Whizzz — The Chat App

Realtime one-to-one chat on Android: Firebase (Auth, Realtime Database, FCM), Jetpack Compose, multi-module layout, Clean Architecture, and MVI-style screens.

Demo

Demo.mp4

Features

• Auth — Sign in, sign up, forgot password; Lottie on login / register.
• Home — Tabs: Chats (paged list), Users (search + directory), Profile (your account).
• Chat — 1:1 threads, composer, errors / retry, read receipts / seen handling.
• Profiles — Edit name & bio, crop profile photo, Coil images, fullscreen viewer (share / save where supported).
• Peer profile — Open the other user from chat.
• Push — FCM for incoming messages; token registration when signed in.
• Presence — Online / offline via process lifecycle + Realtime Database; onDisconnect handling in data layer.
• App Check — Debug vs release (Play Integrity) wired for Firebase.

Architecture

Module	Role
:app	MainActivity, Navigation Compose, Koin, splash, FCM service, process-wide presence.
:domain	Use cases, repository interfaces, models — pure Kotlin, no Android/Firebase.
:data	Firebase Auth, RTDB, Messaging; Koin DataModule; Coroutines + Play Services.
:core:common	Shared helpers (routes, errors, flows).
:core:strings	WhizzzStrings.
:core:ui	Theme, avatars, profile UI, photo overlay, insets.
:feature:auth	Login / register / forgot.
:feature:home	Shell, chats & users lists (embeds profile tab).
:feature:chat	Conversation + peer profile.
:feature:profile	Profile editing, image cropper.

UI: UiState / UiEvent, StateFlow, collectAsStateWithLifecycle, koinViewModel().

Tech stack

Architecture & structure

• Clean Architecture — domain isolated from Android/Firebase; data implements ports; features consume use cases.
• Multi-module Gradle — app, domain, data, core/*, feature/* for clear boundaries and faster incremental builds.
• MVI-style UI — single direction: UiState + UiEvent, ViewModels, predictable screen updates.
• Unidirectional data — Kotlin Flow / StateFlow, collectAsStateWithLifecycle for lifecycle-safe collection.

UI

• Jetpack Compose — declarative UI, Material 3, animations, previews where it helps.
• Navigation Compose — type-safe routes, transitions between auth / home / chat / profile.
• Single-activity — Compose-hosted navigation; splash & fullscreen overlays where needed.
• Coil — image loading; Lottie — auth motion; image cropper for profile photos.

Platform & async

• Kotlin — coroutines, structured concurrency, extension-heavy style.
• Process lifecycle — app-wide foreground/background hooks for presence (not fragile per-screen hacks).
• Firebase — Authentication, Realtime Database, Cloud Messaging, App Check (debug vs release integrity).

DI & tooling

• Koin — lightweight service locator / DI for Android + Compose.
• Gradle Kotlin DSL + version catalog — dependency pins live in gradle/libs.versions.toml if you need exact versions.

Setup

1. Clone the repo.
2. In Firebase Console, add an Android app (com.example.whizzz or your applicationId), download google-services.json → app/google-services.json (local only; not in git).
3. Enable Authentication (email/password), Realtime Database, Cloud Messaging; configure App Check as needed.

Build

./gradlew :app:assembleDebug

Release uses R8 — keep proguard-rules.pro aligned with Firebase.

Notes

• Changing RTDB shape or rules may require a fresh install / clear data.
• Tighten Database / Storage rules before production.

APK

Need a prebuilt APK? Open an issue on the repo.

License

See LICENSE.

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Local config: Each machine needs its own google-services.json and local.properties. Anything secret or IDE-specific belongs in .gitignore — don’t git add -f those files.