import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:lottie/lottie.dart';
import 'dart:async';
import 'dart:math' as math;

Future<void> showRegisterSheet(BuildContext context) {
  return showModalBottomSheet<void>(
    context: context,
    isScrollControlled: true,
    backgroundColor: Colors.transparent,
    shape: const RoundedRectangleBorder(
      borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
    ),
    builder: (ctx) => const _AnimatedAuthSheet(child: RegisterBottomSheet()),
  );
}

class _AnimatedAuthSheet extends StatelessWidget {
  const _AnimatedAuthSheet({required this.child});

  final Widget child;

  @override
  Widget build(BuildContext context) {
    final size = MediaQuery.sizeOf(context);
    const topRadius = Radius.circular(20);

    return TweenAnimationBuilder<double>(
      tween: Tween<double>(begin: 0.0, end: 1.0),
      duration: const Duration(milliseconds: 260),
      curve: Curves.easeOutCubic,
      builder: (context, t, w) {
        return Opacity(
          opacity: t,
          child: Transform.translate(offset: Offset(0, (1 - t) * 12), child: w),
        );
      },
      child: ClipRRect(
        borderRadius: const BorderRadius.vertical(top: topRadius),
        child: Material(
          color: Colors.transparent,
          child: Stack(
            clipBehavior: Clip.none,
            children: [
              Positioned.fill(
                child: Container(
                  decoration: const BoxDecoration(
                    gradient: LinearGradient(
                      begin: Alignment.topCenter,
                      end: Alignment.bottomCenter,
                      colors: [Color(0xFFFFE6F1), Color(0xFFFFC9DF)],
                    ),
                  ),
                ),
              ),
              Positioned(
                left: -size.width * 0.38,
                bottom: -size.width * 0.45,
                child: IgnorePointer(
                  child: SizedBox(
                    width: size.width * 1.05,
                    height: size.width * 1.05,
                    child: Transform.rotate(
                      angle: 28 * math.pi / 180,
                      child: Opacity(
                        opacity: 0.95,
                        child: Lottie.asset(
                          'lottie/Liquid waves.json',
                          fit: BoxFit.cover,
                          repeat: true,
                        ),
                      ),
                    ),
                  ),
                ),
              ),
              child,
            ],
          ),
        ),
      ),
    );
  }
}

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

  @override
  State<RegisterBottomSheet> createState() => _RegisterBottomSheetState();
}

class _RegisterBottomSheetState extends State<RegisterBottomSheet> {
  final _formKey = GlobalKey<FormState>();

  final _nameController = TextEditingController();
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();

  bool _loading = false;

  Future<void> _persistRegistrationData({
    required String uid,
    required String name,
    required String email,
  }) async {
    await FirebaseFirestore.instance
        .collection('users')
        .doc(uid)
        .set({
          'name': name,
          'email': email,
          'createdAt': FieldValue.serverTimestamp(),
        }, SetOptions(merge: true))
        .timeout(const Duration(seconds: 20));
  }

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

  @override
  Widget build(BuildContext context) {
    final viewInsets = MediaQuery.viewInsetsOf(context);
    const accentPink = Color(0xFFFF55A7);
    const primaryTeal = Color(0xFF2F9E94);
    final underlineBorder = UnderlineInputBorder(
      borderSide: BorderSide(color: Colors.black.withValues(alpha: 0.20)),
    );

    return Padding(
      padding: EdgeInsets.only(
        left: 16,
        right: 16,
        top: 12,
        bottom: 16 + viewInsets.bottom,
      ),
      child: ConstrainedBox(
        constraints: const BoxConstraints(maxHeight: 560),
        child: SingleChildScrollView(
          child: Form(
            key: _formKey,
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                Center(
                  child: Container(
                    width: 46,
                    height: 5,
                    decoration: BoxDecoration(
                      color: Colors.black.withValues(alpha: 0.10),
                      borderRadius: BorderRadius.circular(99),
                    ),
                  ),
                ),
                const SizedBox(height: 14),
                const Text(
                  'Criar conta',
                  textAlign: TextAlign.center,
                  style: TextStyle(
                    fontSize: 18,
                    fontWeight: FontWeight.w800,
                    color: accentPink,
                  ),
                ),
                const SizedBox(height: 16),
                TextFormField(
                  controller: _nameController,
                  textInputAction: TextInputAction.next,
                  decoration: InputDecoration(
                    labelText: 'Nome',
                    border: underlineBorder,
                    enabledBorder: underlineBorder,
                    focusedBorder: underlineBorder.copyWith(
                      borderSide: const BorderSide(
                        color: primaryTeal,
                        width: 1.6,
                      ),
                    ),
                    floatingLabelStyle: const TextStyle(
                      color: primaryTeal,
                      fontWeight: FontWeight.w700,
                    ),
                  ),
                  validator: (v) {
                    if (v == null || v.trim().isEmpty) {
                      return 'Informe seu nome';
                    }
                    if (v.trim().length < 2) {
                      return 'Nome muito curto';
                    }
                    return null;
                  },
                ),
                const SizedBox(height: 12),
                TextFormField(
                  controller: _emailController,
                  keyboardType: TextInputType.emailAddress,
                  textInputAction: TextInputAction.next,
                  decoration: InputDecoration(
                    labelText: 'Email',
                    border: underlineBorder,
                    enabledBorder: underlineBorder,
                    focusedBorder: underlineBorder.copyWith(
                      borderSide: const BorderSide(
                        color: primaryTeal,
                        width: 1.6,
                      ),
                    ),
                    floatingLabelStyle: const TextStyle(
                      color: primaryTeal,
                      fontWeight: FontWeight.w700,
                    ),
                  ),
                  validator: (v) {
                    final value = (v ?? '').trim();
                    if (value.isEmpty) return 'Informe seu email';
                    if (!value.contains('@')) return 'Email inválido';
                    return null;
                  },
                ),
                const SizedBox(height: 12),
                TextFormField(
                  controller: _passwordController,
                  obscureText: true,
                  textInputAction: TextInputAction.done,
                  decoration: InputDecoration(
                    labelText: 'Senha',
                    border: underlineBorder,
                    enabledBorder: underlineBorder,
                    focusedBorder: underlineBorder.copyWith(
                      borderSide: const BorderSide(
                        color: primaryTeal,
                        width: 1.6,
                      ),
                    ),
                    floatingLabelStyle: const TextStyle(
                      color: primaryTeal,
                      fontWeight: FontWeight.w700,
                    ),
                  ),
                  validator: (v) {
                    final value = (v ?? '');
                    if (value.isEmpty) return 'Informe sua senha';
                    if (value.length < 6) return 'Mínimo de 6 caracteres';
                    return null;
                  },
                ),
                const SizedBox(height: 16),
                SizedBox(
                  height: 46,
                  child: FilledButton(
                    style: FilledButton.styleFrom(
                      backgroundColor: primaryTeal,
                      foregroundColor: Colors.white,
                      shape: const StadiumBorder(),
                      textStyle: const TextStyle(fontWeight: FontWeight.w800),
                    ),
                    onPressed: _loading ? null : _submit,
                    child: _loading
                        ? const SizedBox(
                            width: 18,
                            height: 18,
                            child: CircularProgressIndicator(strokeWidth: 2),
                          )
                        : const Text('Registrar'),
                  ),
                ),
                const SizedBox(height: 8),
                TextButton(
                  onPressed: _loading
                      ? null
                      : () => Navigator.of(context).pop(),
                  child: const Text('Fechar'),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  Future<void> _submit() async {
    if (!(_formKey.currentState?.validate() ?? false)) return;

    setState(() => _loading = true);
    try {
      final name = _nameController.text.trim();
      final email = _emailController.text.trim();
      final password = _passwordController.text;

      final credential = await FirebaseAuth.instance
          .createUserWithEmailAndPassword(email: email, password: password)
          .timeout(const Duration(seconds: 20));

      final user = credential.user;
      if (user == null) {
        throw StateError('Usuário não encontrado após criar conta.');
      }

      final uid = user.uid;

      if (!mounted) return;

      // Fecha o sheet imediatamente após autenticar.
      // As gravações no Firestore seguem em background para não travar a UI.
      Navigator.of(context).pop();

      unawaited(
        _persistRegistrationData(
          uid: uid,
          name: name,
          email: email,
        ).catchError((_) {}),
      );
    } on FirebaseAuthException catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text(_friendlyAuthError(e))));
    } on TimeoutException {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text(
            'Tempo esgotado. Verifique sua conexão e tente novamente.',
          ),
        ),
      );
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text('Erro: $e')));
    } finally {
      if (mounted && _loading) setState(() => _loading = false);
    }
  }

  String _friendlyAuthError(FirebaseAuthException e) {
    switch (e.code) {
      case 'invalid-email':
        return 'Email inválido.';
      case 'email-already-in-use':
        return 'Este email já está em uso.';
      case 'weak-password':
        return 'Senha fraca. Use pelo menos 6 caracteres.';
      default:
        return e.message ?? 'Falha de autenticação.';
    }
  }
}