ChallengeHub Flutter App

main.dart

import 'package:flutter/material.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(ChallengeHubApp());
}

class ChallengeHubApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'ChallengeHub',
      theme: ThemeData.light(),
      darkTheme: ThemeData.dark(),
      themeMode: ThemeMode.system,
      home: AuthWrapper(),
    );
  }
}

class AuthWrapper extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return StreamBuilder<User?>(
      stream: FirebaseAuth.instance.authStateChanges(),
      builder: (context, snapshot) {
        if (snapshot.hasData) {
          return HomePage();
        }
        return LoginPage();
      },
    );
  }
}

class LoginPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Login')),
      body: Center(
        child: ElevatedButton(
          child: Text('Login with Google'),
          onPressed: () async {
            // Implement Google Sign-In
          },
        ),
      ),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  int _currentIndex = 0;
  final List<Widget> _pages = [
    ChallengesPage(),
    LeaderboardPage(),
    ProfilePage(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('ChallengeHub')),
      body: _pages[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: _currentIndex,
        onTap: (index) {
          setState(() {
            _currentIndex = index;
          });
        },
        items: [
          BottomNavigationBarItem(icon: Icon(Icons.code), label: 'Challenges'),
          BottomNavigationBarItem(icon: Icon(Icons.leaderboard), label: 'Leaderboard'),
          BottomNavigationBarItem(icon: Icon(Icons.person), label: 'Profile'),
        ],
      ),
    );
  }
}

class ChallengesPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return FutureBuilder<List<Challenge>>(
      future: fetchChallenges(),
      builder: (context, snapshot) {
        if (snapshot.connectionState == ConnectionState.waiting) {
          return Center(child: CircularProgressIndicator());
        } else if (snapshot.hasError) {
          return Center(child: Text('Error: ${snapshot.error}'));
        } else {
          return ListView.builder(
            itemCount: snapshot.data!.length,
            itemBuilder: (context, index) {
              return ChallengeCard(challenge: snapshot.data![index]);
            },
          );
        }
      },
    );
  }

  Future<List<Challenge>> fetchChallenges() async {
    // Implement API call to fetch challenges
    // For now, return dummy data
    return [
      Challenge(id: '1', title: 'Algorithmic Puzzle', difficulty: 'Medium'),
      Challenge(id: '2', title: 'UI Challenge', difficulty: 'Hard'),
    ];
  }
}

class Challenge {
  final String id;
  final String title;
  final String difficulty;

  Challenge({required this.id, required this.title, required this.difficulty});
}

class ChallengeCard extends StatelessWidget {
  final Challenge challenge;

  ChallengeCard({required this.challenge});

  @override
  Widget build(BuildContext context) {
    return Card(
      child: ListTile(
        title: Text(challenge.title),
        subtitle: Text('Difficulty: ${challenge.difficulty}'),
        onTap: () {
          Navigator.push(
            context,
            MaterialPageRoute(
              builder: (context) => ChallengeDetailPage(challenge: challenge),
            ),
          );
        },
      ),
    );
  }
}

class ChallengeDetailPage extends StatelessWidget {
  final Challenge challenge;

  ChallengeDetailPage({required this.challenge});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(challenge.title)),
      body: Padding(
        padding: EdgeInsets.all(16.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text('Difficulty: ${challenge.difficulty}'),
            SizedBox(height: 16),
            Text('Description: Lorem ipsum...'), // Replace with actual description
            SizedBox(height: 16),
            ElevatedButton(
              child: Text('Submit Solution'),
              onPressed: () {
                // Implement solution submission
              },
            ),
          ],
        ),
      ),
    );
  }
}

class LeaderboardPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Center(child: Text('Leaderboard - Coming Soon'));
  }
}

class ProfilePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final user = FirebaseAuth.instance.currentUser;
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          CircleAvatar(
            radius: 50,
            backgroundImage: NetworkImage(user?.photoURL ?? ''),
          ),
          SizedBox(height: 16),
          Text(user?.displayName ?? 'User'),
          SizedBox(height: 16),
          ElevatedButton(
            child: Text('Sign Out'),
            onPressed: () async {
              await FirebaseAuth.instance.signOut();
            },
          ),
        ],
      ),
    );
  }
}

pubspec.yaml

dependencies:
  flutter:
    sdk: flutter
  firebase_core: ^1.10.0
  firebase_auth: ^3.3.0
  cloud_firestore: ^3.1.0
  http: ^0.13.3