import 'package:sqflite/sqflite.dart';
// import './state_helper.dart';
// import './db_helper.dart';

// TODO: get access to DB

class DbHelper {
  static late Database db;
  static String dbName = "";

  // DbHelper({
  //   required this.db,
  //   required this.dbName,
  // });

  // remnant from when DB was not static
  // factory DbHelper._openDb(Database database, String dbName) => DbHelper(
  //   db: database,
  //   dbName: dbName,
  // );

  static void initDb(String dbName) async {
    // var db = await openDatabase('/var/db/oeffimaster/transport_db.db');
    var databasesPath = await getDatabasesPath();
    var path = databasesPath + dbName;
    // var newDb = await openDatabase(path);
    // var dbHelper = DbHelper._openDb(newDb, dbName);
    db = await openDatabase(path);
    dbName = dbName;

    // TODO: Make sure the directory exists

    // TODO: future optimisation: batch transactions

    Route.initRouteTable();
    Segment.initSegmentTable();
    Station.initStationTable();
    Vehicle.initVehicleTable();
    Departure.initDepartureTable();
  }
}

/// this class covers two database tables: "route" and "routesegments"
/// while route will for now only hold an id, routesegments will store the
/// m-n/ 1-n relations between routes and segments - the segments contain the most
/// relevant info, while routesegments stores which route the segments belong to
/// and in which order they make up a route
class Route {
  // TODO: add last_viewed, last_modified and such
  int? id;
  List<Segment> segments = List.empty();
  Duration duration = Duration(minutes: 0);

  Route({
    this.id,
    required this.segments,
    required this.duration,
  });

  /// toMap for Route but it's just route ids for now
  Map<String, Object?> toMapRoute() {
    return {"id": id};
  }

  /// toMap for routesegments relational table
  List<Map<String, Object?>> toMapRouteSegments() {
    //asMap() apparently enumerates
    List<Map<String, Object?>> tmp = List.empty();
    for (final (segmentIdx, segment) in segments.indexed) {
      tmp.add({
        "route": id,
        "segmentid": segment.id,
        "segmentorder": segmentIdx,
      });
    }
    return tmp;
  }

  // from trip API request
  // TODO: how to connect this best with the database for read/write?
  factory Route.fromJson(Map<String, dynamic> json) {
    Route newRoute = Route(
      segments: json["LegList"]["Leg"].map((leg) => Segment.fromJson(leg)),
      duration:
          json["LegList"]["Leg"][-1]["Origin"]["time"] -
          json["LegList"]["Leg"][0]["Origin"]["time"],
    );
    newRoute.dbInsertRoute();
    return newRoute;
  }

  static void initRouteTable() async {
    Database database = DbHelper.db;
    database.execute("""CREATE TABLE IF NOT EXISTS route(
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    );
    """);
  }

  static void initRouteSegmentsTable() async {
    Database database = DbHelper.db;
    String segment = Segment.tableName;
    database.execute("""CREATE TABLE IF NOT EXISTS routesegments(
    id            TEXT PRIMARY KEY AUTOINCREMENT,
    route         INTEGER,
    segment       INTEGER,
    segmentorder  INTEGER, -- TODO: implement sorting
    FOREIGN KEY(route) REFERENCES route(id),
    FOREIGN KEY(segment) REFERENCES $segment(id)
    );
    """);
  }

  void dbInsertRoute() async {
    Database database = DbHelper.db;
    id = await database.insert(
      "route",
      toMapRoute(),
      conflictAlgorithm: ConflictAlgorithm.replace,
    );
  }

  void dbInsertRouteSegments() async {
    Database database = DbHelper.db;
    var routeSegments = toMapRouteSegments();
    for (var i = 0; i < routeSegments.length; i++) {
      database.insert(
        "routesegments",
        routeSegments[i],
      );
    }
  }

  void dbDelete() async {
    Database database = DbHelper.db;
    int result = await database.delete(
      "route",
      where: "id = ?",
      whereArgs: [id],
    );
    assert(result == 0);
  }

  void dbDeleteLastRouteSegment() {
    Database database = DbHelper.db;
    database.delete(
      "routesegments",
      where: "route = ? AND segmentorder = ?",
      whereArgs: [id, segments.length - 1], // TODO: test the index
    );
  }

  void dbDeleteTrailingRouteSegment(int position) {
    Database database = DbHelper.db;
    if (position <= segments.length) {
      database.delete(
        "routesegments",
        where: "route = ? AND segmentorder >= ?",
        whereArgs: [id, position],
      );
    }
  }

  // TODO: delete leading segments and decrement following segments
}

class Segment {
  static const String tableName = "segment";

  int? id;
  Station startPoint;
  Station endPoint;
  DateTime startTime;
  DateTime endTime;
  Vehicle vehicle;

  Segment({
    this.id, // might throw errors - needs testing, I guess
    required this.startPoint,
    required this.endPoint,
    required this.startTime,
    required this.endTime,
    required this.vehicle,
  });

  Map<String, Object?> toMap() {
    return {
      "startPoint": startPoint.id,
      "endpoint": endPoint.id,
      "starttime": startTime,
      "endtime": endTime,
      "vehicle": vehicle.id,
    };
  }

  factory Segment.fromJson(Map<String, dynamic> json) {
    Database database = DbHelper.db;
    Segment tmp = Segment(
      startPoint: Station.fromJson(json["Origin"]),
      endPoint: Station.fromJson(json["Destination"]),
      startTime: json["Origin"]["rtTime"],
      endTime: json["Destination"]["rtTime"],
      vehicle: Vehicle.fromJson(json["Product"]),
    );
    tmp.dbInsert();
    return tmp;
  }

  static void initSegmentTable() async {
    Database database = DbHelper.db;
    String station = Station.tableName;
    String vehicle = Vehicle.tableName;
    database.execute("""
    CREATE TABLE IF NOT EXISTS $tableName(
    startpoint  TEXT,
    endpoint    TEXT,
    starttime   TEXT,
    endtime     TEXT,
    vehicle     INTEGER,
    FOREIGN KEY(startpoint) REFERENCES $station(stationid),
    FOREIGN KEY(endpoint) REFERENCES $station(stationid),
    FOREIGN KEY(vehicle) REFERENCES $vehicle(vehicleid)
    );
    """);
  }

  void dbInsert() async {
    Database database = DbHelper.db;
    id = await database.insert(tableName, toMap());
  }

  void dbDelete() {
    Database database = DbHelper.db;
    database.delete(
      tableName,
      where: "rowid = ?",
      whereArgs: [id],
    );
  }
}

class Station {
  static const String tableName = "station";

  String id;
  String name;
  List<Line> transportLines; // could be normalized away

  Station({
    required this.id,
    required this.name,
    required this.transportLines,
  });

  Map<String, Object?> toMap() {
    return {"id": id, "name": name};
  }

  List<Map<String, Object?>> toMapLines() {
    return transportLines
        .map(
          (line) => {"stationid": id, "lineid": line},
        )
        .toList();
  }

  factory Station.fromJson(Map<String, dynamic> json) => Station(
    id: json["id"] as String? ?? json["extId"] as String,
    name: json["name"],
    transportLines: json.containsKey("productAtStop")
        ? json["productAtStop"].map(
            (jsonLine) => Line.fromJson(jsonLine as Map<String, dynamic>),
          )
        : const [],
  );

  static void initStationTable() async {
    Database database = DbHelper.db;
    database.execute("""CREATE TABLE IF NOT EXISTS station(
      stationid TEXT PRIMARY KEY,
      name      TEXT
    );
    """);
  }

  static void initStationLinesTable() async {
    Database database = DbHelper.db;
    database.execute("""CREATE TABLE IF NOT EXISTS stationlines(
      id INTEGER PRIMARY KEY AUTOINCREMENT,
      stationid TEXT,
      lineid TEXT,
      FOREIGN KEY (stationid) REFERENCES station(stationid),
      FOREIGN KEY (lineid) REFERENCES line(lineid)
    );
    """);
  }

  void dbInsertStation() async {
    Database database = DbHelper.db;
    database.insert(tableName, toMap());
  }

  void dbInsertStationLines() async {
    Database database = DbHelper.db;
    var stationLines = toMapLines();
    for (var i = 0; i < stationLines.length; i++) {
      database.insert("stationlines", stationLines[i]);
    }
  }

  void dbDelete() async {
    Database database = DbHelper.db;
    database.delete(tableName, where: "stationid = ?", whereArgs: [id]);
  }

  /// remove all Lines connected to a Station - should be used together with some kind of reparsing.
  void dbDeleteStationLines() async {
    Database database = DbHelper.db;
    database.delete("stationlines", where: "stationid = ?", whereArgs: [id]);
  }
}

class Vehicle {
  static const String tableName = "vehicle";

  String id;
  Line line;

  Vehicle({
    required this.id,
    required this.line,
  });

  Map<String, Object?> toMap() {
    return {
      "id": id,
      "line": line.lineId,
    };
  }

  // we can use the "product" class from within any JSON response
  // (within hafas API, on the appropriate level)
  factory Vehicle.fromJson(Map<String, dynamic> json) => Vehicle(
    id: json["matchId"],
    line: Line.fromJson(json),
  );

  static void initVehicleTable() async {
    Database database = DbHelper.db;
    String line = Line.tableName;
    database.execute("""CREATE TABLE IF NOT EXISTS $tableName(
      id TEXT PRIMARY KEY,
      line      TEXT,
      FOREIGN KEY(line) REFERENCES $line(lineid)
    );
    """);
  }

  void dbInsert() async {
    Database database = DbHelper.db;
    database.insert(tableName, toMap());
  }

  void dbDelete() async {
    Database database = DbHelper.db;
    database.delete(tableName, where: "id = ?", whereArgs: [id]);
  }
}

class Line {
  static const String tableName = "line";

  String lineId;
  Station? destination;
  Station? direction;
  VehicleType mode;
  String name;
  Color? fgColor;
  Color? bgColor;

  Line({
    required this.lineId,
    required this.name,
    required this.mode,
    this.fgColor,
    this.bgColor,
  });

  Map<String, Object?> toMap() {
    return {
      "lineid": lineId,
      "destination": destination,
      "direction": direction,
      "mode": mode,
      "name": name,
      "fgcolor": fgColor,
      "bgcolor": bgColor,
    };
  }

  // TODO: EXPLAIN!!!!!!!!!!!!
  static const _vehicleTypeAsCatCode = [
    VehicleType.metro,
    VehicleType.subway,
    VehicleType.PLACEHOLDER,
    VehicleType.bus,
  ];

  factory Line.fromJson(Map<String, dynamic> json) => Line(
    lineId: json["lineId"],
    name: json["name"],
    mode: _vehicleTypeAsCatCode[int.parse(json["catCode"])],
    fgColor:
        Color.fromJson(json["foregroundColor"]) as Color? ??
        Color(r: 255, g: 255, b: 255), // fallback
    bgColor:
        Color.fromJson(json["backgroundColor"]) as Color? ??
        Color(r: 50, g: 50, b: 50), // fallback
  );
  static void initLineTable() async {
    Database database = DbHelper.db;
    database.execute("""CREATE TABLE IF NOT EXISTS $tableName(
      lineid      TEXT PRIMARY KEY,
      destination TEXT,
      direction   TEXT,
      mode        TEXT,
      name        TEXT,
      fgcolor     TEXT,
      bgcolor     TEXT
    );
    """);
  }

  void dbInsert() async {
    Database database = DbHelper.db;
    database.insert(tableName, toMap());
  }

  void dbDelete() async {
    Database database = DbHelper.db;
    database.delete(tableName, where: "lineid = ?", whereArgs: [lineId]);
  }
}

// TODO: add fromJson
class Departure {
  static const String tableName = "departure";

  int? id;
  Vehicle vehicle;
  Station station;
  DateTime departureTime;

  Departure({
    this.id,
    required this.vehicle,
    required this.station,
    required this.departureTime,
  });

  Map<String, Object?> toMap() {
    return {
      "id": id,
      "vehicle": vehicle,
      "station": station,
      "departuretime": departureTime,
    };
  }

  static void initDepartureTable() async {
    Database database = DbHelper.db;
    String vehicle = Vehicle.tableName;
    String station = Station.tableName;
    database.execute("""CREATE TABLE IF NOT EXISTS $tableName(
      id     INTEGER,
      vehicle         TEXT,
      station         TEXT,
      departuretime   TEXT,
      FOREIGN KEY(vehicle) REFERENCES $vehicle(id),
      FOREIGN KEY(station) REFERENCES $station(id)
     );
     """);
  }

  void dbInsert() async {
    Database database = DbHelper.db;
    id = await database.insert(tableName, toMap());
  }

  void dbDelete() async {
    Database database = DbHelper.db;
    database.delete(tableName, where: "id = ?", whereArgs: [id]);
  }
}

class Color {
  int r;
  int g;
  int b;

  Color({
    required this.r,
    required this.g,
    required this.b,
  });

  factory Color.fromJson(Map<String, dynamic> json) => Color(
    r: json["r"],
    g: json["g"],
    b: json["b"],
  );
}

enum VehicleType {
  bus,
  tram,
  metro,
  subway,
  regionalTrain,
  PLACEHOLDER,
}