<template>
<uni-shadow-root class="vant-circle-index"><view class="van-circle">
  <canvas class="van-circle__canvas" :style="style" canvas-id="van-circle"></canvas>
  <view v-if="(!text)" class="van-circle__text">
    <slot></slot>
  </view>
  <cover-view v-else class="van-circle__text">{{ text }}</cover-view>
</view></uni-shadow-root>
</template>

<script>

global['__wxRoute'] = 'vant/circle/index'
import { VantComponent } from '../common/component';
import { isObj } from '../common/utils';
import { BLUE, WHITE } from '../common/color';
function format(rate) {
    return Math.min(Math.max(rate, 0), 100);
}
const PERIMETER = 2 * Math.PI;
const BEGIN_ANGLE = -Math.PI / 2;
const STEP = 1;
VantComponent({
    props: {
        text: String,
        lineCap: {
            type: String,
            value: 'round'
        },
        value: {
            type: Number,
            value: 0,
            observer: 'reRender'
        },
        speed: {
            type: Number,
            value: 50
        },
        size: {
            type: Number,
            value: 100,
            observer: 'setStyle'
        },
        fill: String,
        layerColor: {
            type: String,
            value: WHITE
        },
        color: {
            type: [String, Object],
            value: BLUE,
            observer: 'setHoverColor'
        },
        strokeWidth: {
            type: Number,
            value: 4
        },
        clockwise: {
            type: Boolean,
            value: true
        }
    },
    data: {
        style: 'width: 100px; height: 100px;',
        hoverColor: BLUE
    },
    methods: {
        getContext() {
            if (!this.ctx) {
                this.ctx = wx.createCanvasContext('van-circle', this);
            }
            return this.ctx;
        },
        setHoverColor() {
            const context = this.getContext();
            const { color, size } = this.data;
            let hoverColor = color;
            if (isObj(color)) {
                const LinearColor = context.createLinearGradient(size, 0, 0, 0);
                Object.keys(color)
                    .sort((a, b) => parseFloat(a) - parseFloat(b))
                    .map(key => LinearColor.addColorStop(parseFloat(key) / 100, color[key]));
                hoverColor = LinearColor;
            }
            this.setData({ hoverColor });
        },
        setStyle() {
            const { size } = this.data;
            const style = `width: ${size}px; height: ${size}px;`;
            this.setData({ style });
        },
        presetCanvas(context, strokeStyle, beginAngle, endAngle, fill) {
            const { strokeWidth, lineCap, clockwise, size } = this.data;
            const position = size / 2;
            const radius = position - strokeWidth / 2;
            context.setStrokeStyle(strokeStyle);
            context.setLineWidth(strokeWidth);
            context.setLineCap(lineCap);
            context.beginPath();
            context.arc(position, position, radius, beginAngle, endAngle, !clockwise);
            context.stroke();
            if (fill) {
                context.setFillStyle(fill);
                context.fill();
            }
        },
        renderLayerCircle(context) {
            const { layerColor, fill } = this.data;
            this.presetCanvas(context, layerColor, 0, PERIMETER, fill);
        },
        renderHoverCircle(context, formatValue) {
            const { clockwise, hoverColor } = this.data;
            // 结束角度
            const progress = PERIMETER * (formatValue / 100);
            const endAngle = clockwise
                ? BEGIN_ANGLE + progress
                : 3 * Math.PI - (BEGIN_ANGLE + progress);
            this.presetCanvas(context, hoverColor, BEGIN_ANGLE, endAngle);
        },
        drawCircle(currentValue) {
            const context = this.getContext();
            const { size } = this.data;
            context.clearRect(0, 0, size, size);
            this.renderLayerCircle(context);
            const formatValue = format(currentValue);
            if (formatValue !== 0) {
                this.renderHoverCircle(context, formatValue);
            }
            context.draw();
        },
        reRender() {
            // tofector 动画暂时没有想到好的解决方案
            const { value, speed } = this.data;
            if (speed <= 0 || speed > 1000) {
                this.drawCircle(value);
                return;
            }
            this.clearInterval();
            this.currentValue = this.currentValue || 0;
            this.interval = setInterval(() => {
                if (this.currentValue !== value) {
                    if (this.currentValue < value) {
                        this.currentValue += STEP;
                    }
                    else {
                        this.currentValue -= STEP;
                    }
                    this.drawCircle(this.currentValue);
                }
                else {
                    this.clearInterval();
                }
            }, 1000 / speed);
        },
        clearInterval() {
            if (this.interval) {
                clearInterval(this.interval);
                this.interval = null;
            }
        }
    },
    created() {
        const { value } = this.data;
        this.currentValue = value;
        this.drawCircle(value);
    },
    destroyed() {
        this.ctx = null;
        this.clearInterval();
    }
});
export default global['__wxComponents']['vant/circle/index']
</script>
<style platform="mp-weixin">
@import '../common/index.css';.van-circle{position:relative;display:inline-block;text-align:center}.van-circle__text{position:absolute;top:50%;left:0;width:100%;-webkit-transform:translateY(-50%);transform:translateY(-50%);color:#323233;color:var(--circle-text-color,#323233)}
</style>