import 'dart:convert';

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

import 'alpaca_env.dart';
import 'alpaca_models.dart';

/// REST client for Alpaca Market Data API v2 (IEX feed on Basic plan).
class AlpacaMarketDataClient {
  AlpacaMarketDataClient({
    required AlpacaEnv env,
    http.Client? httpClient,
  })  : _env = env,
        _client = httpClient ?? http.Client();

  final AlpacaEnv _env;
  final http.Client _client;

  Map<String, String> get _headers => <String, String>{
        'APCA-API-KEY-ID': _env.apiKeyId,
        'APCA-API-SECRET-KEY': _env.apiSecretKey,
      };

  /// `GET /v2/stocks/{symbol}/trades/latest`
  Future<AlpacaLatestTradeResponse> getLatestTrade(String symbol) async {
    _env.requireCredentials();
    final Uri uri = Uri.parse(
      '${_env.dataBaseUrl}/v2/stocks/${Uri.encodeComponent(symbol)}/trades/latest',
    ).replace(queryParameters: <String, String>{'feed': _env.dataFeed});

    final http.Response response = await _client.get(uri, headers: _headers);
    if (response.statusCode != 200) {
      throw AlpacaMarketDataException(
        'getLatestTrade($symbol) failed: ${response.statusCode} ${response.body}',
      );
    }
    return AlpacaLatestTradeResponse.fromJson(
      jsonDecode(response.body) as Map<String, dynamic>,
    );
  }

  /// `GET /v2/stocks/bars` — batched symbols, daily bars newest last.
  Future<AlpacaBarsResponse> getDailyBars(
    List<String> symbols, {
    int limit = 2,
  }) async {
    _env.requireCredentials();
    if (symbols.isEmpty) {
      return AlpacaBarsResponse(barsBySymbol: <String, List<AlpacaBar>>{});
    }

    final Uri uri = Uri.parse('${_env.dataBaseUrl}/v2/stocks/bars').replace(
      queryParameters: <String, String>{
        'symbols': symbols.join(','),
        'timeframe': '1Day',
        'limit': limit.toString(),
        'feed': _env.dataFeed,
      },
    );

    final http.Response response = await _client.get(uri, headers: _headers);
    if (response.statusCode != 200) {
      throw AlpacaMarketDataException(
        'getDailyBars failed: ${response.statusCode} ${response.body}',
      );
    }
    return AlpacaBarsResponse.fromJson(
      jsonDecode(response.body) as Map<String, dynamic>,
    );
  }

  void close() => _client.close();
}

class AlpacaMarketDataException implements Exception {
  AlpacaMarketDataException(this.message);

  final String message;

  @override
  String toString() => message;
}