import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:formz/formz.dart';
import 'package:go_router/go_router.dart';

import '../../../../core/di/injection.dart';
import '../../../../core/theme/design_tokens.dart';
import '../../../../shared/widgets/app_button.dart';
import '../../../../shared/widgets/banner/app_banner.dart';
import '../../../../shared/widgets/link_button.dart';
import '../../../../shared/widgets/toast/toast_type.dart';
import '../../data/auth_repository.dart';
import '../../presentation/bloc/auth_bloc.dart';
import '../../presentation/bloc/auth_event.dart';
import '../../presentation/cubits/login_cubit.dart';
import '../widgets/auth_field.dart';
import '../widgets/auth_page_scaffold.dart';
import '../widgets/password_field.dart';

class LoginScreen extends StatelessWidget {
  const LoginScreen({super.key});

  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (context) => LoginCubit(sl<AuthRepository>()),
      child: const LoginView(),
    );
  }
}

class LoginView extends StatefulWidget {
  const LoginView({super.key});

  @override
  State<LoginView> createState() => _LoginViewState();
}

class _LoginViewState extends State<LoginView> {
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();

  @override
  void dispose() {
    _emailController.dispose();
    _passwordController.dispose();
    super.dispose();
  }

  Future<void> _handleLogin() async {
    final cubit = context.read<LoginCubit>();
    cubit.emailChanged(_emailController.text);
    cubit.passwordChanged(_passwordController.text);

    if (!cubit.state.isValid) {
      return;
    }

    final response = await cubit.submit();
    if (response != null && mounted) {
      context.read<AuthBloc>().add(AuthLoggedIn(user: response.user));
      context.go('/home');
    }
  }

  @override
  Widget build(BuildContext context) {
    return AuthPageScaffold(
      mainContentKey: const Key('login_main_content'),
      footerKey: const Key('login_footer'),
      mainContent: Padding(
        padding: const EdgeInsets.symmetric(horizontal: AppSpacing.sm),
        child: Center(
          child: ConstrainedBox(
            constraints: const BoxConstraints(maxWidth: 380),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.center,
              children: [
                const AuthHeroHeader(showBrand: true),
                SizedBox(height: AppSpacing.xxl),
                BlocBuilder<LoginCubit, LoginState>(
                  builder: (context, state) {
                    final fieldError = state.email.displayError != null
                        ? state.email.error
                        : state.password.displayError != null
                        ? state.password.error
                        : null;

                    return AuthSurfaceCard(
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.stretch,
                        children: [
                          const Text(
                            '登录账号',
                            style: TextStyle(
                              fontSize: 20,
                              fontWeight: FontWeight.w700,
                              color: AppColors.slate900,
                            ),
                          ),
                          SizedBox(height: AppSpacing.xs),
                          SizedBox(height: AppSpacing.xl),
                          AuthSection(
                            child: Column(
                              crossAxisAlignment: CrossAxisAlignment.stretch,
                              children: [
                                AuthField(
                                  label: '邮箱',
                                  hint: 'name@example.com',
                                  controller: _emailController,
                                  keyboardType: TextInputType.emailAddress,
                                ),
                                SizedBox(height: AppSpacing.lg),
                                PasswordField(
                                  controller: _passwordController,
                                  label: '密码',
                                  hint: '请输入密码',
                                ),
                                if (state.errorMessage != null ||
                                    fieldError != null)
                                  Padding(
                                    padding: const EdgeInsets.only(
                                      top: AppSpacing.lg,
                                    ),
                                    child: AppBanner(
                                      message:
                                          state.errorMessage ?? fieldError!,
                                      type: state.errorMessage != null
                                          ? ToastType.error
                                          : ToastType.warning,
                                      title: state.errorMessage != null
                                          ? '登录失败'
                                          : '请检查输入',
                                    ),
                                  ),
                              ],
                            ),
                          ),
                          SizedBox(height: AppSpacing.xl),
                          AppButton(
                            text: '登录',
                            onPressed:
                                state.status == FormzSubmissionStatus.inProgress
                                ? null
                                : _handleLogin,
                            isLoading:
                                state.status ==
                                FormzSubmissionStatus.inProgress,
                          ),
                          SizedBox(height: AppSpacing.sm),
                          Align(
                            alignment: Alignment.centerRight,
                            child: LinkButton(
                              text: '忘记密码？',
                              onTap: () => context.push('/reset-password'),
                            ),
                          ),
                        ],
                      ),
                    );
                  },
                ),
              ],
            ),
          ),
        ),
      ),
      footer: Row(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          const Text(
            '还没有账号？',
            style: TextStyle(fontSize: 14, color: AppColors.authLinkMuted),
          ),
          LinkButton(text: '去注册', onTap: () => context.push('/register')),
        ],
      ),
    );
  }
}