import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../../core/localization/app_localizations.dart';
import '../../../core/theme/app_theme.dart';
import '../providers/auth_provider.dart';

/// 启动密码验证页面
class LoginPage extends ConsumerStatefulWidget {
  const LoginPage({super.key});

  @override
  ConsumerState<LoginPage> createState() => _LoginPageState();
}

class _LoginPageState extends ConsumerState<LoginPage> {
  final _passwordCtrl = TextEditingController();
  final _focusNode = FocusNode();
  String? _errorMsg;
  bool _submitting = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _focusNode.requestFocus();
    });
  }

  @override
  void dispose() {
    _passwordCtrl.dispose();
    _focusNode.dispose();
    super.dispose();
  }

  Future<void> _submit() async {
    if (_submitting) return;
    final password = _passwordCtrl.text.trim();
    if (password.isEmpty) return;

    setState(() {
      _submitting = true;
      _errorMsg = null;
    });

    final success = await ref.read(authProvider.notifier).verify(password);

    if (!mounted) return;
    _passwordCtrl.clear();

    if (!success) {
      final l10n = AppLocalizations.of(context);
      setState(() {
        _submitting = false;
        _errorMsg = l10n?.passwordError ?? '密码错误';
      });
    }
  }

  void _onKeyEvent(KeyEvent event) {
    if (event is KeyDownEvent &&
        event.logicalKey == LogicalKeyboardKey.enter) {
      _submit();
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final authState = ref.watch(authProvider);

    final isLocked = authState.isLocked;
    final lockSeconds = authState.lockSecondsRemaining;

    return Scaffold(
      backgroundColor: AppTheme.bgPage,
      body: Center(
        child: Container(
          constraints: const BoxConstraints(maxWidth: 420),
          padding: const EdgeInsets.all(32),
          decoration: BoxDecoration(
            color: AppTheme.bgSurface,
            borderRadius: BorderRadius.circular(AppTheme.radiusLg),
            border: Border.all(color: AppTheme.borderLight),
            boxShadow: AppTheme.shadowCard,
          ),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              // 设备名称标识
              Icon(
                Icons.shield_outlined,
                size: 48,
                color: AppTheme.primaryColor,
              ),
              const SizedBox(height: 16),
              Text(
                l10n?.authTitle ?? '身份验证',
                style: TextStyle(
                  color: AppTheme.textHeading,
                  fontSize: 22,
                  fontWeight: FontWeight.w600,
                ),
              ),
              const SizedBox(height: 8),
              Text(
                l10n?.authSubtitle ?? '请输入操作员密码以继续使用',
                style: TextStyle(
                  color: AppTheme.textSecondary,
                  fontSize: 14,
                ),
              ),
              const SizedBox(height: 32),
              // 密码输入框
              KeyboardListener(
                focusNode: FocusNode(),
                onKeyEvent: _onKeyEvent,
                child: TextField(
                  controller: _passwordCtrl,
                  focusNode: _focusNode,
                  obscureText: true,
                  enabled: !isLocked && !_submitting,
                  decoration: InputDecoration(
                    labelText: l10n?.enterPassword ?? '请输入密码',
                    border: const OutlineInputBorder(),
                    errorText: _errorMsg,
                    prefixIcon: const Icon(Icons.lock_outline),
                  ),
                ),
              ),
              const SizedBox(height: 24),
              // 确认按钮 / 锁定提示
              if (isLocked)
                Column(
                  children: [
                    Icon(Icons.lock_clock,
                        size: 32, color: AppTheme.warningColor),
                    const SizedBox(height: 8),
                    Text(
                      l10n?.lockCountdown(lockSeconds) ??
                          '请等待 $lockSeconds 秒后重试',
                      style: TextStyle(
                        color: AppTheme.warningColor,
                        fontSize: 14,
                        fontWeight: FontWeight.w500,
                      ),
                    ),
                  ],
                )
              else
                SizedBox(
                  width: double.infinity,
                  child: ElevatedButton(
                    onPressed: _submitting ? null : _submit,
                    style: ElevatedButton.styleFrom(
                      padding: const EdgeInsets.symmetric(vertical: 14),
                    ),
                    child: _submitting
                        ? const SizedBox(
                            width: 20,
                            height: 20,
                            child: CircularProgressIndicator(
                              strokeWidth: 2,
                              color: Colors.white,
                            ),
                          )
                        : Text(l10n?.confirm ?? '确认'),
                  ),
                ),
              // 剩余尝试次数提示
              if (!isLocked && authState.remainingAttempts < 5)
                Padding(
                  padding: const EdgeInsets.only(top: 12),
                  child: Text(
                    l10n?.remainingAttempts(authState.remainingAttempts) ??
                        '剩余 ${authState.remainingAttempts} 次尝试机会',
                    style: TextStyle(
                      color: AppTheme.errorColor,
                      fontSize: 12,
                    ),
                  ),
                ),
            ],
          ),
        ),
      ),
    );
  }
}