<script setup>
import { ref, watch, onUnmounted } from 'vue'

defineOptions({
  name: 'xtx-carousel'
})

const props = defineProps({
  // 轮播图数据
  sliders: {
    type: Array,
    default: () => [],
  },
  // 是否自动轮播
  autoPlay: {
    type: Boolean,
    default: false,
  },
  // 轮播间隔时间
  duration: {
    type: Number,
    default: 3000,
  },
})

// 控制图片的索引
const index = ref(0)
// 自动轮播图的逻辑
let timer = null
const autoPlayFn = () => {
  // 防止定时器重复添加
  clearInterval(timer)
  // 自动播放，每隔多久切换索引
  timer = setInterval(() => {
    index.value++
    if (index.value >= props.sliders.length) {
      index.value = 0
    }
  }, props.duration)
}

// 需要监听sliders数据变化，判断如果有数据且autoPlay是true
watch(
  () => props.sliders,
  newVal => {
    if (newVal.length && props.autoPlay) {
      autoPlayFn()
    }
  },
  { immediate: true }
)

// 2. 鼠标进入暂停  离开开启自动播放（有开启条件）
const stop = () => {
  if (timer) clearInterval(timer)
}

const start = () => {
  if (props.sliders.length && props.autoPlay) {
    autoPlayFn()
  }
}

// 3. 点击点点可以切换，上一张下一张
const toggle = step => {
  // 将要改变的索引
  const newIndex = index.value + step
  // 超出的情况，太大了
  if (newIndex > props.sliders.length - 1) {
    index.value = 0
    return
  }
  // 超出的情况，太小了
  if (newIndex < 0) {
    index.value = props.sliders.length - 1
    return
  }
  // 正常
  index.value = newIndex
}

// 4. 组件卸载，清除定时器
onUnmounted(() => {
  clearInterval(timer)
})
</script>

<template>
  <div class="xtx-carousel" @mouseenter="stop" @mouseleave="start">
    <!-- 图片容器 -->
    <ul class="carousel-body">
      <!-- fade 显示的图片加上 -->
      <li
        class="carousel-item"
        v-for="(item, i) in sliders"
        :key="i"
        :class="{ fade: index === i }"
      >
        <!-- 图片 -->
        <router-link v-if="item.imgUrl" to="/">
          <img :src="item.imgUrl" alt="" />
        </router-link>

        <!-- 商品列表 item=[goods1, goods2, ...]-->
        <div v-else class="slider">
          <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
            <img :src="goods.picture" alt="" />
            <p class="name ellipsis">{{ goods.name }}</p>
            <p class="price">&yen;{{ goods.price }}</p>
          </RouterLink>
        </div>
      </li>
    </ul>
    <!-- 上一张 -->
    <a @click="toggle(-1)" href="javascript:;" class="carousel-btn prev">
      <i class="iconfont icon-angle-left"></i>
    </a>
    <!-- 下一张 -->
    <a @click="toggle(1)" href="javascript:;" class="carousel-btn next">
      <i class="iconfont icon-angle-right"></i>
    </a>
    <!-- 指示器 -->
    <div class="carousel-indicator">
      <!-- active 激活点 -->
      <span
        @click="index = i"
        v-for="(item, i) in sliders"
        :key="i"
        :class="{ active: index === i }"
      ></span>
    </div>
  </div>
</template>

<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 50%;
      transform: translateY(-50%);
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
// 轮播商品
.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;
  > a {
    width: 240px;
    text-align: center;
    img {
      padding: 20px;
      width: 230px !important;
      height: 230px !important;
    }
    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }
    .price {
      font-size: 16px;
      color: var(--price-color);
      margin-top: 15px;
    }
  }
}
</style>
