/**
 * 推荐系统 Mixin — 为维度页面提供个性化推荐加载与行为追踪
 *
 * 用法:
 *   import recommendMixin from '../../mixins/recommend-mixin'
 *   export default {
 *     mixins: [recommendMixin],
 *     methods: {
 *       loadDimensionData: function() {
 *         this.loadRecommendations('action')  // 传入当前维度代码
 *       }
 *     }
 *   }
 *
 * 模板:
 *   <RecommendedSection
 *     v-if="recommendItems.length > 0"
 *     :items="recommendItems"
 *     :hasMore="recommendHasMore"
 *     @itemClick="onRecommendItemClick"
 *     @more="$emit('more')" />
 */
import { getRecommendList, trackRecommendAction } from '../utils/api'

var recommendMixin = {
  data: function() {
    return {
      recommendItems: [],
      recommendHasMore: false,
      _recommendDimension: null
    }
  },
  methods: {
    /**
     * 加载个性化推荐列表
     * @param {String} dimensionCode 维度代码 body/mind/wisdom/action/wealth
     * @param {Number} limit 推荐数量
     */
    loadRecommendations: function(dimensionCode, limit) {
      limit = limit || 6
      this._recommendDimension = dimensionCode
      var self = this
      getRecommendList({
        dimensionCode: dimensionCode,
        size: limit
      }).then(function(res) {
        if (res.code === 200 && res.data && res.data.items) {
          self.recommendItems = res.data.items || []
          self.recommendHasMore = res.data.hasMore || false
        }
      }).catch(function() {
        // 静默失败，不阻塞页面
      })
    },

    /**
     * 推荐项点击处理 — 跳转 + 行为追踪
     */
    onRecommendItemClick: function(item) {
      if (!item) return
      // 追踪点击行为
      this._trackRecommend(item, 'click')
      // 根据内容类型跳转
      this._navigateToRecommend(item)
    },

    /**
     * 内部：追踪推荐行为
     */
    _trackRecommend: function(item, action) {
      trackRecommendAction({
        contentType: item.contentType,
        contentId: item.id,
        action: action
      }).catch(function() {
        // 静默
      })
    },

    /**
     * 内部：根据内容类型导航
     */
    _navigateToRecommend: function(item) {
      var url = ''
      switch (item.contentType) {
        case 'article':
          url = '/pages/article-center/article-detail/article-detail?id=' + item.id
          break
        case 'task':
          url = '/pages/tasks/task-detail/task-detail?id=' + item.id
          break
        case 'product':
          url = '/pages/shop/product-detail/product-detail?id=' + item.id
          break
        case 'activity':
          url = '/pages/activity/activity-detail/activity-detail?id=' + item.id
          break
        default:
          return
      }
      if (url) {
        uni.navigateTo({ url: url })
      }
    }
  },

  /**
   * 页面显示时展示推荐内容（曝光追踪）
   */
  onShow: function() {
    if (this.recommendItems && this.recommendItems.length > 0) {
      var self = this
      // 只追踪前3条曝光（避免过多请求）
      var showItems = this.recommendItems.slice(0, 3)
      showItems.forEach(function(item) {
        self._trackRecommend(item, 'show')
      })
    }
  }
}

export default recommendMixin