import 'dart:convert';

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

import '../models/models.dart';

abstract class ReportDataSource {
  Future<List<ReportCardModel>> recommended();
  Future<List<ReportCardModel>> reports();
  Future<List<Institution>> institutions();
  Future<Institution> institutionDetail(String institutionId);
  Future<List<AudioItem>> listen();
  Future<ReportDetail> reportDetail(String reportId);
  Future<ModuleDetail> moduleDetail(String reportId, String moduleId);
}

class RnbApiDataSource implements ReportDataSource {
  RnbApiDataSource({
    http.Client? client,
    this.baseUrl = const String.fromEnvironment('RNB_API_BASE'),
  }) : client = client ?? http.Client();

  final http.Client client;
  final String baseUrl;

  Future<JsonMap> _get(String path) async {
    if (baseUrl.isEmpty) {
      throw StateError('RNB_API_BASE is required for live API requests.');
    }
    final response = await client.get(Uri.parse('$baseUrl$path'));
    if (response.statusCode != 200) {
      throw StateError('Request failed: ${response.statusCode}');
    }
    return jsonDecode(utf8.decode(response.bodyBytes)) as JsonMap;
  }

  List<JsonMap> _items(JsonMap body) => asMapList(body['items']);

  @override
  Future<List<ReportCardModel>> recommended() async {
    final body = await _get('/feed/recommended');
    return _items(body).map(ReportCardModel.fromJson).toList();
  }

  @override
  Future<List<ReportCardModel>> reports() async {
    final body = await _get('/reports');
    return _items(body).map(ReportCardModel.fromJson).toList();
  }

  @override
  Future<List<Institution>> institutions() async {
    final body = await _get('/institutions');
    return _items(body).map(Institution.fromJson).toList();
  }

  @override
  Future<Institution> institutionDetail(String institutionId) async {
    return Institution.fromJson(await _get('/institutions/$institutionId'));
  }

  @override
  Future<List<AudioItem>> listen() async {
    final body = await _get('/listen');
    return _items(body).map(AudioItem.fromJson).toList();
  }

  @override
  Future<ReportDetail> reportDetail(String reportId) async {
    return ReportDetail.fromJson(await _get('/reports/$reportId'));
  }

  @override
  Future<ModuleDetail> moduleDetail(String reportId, String moduleId) async {
    return ModuleDetail.fromJson(await _get('/reports/$reportId/modules/$moduleId'));
  }
}