import * as THREE from "../../../libs/three.js/build/three.module.js"; 
import { Utils } from "../../utils.js";
import math  from "../../utils/math.js";
import {LineDraw} from "../../utils/DrawUtil.js"; 
import CurveCtrl from  "../../objects/tool/CurveCtrl.js";
import HandleSvg from  "../../objects/tool/HandleSvg.js";
import {/* transitions,*/ easing,  lerp} from '../../utils/transitions.js'
import { EventDispatcher } from "../../EventDispatcher.js";

const colors = {
    position: 'red', 
    target : 'blue'
}
 

let lineMats 
const getLineMat = function(name){
    if(!lineMats){
        lineMats = {
            position: LineDraw.createFatLineMat({
                color: colors.position,  
                lineWidth: 3   
            }),
            target : LineDraw.createFatLineMat({
                color: colors.target,  
                lineWidth: 3  
            }),
            frustum:  LineDraw.createFatLineMat({
                color: colors.position,  
                lineWidth: 2   
            }),
            aimAtTarget: new THREE.LineBasicMaterial({color:colors.target})
        }
    }
    return lineMats[name]
}

 


export class CameraAnimation extends EventDispatcher{

	constructor(viewer){
		super();
		
		this.viewer = viewer;

		this.selectedElement = null;

		//this.controlPoints = [];

		this.uuid = THREE.Math.generateUUID();

		this.node = new THREE.Object3D();
		this.node.name = "camera animation";
		this.viewer.scene.scene.add(this.node);

		this.frustum = this.createFrustum();
		this.node.add(this.frustum);
       

		this.name = "Camera Animation";
		
		// "centripetal", "chordal", "catmullrom"
		this.curveType = "centripetal" 
		this.visible = true;

        this.targets = [];  
		this.createPath();
        this.duration = 5; 
		this.percent = 0;
        this.currentIndex = 0
        this.durations = []
        this.quaternions = [];
        
        if(!Potree.settings.isTest){
            this.setVisible(false)
        }
        
        
        
        this.addEventListener('dispose', ()=>{  
            this.dispose()
        })
        
        
        this.targetLines = new THREE.Object3D
        this.node.add(this.targetLines)
        
        
        
        
        
	}

	static defaultFromView(viewer){
		const animation = new CameraAnimation(viewer);

		const camera = viewer.scene.getActiveCamera();
		const target = viewer.scene.view.getPivot();

		const cpCenter = new THREE.Vector3(
			0.3 * camera.position.x + 0.7 * target.x,
			0.3 * camera.position.y + 0.7 * target.y,
			0.3 * camera.position.z + 0.7 * target.z,
		);

		const targetCenter = new THREE.Vector3(
			0.05 * camera.position.x + 0.95 * target.x,
			0.05 * camera.position.y + 0.95 * target.y,
			0.05 * camera.position.z + 0.95 * target.z,
		);

		const r = 2//camera.position.distanceTo(target) * 0.3;

		//const dir = target.clone().sub(camera.position).normalize();
		const angle = Utils.computeAzimuth(camera.position, target);

		const n = 5;
		for(let i = 0; i < n; i++){
			let u = 1.5 * Math.PI * (i / n) + angle;

			const dx = r * Math.cos(u);
			const dy = r * Math.sin(u);

			const cpPos = new THREE.Vector3(
				cpCenter.x + dx,
				cpCenter.y + dy,
				cpCenter.z,
			)

			const targetPos = new THREE.Vector3(
				targetCenter.x + dx * 0.1,
				targetCenter.y + dy * 0.1,
				targetCenter.z,
            )

			animation.createControlPoint(null,{position:cpPos, target:targetPos});
			 
             
		}

        animation.changeCallback()
		return animation;
	}

	 

	createControlPoint(index, posInfo ){ 
        const length = this.posCurve.points.length
        const position = new THREE.Vector3
        const target = new THREE.Vector3
        
		if(index == void 0 ){
			index = length;
		}
        
        if(!posInfo){
        
            if(length >= 2 && index === 0){ 
                const dir = new THREE.Vector3().subVectors(this.posCurve.points[0], this.posCurve.points[1] ) 
                position.copy(this.posCurve.points[0]).add(dir);
                
                const tDir = new THREE.Vector3().subVectors(this.targets[0].position, this.targets[1].position ) 
                target.copy(this.targets[0].position).add(dir);
                 
            }else if(length >= 2 && index === length){ 
                const dir = new THREE.Vector3().subVectors(this.posCurve.points[length-1], this.posCurve.points[length-2] ) 
                position.copy(this.posCurve.points[length-2]).add(dir);
                 
                const tDir = new THREE.Vector3().subVectors(this.targets[length-1].position, this.targets[length-2].position ) 
                target.copy(this.targets[length-2].position).add(dir);
                 
            }else if(length >= 2){ 
                position.copy(this.posCurve.points[index-1].clone().add(this.posCurve.points[index]).multiplyScalar(0.5));
                target.copy(this.targets[length-1].position.clone().add(this.targets[length]).multiplyScalar(0.5));
            }
        }else{
            position.copy(posInfo.position)
            target.copy(posInfo.target)
             
        }
            
        this.posCurve.addPoint(position, index/* , true */)
        //this.targetCurve.addPoint(target, index/* , true */) 
        let targetSvg = new HandleSvg(target, colors.target)
        targetSvg.visible = this.visible 
        this.targets = [...this.targets.slice(0,index), targetSvg, ...this.targets.slice(index,length)]
        if(this.useDurSlice){//不使用全局的duration,而是分段的
            this.durations = [...this.durations.slice(0,index), posInfo.duration, ...this.durations.slice(index,length)]
        }
        
        
		this.dispatchEvent({
			type: "controlpoint_added", 
            index
		});
        
        {
            let targetLine = LineDraw.createLine([position,target] ,{mat: getLineMat('aimAtTarget')})
            this.targetLines.children = [...this.targetLines.children.slice(0,index), targetLine, ...this.targetLines.children.slice(index,length)]
            
            
            
            this.targets[index].addEventListener('dragged', (e)=>{ 
                this.updatePathCallback()
                this.dragPointCallback(e)
            })
        } 
	}

	 
    dragPointCallback(e){
        
        let index = e.index
        if(e.index == void 0){
            index = this.targets.indexOf(e.target)
        }
        LineDraw.moveLine(this.targetLines.children[index], [this.posCurve.points[index], this.targets[index].position] )
         
        this.updateFrustum()
    } 
     
    updatePathCallback(){
        {
            this.quaternions = [];
            let length = this.posCurve.points.length;
            for(let i=0; i<length; i++){
                let quaternion = math.getQuaFromPosAim(this.posCurve.points[i], this.targets[i].position) 
                this.quaternions.push( quaternion) 
            }
        }
        this.reMapCurvePercent()
    } 
     
     
    removeControlPoint(index){
        this.posCurve.removePoint(index)
        //this.targetCurve.removePoint(index)
        this.targets[index].dispose();
        this.targets.splice(index, 1)
         
        this.dispatchEvent({
			type: "controlpoint_removed",
			index
		});
        this.targetLines.remove(this.targetLines.children[index])
        if(this.useDurSlice){
            this.durations.splice(index, 1)
        }
        
    }



	createPath(){
        this.posCurve = new CurveCtrl([],getLineMat('position'), colors.position, 'posCurve'); 
        //this.targetCurve = new CurveCtrl([], getLineMat('target'), colors.target, 'targetCurve', {noLine:true}); 
        this.posCurve.needsPercent = true
        this.node.add(this.posCurve)
        //this.node.add(this.targetCurve)
        
        this.posCurve.addEventListener('dragCurvePoint', this.dragPointCallback.bind(this))
        this.posCurve.addEventListener('updatePath', this.updatePathCallback.bind(this))
            
         
        
        
	}


     

	createFrustum(){

		const f = 0.3;

		const positions = [
			new THREE.Vector3( 0,  0,  0),
			new THREE.Vector3(-f, -f, +1),

			new THREE.Vector3( 0,  0,  0),
			new THREE.Vector3( f, -f, +1),

			new THREE.Vector3( 0,  0,  0),
			new THREE.Vector3( f,  f, +1),

			new THREE.Vector3( 0,  0,  0),
			new THREE.Vector3(-f,  f, +1),

			new THREE.Vector3(-f, -f, +1),
			new THREE.Vector3( f, -f, +1),

			new THREE.Vector3( f, -f, +1),
			new THREE.Vector3( f,  f, +1),

			new THREE.Vector3( f,  f, +1),
			new THREE.Vector3(-f,  f, +1),

			new THREE.Vector3(-f,  f, +1),
			new THREE.Vector3(-f, -f, +1),
		]
        
        positions.forEach(e=>e.z *= -1)  //因为得到的rotation是camera的，作用在物体上要反向，所以这里反向一下
        
		//geometry.computeBoundingSphere();//? 
		const line = LineDraw.createFatLine( positions, {material:getLineMat('frustum')})
         
        //line.scale.set(20, 20, 20); 
        line.visible = false
		return line;
	}


    reMapCurvePercent(){  //因在不同点在相同位置旋转，由于间隔仅和位置距离相关，导致时间间隔为0，采取重新调整间隔的策略。
        var length = this.posCurve.points.length
        
        if(length<2){
            return this.newPointsPercents = []
        }
        var newPercents = [0];
        
        
        
        if(this.useDurSlice){ //已经设定好了每一段的duration的话
            let sums = [0]
            let sum = 0, last
            for(let i=0;i<length-1;i++){ //去掉最后一个duration,因为已到终点
                let duration = this.durations[i];
                sum += duration;   
                last = duration;
                sums.push(sum) 
            }
            for(let i=1;i<length;i++){ 
                newPercents.push(sum == 0 ? i/length : sums[i] / sum)
            } 
             
        }else{
            
            const maxSpaceDur = this.duration / length  //每两点之间修改间隔时间后，最大时间
            const durPerRad = 0.8     //每弧度应该占用的时间
            const minSpaceDur =  Math.min(0.8, maxSpaceDur)//每两点之间修改间隔时间后，最小时间
            const maxAngleSpaceDur = THREE.Math.clamp(durPerRad * Math.PI, minSpaceDur, maxSpaceDur )// 最大可能差距是180度
            
            
            
            var percents = this.posCurve.pointsPercent; 
            
            
            
            for(let i=1;i<length;i++){
                let diff = (percents[i] - percents[i-1]) * this.duration  //间隔时间
                let percent 
                let curMin = minSpaceDur
                if(diff < maxAngleSpaceDur){ //若小于最大旋转时间
                    let rad = this.quaternions[i].angleTo(this.quaternions[i-1]) 
                    curMin = THREE.Math.clamp(rad * durPerRad, minSpaceDur, maxSpaceDur)
     
                }  

                diff = Math.max(diff, curMin) 
                percent = newPercents[i-1] + (diff / this.duration) //得到新的percent
                
                
                newPercents.push(percent) 
            }
            
            let maxPercent = newPercents[length-1]  //最后一个，若扩充过时间，就会>1


            if( !math.closeTo(maxPercent, 1)){
                let scale = 1 / maxPercent //需要压缩的比例 <1  这一步会让实际得到的间隔更小 
                newPercents = newPercents.map(e=> e*=scale ) 
            }
                
            
        }
        
        this.newPointsPercents = newPercents;
        //console.log(newPercents)
    }


	at(originPercent, delta, transitionRatio){
		 
        originPercent = THREE.Math.clamp(originPercent, 0, 1)
        //修改第一层：起始时间
        let percent = originPercent;
        /* const easePercent = 0.3; //缓动占比  //如果能在所有从静止到运动的中间加缓动就好了呀：lastPos * 0.9 + currentPos *  0.1 ?
        if(originPercent < easePercent){
            console.log('easeIn')
            percent = easing.easeInSine(originPercent, 0, easePercent, easePercent) //currentTime, startY, wholeY, duration   选了一个衔接时接近斜率1的缓动函数
        }else if(originPercent > 1-easePercent){ 
            console.log('easeOut')
            percent = easing.easeOutSine(originPercent-(1-easePercent), 1-easePercent, easePercent, easePercent)
        } */
        
        
		
	 
        let quaternion
        
        if(percent < 1){
            //修改第二层：使用每个点的重定位的 newPointsPercents
            
            this.currentIndex = this.newPointsPercents.findIndex(e=> e>percent ) - 1   
            //假设每个节点的百分比是精确的，那么：
            let curIndexPercent = this.newPointsPercents[this.currentIndex];
            let nextIndexPercent = this.newPointsPercents[this.currentIndex+1];
            let progress = (percent - curIndexPercent) / (nextIndexPercent - curIndexPercent)//在这两个节点间的百分比
            
            //投影到原本的 posCurve.pointsPercent上：
            let curIndexOriPercent = this.posCurve.pointsPercent[this.currentIndex] 
            let nextIndexOriPercent = this.posCurve.pointsPercent[this.currentIndex+1] 
            percent = curIndexOriPercent + (nextIndexOriPercent - curIndexOriPercent) * progress
            
            let endQuaternion = this.quaternions[this.currentIndex+1]
            let startQuaternion = this.quaternions[this.currentIndex]       
            quaternion = (new THREE.Quaternion()).copy(startQuaternion) 
            lerp.quaternion(quaternion, endQuaternion)(progress) 
            
            
        }else{
             
            
            this.currentIndex = this.posCurve.points.length - 1;
            
            quaternion = math.getQuaFromPosAim(this.posCurve.points[this.currentIndex], this.targets[this.currentIndex].position)
        }
        
        
        const position = this.posCurve.getPointAt(percent); // 需要this.posCurve.points.length>1 否则报错
        
        
        //console.log(this.currentIndex, originPercent)
        //缓动：
        var aimQua, aimPos;
        if(delta != void 0 ){
            if(Potree.settings.tourTestCameraMove){
                aimQua = this.frustum.quaternion.clone();
                aimPos = this.frustum.position.clone();
            }else{
                var camera = viewer.scene.getActiveCamera();
                aimQua = camera.quaternion.clone();
                aimPos = camera.position.clone();
            }
            
            transitionRatio = transitionRatio || 1 / Potree.settings.cameraAniSmoothRatio//渐变系数，越小缓动程度越高，越平滑
            transitionRatio *= delta * 60 //假设标准帧率为60fps，当帧率低时（delta大时）要降低缓动
            //console.log(transitionRatio, delta) //画面ui变化会使delta变大
            transitionRatio = THREE.Math.clamp(transitionRatio, 0, 1);
            lerp.quaternion(aimQua, quaternion)(transitionRatio) //每次只改变一点点  
            lerp.vector(aimPos, position)(transitionRatio)
  
        }else{
            aimQua = quaternion;  aimPos = position
        }
        
        
        
        let rotation = new THREE.Euler().setFromQuaternion(aimQua )
  
 
        const frame = {
			position: aimPos,  
            rotation
		};


		return frame;
	}

	set(percent){
		this.percent = percent;
	}

	 

	setVisible(visible){
		this.node.visible = visible;
 
        this.posCurve.visible = visible
        this.targets.forEach(e=>e.visible = visible ) 

		this.visible = visible;
	}

	setDuration(duration){
        if(duration != this.duration){
            this.duration = duration;
            if(this.quaternions.length == this.posCurve.points.length)this.reMapCurvePercent()
            
        } 
	}

	getDuration(duration){
		return this.duration;
	}

	play(startOptions={}){
        if(this.onUpdate){
            return console.error('已经开始播放')
        }
       
        
        
        let startPercent = 0, currentIndex = 0  
        if(startOptions.percent != void 0 ){
            startPercent = startOptions.percent
        }else if(startOptions.index){
            currentIndex = index
            //startPercent = index/(this.posCurve.points.length-1)
            
            startPercent = this.posCurve.pointsPercent[index]
        }
        
        
		//const tStart = performance.now();
        
        


		const duration = this.duration;

		this.originalyVisible = this.visible;
		Potree.settings.tourTestCameraMove || this.setVisible(false);
        
        
        let tStart, startTransitionRatio = 0.2
        let startDelay = 1/startTransitionRatio / 20 ;//因为缓动所以延迟开始，前面前都是at(0),使过渡到开始点位（但是依旧不能准确停在起始点，因为缓动是乘百分比有残留。所以直接平滑衔接到开始后的位置）
        let hasPlayedTime = 0
        
        let finishDelay = Potree.settings.cameraAniSmoothRatio / 60 * 3//结束后还需要多久时间才能大致达到缓动的最终目标
        let hasStoppedTime = 0

		this.onUpdate = (e) => {
            if(this.posCurve.points.length<2){
                if(this.posCurve.points.length == 1){
                    viewer.scene.view.position.copy(this.posCurve.points[0]);
                    viewer.scene.view.rotation = new THREE.Euler().setFromQuaternion(this.quaternions[0])
                }
                this.pause()
                return 
            }
             
            let percent, transitionRatio
            
            if(tStart){ 
                let tNow = performance.now(); 
                let elapsed = (tNow - tStart) / 1000;
                percent = elapsed / duration + startPercent;
            }else{//从当前位置过渡到开始位置 
                percent = 0
                hasPlayedTime += e.delta
                transitionRatio = startTransitionRatio;
                //console.log('延迟开始') 
                if(hasPlayedTime > startDelay){
                    tStart = performance.now(); 
                }
                
            }
             
			this.set(percent);
             
			const frame = this.at(percent, e.delta, transitionRatio);
            
            if(currentIndex != this.currentIndex){
                currentIndex = this.currentIndex
                console.log('updateCurrentIndex', currentIndex)
                this.dispatchEvent({type:'updateCurrentIndex', currentIndex  })
            }
            
            
            
            if(!Potree.settings.tourTestCameraMove){
                viewer.scene.view.position.copy(frame.position);
                //viewer.scene.view.lookAt(frame.target);
                viewer.scene.view.rotation = frame.rotation; 
            }

            this.updateFrustum(frame)

            
            
            
			if(percent >= 1){ 
                if(hasStoppedTime > finishDelay){
                    this.pause()
                }else{ 
                    hasStoppedTime += e.delta
                    //console.log('延迟结束') 
                }
                
			}
             
            
            
		};

		this.viewer.addEventListener("update", this.onUpdate);
         
         
	}

    pause(){ 
        this.setVisible(this.originalyVisible); 
        this.viewer.removeEventListener("update", this.onUpdate);
        this.dispatchEvent('playDone')
        this.onUpdate = null
    }



    updateFrustum(frame){  
        const frustum = this.frustum;
        if(this.posCurve.points.length>1){
            frustum.visible = true
        }else{
            frustum.visible = false;
            return
        }
        
        frame = frame || this.at(this.percent);
        frustum.position.copy(frame.position);
        //frustum.lookAt(...frame.target.toArray());
        frustum.rotation.copy(frame.rotation)
    }

    changeCallback(){
        this.posCurve.update()
        //this.targetCurve.update()
        this.targets.forEach(e=>e.update()) 
        this.updateFrustum()
    }

    dispose(){//add
        this.posCurve.dispose()
        //this.targetCurve.dispatchEvent({type:'dispose'}) 
        this.targets.forEach(e=>e.dispose())
        this.durations = []
        this.node.parent.remove(this.node);
    }
}


//scene.removeCameraAnimation


//修改：不使用targetCurve作为target曲线，因为播放时posCuve的节点和targetCurve并没有对应，且使用target的曲线会使角度变化大的情况过渡生硬。
// 改完旋转了。但是位置也有问题。速度完全和路程相关，当在同一位置设置多点时，这段的总时长为0. (是否要设置最小时长？不过也做不到 - -)