import 'dart:io' show File, FileMode;
import 'package:intl/intl.dart' show DateFormat;
import 'package:gps/models/gps_point.dart';

abstract class GpsPersister {
  void save(Iterable<GpsPoint> data);
}

class CsvGpsPersister implements GpsPersister {
  static const String _csvHeader =
      "#Time, Latitude, Longitude, Accuracy, Speed, Heading";

  /// Format of DateTime part of file name
  static final DateFormat _formatter = DateFormat('yyyyMMdd_HHmmss');

  /// Path where the CSV will be stored
  final String _rootDir;

  const CsvGpsPersister(this._rootDir);

  @override
  void save(Iterable<GpsPoint> points) {
    File file = File("$_rootDir/geo${_formatter.format(DateTime.now())}.csv");

    file.writeAsStringSync(_csvHeader);
    for (var point in points) {
      file.writeAsStringSync("\n${_toCsv(point)}",
          mode: FileMode.writeOnlyAppend);
    }
    file.writeAsString("\n", mode: FileMode.writeOnlyAppend, flush: true);
  }

  String _toCsv(GpsPoint p) =>
      "${p.time}, ${p.latitude}, ${p.longitude}, ${p.accuracy}, ${p.speed}, ${p.heading}";
}