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regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.
-->
<!-- Created by Tw93 on 17/07/28. -->
<!-- Updated by Tw93 on 18/04/10. -->

<template>
  <div class="wxc-tab-page"
       :style="{ height: (tabPageHeight)+'px' }">
    <div class="tab-page-wrap"
         ref="tab-page-wrap"
         :prevent-move-event="true"
         @horizontalpan="startHandler"
         :style="{ height: tabPageHeight+'px' }">
      <div ref="tab-container"
           class="tab-container">
        <slot></slot>
      </div>
    </div>
    <scroller class="tab-title-list"
              ref="tab-title-list"
              :show-scrollbar="false"
              scroll-direction="horizontal"
              :data-spm="spmC"
              :style="{ backgroundColor: tabStyles.bgColor, height: (tabStyles.height)+'px',top:tabStyles.top+'px' }">
      <div class="title-item"
           v-for="(v,index) in tabTitles"
           :key="index"
           :ref="'wxc-tab-title-'+index"
           @click="setPage(index,v.url)"
           :style="{ width: tabStyles.width +'px', height: tabStyles.height +'px', backgroundColor: currentPage == index ? tabStyles.activeBgColor : tabStyles.bgColor }"
           :accessible="true"
           :aria-label="`${v.title?v.title:'标签'+index}`">

        <image :src="currentPage == index ? v.activeIcon : v.icon"
               v-if="titleType == 'icon'"
               :style="{ width: tabStyles.iconWidth + 'px', height:tabStyles.iconHeight+'px'}"></image>

        <text
          :style="{ fontSize: tabStyles.fontSize+'px', fontWeight: (currentPage == index && tabStyles.isActiveTitleBold)? 'bold' : 'normal', color: currentPage == index ? tabStyles.activeTitleColor : tabStyles.titleColor, paddingLeft:(tabStyles.textPaddingLeft?tabStyles.textPaddingLeft:10)+'px', paddingRight:(tabStyles.textPaddingRight?tabStyles.textPaddingRight:10)+'px'}"
          class="tab-text">{{v.title}}</text>

        <div class="border-bottom"
             v-if="tabStyles.hasActiveBottom"
             :style="{ width: tabStyles.activeBottomWidth+'px', left: (tabStyles.width-tabStyles.activeBottomWidth)/2+'px', height: tabStyles.activeBottomHeight+'px', backgroundColor: currentPage == index ? tabStyles.activeBottomColor : 'transparent' }"></div>

      </div>
    </scroller>

  </div>
</template>

<style scoped>
  .wxc-tab-page {
    width: 750px;
    background-color: #f2f3f4;
  }

  .tab-title-list {
    width: 750px;
    position: absolute;
    flex-direction: row;
  }

  .title-item {
    justify-content: center;
    align-items: center;
    border-bottom-style: solid;
  }

  .border-bottom {
    position: absolute;
    bottom: 0;
  }

  .tab-page-wrap {
    width: 750px;
  }

  .tab-container {
    flex: 1;
    flex-direction: row;
    position: absolute;
  }

  .tab-text {
    lines: 1;
    text-overflow: ellipsis;
  }
</style>

<script>
  const dom = weex.requireModule('dom');
  const animation = weex.requireModule('animation');
  const swipeBack = weex.requireModule('swipeBack');
  const expressionBinding = weex.requireModule('expressionBinding');

  import Utils from '../utils';
  import BindEnv from '../utils/bind-env';
  import Binding from 'weex-bindingx/lib/index.weex.js';

  const isIos = Utils.env.isIOS();

  export default {
    props: {
      tabTitles: {
        type: Array,
        default: () => ([])
      },
      panDist: {
        type: Number,
        default: 200
      },
      spmC: {
        type: [String, Number],
        default: ''
      },
      tabStyles: {
        type: Object,
        default: () => ({
          titleColor: '#666666',
          activeTitleColor: '#3D3D3D',
          isActiveTitleBold: true,
          width: 160,
          height: 40,
          fontSize: 24,
          textPaddingLeft: 10,
          textPaddingRight: 10
        })
      },
      titleType: {
        type: String,
        default: 'icon'
      },
      tabPageHeight: {
        type: [String, Number],
        default: 1334
      },
      needSlider: {
        type: Boolean,
        default: true
      },
      duration: {
        type: [Number, String],
        default: 300
      },
      timingFunction: {
        type: String,
        default: 'cubic-bezier(0.25, 0.46, 0.45, 0.94)'
      }
    },
    data: () => ({
      currentPage: 0,
      isMoving: false,
      deltaX: 0
    }),
    mounted() {
      // ios 下面禁止左滑出去
      if (swipeBack && swipeBack.forbidSwipeBack) {
        swipeBack.forbidSwipeBack(true);
      }
      if (BindEnv.supportsEBForIos() && this.needSlider) {
        const tabPageEl = this.$refs['tab-page-wrap'];
        Binding.prepare && Binding.prepare({
          anchor: tabPageEl.ref,
          eventType: 'pan'
        });
      }
    },
    methods: {
      next() {
        let page = this.currentPage;
        if (page < this.tabTitles.length - 1) {
          page++;
        }
        this.setPage(page);
      },
      prev() {
        let page = this.currentPage;
        if (page > 0) {
          page--;
        }
        this.setPage(page);
      },
      startHandler(e) {
        if (BindEnv.supportsEBForIos() && this.isTabView && this.needSlider) {
          this.bindExp(this.$refs['tab-page-wrap']);
        }
      },
      bindExp(element) {
        if (element && element.ref) {

          if (this.isMoving && this.gesToken !== 0) {
            Binding.unbind({
              eventType: 'pan',
              token: this.gesToken
            })
            this.gesToken = 0;
            return;
          }

          const tabElement = this.$refs['tab-container'];
          const { currentPage, panDist } = this;
          const dist = currentPage * 750;

          // x-dist

          const props = [{
            element: tabElement.ref,
            property: 'transform.translateX',
            expression: `{\"type\":\"CallExpression\",\"children\":[{\"type\":\"Identifier\",\"value\":\"min\"},{\"type\":\"Arguments\",\"children\":[{\"type\":\"NumericLiteral\",\"value\":0},{\"type\":\"CallExpression\",\"children\":[{\"type\":\"Identifier\",\"value\":\"max\"},{\"type\":\"Arguments\",\"children\":[{\"type\":\"NumericLiteral\",\"value\":${-(tabTitles.length - 1) * 750}},{\"type\":\"-\",\"children\":[{\"type\":\"Identifier\",\"value\":\"x\"},{\"type\":\"NumericLiteral\",\"value\":${dist}}]}]}]}]}]}`
          }];

          const gesTokenObj = Binding.bind({
            anchor: element.ref,
            eventType: 'pan',
            props
          }, (e) => {
            const { deltaX, state } = e;
            if (state === 'end') {
              if (deltaX < -panDist) {
                this.next();
              } else if (deltaX > panDist) {
                this.prev();
              } else {
                this.setPage(currentPage);
              }
            }
          });
          this.gesToken = gesTokenObj.token;
        }
      },
      setPage(page) {
        if (this.isMoving === true) {
          return;
        }
        this.isMoving = true;
        const previousPage = this.currentPage;
        const currentTabEl = this.$refs[`wxc-tab-title-${page}`][0];
        const { width } = this.tabStyles;
        const appearNum = parseInt(750 / width);
        const tabsNum = this.tabTitles.length;
        const computedPage = tabsNum > appearNum ? 2 : page
        const offset = page > appearNum ? -(750 - width) / 2 : -width * computedPage;

        (previousPage > appearNum || page > 1) && dom.scrollToElement(currentTabEl, {
          offset
        });

        page <= 1 && previousPage > page && dom.scrollToElement(currentTabEl, {
          offset: -width * page
        });
        this._animateTransformX(page);
        this.isMoving = false;
        this.currentPage = page;
        this.$emit('wxcTabPageCurrentTabSelected', { page });
      },
      _animateTransformX(page) {
        const { duration, timingFunction } = this;
        const containerEl = this.$refs[`tab-container`];
        const dist = page * 750;
        animation.transition(containerEl, {
          styles: {
            transform: `translateX(${-dist}px)`
          },
          duration,
          timingFunction,
          delay: 0
        }, () => {
        });
      }
    }
  };
</script>