'use client'

import { useState, useEffect, useCallback, useRef } from 'react'
import {
  saveDraft,
  getDraft,
  deleteDraft,
  hasDraft,
  checkConflict,
  generateDraftId,
  formatDraftTime,
  DraftData,
  DraftStorageConfig,
} from '@/lib/draft-storage'

interface UseDraftStorageOptions<T> extends DraftStorageConfig {
  formType: string
  entityId?: string
  onRestore?: (data: T) => void
  onConflict?: (otherDraft: DraftData<T>) => void
  autoSave?: boolean
}

interface UseDraftStorageReturn<T> {
  // 状态
  draftId: string
  hasDraft: boolean
  lastSaved: string | null
  isConflict: boolean
  conflictDraft: DraftData<T> | null
  
  // 操作
  save: (data: T) => boolean
  restore: () => T | null
  clear: () => void
  checkForConflict: () => boolean
  
  // 格式化
  formatLastSaved: () => string
}

/**
 * 草稿自动保存 Hook
 */
export function useDraftStorage<T extends Record<string, unknown>>(
  options: UseDraftStorageOptions<T>
): UseDraftStorageReturn<T> {
  const {
    formType,
    entityId,
    onRestore,
    onConflict,
    autoSave = true,
    ...config
  } = options

  // 生成草稿ID
  const draftId = generateDraftId(formType, entityId)
  
  // 状态
  const [hasDraftState, setHasDraftState] = useState(false)
  const [lastSaved, setLastSaved] = useState<string | null>(null)
  const [isConflict, setIsConflict] = useState(false)
  const [conflictDraft, setConflictDraft] = useState<DraftData<T> | null>(null)
  
  // 自动保存定时器
  const autoSaveTimerRef = useRef<NodeJS.Timeout | null>(null)
  const pendingDataRef = useRef<T | null>(null)

  // 检查是否存在草稿
  useEffect(() => {
    const exists = hasDraft(draftId, config)
    setHasDraftState(exists)
    
    if (exists) {
      const draft = getDraft<T>(draftId, config)
      if (draft) {
        setLastSaved(draft.updatedAt)
        
        // 检查冲突
        const conflict = checkConflict<T>(draftId, config)
        if (conflict.hasConflict && conflict.otherTabDraft) {
          setIsConflict(true)
          setConflictDraft(conflict.otherTabDraft)
          onConflict?.(conflict.otherTabDraft)
        }
      }
    }
  }, [draftId])

  // 保存草稿
  const save = useCallback((data: T): boolean => {
    const result = saveDraft(draftId, formType, data, config)
    if (result.success) {
      setHasDraftState(true)
      setLastSaved(new Date().toISOString())
      setIsConflict(false)
      setConflictDraft(null)
    }
    return result.success
  }, [draftId, formType, config])

  // 恢复草稿
  const restore = useCallback((): T | null => {
    const draft = getDraft<T>(draftId, config)
    if (draft) {
      onRestore?.(draft.data)
      return draft.data
    }
    return null
  }, [draftId, config, onRestore])

  // 清除草稿
  const clear = useCallback(() => {
    deleteDraft(draftId, config)
    setHasDraftState(false)
    setLastSaved(null)
    setIsConflict(false)
    setConflictDraft(null)
  }, [draftId, config])

  // 检查冲突
  const checkForConflict = useCallback((): boolean => {
    const conflict = checkConflict<T>(draftId, config)
    setIsConflict(conflict.hasConflict)
    if (conflict.hasConflict && conflict.otherTabDraft) {
      setConflictDraft(conflict.otherTabDraft)
    }
    return conflict.hasConflict
  }, [draftId, config])

  // 格式化最后保存时间
  const formatLastSaved = useCallback((): string => {
    if (!lastSaved) return ''
    return formatDraftTime(lastSaved)
  }, [lastSaved])

  // 自动保存逻辑
  const scheduleAutoSave = useCallback((data: T) => {
    if (!autoSave) return
    
    pendingDataRef.current = data
    
    if (autoSaveTimerRef.current) {
      clearTimeout(autoSaveTimerRef.current)
    }
    
    autoSaveTimerRef.current = setTimeout(() => {
      if (pendingDataRef.current) {
        save(pendingDataRef.current)
        pendingDataRef.current = null
      }
    }, config.autoSaveInterval || 3000)
  }, [autoSave, save, config.autoSaveInterval])

  // 清理定时器
  useEffect(() => {
    return () => {
      if (autoSaveTimerRef.current) {
        clearTimeout(autoSaveTimerRef.current)
      }
    }
  }, [])

  return {
    draftId,
    hasDraft: hasDraftState,
    lastSaved,
    isConflict,
    conflictDraft,
    save,
    restore,
    clear,
    checkForConflict,
    formatLastSaved,
  }
}

/**
 * 草稿恢复提示组件的 Props
 */
export interface DraftRecoveryPromptProps<T> {
  hasDraft: boolean
  lastSaved: string | null
  onRestore: () => void
  onDiscard: () => void
  formatLastSaved: () => string
}