// auth_screen.dart — 登录 / 注册页(邮箱 + 验证码流程)
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../l10n/app_text.dart';
import '../pangolin_theme.dart';
import '../services/auth_api.dart';
import '../state/auth_provider.dart';
import 'pangolin_button.dart';
import 'pangolin_icons.dart';
import 'pangolin_logo.dart';

// API base URL（由 --dart-define 注入）
const _kApiUrl = String.fromEnvironment(
  'PANGOLIN_API_URL',
  defaultValue: 'http://localhost:8080',
);

enum _AuthMode { login, register }

class AuthScreen extends ConsumerStatefulWidget {
  const AuthScreen({super.key, required this.onDone, required this.t});
  final VoidCallback onDone;
  final AppText t;

  @override
  ConsumerState<AuthScreen> createState() => _AuthScreenState();
}

class _AuthScreenState extends ConsumerState<AuthScreen> {
  _AuthMode _mode = _AuthMode.login;
  int _step = 0;
  bool _sent = false;
  bool _loading = false;
  String? _errorZh;

  final _email = TextEditingController();
  final _code = TextEditingController();
  final _pw = TextEditingController();

  late final AuthApi _api = AuthApi(baseUrl: _kApiUrl);

  bool get _emailValid => RegExp(r'\S+@\S+\.\S+').hasMatch(_email.text);

  @override
  void dispose() {
    _email.dispose();
    _code.dispose();
    _pw.dispose();
    _api.dispose();
    super.dispose();
  }

  // ── 认证操作 ──────────────────────────────────────────────────

  Future<void> _sendCode() async {
    setState(() { _loading = true; _errorZh = null; });
    try {
      await _api.sendCode(_email.text.trim());
      if (mounted) setState(() { _sent = true; _loading = false; });
    } on AuthApiException catch (e) {
      if (mounted) setState(() { _errorZh = e.messageZh; _loading = false; });
    }
  }

  Future<void> _doRegister() async {
    setState(() { _loading = true; _errorZh = null; });
    try {
      final tokens = await _api.register(
        email: _email.text.trim(),
        code: _code.text.trim(),
        password: _pw.text,
      );
      await ref.read(authProvider.notifier).saveTokens(tokens);
      if (mounted) widget.onDone();
    } on AuthApiException catch (e) {
      if (mounted) setState(() { _errorZh = e.messageZh; _loading = false; });
    }
  }

  Future<void> _doLogin() async {
    setState(() { _loading = true; _errorZh = null; });
    try {
      final tokens = await _api.login(
        email: _email.text.trim(),
        password: _pw.text,
      );
      await ref.read(authProvider.notifier).saveTokens(tokens);
      if (mounted) widget.onDone();
    } on AuthApiException catch (e) {
      if (mounted) setState(() { _errorZh = e.messageZh; _loading = false; });
    }
  }

  // ── UI ──────────────────────────────────────────────────────

  @override
  Widget build(BuildContext context) {
    final c = context.pangolin;
    final t = widget.t;
    return Scaffold(
      backgroundColor: c.bg,
      body: SafeArea(
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 28),
          child: Column(
            children: [
              const SizedBox(height: 18),
              Column(children: [
                const PangolinMark(size: 52),
                const SizedBox(height: 12),
                Text(t.brand, style: PangolinText.h1.copyWith(color: c.fg1)),
                const SizedBox(height: 4),
                Text(t.authTagline, style: PangolinText.sm.copyWith(color: c.accent, fontWeight: FontWeight.w600)),
              ]),
              const SizedBox(height: 28),
              Row(children: [
                _tab(_AuthMode.login, t.tabLogin, c),
                _tab(_AuthMode.register, t.tabRegister, c),
              ]),
              Divider(height: 1, color: c.border),
              const SizedBox(height: 22),
              if (_errorZh != null) ...[
                Container(
                  padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
                  decoration: BoxDecoration(
                    color: c.danger.withAlpha(25),
                    borderRadius: BorderRadius.circular(PangolinRadius.md),
                    border: Border.all(color: c.danger.withAlpha(80)),
                  ),
                  child: Row(children: [
                    Icon(PangolinIcons.x, size: 16, color: c.danger),
                    const SizedBox(width: 8),
                    Expanded(child: Text(_errorZh!, style: PangolinText.sm.copyWith(color: c.danger))),
                  ]),
                ),
                const SizedBox(height: 14),
              ],
              Expanded(child: _mode == _AuthMode.login ? _login(c, t) : _register(c, t)),
              Padding(
                padding: const EdgeInsets.symmetric(vertical: 20),
                child: Text(t.tos, textAlign: TextAlign.center, style: PangolinText.caption.copyWith(color: c.fg3, fontWeight: FontWeight.w400)),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _tab(_AuthMode m, String label, PangolinScheme c) {
    final on = _mode == m;
    return Expanded(
      child: GestureDetector(
        onTap: () => setState(() {
          _mode = m;
          _step = 0;
          _sent = false;
          _errorZh = null;
        }),
        child: Container(
          padding: const EdgeInsets.symmetric(vertical: 10),
          decoration: BoxDecoration(border: Border(bottom: BorderSide(color: on ? c.accent : Colors.transparent, width: 2))),
          child: Center(child: Text(label, style: PangolinText.body.copyWith(color: on ? c.fg1 : c.fg3, fontWeight: on ? FontWeight.w700 : FontWeight.w500))),
        ),
      ),
    );
  }

  Widget _field(PangolinScheme c, {required IconData icon, required String label, required Widget child}) {
    return Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
      Text(label, style: PangolinText.caption.copyWith(color: c.fg2, fontWeight: FontWeight.w600)),
      const SizedBox(height: 7),
      Container(
        padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 2),
        decoration: BoxDecoration(color: c.surface, borderRadius: BorderRadius.circular(PangolinRadius.md), border: Border.all(color: c.borderStrong, width: 1.5)),
        child: Row(children: [Icon(icon, size: 18, color: c.fg3), const SizedBox(width: 10), Expanded(child: child)]),
      ),
    ]);
  }

  InputDecoration get _bare =>
      const InputDecoration(border: InputBorder.none, isCollapsed: true, contentPadding: EdgeInsets.symmetric(vertical: 12));

  Widget _login(PangolinScheme c, AppText t) {
    return Column(children: [
      _field(c, icon: PangolinIcons.mail, label: t.emailLabel,
          child: TextField(controller: _email, decoration: _bare.copyWith(hintText: t.emailPh), onChanged: (_) => setState(() {}))),
      const SizedBox(height: 16),
      _field(c, icon: PangolinIcons.lock, label: t.pwLabel,
          child: TextField(controller: _pw, obscureText: true, decoration: _bare.copyWith(hintText: t.pwPh), onChanged: (_) => setState(() {}))),
      Align(
        alignment: Alignment.centerRight,
        child: Padding(
          padding: const EdgeInsets.only(top: 8),
          child: Text(t.forgotPw, style: PangolinText.sm.copyWith(color: c.accent, fontWeight: FontWeight.w600)),
        ),
      ),
      const SizedBox(height: 18),
      PangolinButton(
        label: _loading ? '...' : t.doLogin,
        expand: true,
        onPressed: (!_loading && _emailValid && _pw.text.isNotEmpty) ? _doLogin : null,
      ),
    ]);
  }

  Widget _register(PangolinScheme c, AppText t) {
    if (_step == 0) {
      return Column(children: [
        _field(c, icon: PangolinIcons.mail, label: t.emailLabel,
            child: Row(children: [
              Expanded(child: TextField(controller: _email, decoration: _bare.copyWith(hintText: t.emailPh), onChanged: (_) => setState(() {}))),
              GestureDetector(
                onTap: (!_loading && _emailValid) ? _sendCode : null,
                child: Text(_sent ? t.resend : t.sendCode,
                    style: PangolinText.caption.copyWith(color: (!_loading && _emailValid) ? c.accent : c.fg3, fontWeight: FontWeight.w700)),
              ),
            ])),
        if (_sent)
          Padding(
            padding: const EdgeInsets.only(top: 8),
            child: Row(children: [
              Icon(PangolinIcons.checkCircle, size: 14, color: c.success),
              const SizedBox(width: 6),
              Expanded(child: Text(t.codeSentTo(_email.text), style: PangolinText.caption.copyWith(color: c.success, fontWeight: FontWeight.w400))),
            ]),
          ),
        const SizedBox(height: 16),
        _field(c, icon: PangolinIcons.shieldCheck, label: t.codeLabel,
            child: TextField(controller: _code, keyboardType: TextInputType.number, maxLength: 6,
                style: PangolinText.mono.copyWith(letterSpacing: 6, color: c.fg1),
                decoration: _bare.copyWith(counterText: '', hintText: '······'), onChanged: (_) => setState(() {}))),
        const SizedBox(height: 8),
        PangolinButton(label: t.doNext, expand: true, onPressed: (_sent && _code.text.length == 6) ? () => setState(() => _step = 1) : null),
      ]);
    }
    // Step 1: set password
    return Column(children: [
      Row(children: [Icon(PangolinIcons.checkCircle, size: 15, color: c.success), const SizedBox(width: 7), Text(_email.text, style: PangolinText.sm.copyWith(color: c.fg2))]),
      const SizedBox(height: 16),
      _field(c, icon: PangolinIcons.lock, label: t.pwLabel,
          child: TextField(controller: _pw, obscureText: true, decoration: _bare.copyWith(hintText: t.setPwPh), onChanged: (_) => setState(() {}))),
      const SizedBox(height: 18),
      PangolinButton(
        label: _loading ? '...' : t.doCreate,
        expand: true,
        onPressed: (!_loading && _pw.text.length >= 6) ? _doRegister : null,
      ),
    ]);
  }
}