import 'package:cloud_firestore/cloud_firestore.dart';
import 'dart:math';

class ChallengesUtils {
  static Future<DocumentSnapshot<Map<String, dynamic>>> getChallenge() async {
    Future<DocumentSnapshot<Map<String, dynamic>>> challenge;
    if(await shouldGenerateChallenge()){
      challenge = generateChallenge();
    } else {
      final user = FirebaseFirestore.instance
          .collection('Users')
          .doc('tlmysIvwTBaoZKWqBofx');
      challenge = user.get().then((value) => value.get('weekly_place').get());
    }
    return challenge;
  }

  static Future<bool> shouldGenerateChallenge() async {
    final user = FirebaseFirestore.instance
        .collection('Users')
        .doc('tlmysIvwTBaoZKWqBofx');
    DateTime now = DateTime.now();
    int secondsSinceEpoch = now.millisecondsSinceEpoch ~/ 1000;
    bool shouldGenerate = await user.get().then((value) {
      final dif = secondsSinceEpoch - value.get('last_challenge_date').seconds;
      return dif / 3600 / 24 > 7;
    });
    return Future.value(shouldGenerate);
  }

  static Future<DocumentSnapshot<Map<String, dynamic>>> generateChallenge() {
    final user = FirebaseFirestore.instance
        .collection('Users')
        .doc('tlmysIvwTBaoZKWqBofx');
    return user.get().then((value) {
      double lat = 0.0144927536231884;
      double lon = 0.0181818181818182;
      double userLat = value.get('address').latitude;
      double userLon = value.get('address').longitude;

      double lowerLat = userLat - (lat * 5);
      double lowerLon = userLon - (lon * 5);
      double upperLat = userLat + (lat * 5);
      double upperLon = userLon + (lon * 5);

      GeoPoint lesserGeoPoint = GeoPoint(lowerLat, lowerLon);
      GeoPoint greaterGeoPoint = GeoPoint(upperLat, upperLon);

      return FirebaseFirestore.instance
          .collection('Places')
          .where('location', isGreaterThan: lesserGeoPoint)
          .where('location', isLessThan: greaterGeoPoint)
          .get()
          .then((snapshot) {
        int numOfPlaces = snapshot.docs.length;
        String id = snapshot.docs[Random().nextInt(numOfPlaces)].id;
        print('updating');
        user.update({
          'weekly_place':
              FirebaseFirestore.instance.collection('Places').doc(id),
          'last_challenge_date': Timestamp.now(),
        });
        return FirebaseFirestore.instance.collection('Places').doc(id).get();
      });
    });
  }
}