// Author: fruit.com.cn

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../../core/data/remote/api_client.dart';
import '../../core/data/services/auth_controller.dart';
import '../../core/platform/haptics.dart';
import '../../core/theme/app_colors.dart';
import '../../core/theme/app_theme.dart';
import '../../l10n/app_localizations.dart';
import 'auth_logic.dart';

const double _minTapTarget = 44;

/// 登录 / 注册页：邮箱 + 密码。
class AuthPage extends StatefulWidget {
  const AuthPage({super.key, this.signUpMode = false});

  final bool signUpMode;

  @override
  State<AuthPage> createState() => _AuthPageState();
}

class _AuthPageState extends State<AuthPage> {
  late AuthLogic _logic;
  late final TextEditingController _emailController;
  late final TextEditingController _passwordController;
  late final FocusNode _emailFocus;
  late final FocusNode _passwordFocus;
  bool _obscurePassword = true;

  @override
  void initState() {
    super.initState();
    _logic = AuthLogic(signUpMode: widget.signUpMode);
    _emailController = TextEditingController();
    _passwordController = TextEditingController();
    _emailFocus = FocusNode(debugLabel: 'auth-email-focus');
    _passwordFocus = FocusNode(debugLabel: 'auth-password-focus');
  }

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

  String _errorText(AppLocalizations l10n, AuthFieldError error) {
    switch (error) {
      case AuthFieldError.emailRequired:
        return l10n.authEmailRequired;
      case AuthFieldError.emailInvalid:
        return l10n.authEmailInvalid;
      case AuthFieldError.passwordRequired:
        return l10n.authPasswordRequired;
      case AuthFieldError.passwordLength:
        return l10n.authPasswordLength;
      case AuthFieldError.passwordWeak:
        return l10n.authPasswordWeak;
    }
  }

  Future<void> _submit() async {
    final l10n = AppLocalizations.of(context)!;
    final invalid = _logic.validate();
    if (invalid != null) {
      setState(() => _logic.errorMessage = _errorText(l10n, invalid));
      return;
    }
    unawaited(context.read<Haptics>().lightImpact());
    FocusScope.of(context).unfocus();
    setState(() {
      _logic.busy = true;
      _logic.errorMessage = null;
    });
    final auth = context.read<AuthController>();
    try {
      if (_logic.signUpMode) {
        await auth.register(
          email: _logic.normalizedEmail,
          password: _logic.password,
        );
      } else {
        await auth.signIn(
          email: _logic.normalizedEmail,
          password: _logic.password,
        );
      }
      if (!mounted) return;
      Navigator.of(context).maybePop();
    } on ApiException catch (error) {
      setState(() => _logic.errorMessage = error.message);
    } catch (_) {
      setState(() => _logic.errorMessage = l10n.authNetworkError);
    } finally {
      if (mounted) setState(() => _logic.busy = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    return Theme(
      data: AppTheme.dark(),
      child: Scaffold(
        resizeToAvoidBottomInset: true,
        backgroundColor: AppColors.ink,
        appBar: AppBar(
          backgroundColor: AppColors.ink,
          elevation: 0,
          foregroundColor: AppColors.onPrimary,
          title: Text(_logic.signUpMode ? l10n.signUp : l10n.signIn),
        ),
        body: SafeArea(
          child: AutofillGroup(
            child: ListView(
              key: const Key('auth-scroll'),
              keyboardDismissBehavior: ScrollViewKeyboardDismissBehavior.onDrag,
              padding: EdgeInsets.fromLTRB(
                20,
                12,
                20,
                28 + MediaQuery.viewInsetsOf(context).bottom,
              ),
              children: [
                _AuthBrand(tagline: l10n.authBrandTagline),
                const SizedBox(height: 26),
                Text(
                  _logic.signUpMode
                      ? l10n.authSignUpTitle
                      : l10n.authSignInTitle,
                  style: const TextStyle(
                    color: AppColors.onPrimary,
                    fontSize: 24,
                    fontWeight: FontWeight.w800,
                  ),
                ),
                const SizedBox(height: 6),
                Text(
                  l10n.authSubtitle,
                  style: const TextStyle(color: AppColors.muted, fontSize: 13),
                ),
                const SizedBox(height: 22),
                _emailField(l10n),
                const SizedBox(height: 14),
                _passwordField(l10n),
                if (_logic.errorMessage != null) ...[
                  const SizedBox(height: 12),
                  _AuthError(message: _logic.errorMessage!),
                ],
                const SizedBox(height: 22),
                _submitButton(l10n),
                const SizedBox(height: 10),
                _switchModeButton(l10n),
              ],
            ),
          ),
        ),
      ),
    );
  }

  Widget _emailField(AppLocalizations l10n) => _field(
    child: TextField(
      key: const Key('auth-email'),
      controller: _emailController,
      focusNode: _emailFocus,
      enabled: !_logic.busy,
      autofocus: true,
      keyboardType: TextInputType.emailAddress,
      textInputAction: TextInputAction.next,
      autofillHints: const [AutofillHints.email],
      onChanged: (value) => _logic.email = value,
      onSubmitted: (_) => _passwordFocus.requestFocus(),
      style: const TextStyle(color: AppColors.onPrimary, fontSize: 15),
      decoration: _decoration(l10n.authEmailLabel, 'name@example.com'),
    ),
  );

  Widget _passwordField(AppLocalizations l10n) => _field(
    child: TextField(
      key: const Key('auth-password'),
      controller: _passwordController,
      focusNode: _passwordFocus,
      enabled: !_logic.busy,
      obscureText: _obscurePassword,
      keyboardType: TextInputType.visiblePassword,
      textInputAction: TextInputAction.done,
      autofillHints: const [AutofillHints.password],
      onChanged: (value) => _logic.password = value,
      onSubmitted: (_) => _submit(),
      style: const TextStyle(color: AppColors.onPrimary, fontSize: 15),
      decoration: _decoration(
        l10n.authPasswordLabel,
        l10n.authPasswordHint,
        suffix: IconButton(
          key: const Key('auth-password-visibility'),
          constraints: const BoxConstraints.tightFor(
            width: _minTapTarget,
            height: _minTapTarget,
          ),
          tooltip: _obscurePassword ? l10n.showPassword : l10n.hidePassword,
          onPressed: _logic.busy
              ? null
              : () => setState(() => _obscurePassword = !_obscurePassword),
          icon: Icon(
            _obscurePassword
                ? Icons.visibility_outlined
                : Icons.visibility_off_outlined,
            color: AppColors.muted,
          ),
        ),
      ),
    ),
  );

  Widget _field({required Widget child}) =>
      Column(crossAxisAlignment: CrossAxisAlignment.start, children: [child]);

  InputDecoration _decoration(String label, String hint, {Widget? suffix}) {
    final scheme = Theme.of(context).colorScheme;
    return InputDecoration(
      labelText: label,
      hintText: hint,
      hintStyle: TextStyle(color: scheme.onSurfaceVariant, fontSize: 14),
      suffixIcon: suffix,
      filled: true,
      fillColor: AppColors.card,
      contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 17),
      border: OutlineInputBorder(
        borderRadius: BorderRadius.circular(12),
        borderSide: BorderSide.none,
      ),
      focusedBorder: OutlineInputBorder(
        borderRadius: BorderRadius.circular(12),
        borderSide: BorderSide(color: scheme.primary, width: 1.5),
      ),
    );
  }

  Widget _submitButton(AppLocalizations l10n) => SizedBox(
    height: 50,
    child: FilledButton(
      key: const Key('auth-submit'),
      onPressed: _logic.busy ? null : _submit,
      style: FilledButton.styleFrom(
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(25)),
      ),
      child: _logic.busy
          ? const SizedBox.square(
              dimension: 18,
              child: CircularProgressIndicator(
                strokeWidth: 2,
                color: AppColors.onPrimary,
              ),
            )
          : Text(
              _logic.signUpMode ? l10n.signUp : l10n.signIn,
              style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w700),
            ),
    ),
  );

  Widget _switchModeButton(AppLocalizations l10n) => TextButton(
    key: const Key('auth-switch-mode'),
    style: TextButton.styleFrom(
      minimumSize: const Size(0, _minTapTarget),
      foregroundColor: AppColors.blueSoft,
    ),
    onPressed: _logic.busy ? null : () => setState(() => _logic.toggleMode()),
    child: Text(
      _logic.signUpMode ? l10n.authSwitchToSignIn : l10n.authSwitchToSignUp,
      style: const TextStyle(fontSize: 13),
    ),
  );
}

class _AuthBrand extends StatelessWidget {
  const _AuthBrand({required this.tagline});

  final String tagline;

  @override
  Widget build(BuildContext context) {
    return Row(
      children: [
        Container(
          width: 48,
          height: 48,
          decoration: const BoxDecoration(
            color: AppColors.blue,
            shape: BoxShape.circle,
          ),
          child: const Icon(
            Icons.play_arrow_rounded,
            color: AppColors.onPrimary,
            size: 30,
          ),
        ),
        const SizedBox(width: 12),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                AppLocalizations.of(context)!.appName,
                style: const TextStyle(
                  color: AppColors.onPrimary,
                  fontSize: 20,
                  fontWeight: FontWeight.w800,
                ),
              ),
              const SizedBox(height: 2),
              Text(
                tagline,
                style: const TextStyle(color: AppColors.blueSoft, fontSize: 12),
              ),
            ],
          ),
        ),
      ],
    );
  }
}

class _AuthError extends StatelessWidget {
  const _AuthError({required this.message});

  final String message;

  @override
  Widget build(BuildContext context) {
    final color = Theme.of(context).colorScheme.error;
    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Icon(Icons.error_outline, color: color, size: 18),
        const SizedBox(width: 6),
        Expanded(
          child: Text(
            message,
            key: const Key('auth-error'),
            style: TextStyle(color: color, fontSize: 13),
          ),
        ),
      ],
    );
  }
}