Generating challenges

app/lib/navigation/challenge_page.dart

@@ -0,0 +1,23 @@
+import 'package:cloud_firestore/cloud_firestore.dart';
+import 'package:flutter/material.dart';
+import 'package:physigo/navigation/utils/challenges_utils.dart';
+
+class ChallengePage extends StatelessWidget {
+
+  const ChallengePage({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: FutureBuilder<DocumentSnapshot<Map<String, dynamic>>>(
+        future: ChallengesUtils.getChallenge(),
+        builder: (context, snapshot) {
+          if(snapshot.hasData) {
+            print(snapshot.data?.get('name'));
+          }
+          return const Text('Challenges are here');
+        },
+      ),
+    );
+  }
+}

app/lib/navigation/utils/challenges_utils.dart

@@ -0,0 +1,67 @@
+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();
+      });
+    });
+  }
+}