class MarkerRenderByPath {
    isClip = false;
    clipX = 0;
    container = null;
    config = null;
    lastPosition = null;
    ctx = null;
    width = 0;
    height = 0;
    top = 0;
    left = 0;
    markerEls = [];
    mouseDownStatus = false;
    // 当前轨道索引
    currentTrackIndex = 0;
    // 当前轨道配置数据
    currentTrackData = null;
    // 当前轨道路径
    currentTrackPath = null;
    // 当前角度,0-1 表示0-Math.PI*2
    currentAngle = 0;
    // 当前帧步
    currentFrameStep = 0;
    // 轨道下的图像数据
    trackImageMap = {

    }

    downloadImagesCount = 0
    downloadingImagesCount = 0
    downloadStartedAt = 0    
    handler = {}
    // 相机
    camera = null;
    constructor(options){
        this.container = options.container
        this.container.style.cursor = 'grab'
        this.config = options.config
        this.isClip = options.isClip
        this.currentTrackData = this.config.tracks[0]
        this.generateEl()
        this.createMarkers()
        this.changeTrack(null)
        this.preDownloadImages()
        this.camera = new THREE.PerspectiveCamera(75, this.width / this.height, 0.1, 1000);        
    }

    on(type, fn){
        this.handler[type] = fn
    }

    generateEl(){
        const rect = this.container.getBoundingClientRect()
        const canvasEl = document.createElement('canvas')        
        this.width = rect.width
        this.height = rect.height
        if(this.isClip){
            this.clipX = (this.config.globalMeta.photoSize[0] / this.config.globalMeta.photoSize[1]) * this.height - this.width
        }
        this.top = rect.top
        this.left = rect.left
        canvasEl.width = rect.width
        canvasEl.height = rect.height
        const ctx = canvasEl.getContext('2d')
        this.ctx = ctx;
        canvasEl.addEventListener('mousemove', this.mouseMoveHandler)
        canvasEl.addEventListener('mousedown', this.mouseDownHandler)
        canvasEl.addEventListener('mouseup', this.mouseUpHandler)
        this.container.appendChild(canvasEl)
    }

    /**
     * 获取当前轨道帧数据
     */
     renderFrameData(){
        const images = this.trackImageMap[this.currentTrackData.name]
        if(images){
            const frame = images[this.currentFrameStep]
            if(frame){
                this.ctx.clearRect(0,0,this.width,this.height)
                this.ctx.drawImage(frame.image, 0, 0, frame.image.width, frame.image.height, 0, 0, this.width, this.height)
                this.updateCamera(frame)
                this.updateMarkers(frame)
            }
        }
    }

    updateCamera(frame){
        const {camera} = this
        const _point = frame.frameData.cPoint
        const _target = frame.frameData.cTarget
        const cpoint = new THREE.Vector3(_point[0], _point[1], _point[2])
        camera.position.copy(cpoint)
        camera.lookAt(new THREE.Vector3(_target[0], _target[1], _target[2]))
        camera.updateMatrix()
        camera.updateMatrixWorld()
        camera.updateWorldMatrix()
        camera.updateProjectionMatrix()
    }

    /**
     * 创建markers
     */
    createMarkers(){
        this.config.markers.forEach(marker =>{
            const divEl = document.createElement('div')
            divEl.setAttribute('d-markerId', marker.id)            
            marker._point = new THREE.Vector3(marker.position[0], marker.position[1], marker.position[2])
            this.markerEls.push({
                marker: marker,
                el: divEl
            })
            divEl.addEventListener('click', this.clickMarker)
            this.container.appendChild(divEl)
        })
    }

    clickMarker =(ev)=>{
        const fn = this.handler['markerClicked']
        if(fn){
            const markerId = ev.target.getAttribute('d-markerId')
            fn(markerId)
        }
    }

    updateMarkers(){
        this.markerEls.forEach(markerItem => {
            if(markerItem.marker.type.indexOf('camera')>-1){
                markerItem.el.className = 'marker-anmi-camera'
            }
            if(markerItem.marker.type.indexOf('mic')>-1){
                markerItem.el.className = 'marker-anmi-mic'
            }
            const sP = this.scenePositionToScreenLocation(new THREE.Vector3().copy(markerItem.marker._point))
            markerItem.el.style.top = `${sP.y}px`
            markerItem.el.style.left = `${sP.x}px`
        })
    }

    scenePositionToScreenLocation(position){
        const {camera, width, height} = this
        const centerX = width / 2
        const centerY = height / 2
        const ppv = position.project(camera)
        return {
            x: Math.round(centerX*ppv.x + centerX),
            y: Math.round(-centerY*ppv.y + centerY)
        }
    }

    /**
     * 预加载图片
     */
    preDownloadImages(){
        // 总步数
        if(this.trackImageMap[this.currentTrackData.name]){
            return
        }
        const vm = this
        this.config.tracks.forEach(track => {
            vm.downloadImagesCount += track.steps
        })
        this.config.tracks.forEach(track => {
            const frameDatas = []
            this.trackImageMap[track.name] = frameDatas
            const stepCount = track.steps
            for(let i=0;i<stepCount;i++){
                const image = new Image()
                const frameData = this.getFrameData(i / stepCount, track)
                image.onload = ()=>{
                    vm.downloadingImagesCount++
                    frameDatas.push({
                        step: i,
                        image: image,
                        frameData: frameData
                    })
                    if(vm.downloadImagesCount === vm.downloadingImagesCount){
                        const fn = this.handler['imagesDownloaded']
                        if(fn){
                            const at = new Date().getTime()
                            fn(at - vm.downloadStartedAt)
                        }
                        console.log('downloadFinished')
                        vm.changeTrack(null)
                        vm.renderFrameData()
                    }
                }
                image.src = frameData.imageUrl
            }
        })
    }

    /**
     * 获取帧数据
     * 首先通过公式取，再以值修正
     */
    getFrameData(step, track){
        // 首先通过公式取，再以值修正
        const fixData = track.stepParams.find(stepParamItem => {
            return Math.abs(stepParamItem.stepValue - step) < 0.05
        })
        let imageUrl = ''
        let cPoint = null
        let cTarget = null
        if(fixData){
            // 有修正数据，使用修正数据
            imageUrl = fixData.photoUrl,
            cTarget = fixData.target,
            cPoint = fixData.camera_position
        }else{
            // 使用轨道数据
            imageUrl = track.photoUrl.replace('{step}', step.toFixed(2))
            cTarget = track.target
            const cPath = new THREE.Path()
            cPath.absarc(track.origin[0], track.origin[1], track.radis)
            const point = cPath.getPointAt(Number(step))
            cPoint = [point.x, track.height, point.y]
        }        
        return {
            cPoint: cPoint,
            imageUrl: imageUrl,
            cTarget: cTarget
        }
    }

    changeTrack(type){
        if(type === 'next'){
            // 切换下一个轨道
            this.currentTrackIndex++
        }
        if(type === 'prev'){
            // 切换上一个轨道
            this.currentTrackIndex--
        }
        if(this.currentTrackIndex > this.config.tracks.length){
            this.currentTrackIndex = this.config.tracks.length - 1
        }
        if(this.currentTrackIndex < 0){
            this.currentTrackIndex = 0
        }
        if(this.config.tracks[this.currentTrackIndex]){
            this.currentTrackData = this.config.tracks[this.currentTrackIndex]
            const cPath = new THREE.Path()
            cPath.absarc(this.currentTrackData.origin[0], this.currentTrackData.origin[1], this.currentTrackData.radis)
            this.currentTrackPath = cPath
            this.preDownloadImages()
            const fn = this.handler['trackChanged']
            if(fn){
                fn(this.currentTrackData.name)
            }
            this.renderFrameData()
        }
    }
    
    mouseMoveHandler = (ev)=>{
        if(this.mouseDownStatus){
            const diffX = ev.clientX - this.lastPosition.x
            const diffY = ev.clientY - this.lastPosition.y
            if(Math.abs(diffX) > Math.abs(diffY)){
                // 水平方向移动，触发图像更新
                if(Math.abs(diffX) > 10){
                    // 阈值
                    this.currentFrameStep += ev.clientX > this.lastPosition.x ? 1 : -1
                    this.currentFrameStep = this.currentFrameStep%this.currentTrackData.steps
                    if(this.currentFrameStep < 0){
                        this.currentFrameStep = this.currentTrackData.steps + this.currentFrameStep
                    }
                    this.renderFrameData()
                    this.lastPosition = {
                        x: ev.clientX,
                        y: ev.clientY
                    }
                }
            }else{
                // 竖直方向移动，触发轨道切换
                if(Math.abs(diffY)>20){
                    this.changeTrack(ev.clientY > this.lastPosition.y ? 'next' : 'prev')
                    this.lastPosition = {
                        x: ev.clientX,
                        y: ev.clientY
                    }
                }
            }
        }
    }
    mouseDownHandler = (ev)=>{
        this.mouseDownStatus = true
        this.lastPosition = {
            x: ev.clientX,
            y: ev.clientY
        }
    }
    mouseUpHandler = (ev)=>{
        this.mouseDownStatus = false
    }
}