/**
 * Offline Sync Hook
 */

import { useState, useEffect, useCallback } from 'react';

interface UseOfflineSyncOptions {
  autoSync?: boolean;
  syncDelay?: number;
  onSyncStart?: () => void;
  onSyncSuccess?: () => void;
  onSyncError?: (error: Error) => void;
}

interface UseOfflineSyncReturn {
  isOnline: boolean;
  isSyncing: boolean;
  syncStatus: 'idle' | 'syncing' | 'completed' | 'error' | 'success';
  queueSize: number;
  syncProgress: number;
  syncTotal: number;
  syncError: string | null;
  currentConflict: any | null;
  manualSync: () => Promise<void>;
  clearError: () => void;
  resolveConflict: (options: { choice: 'server' | 'local' | 'merged'; mergedData?: any }) => void;
}

export const useOfflineSync = (options?: UseOfflineSyncOptions): UseOfflineSyncReturn => {
  const [isOnline, setIsOnline] = useState(true);
  const [isSyncing, setIsSyncing] = useState(false);
  const [syncStatus, setSyncStatus] = useState<'idle' | 'syncing' | 'completed' | 'error' | 'success'>('idle');
  const [queueSize, setQueueSize] = useState(0);
  const [syncProgress, setSyncProgress] = useState(0);
  const [syncTotal, setSyncTotal] = useState(0);
  const [syncError, setSyncError] = useState<string | null>(null);
  const [currentConflict, setCurrentConflict] = useState<any | null>(null);

  useEffect(() => {
    setIsOnline(navigator.onLine);
    const handler = () => setIsOnline(navigator.onLine);
    window.addEventListener('online', handler);
    window.addEventListener('offline', handler);
    return () => {
      window.removeEventListener('online', handler);
      window.removeEventListener('offline', handler);
    };
  }, []);

  // Auto sync when online
  useEffect(() => {
    if (options?.autoSync && isOnline && queueSize > 0 && !isSyncing) {
      const timer = setTimeout(() => {
        manualSync();
      }, options?.syncDelay || 1000);
      return () => clearTimeout(timer);
    }
  }, [options?.autoSync, options?.syncDelay, isOnline, queueSize, isSyncing]);

  const manualSync = useCallback(async () => {
    if (isSyncing) return;

    setIsSyncing(true);
    setSyncStatus('syncing');
    options?.onSyncStart?.();

    try {
      // Placeholder implementation
      setSyncProgress(0);
      setSyncTotal(queueSize);

      // Simulate sync
      await new Promise(resolve => setTimeout(resolve, 1000));

      setSyncProgress(queueSize);
      setQueueSize(0);
      setIsSyncing(false);
      setSyncStatus('success');
      options?.onSyncSuccess?.();
    } catch (error) {
      setIsSyncing(false);
      setSyncStatus('error');
      setSyncError(error instanceof Error ? error.message : 'Sync failed');
      options?.onSyncError?.(error instanceof Error ? error : new Error('Sync failed'));
    }
  }, [isSyncing, queueSize, options]);

  const clearError = useCallback(() => {
    setSyncError(null);
    if (syncStatus === 'error') {
      setSyncStatus('idle');
    }
  }, [syncStatus]);

  const resolveConflict = useCallback((options: { choice: 'server' | 'local' | 'merged'; mergedData?: any }) => {
    // Placeholder implementation
    setCurrentConflict(null);
  }, []);

  return {
    isOnline,
    isSyncing,
    syncStatus,
    queueSize,
    syncProgress,
    syncTotal,
    syncError,
    currentConflict,
    manualSync,
    clearError,
    resolveConflict,
  };
};
