soul-yongping/miniprogram/utils/chapterAccessManager.js

/**
 * 章节权限管理器
 * 统一管理章节权限判断、状态流转、异常处理
 */

const app = getApp()

class ChapterAccessManager {
  constructor() {
    this.accessStates = {
      UNKNOWN: 'unknown',
      FREE: 'free',
      LOCKED_NOT_LOGIN: 'locked_not_login',
      LOCKED_NOT_PURCHASED: 'locked_not_purchased',
      UNLOCKED_PURCHASED: 'unlocked_purchased',
      ERROR: 'error'
    }
  }

  /**
   * 拉取最新配置（免费章节列表、价格等）
   */
  async fetchLatestConfig() {
    try {
      const res = await app.request({ url: '/api/miniprogram/config', silent: true, timeout: 3000 })
      if (res.success && res.freeChapters) {
        return {
          freeChapters: res.freeChapters,
          prices: res.prices || { section: 1, fullbook: 9.9 }
        }
      }
    } catch (e) {
      console.warn('[AccessManager] 获取配置失败，使用默认配置:', e)
    }
    
    // 默认配置
    return {
      freeChapters: ['preface', 'epilogue', '1.1', 'appendix-1', 'appendix-2', 'appendix-3'],
      prices: { section: 1, fullbook: 9.9 }
    }
  }

  /**
   * 判断章节是否免费
   */
  isFreeChapter(sectionId, freeList) {
    return freeList.includes(sectionId)
  }

  /**
   * 【核心方法】确定章节权限状态
   * @param {string} sectionId - 章节ID
   * @param {Array} freeList - 免费章节列表
   * @returns {Promise<string>} accessState
   */
  async determineAccessState(sectionId, freeList) {
    try {
      // 1. 检查是否免费
      if (this.isFreeChapter(sectionId, freeList)) {
        console.log('[AccessManager] 免费章节:', sectionId)
        return this.accessStates.FREE
      }

      // 2. 检查是否登录
      const userId = app.globalData.userInfo?.id
      if (!userId) {
        console.log('[AccessManager] 未登录，需要登录:', sectionId)
        return this.accessStates.LOCKED_NOT_LOGIN
      }

      // 3. 请求服务端校验是否已购买（带重试）
      const res = await this.requestWithRetry(
        `/api/miniprogram/user/check-purchased?userId=${encodeURIComponent(userId)}&type=section&productId=${encodeURIComponent(sectionId)}`,
        { timeout: 5000 },
        2 // 最多重试2次
      )

      if (res.success && res.data?.isPurchased) {
        console.log('[AccessManager] 已购买:', sectionId, res.data.reason)
        
        // 同步更新本地缓存（仅用于展示，不作权限依据）
        this.syncLocalCache(sectionId, res.data)
        
        return this.accessStates.UNLOCKED_PURCHASED
      }

      console.log('[AccessManager] 未购买:', sectionId)
      return this.accessStates.LOCKED_NOT_PURCHASED

    } catch (error) {
      console.error('[AccessManager] 权限判断失败:', error)
      // 网络/服务端错误 → 保守策略：返回错误状态
      return this.accessStates.ERROR
    }
  }

  /**
   * 带重试的请求
   */
  async requestWithRetry(url, options = {}, maxRetries = 3) {
    let lastError = null
    
    for (let i = 0; i < maxRetries; i++) {
      try {
        const res = await app.request(url, options)
        return res
      } catch (e) {
        lastError = e
        console.warn(`[AccessManager] 第 ${i+1} 次请求失败:`, url, e.message)
        
        // 如果不是最后一次，等待后重试（指数退避）
        if (i < maxRetries - 1) {
          await this.sleep(1000 * (i + 1))
        }
      }
    }
    
    throw lastError
  }

  /**
   * 同步更新本地购买缓存（仅用于展示，不作权限依据）
   */
  syncLocalCache(sectionId, purchaseData) {
    if (purchaseData.reason === 'has_full_book') {
      app.globalData.hasFullBook = true
    }
    
    if (!app.globalData.purchasedSections.includes(sectionId)) {
      app.globalData.purchasedSections = [...app.globalData.purchasedSections, sectionId]
    }
    
    // 更新 storage
    const userInfo = app.globalData.userInfo || {}
    userInfo.hasFullBook = app.globalData.hasFullBook
    userInfo.purchasedSections = app.globalData.purchasedSections
    wx.setStorageSync('userInfo', userInfo)
  }

  /**
   * 刷新用户购买状态（从 orders 表拉取最新）
   */
  async refreshUserPurchaseStatus() {
    const userId = app.globalData.userInfo?.id
    if (!userId) return
    
    try {
      const res = await app.request(`/api/miniprogram/user/purchase-status?userId=${encodeURIComponent(userId)}`)
      
      if (res.success && res.data) {
        app.globalData.hasFullBook = res.data.hasFullBook || false
        app.globalData.purchasedSections = res.data.purchasedSections || []
        
        const userInfo = app.globalData.userInfo || {}
        userInfo.hasFullBook = res.data.hasFullBook
        userInfo.purchasedSections = res.data.purchasedSections
        wx.setStorageSync('userInfo', userInfo)
        
        console.log('[AccessManager] 购买状态已刷新:', {
          hasFullBook: res.data.hasFullBook,
          purchasedCount: res.data.purchasedSections.length
        })
      }
    } catch (e) {
      console.error('[AccessManager] 刷新购买状态失败:', e)
    }
  }

  /**
   * 获取状态对应的用户提示文案
   */
  getStateMessage(accessState) {
    const messages = {
      [this.accessStates.UNKNOWN]: '加载中...',
      [this.accessStates.FREE]: '免费阅读',
      [this.accessStates.LOCKED_NOT_LOGIN]: '登录后继续阅读',
      [this.accessStates.LOCKED_NOT_PURCHASED]: '购买后继续阅读',
      [this.accessStates.UNLOCKED_PURCHASED]: '已解锁',
      [this.accessStates.ERROR]: '网络异常，请重试'
    }
    return messages[accessState] || '未知状态'
  }

  /**
   * 判断是否可访问全文
   */
  canAccessFullContent(accessState) {
    return [this.accessStates.FREE, this.accessStates.UNLOCKED_PURCHASED].includes(accessState)
  }

  /**
   * 工具：延迟
   */
  sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms))
  }
}

// 导出单例
const accessManager = new ChapterAccessManager()
export default accessManager