<template>
	<view class="shell">
		<view class="l">
			<!-- 小灯列表 -->
			<view class="lamp" v-for="(item,index) in lamps" :key="item.color" :style="{'background-color': item.color,'box-shadow': '0 0 5px '+item.color}"></view>
		</view>
		<view class="c">
			<view class="HMSM">
				<!-- 背景 -->
				<view class="HMSM-display-bg">
					<view v-for="(shaft,index) in shaftList" :key="index" class="box"></view>
				</view>
				<!-- 奖品列表 -->
				<view class="HMSM-display">
					<view v-for="(shaft,index) in shaftList" :key="index" class="HMSM-shaft"
						:style="{transform: 'translate3d(0, '+translateY[index]+'%, 0)','transition-duration':duration+'ms'}"
						:class="{'roll_animation':(rollState=='start')}">
						<view v-for="(item,shaftIndex) in shaft" :key="item.HMSM_id">
							<image :src="item.img"></image>
						</view>
					</view>
				</view>
			</view>
		</view>
		<view class="r">
			<!-- 小灯列表 -->
			<view class="lamp" v-for="(item,index) in lamps" :key="item.color" :style="{'background-color': item.color,'box-shadow': '0 0 5px '+item.color}"></view>
		</view>
	</view>
	
</template>
<script>
	// 实现原理
	// 就是一个长列表，做一个translateY的位移，然后加上延迟
	// 只要这个列表足够长，设置好动画曲线，就能实现效果了
	
	export default {
		name: 'HM-slotMachine',
		data() {
			return {
				// 低二/三列开始滚动的延迟
				delay:0,
				// 总的摇奖时间 单位毫秒
				duration: 0,
				// 摇奖方向 可选 up down
				direction: 'up',
				// 摇奖状态
				rollState: 'stop',
				// 奖品列表
				prizeList: [],
				// 位置
				translateY: [0, 0, 0],
				// 滚动列表
				shaftList: [],
				// 控制小灯切换的定时器
				lampTimer:false,
				// 小灯颜色
				lamps:[
					{color:'#97eefb'},
					{color:'#fecc6a'},
					{color:'#fb7c84'},
					{color:'#a097ff'},
					{color:'#fd0100'}
				]
			}
		},
		// #ifdef VUE3
		emits: ['init','roll'],
		// #endif
		methods: {
			// 初始化
			init({
				// 奖品列表
				prizeList,
				// 默认显示奖品
				defaultResults=[],
				// 滚动延迟 默认500ms
				delay = 500,
				// 滚动时间 从开始滚动到所有滚动结束 默认4000ms
				duration = 4000,
				// 滚动方向
				direction = 'up'
				
			}) {
				// 校验传入参数
				if(typeof delay !=='number'){
					console.warn('delay参数应该传入整型');
					delay = parseInt(delay)
					delay = isNaN(delay)?500:delay;
				}
				if(typeof duration !=='number'){
					console.warn('duration参数应该传入整型');
					duration = parseInt(duration)
					duration = isNaN(duration)?4000:duration;
				}
				if(typeof prizeList !=='object'){
					return console.error('prizeList参数应该传入数组对象');
				}
				if(typeof defaultResults !=='object'){
					return console.error('defaultResults参数应该传入数组');
				}
				if(direction !='up' && direction !='down'){
					return console.error('direction参数应该传入"up"或者"down"');
				}
				// 校验完毕
				
				this.direction = direction;
				
				// 最低4秒
				if (duration < 4000) {
					duration = 4000
				};
				// 总时长要扣除延迟滚动那一部分时间
				duration = duration - (delay*2);
				
				this.prizeList = prizeList;
				let shaftList = [];
				shaftList.length = 3;
				for (let i = 0; i < 3; i++) {
					// 打乱顺序和扩充列表
					shaftList[i] = this.shuffle(prizeList);
					for (let j = 0, len = shaftList[i].length; j < len; j++) {
						shaftList[i][j].HMSM_id = 'id_'+i+'_'+j;
					}
				}
				this.shaftList = shaftList;
				if(defaultResults.length==3){
					this.setTranslateY(defaultResults);
					setTimeout(()=>{
						this.stop();
					},50)
				}{
					if(this.direction == 'down'){
						// 如果是向下滚动，则定位到最底部
						let topY = (this.shaftList[1].length-1)*-100;
						this.translateY.splice(0,3,topY,topY,topY);
					}
				}
				this.$nextTick(function(){
					this.duration = duration;
					this.delay = delay;
					
				})
			},
			// 摇奖
			roll({
				// 开奖结果
				results = null,
				// 开奖回调
				success = null
			}) {
				if(this.rollState == 'start'){
					return console.warn('正在抽奖哦！');
				}
				if (typeof results != 'object') {
					return console.error('请传入正确的开奖结果参数results');
				}
				this.rollState = 'start';
				// 滚动位置
				let res = this.setTranslateY(results);
				this.lampTimer&&clearInterval(this.lampTimer);
				// 切换灯光
				this.startSwitchLamp();
				setTimeout(() => {
					typeof success == "function" && success(res);
					this.stop();
				}, this.duration + 1000);
				
			},
			// 设定位置
			setTranslateY(results){
				let res = {
					results: []
				}
				console.log("results: ",results);
				for (let i = 0, len = results.length; i < len; i++) {
					if(this.direction == 'up'){
						// 倒序遍历奖品列表，找出开奖结果的最靠后的下标
						for (let k = this.shaftList[i].length - 1; k >= 0; k--) {
							if (this.shaftList[i][k].value == results[i]) {
								res.results.push(JSON.parse(JSON.stringify(this.shaftList[i][k])));
								// 延迟滚动
								setTimeout(() => {
									this.translateY.splice(i,1,k * -100)
								}, i * this.delay)
								break;
							}
						}
					}else{
						// 顺序遍历奖品列表，找出开奖结果的最靠前的下标
						for (let k = 0,len = this.shaftList[i].length; k < len; k++) {
							if (this.shaftList[i][k].value == results[i]) {
								res.results.push(JSON.parse(JSON.stringify(this.shaftList[i][k])));
								// 延迟滚动
								setTimeout(() => {
									this.translateY.splice(i,1,k * -100);
								}, i * this.delay)
								break;
							}
						}
					}
				}
				return res;
			},
			// 摇奖停止
			stop() {
				this.rollState = 'stop';
				this.lampTimer&&clearInterval(this.lampTimer);
				this.$nextTick(function(){
					let tolerance = (this.shaftList[0].length/this.prizeList.length-1)*this.prizeList.length*100; //公差
					tolerance = this.direction == 'up'&&tolerance||-tolerance
					// 停止滚动之后，位移到 最前面/最后面 对应位置，为下一次摇奖留下滚动空间，实现多次摇奖无缝滚动效果
					for(let i=0,len=this.translateY.length;i<len;i++){
						let topY = this.translateY[i] + tolerance;
						this.translateY.splice(i,1,topY)
					}
				})
			},
			// 两边的小灯切换
			startSwitchLamp(){
				this.lampTimer = setInterval(()=>{
					if(this.rollState != 'stop'){
						
						// #ifndef APP-PLUS
						if(this.direction == 'up'){
							this.lamps.push(this.lamps.shift())
						}else{
							this.lamps.unshift(this.lamps.pop())
						}
						// #endif
						
						// #ifdef APP-PLUS
						if(this.direction == 'up'){
							const tmp = this.lamps[0];
							[this.lamps[0],this.lamps[1],this.lamps[2],this.lamps[3]] = [this.lamps[1],this.lamps[2],this.lamps[3],this.lamps[4]];
							this.$nextTick(function(){
								this.lamps[4] = tmp;
							})
						
						}else{
							const tmp = this.lamps[4];
							[this.lamps[1],this.lamps[2],this.lamps[3],this.lamps[4]] = [this.lamps[0],this.lamps[1],this.lamps[2],this.lamps[3]];
							this.$nextTick(function(){
								this.lamps[0] = tmp;
							})
						}
						// #endif
						
					}
				},50)
			},
			// 打乱顺序
			shuffle(arr) {
				let tmpArr = JSON.parse(JSON.stringify(arr))
				for (let i = 1; i < tmpArr.length; i++) {
					const random = Math.floor(Math.random() * (i + 1));
					[tmpArr[i], tmpArr[random]] = [tmpArr[random], tmpArr[i]];
				}
				// 保证最低有40个奖品列表，保证滚动摇奖时候效果
				// 如果抽奖总时长比较长时候，请适当调大40
				let len = Math.ceil(40/arr.length);  //倍数
				let tmpShaft = []; 
				while (len>0){
					tmpShaft.push(...tmpArr);
					len--;
				}
				return JSON.parse(JSON.stringify(tmpShaft));
			}
		}

	}
</script>
<style lang="scss" scoped>
	.shell{
		width: 630rpx;
		height: 352rpx;
		background-image: linear-gradient(to right,#6543BC, #754EAE);
		border-radius: 50rpx;
		display: flex;
		align-items: center;
		.l,.r{
			width: 36rpx;
			height: 260rpx;
			display: flex;
			flex-direction: column;
			align-items: center;
			justify-content: space-between;
			.lamp{
				width: 14rpx;
				height: 14rpx;
				// box-shadow: 0 0 2px rgba($color: #000000, $alpha: 0.5);
				
				border-radius: 50%;
			}
		}
		.l{
			padding-left: 10rpx;
		}
		.r{
			padding-right: 10rpx;
		}
		.c{
			width: 540rpx;
			height: 270rpx;
			background-color: #8461E9;
			border: solid 1rpx #6443B6;
			// box-shadow: 0 0 2px rgba($color: #000000, $alpha: 0.2);
			border-radius: 30rpx;
			flex-shrink: 0;
			display: flex;
			justify-content: center;
			align-items: center;
			.HMSM {
				width: 510rpx;
				height: 240rpx;
				position: relative;
				.HMSM-display-bg{
					width: 100%;
					height: 240rpx;
					position: absolute;
					left: 0;
					top: 0;
					z-index: 2;
					display: flex;
					flex-direction: row;
					justify-content: space-between;
					.box{
						width: 160rpx;
						height: 240rpx;
						// background-color: #fff;
						background-image: linear-gradient(to top,#E4DEFC, rgba(255,255,255,0));
						box-shadow: 0 0 2px rgba($color: #fff, $alpha: 1);
						border: solid 1px #9d82ea;
						box-sizing: border-box;
						&:first-child{
							border-radius: 20rpx 0 0 20rpx;
						}
						&:last-child{
							border-radius: 0 20rpx 20rpx 0;
						}
					}
				}
				.HMSM-display {
					position: absolute;
					left: 0;
					top: 0;
					z-index: 3;
					width: 100%;
					height: 240rpx;
					overflow: hidden;
					display: flex;
					flex-direction: row;
					justify-content: space-between;
					border-radius: 20rpx;
					.HMSM-shaft {
						width: 160rpx;
						transition-property:none;
						transition-duration:0s;
						

						
						&.roll_animation {
							transition-property: transform;
							transition-timing-function: cubic-bezier(0.5, 0, 0.1, 1);
						}
						>view {
							width: 160rpx;
							height: 240rpx;
							display: flex;
							justify-content: center;
							align-items: center;
							overflow: hidden;
							background-color: #fff;
							image{
								width: 160rpx;
								height: 240rpx;
							}
						}
						
					}
				}
			}
		}
	}
	
</style>
