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

import 'dart:core';
import 'dart:convert';

import 'transport_helper.dart';

String timeOf(DateTime fullDT) {
  // doing it this way so we always get two digits on the hour
  String full = fullDT.toString();
  List<String> splits = full.split(" ")[1].split(":");
  String time = '${splits[0]}:${splits[1]}';
  return time;
}

class ApiHandler {
  // TODO: Split next line for better Error Handling
  static final String baseUrl = dotenv.get("VBB_API_URL");
  static final String accessID = dotenv.get("VBB_API_KEY");

  //static Future<Map<String, dynamic>> findStations(String locationName) async {
  static Future<List<Station>> findStations(
    String locationName, {
    int? maxStations = 5,
  }) async {
    String urlPath = '/api/fahrinfo/latest/location.name';
    Uri url = Uri.https(baseUrl, urlPath, {
      'accessId': accessID,
      'input': locationName,
      'maxNo': maxStations.toString(),
      'type': 'S', // Station/Stops only
    });
    //print(url);
    var jsonResponse = await http.get(
      url,
      headers: {'Accept': 'application/json'},
    );
    final httpPackageJson =
        json.decode(jsonResponse.body) as Map<String, dynamic>;
    //print(httpPackageJson["stopLocationOrCoordLocation"]);
    List<Station> stationList = httpPackageJson["stopLocationOrCoordLocation"]
        .map(
          (x) => Station.fromJson(x["StopLocation"]),
        )
        .toList()
        .cast<Station>();
    return stationList;
  }

  static Future<List<Station>> nearbyStations(
    String latitude,
    String longitude, {
    int? maxStations = 5,
  }) async {
    String urlPath = '/api/fahrinfo/latest/location.nearbystops';
    Uri url = Uri.https(baseUrl, urlPath, {
      'accessId': accessID,
      'originCoordLat': latitude,
      'originCoordLong': longitude,
      'maxNo': maxStations.toString(),
      'type': 'S', // Station/Stops only
    });
    var jsonResponse = await http.get(
      url,
      headers: {'Accept': 'application/json'},
    );
    final httpPackageJson =
        json.decode(jsonResponse.body) as Map<String, dynamic>;
    final stationList = httpPackageJson["stopLocationOrCoordLocation"]
        .map(
          (x) => Station.fromJson(x["StopLocation"]),
        )
        .toList()
        .cast<Station>();
    return stationList;
  }

  static Future<List<Departure>> departures(
    String stationId, {
    int? maxDepartures = -1,
    DateTime? time,
    int? duration = 0,
  }) async {
    String urlPath = '/api/fahrinfo/latest/departureBoard';
    String stationString = stationId.replaceAll(' ', '%20'); // reform for URL

    Uri url = Uri.https(baseUrl, urlPath, {
      'accessId': accessID,
      'id': stationString,
      'time': timeOf(
        time ?? DateTime.now(),
      ), //time from which departures will be shown
      'duration': duration.toString(), //interval time in minutes
      'maxJourneys': maxDepartures.toString(),
      //'type': 'S', // Station/Stops only
    });
    var jsonResponse = await http.get(
      url,
      headers: {'Accept': 'application/json'},
    );
    final httpPackageJson =
        json.decode(jsonResponse.body) as Map<String, dynamic>;

    // try {
    List<Departure> departureList = httpPackageJson["Departure"]
        .map(
          (x) => Departure.fromJson(x),
        )
        .toList()
        .cast<Departure>();
    return departureList;
    // } catch (e) {
    //  //  TODO: logging
    //   // empty response
    //   print('Error: $e');
    //   // print(
    //   //   'Response for Station-id "$stationString" contains no field "Departure": $httpPackageJson',
    //   // );
    //   return [];
    // }
  }

  static Future<List<Departure>> departuresAggregate(
    List<String> stationList, {
    int? maxDepartures = -1,
    int? duration = -1,
  }) async {
    String urlPath = '/api/fahrinfo/latest/multiDepartureBoard';
    String stationListString = stationList
        .reduce((value, element) => '$value|$element')
        .replaceAll(' ', '%20'); // reform for URL

    Uri url = Uri.https(baseUrl, urlPath, {
      'accessId': accessID,
      'id': stationListString,
      ////'time': /current time //time from which departures will be shown
      'duration': duration.toString(), //interval time in minutes
      'maxJourneys': maxDepartures.toString(),
      'type': 'S', // Station/Stops only
    });
    var jsonResponse = await http.get(
      url,
      headers: {'Accept': 'application/json'},
    );
    final httpPackageJson =
        json.decode(jsonResponse.body) as Map<String, dynamic>;
    List<Departure> departureList = httpPackageJson["Departure"]
        .map(
          (x) => Departure.fromJson(x),
        )
        .toList()
        .cast<Departure>();
    return departureList;
  }

  static Future<List<Segment>> trip(
    String originId,
    String destinationId, {
    String? via,
    String? viaID,
    String? date,
    String? time,
    int? maxChange,
    int? minChangeTime,
    int? maxChangeTime,
    bool? arrivalTime,
    // int? products, // which transport modi to use - ignore for now
    // String rtMode, // wherether to use real time data
    // String trainFilter,
  }) async {
    String urlPath = '/api/fahrinfo/latest/trip';
    String startId = originId.replaceAll(' ', '%20'); // reform for URL
    String endId = destinationId.replaceAll(' ', '%20'); // reform for URL

    Uri url = Uri.https(baseUrl, urlPath, {
      'accessId': accessID,
      'originId': startId,
      'destId': endId,
      ////'time': /current time //time from which departures will be shown
      'time': time.toString(), //interval time in minutes
      'maxChange': maxChange.toString(),
      'type': 'S', // Station/Stops only
    });
    var jsonResponse = await http.get(
      url,
      headers: {'Accept': 'application/json'},
    );
    final httpPackageJson =
        json.decode(jsonResponse.body) as Map<String, dynamic>;
    // TODO: here lurk problems - do we get a list of list of segments? can't cast it–
    //  what do we want from this?
    List<Segment> SegmentList = httpPackageJson["Trip"]
        .map(
          (x) => x["LegList"]["Leg"].map((y) => Segment.fromJson(y)),
        )
        .toList();
    return SegmentList;
  }

  static Future<List<Departure>> tripDetail(
    String id, {
    String? date,
    String? fromId,
    int? fromIdx,
    String? toId,
    int? toIdx,
    String? startStationId,
  }) async {
    String urlPath = '/api/fahrinfo/latest/journeyDetail';
    Uri url = Uri.https(baseUrl, urlPath, {
      'accessId': accessID,
      'id': id,
      'fromId': fromId,
      'toId': toId,
    });
    var jsonResponse = await http.get(
      url,
      headers: {'Accept': 'application/json'},
    );
    final httpPackageJson =
        json.decode(jsonResponse.body) as Map<String, dynamic>;
    Iterable<Departure> DepartureList = httpPackageJson["Stops"]["Stop"]
        .map(
          (x) => Departure.fromJson(
            // needed because I'm too lazy to write a second mostly identical
            // constructor and a wrapper
            _expandDeparturesJson(httpPackageJson, x, [
              "ref",
              "Product",
              "Directions",
            ]),
          ),
        )
        .cast<Departure>();

    // preferably this happens always?
    if (startStationId != null) {
      // show Stations after the one we are at
      return DepartureList.skipWhile(
        (x) => x.stationId != startStationId,
      ).skip(1).toList();
    }

    return DepartureList.toList().cast<Departure>();
  }

  // workaround for the fact that json from tripDetail and DepartureBoard are
  // quite different from each other in their structure... but I don't wish to
  // build a second constructor >:(
  // so this function duplicates topLevel Maps into a lower level to be used in
  // mapping functions and such
  static Map<String, dynamic> _expandDeparturesJson(
    Map<String, dynamic> topLevelJson,
    Map<String, dynamic> subLevelJson,
    List<String> topLevelKeys,
  ) {
    for (final String entry in topLevelKeys) {
      subLevelJson[entry] = topLevelJson[entry];
    }
    return subLevelJson;
  }
}