'use client'

import { useState, useEffect } from 'react'
import { useOfflineSync } from '@/hooks'
import { WifiOff, Wifi, RefreshCw, AlertCircle } from 'lucide-react'

/**
 * Offline indicator component
 * Shows connection status and sync progress
 * Validates: Requirements 4.5
 */
export default function OfflineIndicator() {
  const [mounted, setMounted] = useState(false)
  const { isOnline, isSyncing, syncError, queueLength, triggerSync } = useOfflineSync()

  useEffect(() => {
    setMounted(true)
  }, [])

  // Don't render on server to avoid hydration mismatch
  if (!mounted) {
    return null
  }

  // Don't show anything if online and no pending syncs
  if (isOnline && queueLength === 0 && !syncError) {
    return null
  }

  return (
    <div className="fixed bottom-4 right-4 z-50">
      <div
        className={`
          flex items-center gap-2 px-4 py-3 rounded-lg shadow-lg
          ${!isOnline ? 'bg-gray-800 text-white' : ''}
          ${isOnline && queueLength > 0 ? 'bg-blue-600 text-white' : ''}
          ${syncError ? 'bg-red-600 text-white' : ''}
        `}
      >
        {/* Icon */}
        {!isOnline && <WifiOff className="w-5 h-5" />}
        {isOnline && !syncError && <Wifi className="w-5 h-5" />}
        {syncError && <AlertCircle className="w-5 h-5" />}

        {/* Status text */}
        <div className="flex flex-col">
          {!isOnline && (
            <>
              <span className="text-sm font-medium">Offline</span>
              {queueLength > 0 && (
                <span className="text-xs opacity-90">
                  {queueLength} change{queueLength !== 1 ? 's' : ''} pending
                </span>
              )}
            </>
          )}

          {isOnline && isSyncing && (
            <>
              <span className="text-sm font-medium">Syncing...</span>
              <span className="text-xs opacity-90">
                {queueLength} change{queueLength !== 1 ? 's' : ''} remaining
              </span>
            </>
          )}

          {isOnline && !isSyncing && queueLength > 0 && !syncError && (
            <>
              <span className="text-sm font-medium">Ready to sync</span>
              <span className="text-xs opacity-90">
                {queueLength} change{queueLength !== 1 ? 's' : ''} pending
              </span>
            </>
          )}

          {syncError && (
            <>
              <span className="text-sm font-medium">Sync failed</span>
              <span className="text-xs opacity-90">{syncError.message}</span>
            </>
          )}
        </div>

        {/* Sync button */}
        {isOnline && queueLength > 0 && !isSyncing && (
          <button
            onClick={triggerSync}
            className="ml-2 p-1 hover:bg-white/20 rounded transition-colors"
            aria-label="Sync now"
          >
            <RefreshCw className="w-4 h-4" />
          </button>
        )}

        {/* Syncing spinner */}
        {isSyncing && (
          <RefreshCw className="w-4 h-4 animate-spin ml-2" />
        )}
      </div>
    </div>
  )
}