import 'package:flutter/material.dart';
import 'package:flutter/services.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/router/app_routes.dart';
import '../../../../core/theme/design_tokens.dart';
import '../../../../shared/widgets/app_button.dart';
import '../../../../shared/widgets/banner/app_banner.dart';
import '../../../../shared/widgets/confirm_sheet.dart';
import '../../../../shared/widgets/link_button.dart';
import '../../../../shared/widgets/phone_prefix_selector.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';

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> {
  static const _dialCodes = <String>['+86', '+1', '+44', '+81', '+65'];

  final _phoneController = TextEditingController();
  final _codeController = TextEditingController();
  bool _agreedToTerms = false;

  @override
  void dispose() {
    _phoneController.dispose();
    _codeController.dispose();
    super.dispose();
  }

  Future<void> _handleLogin() async {
    final cubit = context.read<LoginCubit>();
    cubit.phoneChanged(_phoneController.text);
    cubit.codeChanged(_codeController.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(AppRoutes.homeMain);
    }
  }

  Future<void> _handleSendCode() async {
    if (!_agreedToTerms) {
      final confirmed = await _showAgreementDialog();
      if (!confirmed || !mounted) return;
      setState(() => _agreedToTerms = true);
    }

    final cubit = context.read<LoginCubit>();
    cubit.phoneChanged(_phoneController.text);
    final sent = await cubit.sendCode();
    if (!mounted || !sent) {
      return;
    }
  }

  Future<bool> _showAgreementDialog() async {
    return await showConfirmSheet(
      context,
      title: '请先同意协议',
      message: '在使用我们的服务之前，请先阅读并同意《用户协议》和《隐私政策》。\n\n只有您同意上述协议，我们才能为您提供服务。',
      confirmText: '确认',
      cancelText: '取消',
    );
  }

  Widget _buildAgreementCheckbox() {
    return Center(
      child: Row(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          Semantics(
            label: '同意用户协议与隐私政策',
            checked: _agreedToTerms,
            button: true,
            child: InkWell(
              borderRadius: BorderRadius.circular(AppRadius.md),
              onTap: () => setState(() => _agreedToTerms = !_agreedToTerms),
              child: SizedBox(
                width: 44,
                height: 44,
                child: Center(
                  child: Container(
                    width: 20,
                    height: 20,
                    margin: const EdgeInsets.only(right: AppSpacing.sm),
                    decoration: BoxDecoration(
                      color: _agreedToTerms
                          ? AppColors.blue600
                          : Colors.transparent,
                      borderRadius: BorderRadius.circular(4),
                      border: Border.all(
                        color: _agreedToTerms
                            ? AppColors.blue600
                            : AppColors.slate400,
                        width: 1.5,
                      ),
                    ),
                    child: _agreedToTerms
                        ? const Icon(
                            Icons.check,
                            size: 14,
                            color: AppColors.white,
                          )
                        : null,
                  ),
                ),
              ),
            ),
          ),
          RichText(
            text: TextSpan(
              style: const TextStyle(fontSize: 13, color: AppColors.slate600),
              children: [
                const TextSpan(text: '我已同意'),
                TextSpan(
                  text: '《用户协议》',
                  style: const TextStyle(
                    color: AppColors.blue600,
                    decoration: TextDecoration.underline,
                  ),
                ),
                const TextSpan(text: '与'),
                TextSpan(
                  text: '《隐私政策》',
                  style: const TextStyle(
                    color: AppColors.blue600,
                    decoration: TextDecoration.underline,
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return AuthPageScaffold(
      resizeOnKeyboard: false,
      mainContentKey: const Key('login_main_content'),
      mainContent: LayoutBuilder(
        builder: (context, constraints) {
          final bottomInset = MediaQuery.of(context).viewInsets.bottom;
          return SingleChildScrollView(
            padding: EdgeInsets.fromLTRB(
              AppSpacing.lg,
              0,
              AppSpacing.lg,
              bottomInset + AppSpacing.lg,
            ),
            child: ConstrainedBox(
              constraints: BoxConstraints(minHeight: constraints.maxHeight),
              child: Center(
                child: ConstrainedBox(
                  constraints: const BoxConstraints(maxWidth: 320),
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      const AuthHeroHeader(showBrand: true),
                      SizedBox(height: AppSpacing.xxl),
                      BlocBuilder<LoginCubit, LoginState>(
                        builder: (context, state) {
                          final fieldError = state.phone.displayError != null
                              ? state.phone.error
                              : state.code.displayError != null
                              ? state.code.error
                              : null;

                          return Column(
                            crossAxisAlignment: CrossAxisAlignment.stretch,
                            children: [
                              AuthSection(
                                child: Column(
                                  crossAxisAlignment:
                                      CrossAxisAlignment.stretch,
                                  children: [
                                    AuthField(
                                      hint: '输入手机号',
                                      controller: _phoneController,
                                      onChanged: (value) {
                                        context.read<LoginCubit>().phoneChanged(
                                          value,
                                        );
                                      },
                                      keyboardType: TextInputType.phone,
                                      prefix: PhonePrefixSelector(
                                        value: state.dialCode,
                                        items: _dialCodes,
                                        onChanged: (value) {
                                          context
                                              .read<LoginCubit>()
                                              .dialCodeChanged(value);
                                        },
                                      ),
                                      inputFormatters: [
                                        FilteringTextInputFormatter.digitsOnly,
                                        LengthLimitingTextInputFormatter(14),
                                      ],
                                    ),
                                    SizedBox(height: AppSpacing.lg),
                                    AuthField(
                                      hint: '输入验证码',
                                      controller: _codeController,
                                      onChanged: (value) {
                                        context.read<LoginCubit>().codeChanged(
                                          value,
                                        );
                                      },
                                      keyboardType: TextInputType.number,
                                      inputFormatters: [
                                        FilteringTextInputFormatter.digitsOnly,
                                        LengthLimitingTextInputFormatter(6),
                                      ],
                                      suffixIcon: Padding(
                                        padding: const EdgeInsets.only(
                                          right: AppSpacing.md,
                                        ),
                                        child: LinkButton(
                                          text: state.resendCooldownSeconds > 0
                                              ? '${state.resendCooldownSeconds}s'
                                              : '发送验证码',
                                          onTap: state.canSendCode
                                              ? _handleSendCode
                                              : null,
                                        ),
                                      ),
                                    ),
                                    if (state.errorMessage != null ||
                                        fieldError != null)
                                      Padding(
                                        padding: const EdgeInsets.only(
                                          top: AppSpacing.md,
                                        ),
                                        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.xxl),
                              AppButton(
                                text: '登录/注册',
                                onPressed:
                                    state.status ==
                                        FormzSubmissionStatus.inProgress
                                    ? null
                                    : _handleLogin,
                                isLoading:
                                    state.status ==
                                    FormzSubmissionStatus.inProgress,
                              ),
                              SizedBox(height: AppSpacing.xxl * 2),
                              _buildAgreementCheckbox(),
                            ],
                          );
                        },
                      ),
                    ],
                  ),
                ),
              ),
            ),
          );
        },
      ),
    );
  }
}