import 'dart:convert';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';

class BillingAuthService {
  static const String baseUrl = 'http://127.0.0.1:8000/api/v1';

  /// Sincroniza las credenciales fiscales automáticamente usando el correo de sesión:
  static Future<bool> pairByEmail(String email, {String? deviceName}) async {
    try {
      final response = await http.post(
        Uri.parse('$baseUrl/auth/pair-by-email'),
        headers: {'Content-Type': 'application/json'},
        body: jsonEncode({
          'email': email,
          'device_name': deviceName ?? 'Flutter POS Terminal',
        }),
      );

      final data = jsonDecode(response.body);
      if (response.statusCode == 200 && data['success'] == true) {
        final prefs = await SharedPreferences.getInstance();
        await prefs.setString('billing_token', data['token']);
        await prefs.setString('billing_issuer_id', data['issuer']['id']);
        await prefs.setString('billing_tax_id', data['issuer']['tax_id']);
        await prefs.setString('billing_legal_name', data['issuer']['legal_name']);
        return true;
      }
      return false;
    } catch (_) {
      return false;
    }
  }

  /// Emite un comprobante a SUNAT usando las credenciales del emisor asociado:
  static Future<Map<String, dynamic>> emitirComprobante(Map<String, dynamic> documento) async {
    final prefs = await SharedPreferences.getInstance();
    final token = prefs.getString('billing_token');
    final issuerId = prefs.getString('billing_issuer_id');

    if (token == null || issuerId == null) {
      throw Exception('Dispositivo POS no vinculado con ninguna empresa emisora.');
    }

    final response = await http.post(
      Uri.parse('$baseUrl/documents'),
      headers: {
        'Content-Type': 'application/json',
        'Authorization': 'Bearer $token',
        'X-Issuer-Id': issuerId,
      },
      body: jsonEncode(documento),
    );

    return jsonDecode(response.body);
  }
}