = normalize( worldPos.xyz ) * 1e5;
				vec3 lineDir = worldEnd - worldStart;
				vec2 params = closestLineToLine( worldStart, worldEnd, vec3( 0.0, 0.0, 0.0 ), rayEnd );

				vec3 p1 = worldStart + lineDir * params.x;
				vec3 p2 = rayEnd * params.y;
				vec3 delta = p1 - p2;
				float len = length( delta );
				float norm = len / lineWidth;

				#ifndef USE_DASH

					#ifdef USE_ALPHA_TO_COVERAGE

						float dnorm = fwidth( norm );
						alpha = 1.0 - smoothstep( 0.5 - dnorm, 0.5 + dnorm, norm );

					#else

						if ( norm > 0.5 ) {

							discard;

						}

					#endif

				#endif

			#else

				#ifdef USE_ALPHA_TO_COVERAGE

					// artifacts appear on some hardware if a derivative is taken within a conditional
					float a = vUv.x;
					float b = ( vUv.y > 0.0 ) ? vUv.y - 1.0 : vUv.y + 1.0;
					float len2 = a * a + b * b;
					float dlen = fwidth( len2 );

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

						alpha = 1.0 - smoothstep( 1.0 - dlen, 1.0 + dlen, len2 );

					}

				#else

					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;

					}

				#endif

			#endif

			vec4 diffuseColor = vec4( diffuse, alpha );


            //加
            #if defined(GL_EXT_frag_depth) && defined(useDepth)    
               
                float mixFactor = 0.0;
                float clipFactor = 0.0;

                float fragDepth = convertToLinear(gl_FragCoord.z);
                //gl_FragCoord大小为 viewport client大小 
                vec2 depthTxtCoords = vec2(gl_FragCoord.x - viewportOffset.x,  gl_FragCoord.y - viewportOffset.y) / resolution;

                float textureDepth = convertToLinear(texture2D(depthTexture, depthTxtCoords).r);

                float delta = fragDepth - textureDepth;

                if (delta > 0.0)
                {
                    
                    mixFactor = clamp(delta / occlusionDistance, 0.0, 1.0);
                    clipFactor = clamp(delta / clipDistance, 0.0, maxClipFactor);
                }
                 
                if (clipFactor == 1.0)
                {
                    discard;
                }
                
                vec4 backColor_ = vec4(backColor, opacity); //vec4(0.8,0.8,0.8, 0.8*opacity);
                 
                #ifdef DASH_with_depth  
                    // 只在被遮住的部分显示虚线, 所以若同时是虚线不可见部分和被遮住时， a为0
                    if(unvisible) backColor_.a = 0.0;
                #endif 
                
                //vec4 diffuseColor = vec4(mix(diffuse, backColor_, mixFactor), opacity*(1.0 - clipFactor));
               
               
               
                diffuseColor = mix(diffuseColor, backColor_ , mixFactor);   
               
               
                diffuseColor.a *= (1.0 - clipFactor);  
                
            #endif



			#include <logdepthbuf_fragment>
			#include <color_fragment>

			//gl_FragColor = vec4( diffuseColor.rgb, alpha );
			gl_FragColor = vec4( diffuseColor.rgb, diffuseColor.a );
			#include <tonemapping_fragment>
			#include <encodings_fragment>
			#include <fog_fragment>
			#include <premultiplied_alpha_fragment>

		}
		`
};

class LineMaterial extends ShaderMaterial {

	constructor( parameters ) {

		super( {

			type: 'LineMaterial',

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

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

			clipping: true // required for clipping support

		} );

		this.isLineMaterial = true;
        this.lineWidth_ = 0
        this.supportExtDepth = parameters.supportExtDepth 
        this.depthTestWhenPick = false //pick时是否识别点云等
        
        
        if(parameters.color){
            this.color = new Color(parameters.color)  
        }
        if(parameters.backColor){
            this.uniforms.backColor.value = new Color(parameters.backColor)
        }
        if(parameters.clipDistance){
            this.uniforms.clipDistance.value = parameters.clipDistance
        }
        if(parameters.occlusionDistance){
            this.uniforms.occlusionDistance.value = parameters.occlusionDistance
        }
        if(parameters.maxClipFactor){
            this.uniforms.maxClipFactor.value = parameters.maxClipFactor
        }
        
		Object.defineProperties( this, {

			color: {

				enumerable: true,

				get: function () {

					return this.uniforms.diffuse.value;

				},

				set: function ( value ) {

					this.uniforms.diffuse.value = value;

				}

			},

			worldUnits: {

				enumerable: true,

				get: function () {

					return 'WORLD_UNITS' in this.defines;

				},

				set: function ( value ) {

					if ( value === true ) {

						this.defines.WORLD_UNITS = '';

					} else {

						delete this.defines.WORLD_UNITS;

					}

				}

			},

			lineWidth: {

				enumerable: true,

				get: function () {

					return this.lineWidth_;//this.uniforms.lineWidth.value;

				},

				set: function ( value ) {

					this.uniforms.lineWidth.value = value * window.devicePixelRatio;
                    this.lineWidth_ = value
				}

			},

			dashed: {

				enumerable: true,

				get: function () {

					return Boolean( 'USE_DASH' in this.defines );

				},

				set( value ) {

					if ( Boolean( value ) !== Boolean( 'USE_DASH' in this.defines ) ) {

						this.needsUpdate = true;

					}

					if ( value === true ) {

						this.defines.USE_DASH = '';

					} else {

						delete this.defines.USE_DASH;

					}

				}

			},

			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;

				}

			},

			dashOffset: {

				enumerable: true,

				get: function () {

					return this.uniforms.dashOffset.value;

				},

				set: function ( value ) {

					this.uniforms.dashOffset.value = value;

				}

			},

			gapSize: {

				enumerable: true,

				get: function () {

					return this.uniforms.gapSize.value;

				},

				set: function ( value ) {

					this.uniforms.gapSize.value = value;

				}

			},

			opacity: {

				enumerable: true,

				get: function () {

					return this.uniforms.opacity.value;

				},

				set: function ( value ) {

					this.uniforms.opacity.value = value;

				}

			},

			resolution: {

				enumerable: true,

				get: function () {

					return this.uniforms.resolution.value;

				},

				set: function ( value ) {

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

				}

			},

			alphaToCoverage: {

				enumerable: true,

				get: function () {

					return Boolean( 'USE_ALPHA_TO_COVERAGE' in this.defines );

				},

				set: function ( value ) {

					if ( Boolean( value ) !== Boolean( 'USE_ALPHA_TO_COVERAGE' in this.defines ) ) {

						this.needsUpdate = true;

					}

					if ( value === true ) {

						this.defines.USE_ALPHA_TO_COVERAGE = '';
						this.extensions.derivatives = true;

					} else {

						delete this.defines.USE_ALPHA_TO_COVERAGE;
						this.extensions.derivatives = false;

					}

				}

			}
            ,
            
            useDepth:{//add
                enumerable: true,

                get: function () {

                    return 'useDepth' in this.defines 

                },

                set: function ( value ) {
                    
                    value = value && !!this.supportExtDepth
                    
                    if(value != this.useDepth){ 
                        if(value){
                            this.defines.useDepth = ''
                            this.updateDepthParams()
                        }else{
                            delete this.defines.useDepth
                        }
                        this.needsUpdate = true
                    }
                }  
            },
            
            dashWithDepth:{//add 
                enumerable: true,

                get: function () {

                    return 'DASH_with_depth' in this.defines 

                },

                set: function ( value ) {
                    
                    value = value && !!this.supportExtDepth
                    
                    
                    if(value != this.dashWithDepth){ 
                        if(value){
                            this.defines.DASH_with_depth = '' 
                        }else{
                            delete this.defines.DASH_with_depth
                        }
                        this.needsUpdate = true
                    }
                }  
            },
           
                
            

		} ); 


		this.setValues( parameters );
        
        
            
        let setSize = (e)=>{ 
            let viewport = e.viewport
            let viewportOffset = viewport.offset || new Vector2() 
            this.uniforms.resolution.value.copy(viewport.resolution) 
            this.uniforms.viewportOffset.value.copy(viewportOffset) 
            this.uniforms.devicePixelRatio.value = window.devicePixelRatio
            this.lineWidth = this.lineWidth_
        }
        
        let viewport = viewer.mainViewport;
         
        setSize({viewport})


        viewer.addEventListener('resize',(e)=>{
            setSize(e)     
        })  

        
        
        if(this.supportExtDepth){
         
            //add
            this.updateDepthParams()
            
            /* viewer.addEventListener('camera_changed', (e)=>{
                if(e.viewport.name != 'mapViewport') this.updateDepthParams(e) 
            })  */  
     
        
            viewer.addEventListener("render.begin", (e)=>{//before render  如果有大于两个viewport的话，不同viewport用不同的depthTex
                if(e.viewport.camera.isPerspectiveCamera) this.updateDepthParams(e)
            }) 

        }
 

	}
    
    updateDepthParams(e={}){
        
        if(this.useDepth){ 
            var viewport = e.viewport || viewer.mainViewport;
            var camera = viewport.camera;
            this.uniforms.depthTexture.value = viewer.getPRenderer().getRtEDL(viewport).depthTexture  //viewer.getPRenderer().rtEDL.depthTexture  
            this.uniforms.nearPlane.value = camera.near; //似乎因为这个所以对OrthographicCamera 无效
            this.uniforms.farPlane.value = camera.far; 
        }
            
    }

}

export { LineMaterial };