import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_stripe/flutter_stripe.dart';
import 'package:go_router/go_router.dart';
import 'package:intl/intl.dart';

import '../../../core/api/api_response.dart';
import '../../../core/time/server_time.dart';
import '../../../core/theme/app_colors.dart';
import '../data/wallet_repository.dart';

const _presetAmounts = [10.0, 20.0, 50.0];
const _minAmount = 5.0;
const _maxAmount = 150.0;

/// Écran de rechargement du portefeuille via Stripe Payment Sheet.
class WalletTopUpScreen extends ConsumerStatefulWidget {
  const WalletTopUpScreen({super.key});

  @override
  ConsumerState<WalletTopUpScreen> createState() => _WalletTopUpScreenState();
}

class _WalletTopUpScreenState extends ConsumerState<WalletTopUpScreen> {
  final _amountController = TextEditingController();
  double? _selectedPreset;
  bool _isProcessing = false;

  @override
  void dispose() {
    _amountController.dispose();
    super.dispose();
  }

  double? get _amount {
    if (_selectedPreset != null) {
      return _selectedPreset;
    }

    final raw = _amountController.text.trim().replaceAll(',', '.');
    if (raw.isEmpty) {
      return null;
    }

    return double.tryParse(raw);
  }

  String? _validateAmount(double? amount) {
    if (amount == null) {
      return 'Saisissez un montant';
    }
    if (amount < _minAmount || amount > _maxAmount) {
      return 'Montant entre $_minAmount € et $_maxAmount €';
    }
    return null;
  }

  bool get _canPay => !_isProcessing && _validateAmount(_amount) == null;

  Future<void> _pay() async {
    final amount = _amount;
    final validationError = _validateAmount(amount);
    if (validationError != null) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(validationError)),
      );
      return;
    }

    setState(() => _isProcessing = true);

    try {
      final idempotencyKey =
          'topup-${ServerTime.now().millisecondsSinceEpoch}';
      final payment = await ref.read(walletRepositoryProvider).initiateTopUp(
            amount: amount!,
            idempotencyKey: idempotencyKey,
          );

      if (payment.provider == 'stripe') {
        final stripe = payment.stripe;
        if (stripe == null) {
          throw StateError('Réponse Stripe incomplète');
        }

        Stripe.publishableKey = stripe.publishableKey;
        await Stripe.instance.applySettings();

        await Stripe.instance.initPaymentSheet(
          paymentSheetParameters: SetupPaymentSheetParameters(
            paymentIntentClientSecret: stripe.clientSecret,
            merchantDisplayName: 'Laverie Connectée',
          ),
        );

        await Stripe.instance.presentPaymentSheet();
      }

      final result = await ref.read(walletRepositoryProvider).confirmTopUp(
            paymentUuid: payment.uuid,
          );

      ref.invalidate(walletProvider);
      ref.invalidate(walletTransactionsProvider);

      if (!mounted) return;

      final currency = NumberFormat.currency(locale: 'fr_FR', symbol: '€');
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(
            'Rechargement confirmé — nouveau solde : ${currency.format(result.balance)}',
          ),
          backgroundColor: AppColors.success,
        ),
      );
      context.pop();
    } on StripeException catch (e) {
      if (!mounted) return;
      final message = e.error.localizedMessage ?? 'Paiement annulé';
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(message)),
      );
    } on DioException catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(ApiResponse.errorMessage(e, fallback: 'Erreur de paiement')),
          backgroundColor: AppColors.error,
        ),
      );
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('$e'),
          backgroundColor: AppColors.error,
        ),
      );
    } finally {
      if (mounted) {
        setState(() => _isProcessing = false);
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final currency = NumberFormat.currency(locale: 'fr_FR', symbol: '€');

    return Scaffold(
      backgroundColor: AppColors.background,
      appBar: AppBar(title: const Text('Recharger')),
      body: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          Text(
            'Choisissez le montant à ajouter à votre portefeuille.',
            style: Theme.of(context).textTheme.bodyLarge,
          ),
          const SizedBox(height: 20),
          Wrap(
            spacing: 10,
            runSpacing: 10,
            children: _presetAmounts.map((amount) {
              final selected = _selectedPreset == amount;
              return ChoiceChip(
                label: Text(currency.format(amount)),
                selected: selected,
                onSelected: _isProcessing
                    ? null
                    : (value) {
                        setState(() {
                          _selectedPreset = value ? amount : null;
                          if (value) {
                            _amountController.clear();
                          }
                        });
                      },
              );
            }).toList(),
          ),
          const SizedBox(height: 24),
          Text('Ou saisissez un montant', style: Theme.of(context).textTheme.titleSmall),
          const SizedBox(height: 8),
          TextField(
            controller: _amountController,
            enabled: !_isProcessing,
            keyboardType: const TextInputType.numberWithOptions(decimal: true),
            inputFormatters: [
              FilteringTextInputFormatter.allow(RegExp(r'[0-9.,]')),
            ],
            decoration: InputDecoration(
              suffixText: '€',
              hintText: 'Ex. 15',
              helperText: 'Entre ${currency.format(_minAmount)} et ${currency.format(_maxAmount)}',
              border: const OutlineInputBorder(),
            ),
            onChanged: (_) => setState(() => _selectedPreset = null),
          ),
          const SizedBox(height: 32),
          FilledButton.icon(
            onPressed: _canPay ? _pay : null,
            icon: _isProcessing
                ? const SizedBox(
                    width: 18,
                    height: 18,
                    child: CircularProgressIndicator(strokeWidth: 2, color: Colors.white),
                  )
                : const Icon(Icons.lock_outline),
            label: Text(_isProcessing ? 'Paiement en cours…' : 'Payer'),
          ),
          const SizedBox(height: 16),
          Center(
            child: Text(
              'Paiement sécurisé par Stripe',
              textAlign: TextAlign.center,
              style: Theme.of(context).textTheme.bodySmall?.copyWith(
                    color: AppColors.textSecondary,
                  ),
            ),
          ),
        ],
      ),
    );
  }
}