import { useCallback, useRef } from 'react'
import { useTabStore } from '../stores/tabStore'
import { useEditorStore } from '../stores/editorStore'
import { recentFilesRepository } from '../db/recentFilesRepository'
import { logError } from '../lib/errorHandler'
import { MeToast, showToast } from '../lib/toast'

/**
 * AR-01: 从 App.tsx 提取的文件操作逻辑
 * UX-02: 添加 loading 状态指示
 * v0.1.9: handleSave 添加防重入锁，避免编辑器 onSave + 全局 Ctrl+S 双重触发
 * v0.6.0: loading 改用 MeToast.loading 链式转换，保存结果用 MeToast.promise 提示
 */
export function useFileOperations() {
  const createTab = useTabStore(s => s.createTab)
  const getActiveTab = useTabStore(s => s.getActiveTab)
  const setLoading = useEditorStore(s => s.setLoading)

  // 防重入：onSave 回调 + 全局 Ctrl+S handler 可能在 300ms 内双重触发
  const savingGate = useRef(false)

  const handleOpenFile = useCallback(async (): Promise<void> => {
    if (!window.electronAPI) return
    const loading = MeToast.loading('打开文件...')
    try {
      setLoading('file-open', true)
      const result = await window.electronAPI.openFile()
      if (result && 'filePath' in result) {
        createTab(result.filePath, result.content)
        if (result.filePath) recentFilesRepository.add(result.filePath)
        setTimeout(() => useTabStore.getState().saveToDB(), 100)
        loading.success('文件已打开')
      } else {
        loading.dismiss()
      }
    } catch (error) {
      logError('打开文件失败', error)
      loading.error('打开文件失败')
    } finally {
      setLoading('file-open', false)
    }
  }, [createTab, setLoading])

  const handleSave = useCallback(async (): Promise<void> => {
    // 防重入：300ms 内忽略重复调用（编辑器 onSave + 全局 Ctrl+S 双重触发）
    if (savingGate.current) return
    savingGate.current = true
    try {
      const tab = getActiveTab()
      if (!tab || !window.electronAPI) return
      // v0.6.0: promise 监听保存生命周期 — 自动 loading → success/error，返回原 Promise
      const result = await MeToast.promise(
        window.electronAPI.saveFile({
          filePath: tab.filePath,
          content: tab.content,
        }),
        {
          loading: '保存中...',
          success: '已保存',
          error: '保存失败',
        },
      )
      if (result.success) {
        useTabStore.getState().setModified(tab.id, false)
      } else {
        // IPC 返回 success:false 不 reject，promise 的 error 文案不会触发，需显式提示
        showToast('保存失败', 'error')
      }
    } catch (error) {
      logError('保存文件失败', error)
    } finally {
      // 300ms 后释放锁，允许下次保存
      setTimeout(() => {
        savingGate.current = false
      }, 300)
    }
  }, [getActiveTab])

  const handleSaveAs = useCallback(async (): Promise<void> => {
    try {
      const tab = getActiveTab()
      if (!tab || !window.electronAPI) return
      const result = await MeToast.promise(
        window.electronAPI.saveFileAs({ content: tab.content }),
        {
          loading: '另存为...',
          success: '已保存',
          error: '另存为失败',
        },
      )
      if (result.success) {
        useTabStore.getState().setModified(tab.id, false)
      } else if (!result.canceled) {
        showToast('另存为失败', 'error')
      }
    } catch (error) {
      logError('另存为失败', error)
    }
  }, [getActiveTab])

  const handleOpenRecent = useCallback(
    async (filePath: string): Promise<void> => {
      if (!window.electronAPI) return
      setLoading('file-open', true)
      try {
        const result = await window.electronAPI.readFile(filePath)
        if (result.success && result.content !== undefined) {
          createTab(filePath, result.content)
          recentFilesRepository.add(filePath)
          setTimeout(() => useTabStore.getState().saveToDB(), 100)
        }
      } finally {
        setLoading('file-open', false)
      }
    },
    [createTab, setLoading],
  )

  return { handleOpenFile, handleSave, handleSaveAs, handleOpenRecent }
}