(function (window) {
  const l = 42, // 滑块边长
    r = 9, // 滑块半径
    w = 310, // canvas宽度
    h = 155, // canvas高度
    PI = Math.PI
  const L = l + r * 2 + 3 // 滑块实际边长

  function getRandomNumberByRange (start, end) {
    return Math.round(Math.random() * (end - start) + start)
  }

  function createCanvas (width, height) {
    const canvas = createElement('canvas')
    canvas.width = width
    canvas.height = height
    return canvas
  }

  function createImg (onload) {
    const img = createElement('img')
    img.crossOrigin = "Anonymous"
    img.onload = onload
    img.onerror = () => {
      img.src = getRandomImg()
    }
    img.src = getRandomImg()
    return img
  }

  function createElement (tagName, className) {
    const elment = document.createElement(tagName)
    elment.className = className
    return elment
  }

  function addClass (tag, className) {
    tag.classList.add(className)
  }

  function removeClass (tag, className) {
    tag.classList.remove(className)
  }

  function getRandomImg () {
    return 'https://picsum.photos/300/150/?image=' + getRandomNumberByRange(0, 1084)
  }

  function draw (ctx, x, y, operation) {
    ctx.beginPath()
    ctx.moveTo(x, y)
    ctx.arc(x + l / 2, y - r + 2, r, 0.72 * PI, 2.26 * PI)
    ctx.lineTo(x + l, y)
    ctx.arc(x + l + r - 2, y + l / 2, r, 1.21 * PI, 2.78 * PI)
    ctx.lineTo(x + l, y + l)
    ctx.lineTo(x, y + l)
    ctx.arc(x + r - 2, y + l / 2, r + 0.4, 2.76 * PI, 1.24 * PI, true)
    ctx.lineTo(x, y)
    ctx.lineWidth = 2
    ctx.fillStyle = 'rgba(255, 255, 255, 0.7)'
    ctx.strokeStyle = 'rgba(255, 255, 255, 0.7)'
    ctx.stroke()
    ctx[operation]()
    ctx.globalCompositeOperation = 'overlay'
  }

  function sum (x, y) {
    return x + y
  }

  function square (x) {
    return x * x
  }

  class jigsaw {
    constructor ({ el, onSuccess, onFail, onRefresh }) {
      el.style.position = el.style.position || 'relative'
      this.el = el
      this.onSuccess = onSuccess
      this.onFail = onFail
      this.onRefresh = onRefresh
      
      this.validateSuc = false;
    }

    init () {
      this.initDOM()
      this.initImg()
      this.bindEvents()
    }

    initDOM () {
      const canvas = createCanvas(w, h) // 画布
      const block = canvas.cloneNode(true) // 滑块
      const sliderContainer = createElement('div', 'sliderContainer')
      const refreshIcon = createElement('div', 'refreshIcon')
      const sliderMask = createElement('div', 'sliderMask')
      const slider = createElement('div', 'slider')
      const sliderIcon = createElement('span', 'sliderIcon')
      const text = createElement('span', 'sliderText')
      
      

	  const picContainer = createElement('div', 'picContainer')
	  picContainer.id = "picContainer"
	  picContainer.style.display = "none"

      block.className = 'block'
      text.innerHTML = '向右滑动填充拼图'

      const el = this.el
	  picContainer.appendChild(canvas)
	  picContainer.appendChild(refreshIcon)
	  picContainer.appendChild(block)
      el.appendChild(picContainer)      
     
      slider.appendChild(sliderIcon)
      sliderMask.appendChild(slider)
      sliderContainer.appendChild(sliderMask)
      sliderContainer.appendChild(text)
      el.appendChild(sliderContainer)

      Object.assign(this, {
        canvas,
        block,
        sliderContainer,
        refreshIcon,
        slider,
        sliderMask,
        sliderIcon,
        text,
        canvasCtx: canvas.getContext('2d'),
        blockCtx: block.getContext('2d')
      })


    }

    initImg () {
      const img = createImg(() => {
        this.draw()
        this.canvasCtx.drawImage(img, 0, 0, w, h)
        this.blockCtx.drawImage(img, 0, 0, w, h)
        const y = this.y - r * 2 - 1
        const ImageData = this.blockCtx.getImageData(this.x - 3, y, L, L)
        this.block.width = L
        this.blockCtx.putImageData(ImageData, 0, y)
      })
      this.img = img
    }

    draw () {
      // 随机创建滑块的位置
      this.x = getRandomNumberByRange(L + 10, w - (L + 10))
      this.y = getRandomNumberByRange(10 + r * 2, h - (L + 10))
      draw(this.canvasCtx, this.x, this.y, 'fill')
      draw(this.blockCtx, this.x, this.y, 'clip')
    }

    clean () {
      this.canvasCtx.clearRect(0, 0, w, h)
      this.blockCtx.clearRect(0, 0, w, h)
      this.block.width = w
    }

    bindEvents () {
      this.el.onselectstart = () => false
      this.refreshIcon.onclick = () => {
        this.reset()
        typeof this.onRefresh === 'function' && this.onRefresh()
      }

      let originX, originY, trail = [], isMouseDown = false

      const handleDragStart = function (e) {
        originX = e.clientX || e.touches[0].clientX
        originY = e.clientY || e.touches[0].clientY
        isMouseDown = true
      }

      const handleDragMove = (e) => {
        if (!isMouseDown) return false
        const eventX = e.clientX || e.touches[0].clientX
        const eventY = e.clientY || e.touches[0].clientY
        const moveX = eventX - originX
        const moveY = eventY - originY
        if (moveX < 0 || moveX + 38 >= w) return false
        this.slider.style.left = moveX + 'px'
        const blockLeft = (w - 40 - 20) / (w - 40) * moveX
        this.block.style.left = blockLeft + 'px'

        addClass(this.sliderContainer, 'sliderContainer_active')
        this.sliderMask.style.width = moveX + 'px'
        trail.push(moveY)
      }

      const handleDragEnd = (e) => {
        if (!isMouseDown) return false
        isMouseDown = false
        const eventX = e.clientX || e.changedTouches[0].clientX
        if (eventX == originX) return false
        removeClass(this.sliderContainer, 'sliderContainer_active')
        this.trail = trail
        const { spliced, verified } = this.verify()
        if (spliced) {
          if (verified) {
            addClass(this.sliderContainer, 'sliderContainer_success')
            this.validateSuc = true;
            $("#picContainer").hide(300);
            typeof this.onSuccess === 'function' && this.onSuccess()
          } else {
            addClass(this.sliderContainer, 'sliderContainer_fail')
            this.text.innerHTML = '再试一次'
            this.reset()
          }
        } else {
          addClass(this.sliderContainer, 'sliderContainer_fail')
          typeof this.onFail === 'function' && this.onFail()
          setTimeout(() => {
            this.reset()
          }, 1000)
        }
      }
      this.slider.addEventListener('mousedown', handleDragStart)
      this.slider.addEventListener('touchstart', handleDragStart)
      document.addEventListener('mousemove', handleDragMove)
      document.addEventListener('touchmove', handleDragMove)
      document.addEventListener('mouseup', handleDragEnd)
      document.addEventListener('touchend', handleDragEnd)

  	  //处理悬浮事件
	  $(".sliderContainer").hover(()=> {
		  if(!this.validateSuc)
            $("#picContainer").show(300)
        }, function() {
//        	$("#picContainer").hide(300)
        });
      
      $(document).on('click','',function(event){
    	  if(event.target.className != "picContainer" && 
			  event.target.className != "sliderContainer" && 
			  event.target.className != "sliderIcon" && 
			  event.target.className != "sliderText" && 
			  event.target.className != "slider" && 
			  event.target.tagName != "CANVAS")
		  {
    		  $("#picContainer").hide(300)
		  }
    		  
      })
    }

    verify () {
      const arr = this.trail // 拖动时y轴的移动距离
      const average = arr.reduce(sum) / arr.length
      const deviations = arr.map(x => x - average)
      const stddev = Math.sqrt(deviations.map(square).reduce(sum) / arr.length)
      const left = parseInt(this.block.style.left)
      return {
        spliced: Math.abs(left - this.x) < 10,
        verified: stddev !== 0, // 简单验证下拖动轨迹，为零时表示Y轴上下没有波动，可能非人为操作
      }
    }

    reset () {
      this.sliderContainer.className = 'sliderContainer'
      this.slider.style.left = 0
      this.block.style.left = 0
      this.sliderMask.style.width = 0
      this.clean()
      this.img.src = getRandomImg()
    }

  }

  window.jigsaw = {
    init: function (opts) {
      return new jigsaw(opts).init()
    }
  }
}(window))