import 'dart:io';
import 'package:path/path.dart';
import 'package:sqflite/sqflite.dart';
import 'package:path_provider/path_provider.dart';

class DatabaseHelper {
  
  static final _databaseName = "LnLShare.db";
  static final _databaseVersion = 1;

  static final table = 'gmaplocations';
  static final weatherTable = 'weather';
  
  static final columnMapLocation = 'mapLocation';
  static final columnLatLong = 'latLong';
  static final columnLnlTime = 'lnlTime';
  static final columnViewTime = 'viewTime';
  static final columnElev = 'elev';
  static final columnElevTime = 'elevTime';
  static final columnWeatherID = 'weatherID';

  static final columnWeatherWeatherID = 'weatherID';
  static final columnWeather = 'weather';
  static final columnWeatherForecast = 'weatherForecast';

  // make this a singleton class
  DatabaseHelper._privateConstructor();
  static final DatabaseHelper instance = DatabaseHelper._privateConstructor();

  // only have a single app-wide reference to the database
  static Database _database;
  Future<Database> get database async {
    if (_database != null) return _database;
    // lazily instantiate the db the first time it is accessed
    _database = await _initDatabase();
    return _database;
  }
  
  // this opens the database (and creates it if it doesn't exist)
  _initDatabase() async {
    Directory documentsDirectory = await getApplicationDocumentsDirectory();
    String path = join(documentsDirectory.path, _databaseName);
    return await openDatabase(path,
        version: _databaseVersion,
        onCreate: _onCreate);
  }

  // SQL code to create the database table
  Future _onCreate(Database db, int version) async {
    await db.execute('''
          CREATE TABLE $table (
            $columnMapLocation VARCHAR UNIQUE,
            $columnLatLong TEXT,
            $columnLnlTime INT,
            $columnViewTime INT,
            $columnElev INT,
            $columnElevTime INT,
            $columnWeatherID INT 
          )
          ''');
    await db.execute('''
          CREATE TABLE $weatherTable (
            $columnWeatherWeatherID INT UNIQUE,
            $columnWeather TEXT,
            $columnWeatherForecast TEXT
          )
          ''');
  }
  
  Future<int> insert(Map<String, dynamic> row) async {
    Database db = await instance.database;
    return await db.insert(table, row);
  }

  Future<int> insertWeatherRow(Map<String, dynamic> row) async {
    Database db = await instance.database;
    return await db.insert(weatherTable, row);
  }

  Future<List<Map<String, dynamic>>> queryAllRows() async {
    Database db = await instance.database;
    return await db.query(table);
  }

  Future<int> queryRowCount() async {
    Database db = await instance.database;
    return Sqflite.firstIntValue(await db.rawQuery('SELECT COUNT(*) FROM $table'));
  }

  Future<int> queryRowExists(String mapLocation) async {
    Database db = await instance.database;
    return Sqflite.firstIntValue(await db.rawQuery('SELECT EXISTS (SELECT $columnMapLocation FROM $table WHERE $columnMapLocation=\'$mapLocation\')'));
  }

  Future<int> queryWeatherIDExists(int weatherID) async {
    Database db = await instance.database;
    return Sqflite.firstIntValue(await db.rawQuery('SELECT EXISTS (SELECT $columnWeatherWeatherID FROM $weatherTable WHERE $columnWeatherWeatherID=\'$weatherID\')'));
  }

  Future<String> queryNewestMapLocation() async {
    Database db = await instance.database;
    List<Map> result = await db.rawQuery('SELECT $columnMapLocation FROM $table ORDER BY $columnViewTime DESC LIMIT 1');
    return (result.length == 0) ?  'Plataea\nGreece\nhttps://maps.app.goo.gl/1NW9z': result[0]['mapLocation'];
  }

  Future<List<String>> sortedMapLocations() async {
    Database db = await instance.database;
    var result = await db.rawQuery('SELECT $columnMapLocation FROM $table ORDER BY $columnViewTime DESC');
    List<String> result_list = new List<String>();
    for (var i = 0; i < result.length; i++) {
      result_list.add(result[i]['mapLocation']);
    }
    return result_list;
  }

  Future<String> queryLatNLong(String mapLocation) async {
    Database db = await instance.database;
    List<Map> result = await db.rawQuery('SELECT $columnLatLong FROM $table WHERE $columnMapLocation = ?',[mapLocation]);
    return (result[0]['latLong'] == null) ? 'NA' : result[0]['latLong'];
  }

  Future<String> queryWeather(int weatherID) async {
    Database db = await instance.database;
    List<Map> result = await db.rawQuery('SELECT $columnWeather FROM $weatherTable WHERE $columnWeatherWeatherID = ?',[weatherID]);
    return result[0]['weather'];
  }

  Future<int> queryElevation(String mapLocation) async {
    Database db = await instance.database;
    List<Map> result = await db.rawQuery('SELECT $columnElev FROM $table WHERE $columnMapLocation = ?',[mapLocation]);
    return result[0]['elev'];
  }

  Future<int> queryWeatherID(String mapLocation) async {
    Database db = await instance.database;
    List<Map> result = await db.rawQuery('SELECT $columnWeatherID FROM $table WHERE $columnMapLocation = ?',[mapLocation]);
    return result[0]['weatherID'];
  }

  Future<int> update(Map<String, dynamic> row) async {
    Database db = await instance.database;
    String mapLocation = row[columnMapLocation];
    return await db.update(table, row, where: '$columnMapLocation = ?', whereArgs: [mapLocation]);
  }

  Future<int> updateWeathTbl(Map<String, dynamic> row) async {
    Database db = await instance.database;
    int weatherID = row[columnWeatherWeatherID];
    return await db.update(weatherTable, row, where: '$columnWeatherWeatherID = ?', whereArgs: [weatherID]);
  }

  Future<int> delete(String ml) async {
    Database db = await instance.database;
    return await db.delete(table, where: '$columnMapLocation = ?', whereArgs: [ml]);
  }
}