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

class APIError implements Exception {
  final int statusCode;
  final String message;
  APIError(this.statusCode, this.message);
  @override
  String toString() => 'APIError $statusCode: $message';
}

class APIClient {
  final String baseUrl;

  APIClient({this.baseUrl = 'http://localhost:8000'});

  String _url(String path) => '$baseUrl$path';

  static dynamic _decodeBody(http.Response response) {
    return jsonDecode(response.body);
  }

  static Map<String, dynamic>? _asMap(dynamic d) {
    if (d is Map<String, dynamic>) return d;
    if (d is Map) return d.cast<String, dynamic>();
    return null;
  }

  static void _checkError(http.Response response) {
    if (response.statusCode >= 400) {
      final body = _decodeBody(response);
      final map = _asMap(body) ?? {};
      throw APIError(
        response.statusCode,
        map['error'] as String? ?? 'Request failed',
      );
    }
  }

  Future<List<Pipeline>> listPipelines() async {
    final res = await http.get(Uri.parse(_url('/api/pipelines')));
    _checkError(res);
    final data = _decodeBody(res);
    final arr = data is List ? data : [];
    final result = <Pipeline>[];
    for (final e in arr) {
      final m = _asMap(e);
      if (m != null) result.add(Pipeline.fromJson(m));
    }
    return result;
  }

  Future<Pipeline> getPipeline(String id) async {
    final res = await http.get(Uri.parse(_url('/api/pipelines/$id')));
    _checkError(res);
    final data = _decodeBody(res);
    final map = _asMap(data) ?? {};
    final inner = _asMap(map['data']) ?? map;
    return Pipeline.fromJson(inner);
  }

  Future<Pipeline> createPipeline(Pipeline pipeline) async {
    final res = await http.post(
      Uri.parse(_url('/api/pipelines')),
      headers: {'Content-Type': 'application/json'},
      body: jsonEncode(pipeline.toJson()),
    );
    _checkError(res);
    final data = _decodeBody(res);
    final map = _asMap(data) ?? {};
    final inner = _asMap(map['data']) ?? map;
    return Pipeline.fromJson(inner);
  }

  Future<void> deletePipeline(String id) async {
    final res = await http.delete(Uri.parse(_url('/api/pipelines/$id')));
    _checkError(res);
  }

  Future<Map<String, dynamic>> startRun(String pipelineId) async {
    final res = await http.post(
      Uri.parse(_url('/api/runs')),
      headers: {'Content-Type': 'application/json'},
      body: jsonEncode({'pipeline_id': pipelineId}),
    );
    _checkError(res);
    final data = _decodeBody(res);
    final map = _asMap(data) ?? {};
    return _asMap(map['data']) ?? map;
  }

  Future<RunState> getRunStatus(String runId) async {
    final res = await http.get(Uri.parse(_url('/api/runs/$runId/status')));
    _checkError(res);
    final data = _decodeBody(res);
    final map = _asMap(data) ?? {};
    final inner = _asMap(map['data']) ?? map;
    return RunState.fromJson(inner);
  }

  Future<String> getRunLog(String runId) async {
    final res = await http.get(Uri.parse(_url('/api/runs/$runId/log')));
    _checkError(res);
    return res.body;
  }
}