<template>
  <view class="page">
    <view @click="back" class="nav-back">
      <image class="back-img" src="/static/template/scroll-fold-nav/back.png" mode="widthFix"></image>
    </view>
    <swiper class="swiper" :current="current" :circular="index != 0" :vertical="true" @change="onSwiperChange"
      @transition="onTransition">
      <swiper-item class="swiper-item" v-for="(item,i) in visibleList" :key="i">
        <video @click="changeState(i)" ref="video" class="video-box" objectFit="cover" :id="'video-'+i"
          @loadstart="onLoadstart(i)" :src="item.src" :poster="item.poster_src" :autoplay="false"
          :show-center-play-btn="false" :loop="true" @play="onPlay(i)" @pause="onPause(i)"></video>
        <view class="video-cover" @click="changeState(i)">
          <image v-if="state[i] === 'pause'" class="play-btn" src="/static/template/swiper-vertical-video/play.png"
            mode="widthFix"></image>
        </view>
        <view class="video-info" v-if="0">
          <text class="video-info-text">容器：第 {{i}} 个</text>
          <text class="video-info-text">内容：{{item.content}}</text>
        </view>
      </swiper-item>
    </swiper>
    <view class="debug-info" v-if="0">
      <text class="status-text">debug-info 播放状态:</text>
      <text class="status-text" v-for="(value,index) in state">第{{index+1}}个:{{ value }}</text>
    </view>
  </view>
</template>
<script>
  type ListItem = { _id : string, content : string, src : string, poster_src : string }
  let page : number = 0,
    currentPageIsShow : boolean = true;

  export default {
    components: {},
    data() {
      return {
        $videoContextMap: new Map<string, VideoContext>(),
        list: [] as ListItem[],
        visibleList: [] as ListItem[],// 提高性能 可见的只有3个
        current: 0 as number,
        index: 0,
        state: ["unPlay", "unPlay", "unPlay"] as string[]
      }
    },
    created() {
      this.list = this.getData()
      this.visibleList = this.list.slice(0, 3)
    },
    watch: {
      current(current : number, oldCurrent : number) {
        let changeNumber = current - oldCurrent
        if (changeNumber == 1 || changeNumber == -2) {
          // console.error('向右');
          this.index++
        } else {
          // console.error('向左');
          this.index--
        }
        // //翻页（3项为一页）
        if (Math.abs(changeNumber) == 2) {
          // console.log('翻页');
          page = Math.floor(this.index / 3);
          // console.log(this.index);
          // console.log('page',page);
          // console.log('slice',3*page,3*page+3);
          if (this.list.length < 3 * page + 3) {
            let list : ListItem[] = this.getData()
            this.list.push(...list)
          }

          let visibleList = this.list.slice(3 * page, 3 * page + 3)
          // 换数据
          this.visibleList = visibleList
        }

        this.state.forEach((_ : string, index : number) => {
          if (index === current) {
            this.doPlay(current)
          } else {
            // 除了选中的其他已经播放的都需要停止
            this.doStop(index)
            console.log('index:' + index + '已被执行停止');
          }
        })
      }
    },
    onReady() {
      // 一启动完成，就播放第一个
      this.doPlay(0)
    },
    onShow() {
      currentPageIsShow = true
    },
    onHide() {
      currentPageIsShow = false
      console.log('pages-onHide');
      this.doPause(this.current)
    },
    onUnload() {
      this.doPause(this.current)
    },
    methods: {
      changeState(index : number) {
        if (this.state[index] === 'play') {
          this.doPause(index)
        } else {
          this.doPlay(this.current)
        }
      },
      onLoadstart(index : number) {
        console.error("onLoadstart  video" + index);
      },
      getVideoContext(index : number) : VideoContext {
        const videoContextMap = this.$data['$videoContextMap'] as Map<string, VideoContext>
        let videoContext : VideoContext | null = videoContextMap.get('video-' + index)
        if (videoContext == null) {
          videoContext = uni.createVideoContext('video-' + index, this) as VideoContext
          videoContextMap.set('video-' + index, videoContext)
        }
        return videoContext
      },
      doPlay(index : number) {
        console.log("doPlay  video" + index);
        this.getVideoContext(index).play()
      },
      doStop(index : number) {
        console.log("doStop  video-" + index);
        this.getVideoContext(index).stop();
        // TODO 临时方案：解决.stop()时触发了doPause的问题
        setTimeout(() => {
          this.state[index] = 'unPlay'
        }, 1000)
      },
      doPause(index : number) {
        this.getVideoContext(index).pause()
        console.log("doPause  video-" + index);
      },
      onPause(index : number) {
        this.state[index] = 'pause'
        console.log('onPause', index);
      },
      onPlay(index : number) {
        if (this.current != index || !currentPageIsShow) {
          this.onPause(index)
        } else {
          this.state[index] = 'play'
          console.log('onPlay', index);
        }
      },
      getData() : ListItem[] {
        let videoUrlList = [
          'https://qiniu-web-assets.dcloud.net.cn/uni-app-x/static/video/swiper-vertical-video/uts.mp4',
          'https://qiniu-web-assets.dcloud.net.cn/uni-app-x/static/video/swiper-vertical-video/uni-ai.mp4',
          'https://qiniu-web-assets.dcloud.net.cn/uni-app-x/static/video/swiper-vertical-video/uni-verify.mp4'
        ] as string[]

        let posterSrcList = [
          'https://qiniu-web-assets.dcloud.net.cn/uni-app-x/static/images/swiper-vertical-video-poster/uni-uts.jpg',
          'https://qiniu-web-assets.dcloud.net.cn/uni-app-x/static/images/swiper-vertical-video-poster/uni-ai.jpg',
          'https://qiniu-web-assets.dcloud.net.cn/uni-app-x/static/images/swiper-vertical-video-poster/uni-verify.jpg'
        ] as string[]

        let list = [] as ListItem[];
        for (let i = 0; i < 6; i++) {
          let index = this.list.length + i;
          let listItem : ListItem = {
            "_id": "a00" + index,
            "content": "这是第" + index + "条数据，url地址" + videoUrlList[i % 3],
            "src": videoUrlList[i % 3],
            "poster_src": posterSrcList[i % 3]
          }
          list.push(listItem)
        }
        return list
      },
      onSwiperChange(e : SwiperChangeEvent) {
        // console.error('SwiperChangeEvent',e.detail.current);
        this.current = e.detail.current;
      },
      onTransition(/*e : SwiperTransitionEvent*/) {
        // console.log('onTransition e.detail.dx', e.detail.dx);
      },
      back() {
        uni.navigateBack({
          success(result) {
            console.log('navigateBack success', result.errMsg)
          },
          fail(error) {
            console.log('navigateBack fail', error.errMsg)
          },
          complete(result) {
            console.log('navigateBack complete', result.errMsg)
          }
        })
      }
    }
  }
</script>

<style>
  .page {
    width: 750rpx;
    flex: 1;
  }

  .swiper,
  .swiper-item,
  .video-box,
  .video-cover {
    width: 750rpx;
    flex: 1;
    height: 100%;
  }

  .swiper-item {
    position: relative;
  }

  .video-box {
    width: 750rpx;
  }

  .video-cover {
    position: absolute;
    justify-content: center;
    align-items: center;
    align-content: center;
  }

  .play-btn {
    width: 80rpx;
    height: 80rpx;
  }

  .video-info {
    position: absolute;
    bottom: 0;
    padding: 15px;
  }

  .video-info-text {
    font-size: 14px;
    color: red;
    line-height: 20px;
  }

  .debug-info {
    position: fixed;
    top: 15px;
    width: 750rpx;
    background-color: rgba(255, 255, 255, 0.3);
  }

  .status-text {
    color: red;
    padding: 15px;
  }

  .nav-back {
    position: absolute;
    top: 20px;
    left: 8px;
    background-color: rgba(220, 220, 220, 0.8);
    border-radius: 100px;
    width: 28px;
    height: 28px;
    justify-content: center;
    align-items: center;
    z-index: 10;
  }

  .nav-back .back-img {
    width: 18px;
    height: 18px;
  }
</style>
