// subpages/index/checkOutConfirm/sign/sign.js

 
Page({
    data: {
        canvasName: 'signCanvas',
        ctx: '', 
        canvas: '', 
        canvasWidth: 0,
        canvasHeight: 0,
        transparent: 1, 
        selectColor: 'black',
        lineColor: '#1A1A1A', 
        lineSize: 1.5, 
        lineMin: 0.5, 
        lineMax: 4, 
        pressure: 1, 
        smoothness: 60, 
        currentPoint: {},
        currentLine: [], 
        firstTouch: true, 
        radius: 1, 
        cutArea: { top: 0, right: 0, bottom: 0, left: 0 }, 
        bethelPoint: [], 
        lastPoint: 0,
        chirography: [], 
        currentChirography: {}, 
        linePrack: [], 
        isDraw: false, 
        upPageNumber: 0,
        offCanvas: '',
        offCtx: '',
        dpr: ''
    },
 
    onLoad: function (options) {
        this.data.dpr = wx.getSystemInfoSync().pixelRatio
        const query = wx.createSelectorQuery()
        query
            .select('.handCenter')
            .boundingClientRect(rect => {
                this.data.canvasWidth = rect.width * this.data.dpr
                this.data.canvasHeight = rect.height * this.data.dpr
            })
            .exec()
        const query1 = wx.createSelectorQuery()
        query1
            .select('#signCanvas')
            .fields({ node: true, size: true })
            .exec(res => {
                const canvas = res[0].node
                this.data.ctx = canvas.getContext('2d')
                canvas.width = this.data.canvasWidth
                canvas.height = this.data.canvasHeight
 
                this.data.canvas = canvas
 
                this.data.ctx.scale(this.data.dpr, this.data.dpr)
                this.setCanvasBg('#fff')
            })
        const query2 = wx.createSelectorQuery()
        query2
            .select('#offCanvas')
            .fields({ node: true, size: true })
            .exec(res => {
                const canvas = res[0].node
                const ctx = canvas.getContext('2d')
                canvas.width = this.data.canvasHeight
                canvas.height = this.data.canvasWidth
                this.data.offCanvas = canvas
                this.data.offCtx = ctx
                this.data.offCtx.scale(this.data.dpr, this.data.dpr)
            })
    },
 
    retDraw() {
        this.data.ctx.clearRect(0, 0, 700, 730)
        this.setCanvasBg('#fff')
        this.data.isDraw = false
        this.data.currentPoint = {}
    },
 
    pointToLine(line) {
        this.calcBethelLine(line)
        return
    },
 
    uploadScaleStart(e) {
        if (e.type != 'touchstart') return false
        let ctx = this.data.ctx
        ctx.fillStyle = this.data.lineColor 
        ctx.globalAlpha = this.data.transparent 
        let currentPoint = {
            x: e.touches[0].x,
            y: e.touches[0].y
        }
        let currentLine = this.data.currentLine
        currentLine.unshift({
            time: new Date().getTime(),
            dis: 0,
            x: currentPoint.x,
            y: currentPoint.y
        })
        this.setData({
            currentPoint
        })
        if (this.data.firstTouch) {
            this.setData({
                cutArea: {
                    top: currentPoint.y,
                    right: currentPoint.x,
                    bottom: currentPoint.y,
                    left: currentPoint.x
                },
                firstTouch: false
            })
        }
        this.pointToLine(currentLine)
    },
 
    uploadScaleMove(e) {
        if (e.type != 'touchmove') return false
        if (e.cancelable) {
 
            if (!e.defaultPrevented) {
                e.preventDefault()
            }
        }
        let point = {
            x: e.touches[0].x,
            y: e.touches[0].y
        }
 
        if (point.y < this.data.cutArea.top) {
            this.data.cutArea.top = point.y
        }
        if (point.y < 0) this.data.cutArea.top = 0
 
        if (point.x > this.data.cutArea.right) {
            this.data.cutArea.right = point.x
        }
        if (this.data.canvasWidth - point.x <= 0) {
            this.data.cutArea.right = this.data.canvasWidth
        }
        if (point.y > this.data.cutArea.bottom) {
            this.data.cutArea.bottom = point.y
        }
        if (this.data.canvasHeight - point.y <= 0) {
            this.data.cutArea.bottom = this.data.canvasHeight
        }
        if (point.x < this.data.cutArea.left) {
            this.data.cutArea.left = point.x
        }
        if (point.x < 0) this.data.cutArea.left = 0
 
        this.setData({
            lastPoint: this.data.currentPoint,
            currentPoint: point
        })
        let currentLine = this.data.currentLine
        currentLine.unshift({
            time: new Date().getTime(),
            dis: this.distance(this.data.currentPoint, this.data.lastPoint),
            x: point.x,
            y: point.y
        })
        // this.setData({
        //   currentLine
        // })
        this.pointToLine(currentLine)
    },
 
    uploadScaleEnd(e) {
        if (e.type != 'touchend') return 0
        let point = {
            x: e.changedTouches[0].x,
            y: e.changedTouches[0].y
        }
        this.setData({
            lastPoint: this.data.currentPoint,
            currentPoint: point
        })
        let currentLine = this.data.currentLine
        currentLine.unshift({
            time: new Date().getTime(),
            dis: this.distance(this.data.currentPoint, this.data.lastPoint),
            x: point.x,
            y: point.y
        })
        // this.setData({
        //   currentLine
        // })
        if (currentLine.length > 2) {
            var info =
                (currentLine[0].time - currentLine[currentLine.length - 1].time) / currentLine.length
        }
 
        this.pointToLine(currentLine)
        var currentChirography = {
            lineSize: this.data.lineSize,
            lineColor: this.data.lineColor
        }
        var chirography = this.data.chirography
        chirography.unshift(currentChirography)
        this.setData({
            chirography
        })
        var linePrack = this.data.linePrack
        linePrack.unshift(this.data.currentLine)
        this.setData({
            linePrack,
            currentLine: []
        })
        this.data.isDraw = true
    },
 
    calcBethelLine(line) {
        if (line.length <= 1) {
            line[0].r = this.data.radius
            return
        }
        let x0,
            x1,
            x2,
            y0,
            y1,
            y2,
            r0,
            r1,
            r2,
            len,
            lastRadius,
            dis = 0,
            time = 0,
            curveValue = 0.5
        if (line.length <= 2) {
            x0 = line[1].x
            y0 = line[1].y
            x2 = line[1].x + (line[0].x - line[1].x) * curveValue
            y2 = line[1].y + (line[0].y - line[1].y) * curveValue
            x1 = x0 + (x2 - x0) * curveValue
            y1 = y0 + (y2 - y0) * curveValue
        } else {
            x0 = line[2].x + (line[1].x - line[2].x) * curveValue
            y0 = line[2].y + (line[1].y - line[2].y) * curveValue
            x1 = line[1].x
            y1 = line[1].y
            x2 = x1 + (line[0].x - x1) * curveValue
            y2 = y1 + (line[0].y - y1) * curveValue
        }
 
        len = this.distance({ x: x2, y: y2 }, { x: x0, y: y0 })
        lastRadius = this.data.radius
        for (let n = 0; n < line.length - 1; n++) {
            dis += line[n].dis
            time += line[n].time - line[n + 1].time
            if (dis > this.data.smoothness) break
        }
        this.setData({
            radius:
                Math.min((time / len) * this.data.pressure + this.data.lineMin, this.data.lineMax) *
                this.data.lineSize
        })
        line[0].r = this.data.radius
 
        if (line.length <= 2) {
            r0 = (lastRadius + this.data.radius) / 2
            r1 = r0
            r2 = r1
        } else {
            r0 = (line[2].r + line[1].r) / 2
            r1 = line[1].r
            r2 = (line[1].r + line[0].r) / 2
        }
        let n = 5
        let point = []
        for (let i = 0; i < n; i++) {
            let t = i / (n - 1)
            let x = (1 - t) * (1 - t) * x0 + 2 * t * (1 - t) * x1 + t * t * x2
            let y = (1 - t) * (1 - t) * y0 + 2 * t * (1 - t) * y1 + t * t * y2
            let r = lastRadius + ((this.data.radius - lastRadius) / n) * i
            point.push({ x: x, y: y, r: r })
            if (point.length == 3) {
                let a = this.ctaCalc(
                    point[0].x,
                    point[0].y,
                    point[0].r,
                    point[1].x,
                    point[1].y,
                    point[1].r,
                    point[2].x,
                    point[2].y,
                    point[2].r
                )
                a[0].color = this.data.lineColor
                this.bethelDraw(a, 1)
                point = [{ x: x, y: y, r: r }]
            }
        }
        this.setData({
            currentLine: line
        })
    },
 
    distance(a, b) {
        let x = b.x - a.x
        let y = b.y - a.y
        return Math.sqrt(x * x + y * y)
    },
 
    ctaCalc(x0, y0, r0, x1, y1, r1, x2, y2, r2) {
        let a = [],
            vx01,
            vy01,
            norm,
            n_x0,
            n_y0,
            vx21,
            vy21,
            n_x2,
            n_y2
        vx01 = x1 - x0
        vy01 = y1 - y0
        norm = Math.sqrt(vx01 * vx01 + vy01 * vy01 + 0.0001) * 2
        vx01 = (vx01 / norm) * r0
        vy01 = (vy01 / norm) * r0
        n_x0 = vy01
        n_y0 = -vx01
        vx21 = x1 - x2
        vy21 = y1 - y2
        norm = Math.sqrt(vx21 * vx21 + vy21 * vy21 + 0.0001) * 2
        vx21 = (vx21 / norm) * r2
        vy21 = (vy21 / norm) * r2
        n_x2 = -vy21
        n_y2 = vx21
        a.push({ mx: x0 + n_x0, my: y0 + n_y0, color: '#1A1A1A' })
        a.push({
            c1x: x1 + n_x0,
            c1y: y1 + n_y0,
            c2x: x1 + n_x2,
            c2y: y1 + n_y2,
            ex: x2 + n_x2,
            ey: y2 + n_y2
        })
        a.push({
            c1x: x2 + n_x2 - vx21,
            c1y: y2 + n_y2 - vy21,
            c2x: x2 - n_x2 - vx21,
            c2y: y2 - n_y2 - vy21,
            ex: x2 - n_x2,
            ey: y2 - n_y2
        })
        a.push({
            c1x: x1 - n_x2,
            c1y: y1 - n_y2,
            c2x: x1 - n_x0,
            c2y: y1 - n_y0,
            ex: x0 - n_x0,
            ey: y0 - n_y0
        })
        a.push({
            c1x: x0 - n_x0 - vx01,
            c1y: y0 - n_y0 - vy01,
            c2x: x0 + n_x0 - vx01,
            c2y: y0 + n_y0 - vy01,
            ex: x0 + n_x0,
            ey: y0 + n_y0
        })
        a[0].mx = a[0].mx.toFixed(1)
        a[0].mx = parseFloat(a[0].mx)
        a[0].my = a[0].my.toFixed(1)
        a[0].my = parseFloat(a[0].my)
        for (let i = 1; i < a.length; i++) {
            a[i].c1x = a[i].c1x.toFixed(1)
            a[i].c1x = parseFloat(a[i].c1x)
            a[i].c1y = a[i].c1y.toFixed(1)
            a[i].c1y = parseFloat(a[i].c1y)
            a[i].c2x = a[i].c2x.toFixed(1)
            a[i].c2x = parseFloat(a[i].c2x)
            a[i].c2y = a[i].c2y.toFixed(1)
            a[i].c2y = parseFloat(a[i].c2y)
            a[i].ex = a[i].ex.toFixed(1)
            a[i].ex = parseFloat(a[i].ex)
            a[i].ey = a[i].ey.toFixed(1)
            a[i].ey = parseFloat(a[i].ey)
        }
        return a
    },
 
    bethelDraw(point, is_fill, color) {
        let ctx = this.data.ctx
        ctx.beginPath()
        ctx.moveTo(point[0].mx, point[0].my)
        if (undefined != color) {
            ctx.fillStyle = color
            ctx.strokeStyle = color
        } else {
            ctx.fillStyle = point[0].color
            ctx.strokeStyle = point[0].color
        }
        for (let i = 1; i < point.length; i++) {
            ctx.bezierCurveTo(
                point[i].c1x,
                point[i].c1y,
                point[i].c2x,
                point[i].c2y,
                point[i].ex,
                point[i].ey
            )
        }
        ctx.stroke()
        if (undefined != is_fill) {
            ctx.fill() 
        }
    },
 
    setCanvasBg(color) {
        this.data.ctx.rect(0, 0, this.data.canvasWidth, this.data.canvasHeight - 4)
        this.data.ctx.fillStyle = color
        this.data.ctx.fill() 
    },
 
    subCanvas() {
        if (Object.keys(this.data.currentPoint).length == 0) {
            wx.showModal({
                title: "提示",
                content: "签名内容不能为空！",
                showCancel: false
            });
        } else {
            console.log('========sub')
            const canvas = this.data.canvas;
            const ctx = canvas.getContext('2d');
            ctx.save();
            ctx.translate(canvas.width/2, canvas.height/2);
            ctx.rotate(Math.PI/2); 
            ctx.restore();
            // 然后生成图片
            let imgSrc = canvas.toDataURL('image/png', 1);
            wx.showLoading({
                title: '正在跳转',
            })
            setTimeout(function () {
                wx.hideLoading()
                wx.navigateTo({
                  url: `/subpages/index/checkOutConfirm/index/index?imgSrc=${encodeURIComponent(
                    imgSrc
                  )}`
                });
            }, 1500)
        }
 
    },
})