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

class AdminRepository {
  AdminRepository({required this.client, required this.baseUrl});
  final http.Client client;
  final String baseUrl;
  Future<Set<String>> permissions() async =>
      ((await _get('/me'))['permissions'] as List).cast<String>().toSet();
  Future<Map<String, Object?>> dashboard() async {
    final values = await Future.wait([
      _get('/admin/metrics'),
      _list('/admin/organization/departments'),
      _list('/admin/organization/roles'),
      _list('/admin/organization/users'),
      _list('/admin/workflows/definitions'),
      _list('/admin/workflows/instances'),
      _list('/admin/audit-events?limit=100'),
      _list('/admin/process-configuration/forms'),
      _list('/admin/process-configuration/bindings'),
    ]);
    return {
      'metrics': values[0],
      'departments': values[1],
      'roles': values[2],
      'users': values[3],
      'definitions': values[4],
      'instances': values[5],
      'audits': values[6],
      'formVersions': values[7],
      'bindings': values[8],
    };
  }

  Future<void> createDepartment(String code, String name) => _write(
    'POST',
    '/admin/organization/departments',
    {'code': code, 'name': name},
  );
  Future<void> replaceRoles(String userId, Set<String> roles) => _write(
    'PUT',
    '/admin/organization/users/$userId/roles',
    {'roles': roles.toList()},
  );
  Future<Map<String, Object?>> _get(String path) async {
    final r = await client.get(Uri.parse('$baseUrl$path'));
    _ok(r);
    return Map<String, Object?>.from(jsonDecode(r.body) as Map);
  }

  Future<List<Map<String, Object?>>> _list(String path) async {
    final r = await client.get(Uri.parse('$baseUrl$path'));
    _ok(r);
    return (jsonDecode(r.body) as List)
        .map((e) => Map<String, Object?>.from(e as Map))
        .toList();
  }

  Future<void> _write(
    String method,
    String path,
    Map<String, Object?> body,
  ) async {
    final request = http.Request(method, Uri.parse('$baseUrl$path'))
      ..headers['Content-Type'] = 'application/json'
      ..body = jsonEncode(body);
    final r = await http.Response.fromStream(await client.send(request));
    _ok(r);
  }

  void _ok(http.Response r) {
    if (r.statusCode < 200 || r.statusCode >= 300) {
      throw Exception('管理请求失败（${r.statusCode}）');
    }
  }
}