<template>
	<view>
		<view
		    ref="uni-rate"
		    class="uni-rate"
		>
			<view
			    class="uni-rate__icon"
			    :style="{ 'margin-right': margin + 'px' }"
			    v-for="(star, index) in stars"
			    :key="index"
			    @touchstart.stop="touchstart"
			    @touchmove.stop="touchmove"
			>
				<uni-icons
				    :color="color"
				    :size="size"
				    :type="isFill ? 'star-filled' : 'star'"
				/>
				<!-- #ifdef APP-NVUE -->
				<view
				    :style="{ width: star.activeWitch.replace('%','')*size/100+'px'}"
				    class="uni-rate__icon-on"
				>
					<uni-icons
					    style="text-align: left;"
					    :color="disabled?'#ccc':activeColor"
					    :size="size"
					    type="star-filled"
					/>
				</view>
				<!-- #endif -->
				<!-- #ifndef APP-NVUE -->
				<view
				    :style="{ width: star.activeWitch}"
				    class="uni-rate__icon-on"
				>
					<uni-icons
					    :color="disabled?disabledColor:activeColor"
					    :size="size"
					    type="star-filled"
					/>
				</view>
				<!-- #endif -->
			</view>
		</view>
	</view>
</template>

<script>
	// #ifdef APP-NVUE
	const dom = uni.requireNativePlugin('dom');
	// #endif
	/**
	 * Rate 评分
	 * @description 评分组件
	 * @tutorial https://ext.dcloud.net.cn/plugin?id=33
	 * @property {Boolean} 	isFill = [true|false] 		星星的类型，是否为实心类型, 默认为实心
	 * @property {String} 	color 						未选中状态的星星颜色，默认为 "#ececec"
	 * @property {String} 	activeColor 				选中状态的星星颜色，默认为 "#ffca3e"
	 * @property {String} 	disabledColor 				禁用状态的星星颜色，默认为 "#c0c0c0"
	 * @property {Number} 	size 						星星的大小
	 * @property {Number} 	value/v-model 				当前评分
	 * @property {Number} 	max 						最大评分评分数量，目前一分一颗星
	 * @property {Number} 	margin 						星星的间距，单位 px
	 * @property {Boolean} 	disabled = [true|false] 	是否为禁用状态，默认为 false
	 * @property {Boolean} 	readonly = [true|false] 	是否为只读状态，默认为 false
	 * @property {Boolean} 	allowHalf = [true|false] 	是否实现半星，默认为 false
	 * @property {Boolean} 	touchable = [true|false] 	是否支持滑动手势，默认为 true
	 * @event {Function} change 						uniRate 的 value 改变时触发事件，e={value:Number}
	 */

	export default {
		name: "UniRate",
		props: {
			isFill: {
				// 星星的类型，是否镂空
				type: [Boolean, String],
				default: true
			},
			color: {
				// 星星未选中的颜色
				type: String,
				default: "#ececec"
			},
			activeColor: {
				// 星星选中状态颜色
				type: String,
				default: "#ffca3e"
			},
			disabledColor: {
				// 星星禁用状态颜色
				type: String,
				default: "#c0c0c0"
			},
			size: {
				// 星星的大小
				type: [Number, String],
				default: 24
			},
			value: {
				// 当前评分
				type: [Number, String],
				default: 1
			},
			max: {
				// 最大评分
				type: [Number, String],
				default: 5
			},
			margin: {
				// 星星的间距
				type: [Number, String],
				default: 0
			},
			disabled: {
				// 是否可点击
				type: [Boolean, String],
				default: false
			},
			readonly: {
				// 是否只读
				type: [Boolean, String],
				default: false
			},
			allowHalf: {
				// 是否显示半星
				type: [Boolean, String],
				default: false
			},
			touchable: {
				// 是否支持滑动手势
				type: [Boolean, String],
				default: true
			}
		},
		data() {
			return {
				valueSync: ""
			};
		},
		watch: {
			value(newVal) {
				this.valueSync = Number(newVal);
			}
		},
		computed: {
			stars() {
				const value = this.valueSync ? this.valueSync : 0;
				const starList = [];
				const floorValue = Math.floor(value);
				const ceilValue = Math.ceil(value);
				for (let i = 0; i < this.max; i++) {
					if (floorValue > i) {
						starList.push({
							activeWitch: "100%"
						});
					} else if (ceilValue - 1 === i) {
						starList.push({
							activeWitch: (value - floorValue) * 100 + "%"
						});
					} else {
						starList.push({
							activeWitch: "0"
						});
					}
				}
				return starList;
			}
		},
		created() {
			this.valueSync = Number(this.value);
			this._rateBoxLeft = 0
			this._oldValue = null
		},
		mounted() {
				setTimeout(() => {
					this._getSize()
				}, 100)
		},
		methods: {
			touchstart(e) {
				if (this.readonly || this.disabled) return
				const {
					clientX,
					screenX
				} = e.changedTouches[0]
				// TODO 做一下兼容，只有 Nvue 下才有 screenX，其他平台式 clientX
				this._getRateCount(clientX || screenX)
			},
			touchmove(e) {
				if (this.readonly || this.disabled || !this.touchable) return
				const {
					clientX,
					screenX
				} = e.changedTouches[0]
				this._getRateCount(clientX || screenX)
			},
			/**
			 * 获取星星个数
			 */
			_getRateCount(clientX) {
				const rateMoveRange = clientX - this._rateBoxLeft
				const index = parseInt(rateMoveRange / (this.size + this.margin))
				const range = parseInt(rateMoveRange - ((this.size + this.margin) * index))
				let value = 0

				if (this.allowHalf) {
					if (range > (this.size / 2)) {
						value = index + 1
					} else {
						value = index + 0.5
					}
				} else {
					value = index + 1
				}

				value = Math.max(0.5, Math.min(value, this.max))
				if (this.valueSync !== value) {
					this.valueSync = value
					this._onChange()
				}
				// const rateCount = parseInt(rateMoveRange / (this.size / 2)) + 1
			},

			/**
			 * 触发动态修改
			 */
			_onChange() {

				this.$emit("input", this.valueSync);
				this.$emit("change", {
					value: this.valueSync
				});
			},
			/**
			 * 获取星星距离屏幕左侧距离
			 */
			_getSize() {
				// #ifndef APP-NVUE
				uni.createSelectorQuery()
					.in(this)
					.select('.uni-rate')
					.boundingClientRect()
					.exec(ret => {
						if (ret) {
							this._rateBoxLeft = ret[0].left
						}
					})
				// #endif
				// #ifdef APP-NVUE
				dom.getComponentRect(this.$refs['uni-rate'], (ret) => {
					const size = ret.size
					if (size) {
						this._rateBoxLeft = size.left
					}
				})
				// #endif
			}
		}
	};
</script>

<style
    lang="scss"
    scoped
>
	.uni-rate {
		/* #ifndef APP-NVUE */
		display: flex;
		/* #endif */
		line-height: 1;
		font-size: 0;
		flex-direction: row;
	}

	.uni-rate__icon {
		position: relative;
		line-height: 1;
		font-size: 0;
	}

	.uni-rate__icon-on {
		overflow: hidden;
		position: absolute;
		top: 0;
		left: 0;
		line-height: 1;
		text-align: left;
	}
</style>