frontend/src/services/dataSyncService.ts

import api from '@/services'
import { debounce } from 'lodash'

class DataSyncService {
  private currentPPTId: string | null = null
  private saveTimeout: number | null = null
  private isOnline = true
  private autoSaveDelay = 300000 // 默认5分钟，可配置
  private isInitialized = false
  private debouncedSave: any = null

  constructor() {
    this.setupNetworkMonitoring()
  }

  // 延迟初始化，在 Pinia 可用后调用
  async initialize() {
    if (this.isInitialized) return
    await this.setupAutoSave()
    this.isInitialized = true
  }

  // 设置自动保存延迟时间（毫秒）
  setAutoSaveDelay(delay: number) {
    this.autoSaveDelay = Math.max(500, delay) // 最小500ms
    if (this.isInitialized) {
      this.setupAutoSave() // 重新设置自动保存
    }
  }

  // 获取当前自动保存延迟时间
  getAutoSaveDelay(): number {
    return this.autoSaveDelay
  }

  // 设置当前PPT ID
  setCurrentPPTId(pptId: string) {
    this.currentPPTId = pptId
  }

  // 自动保存功能
  private async setupAutoSave() {
    if (this.debouncedSave) {
      this.debouncedSave.cancel()
    }

    this.debouncedSave = debounce(async () => {
      await this.savePPT()
    }, this.autoSaveDelay) // 使用可配置的延迟时间

    // 监听slides变化
    try {
      const { useSlidesStore } = await import('@/store')
      const slidesStore = useSlidesStore()
      slidesStore.$subscribe(() => {
        if (this.isOnline && this.currentPPTId) {
          this.debouncedSave()
        }
      })
    } 
    catch (error) {
      // console.warn('无法设置自动保存，store 未就绪:', error)
    }
  }

  // 网络状态监控
  private setupNetworkMonitoring() {
    window.addEventListener('online', () => {
      this.isOnline = true
      // console.log('网络已连接，恢复自动保存')
    })

    window.addEventListener('offline', () => {
      this.isOnline = false
      // console.log('网络已断开，暂停自动保存')
    })
  }

  // 保存PPT到后端
  async savePPT(force = false): Promise<boolean> {
    // 动态导入 store，避免初始化时的依赖问题
    const { useAuthStore, useSlidesStore } = await import('@/store')
    
    try {
      const authStore = useAuthStore()
      const slidesStore = useSlidesStore()

      if (!authStore.isLoggedIn) {
        // console.warn('用户未登录，无法保存')
        return false
      }

      // 如果没有当前PPT ID且是强制保存，创建新PPT
      if (!this.currentPPTId && force) {
        try {
          const response = await api.createPPT(slidesStore.title || '未命名演示文稿')
          this.currentPPTId = response.pptId
          
          // 更新slides store中的数据以匹配新创建的PPT
          if (response.ppt) {
            slidesStore.setSlides(response.ppt.slides)
            slidesStore.setTitle(response.ppt.title)
            slidesStore.setTheme(response.ppt.theme)
          }
          
          // console.log('创建新PPT并保存成功')
          return true
        } 
        catch (createError) {
          // console.error('创建新PPT失败:', createError)
          return false
        }
      }

      if (!this.currentPPTId && !force) {
        // console.warn('没有当前PPT ID')
        return false
      }

      const pptData = {
        pptId: this.currentPPTId,
        title: slidesStore.title,
        slides: slidesStore.slides,
        theme: slidesStore.theme
      }

      await api.savePPT(pptData)
      // console.log('PPT保存成功')
      return true
    } 
    catch (error) {
      // console.error('PPT保存失败:', error)
      return false
    }
  }

  // 创建新PPT
  async createNewPPT(title: string): Promise<string | null> {
    const { useAuthStore } = await import('@/store')
    const authStore = useAuthStore()

    if (!authStore.isLoggedIn) {
      throw new Error('用户未登录')
    }

    try {
      const response = await api.createPPT(title)
      this.setCurrentPPTId(response.pptId)
      return response.pptId
    } 
    catch (error) {
      // console.error('创建PPT失败:', error)
      throw error
    }
  }

  // 加载PPT
  async loadPPT(pptId: string): Promise<boolean> {
    const { useAuthStore, useSlidesStore } = await import('@/store')
    const authStore = useAuthStore()
    const slidesStore = useSlidesStore()

    if (!authStore.isLoggedIn) {
      throw new Error('用户未登录')
    }

    try {
      const pptData = await api.getPPT(pptId)
      
      slidesStore.setSlides(pptData.slides)
      slidesStore.setTitle(pptData.title)
      if (pptData.theme) {
        slidesStore.setTheme(pptData.theme)
      }
      
      this.setCurrentPPTId(pptId)
      // console.log('PPT加载成功')
      return true
    } 
    catch (error) {
      // console.error('PPT加载失败:', error)
      throw error
    }
  }

  // 获取PPT列表
  async getPPTList() {
    const { useAuthStore } = await import('@/store')
    const authStore = useAuthStore()

    if (!authStore.isLoggedIn) {
      throw new Error('用户未登录')
    }

    return await api.getPPTList()
  }

  // 删除PPT
  async deletePPT(pptId: string): Promise<boolean> {
    const { useAuthStore } = await import('@/store')
    const authStore = useAuthStore()

    if (!authStore.isLoggedIn) {
      throw new Error('用户未登录')
    }

    try {
      await api.deletePPT(pptId)
      
      // 如果删除的是当前PPT，清除当前PPT ID
      if (this.currentPPTId === pptId) {
        this.currentPPTId = null
      }
      
      // console.log('PPT删除成功')
      return true
    } 
    catch (error) {
      // console.error('PPT删除失败:', error)
      throw error
    }
  }

  // 生成分享链接
  async generateShareLink(slideIndex = 0) {
    const { useAuthStore } = await import('@/store')
    const authStore = useAuthStore()

    if (!authStore.isLoggedIn || !this.currentPPTId) {
      throw new Error('用户未登录或没有当前PPT')
    }

    try {
      const response = await api.generateShareLink(
        authStore.currentUser!.id,
        this.currentPPTId,
        slideIndex
      )
      return response
    } 
    catch (error) {
      // console.error('生成分享链接失败:', error)
      throw error
    }
  }

  // 手动保存
  async manualSave(): Promise<boolean> {
    return await this.savePPT(true)
  }
}

// 创建单例实例
export const dataSyncService = new DataSyncService()
export default dataSyncService