import 'dart:convert';

import 'package:flutter_test/flutter_test.dart';
import 'package:glp1_companion/features/nutrition/data/datasources/usda_fdc_client.dart';
import 'package:http/http.dart' as http;
import 'package:http/testing.dart';

/// Representative USDA FoodData Central `foods/search` payload with the six
/// nutrient IDs the client maps.
String _fdcSearchResponse() => jsonEncode({
      'totalHits': 1,
      'foods': [
        {
          'fdcId': 12345,
          'description': 'YOGURT, PLAIN, WHOLE MILK',
          'dataType': 'Foundation',
          'foodNutrients': [
            {'nutrientId': 1008, 'value': 61},
            {'nutrientId': 1003, 'value': 3.5},
            {'nutrientId': 1004, 'value': 3.3},
            {'nutrientId': 1005, 'value': 4.7},
            {'nutrientId': 1079, 'value': 0},
            // USDA reports sodium (1093) in mg directly — unlike OFF, which
            // reports grams; the client passes it through unchanged.
            {'nutrientId': 1093, 'value': 46},
          ],
        },
      ],
    });

void main() {
  group('UsdaFdcClient request shape', () {
    test('sends api_key as a QUERY parameter, never in the JSON body',
        () async {
      late http.Request captured;
      final client = MockClient((request) async {
        captured = request;
        return http.Response(_fdcSearchResponse(), 200);
      });

      final usda = UsdaFdcClient(client: client, apiKey: 'TEST_KEY');
      await usda.searchByText('yogurt');

      // Regression (field-reported 2026-10-17): the FDC API only validates
      // the key from the query string — a body-only `apiKey` yields
      // HTTP 403 API_KEY_MISSING.
      expect(captured.url.queryParameters['api_key'], 'TEST_KEY');
      expect(captured.url.queryParameters.containsKey('apiKey'), isFalse);

      final body = jsonDecode(captured.body) as Map<String, dynamic>;
      expect(body.containsKey('apiKey'), isFalse,
          reason: 'the JSON body must not carry the key');
      expect(body['query'], 'yogurt');
    });

    test('falls back to DEMO_KEY when no override or .env entry exists',
        () async {
      late Uri capturedUrl;
      final client = MockClient((request) async {
        capturedUrl = request.url;
        return http.Response(_fdcSearchResponse(), 200);
      });

      // No constructor key; dotenv is uninitialized in tests, so the client
      // must degrade to the public DEMO_KEY.
      await UsdaFdcClient(client: client).searchByText('yogurt');

      expect(capturedUrl.queryParameters['api_key'], 'DEMO_KEY');
    });

    test('maps nutrient IDs onto the FoodProduct entity', () async {
      final client = MockClient((request) async {
        return http.Response(_fdcSearchResponse(), 200);
      });

      final results =
          await UsdaFdcClient(client: client, apiKey: 'k').searchByText('yogurt');

      expect(results, hasLength(1));
      final product = results.single;
      expect(product.id, 'fdc:12345');
      expect(product.productName, 'YOGURT, PLAIN, WHOLE MILK');
      expect(product.calories, 61);
      expect(product.proteinGrams, 3.5);
      expect(product.fatGrams, 3.3);
      expect(product.carbsGrams, 4.7);
      expect(product.fiberGrams, 0);
      expect(product.sodiumMg, 46, reason: 'grams are converted to mg');
      expect(product.servingSizeGrams, 100);
      expect(product.servingSizeUnit, 'g',
          reason: 'FDC defaults to a per-100 g basis when no unit is given');
    });

    test('barcode lookups restrict the query to Branded foods', () async {
      late Map<String, dynamic> capturedBody;
      final client = MockClient((request) async {
        capturedBody = jsonDecode(request.body) as Map<String, dynamic>;
        return http.Response(_fdcSearchResponse(), 200);
      });

      await UsdaFdcClient(client: client, apiKey: 'k')
          .lookupBarcode('012345678905');

      expect(capturedBody['query'], '012345678905');
      expect(capturedBody['dataType'], ['Branded']);
    });

    test('non-200 responses throw UsdaFdcException', () async {
      final client = MockClient(
        (request) async => http.Response('{"error":{"code":"API_KEY_MISSING"}}', 403),
      );

      final usda = UsdaFdcClient(client: client, apiKey: 'bad');
      expect(
        usda.searchByText('yogurt'),
        throwsA(isA<UsdaFdcException>()),
      );
    });
  });
}