<template>
	<view class="tui-circular-container" :style="{ width: diam + 'px', height: (height || diam) + 'px' }">
		<canvas
			class="tui-circular-default"
			:canvas-id="defaultCanvasId"
			:id="defaultCanvasId"
			:style="{ width: diam + 'px', height: (height || diam) + 'px' }"
			v-if="defaultShow"
		></canvas>
		<canvas class="tui-circular-progress" :canvas-id="progressCanvasId" :id="progressCanvasId" :style="{ width: diam + 'px', height: (height || diam) + 'px' }"></canvas>
		<slot />
	</view>
</template>

<script>
export default {
	name: 'tuiCircularProgress',
	props: {
		/*
			  传值需使用rpx进行转换保证各终端兼容
			  px = rpx / 750 * wx.getSystemInfoSync().windowWidth
			  圆形进度条(画布)宽度，直径 [px]
			*/
		diam: {
			type: Number,
			default: 60
		},
		//圆形进度条(画布)高度，默认取diam值[当画半弧时传值，height有值时则取height]
		height: {
			type: Number,
			default: 0
		},
		//进度条线条宽度[px]
		lineWidth: {
			type: Number,
			default: 4
		},
		/*
			 线条的端点样式
			 butt：向线条的每个末端添加平直的边缘
			 round	向线条的每个末端添加圆形线帽
			 square	向线条的每个末端添加正方形线帽
			*/
		lineCap: {
			type: String,
			default: 'round'
		},
		//圆环进度字体大小 [px]
		fontSize: {
			type: Number,
			default: 12
		},
		//圆环进度字体颜色
		fontColor: {
			type: String,
			default: '#5677fc'
		},
		//是否显示进度文字
		fontShow: {
			type: Boolean,
			default: true
		},
		/*
			 自定义显示文字[默认为空，显示百分比，fontShow=true时生效]
			 可以使用 slot自定义显示内容
			*/
		percentText: {
			type: String,
			default: ''
		},
		//是否显示默认(背景)进度条
		defaultShow: {
			type: Boolean,
			default: true
		},
		//默认进度条颜色
		defaultColor: {
			type: String,
			default: '#CCC'
		},
		//进度条颜色
		progressColor: {
			type: String,
			default: '#5677fc'
		},
		//进度条渐变颜色[结合progressColor使用，默认为空]
		gradualColor: {
			type: String,
			default: ''
		},
		//起始弧度，单位弧度
		sAngle: {
			type: Number,
			default: -Math.PI / 2
		},
		//指定弧度的方向是逆时针还是顺时针。默认是false，即顺时针
		counterclockwise: {
			type: Boolean,
			default: false
		},
		//进度百分比 [10% 传值 10]
		percentage: {
			type: Number,
			default: 0
		},
		//进度百分比缩放倍数[使用半弧为100%时，则可传2]
		multiple: {
			type: Number,
			default: 1
		},
		//动画执行时间[单位毫秒，低于50无动画]
		duration: {
			type: Number,
			default: 800
		},
		//backwards: 动画从头播；forwards：动画从上次结束点接着播
		activeMode: {
			type: String,
			default: 'backwards'
		}
	},
	watch: {
		percentage(val) {
			this.initDraw();
		}
	},
	data() {
		return {
			// #ifdef MP-WEIXIN
			progressCanvasId: 'progressCanvasId',
			defaultCanvasId: 'defaultCanvasId',
			// #endif
			// #ifndef MP-WEIXIN
			progressCanvasId: this.getCanvasId(),
			defaultCanvasId: this.getCanvasId(),
			// #endif
			progressContext: null,
			linearGradient: null,
			//起始百分比
			startPercentage: 0
			// dpi
			//pixelRatio: uni.getSystemInfoSync().pixelRatio
		};
	},
	mounted() {
		this.initDraw(true);
	},
	methods: {
		//初始化绘制
		initDraw(init) {
			let start = this.activeMode === 'backwards' ? 0 : this.startPercentage;
			start = start > this.percentage ? 0 : start;
			if (this.defaultShow && init) {
				this.drawDefaultCircular();
			}
			this.drawProgressCircular(start);
		},
		//默认(背景)圆环
		drawDefaultCircular() {
			let ctx = uni.createCanvasContext(this.defaultCanvasId, this);
			ctx.setLineWidth(this.lineWidth);
			ctx.setStrokeStyle(this.defaultColor);
			//终止弧度
			let eAngle = Math.PI * (this.height ? 1 : 2) + this.sAngle;
			this.drawArc(ctx, eAngle);
		},
		//进度圆环
		drawProgressCircular(startPercentage) {
			let ctx = this.progressContext;
			let gradient = this.linearGradient;
			if (!ctx) {
				ctx = uni.createCanvasContext(this.progressCanvasId, this);
				//创建一个线性的渐变颜色 CanvasGradient对象
				gradient = ctx.createLinearGradient(0, 0, this.diam, 0);
				gradient.addColorStop('0', this.progressColor);
				if (this.gradualColor) {
					gradient.addColorStop('1', this.gradualColor);
				}
				// #ifdef APP-PLUS
				const res = uni.getSystemInfoSync();
				if (!this.gradualColor && res.platform.toLocaleLowerCase() == 'android') {
					gradient.addColorStop('1', this.progressColor);
				}
				// #endif
				this.progressContext = ctx;
				this.linearGradient = gradient;
			}
			ctx.setLineWidth(this.lineWidth);
			ctx.setStrokeStyle(gradient);
			let time = this.percentage == 0 || this.duration < 50 ? 0 : this.duration / this.percentage;
			if (this.percentage > 0) {
				startPercentage = this.duration < 50 ? this.percentage - 1 : startPercentage;
				startPercentage++;
			}
			if (this.fontShow) {
				ctx.setFontSize(this.fontSize);
				ctx.setFillStyle(this.fontColor);
				ctx.setTextAlign('center');
				ctx.setTextBaseline('middle');
				let percentage = this.percentText;
				if (!percentage) {
					percentage = this.counterclockwise ? 100 - startPercentage * this.multiple : startPercentage * this.multiple;
					percentage = `${percentage}%`;
				}
				let radius = this.diam / 2;
				ctx.fillText(percentage, radius, radius);
			}
			if (this.percentage == 0 || (this.counterclockwise && startPercentage == 100)) {
				ctx.draw();		
			}else{
				let eAngle = ((2 * Math.PI) / 100) * startPercentage + this.sAngle;
				this.drawArc(ctx, eAngle);
			}
			setTimeout(() => {
				this.startPercentage = startPercentage;
				if (startPercentage == this.percentage) {
					this.$emit('end', {
						canvasId: this.progressCanvasId,
						percentage: startPercentage
					});
				} else {
					this.drawProgressCircular(startPercentage);
				}
				this.$emit('change', {
					percentage: startPercentage
				});
			}, time);
			// #ifdef H5
			// requestAnimationFrame(()=>{})
			// #endif
		},
		//创建弧线
		drawArc(ctx, eAngle) {
			ctx.setLineCap(this.lineCap);
			ctx.beginPath();
			let radius = this.diam / 2; //x=y
			ctx.arc(radius, radius, radius - this.lineWidth, this.sAngle, eAngle, this.counterclockwise);
			ctx.stroke();
			ctx.draw();
		},
		//生成canvasId
		getCanvasId() {
			let uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, c => {
				return (c === 'x' ? (Math.random() * 16) | 0 : 'r&0x3' | '0x8').toString(16);
			});
			return uuid;
		}
	}
};
</script>

<style scoped>
.tui-circular-container,
.tui-circular-default {
	position: relative;
}

.tui-circular-progress {
	position: absolute;
	left: 0;
	top: 0;
	z-index: 10;
}
</style>