Firebase Integration

import 'package:firebase_core/firebase_core.dart';
import 'package:flutter/material.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  // Initialize Firebase
  await Firebase.initializeApp();

  runApp(const MyApp());
}

import 'package:firebase_auth/firebase_auth.dart';

class AuthService {
  final FirebaseAuth _auth = FirebaseAuth.instance;

  // Register
  Future<User?> registerWithEmail(String email, String password) async {
    try {
      final credential = await _auth.createUserWithEmailAndPassword(
        email: email,
        password: password,
      );
      return credential.user;
    } on FirebaseAuthException catch (e) {
      print('Registration failed: ${e.message}');
      return null;
    }
  }

  // Login
  Future<User?> signInWithEmail(String email, String password) async {
    try {
      final credential = await _auth.signInWithEmailAndPassword(
        email: email,
        password: password,
      );
      return credential.user;
    } on FirebaseAuthException catch (e) {
      print('Login failed: ${e.message}');
      return null;
    }
  }

  // Logout
  Future<void> signOut() async {
    await _auth.signOut();
  }

  // Listen to login status
  Stream<User?> get authStateChanges {
    return _auth.authStateChanges();
  }
}

import 'package:cloud_firestore/cloud_firestore.dart';

class FirestoreService {
  final FirebaseFirestore _db = FirebaseFirestore.instance;

  // Add a document
  Future<void> addUser(Map<String, dynamic> user) async {
    await _db.collection('users').add(user);
    // Or specify an ID
    // await _db.collection('users').doc('user_id').set(user);
  }

  // Get a single document
  Future<Map<String, dynamic>?> getUser(String id) async {
    final doc = await _db.collection('users').doc(id).get();
    return doc.data();
  }

  // Get all documents in the collection
  Future<List<Map<String, dynamic>>> getUsers() async {
    final snapshot = await _db.collection('users').get();
    return snapshot.docs.map((doc) => doc.data()).toList();
  }

  // Conditional query
  Future<List<Map<String, dynamic>>> getUsersByAge(int age) async {
    final snapshot = await _db
        .collection('users')
        .where('age', isGreaterThanOrEqualTo: age)
        .get();
    return snapshot.docs.map((doc) => doc.data()).toList();
  }

  // Update document
  Future<void> updateUser(String id, Map<String, dynamic> data) async {
    await _db.collection('users').doc(id).update(data);
  }

  // Delete document
  Future<void> deleteUser(String id) async {
    await _db.collection('users').doc(id).delete();
  }

  // Real-time listener
  Stream<QuerySnapshot> watchUsers() {
    return _db.collection('users').snapshots();
  }
}

import 'package:firebase_storage/firebase_storage.dart';
import 'dart:io';

class StorageService {
  final FirebaseStorage _storage = FirebaseStorage.instance;

  // Upload file
  Future<String?> uploadFile(File file, String path) async {
    try {
      final ref = _storage.ref().child(path);
      final result = await ref.putFile(file);
      return await result.ref.getDownloadURL();
    } on FirebaseException catch (e) {
      print('Upload failed: ${e.message}');
      return null;
    }
  }

  // Download file URL
  Future<String?> getDownloadURL(String path) async {
    try {
      final ref = _storage.ref().child(path);
      return await ref.getDownloadURL();
    } on FirebaseException catch (e) {
      print('Failed to get URL: ${e.message}');
      return null;
    }
  }

  // Delete file
  Future<void> deleteFile(String path) async {
    await _storage.ref().child(path).delete();
  }
}