https://github.com/pedrazamiguez/split-trip

SplitTrip is a modular Android application designed for travelers to manage shared expenses efficiently.
https://github.com/pedrazamiguez/split-trip

android clean-architecture detekt firebase-auth firebase-cloud-functions firebase-firestore firebase-storage github-actions jetpack-compose konsist kotlin kotlin-flow material3-expressive multi-module mvi offline-first room-database

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SplitTrip is a modular Android application designed for travelers to manage shared expenses efficiently.

• Host: GitHub
• URL: https://github.com/pedrazamiguez/split-trip
• Owner: pedrazamiguez
• License: other
• Created: 2025-08-07T15:09:15.000Z (10 months ago)
• Default Branch: develop
• Last Pushed: 2026-04-06T15:21:51.000Z (about 2 months ago)
• Last Synced: 2026-04-06T16:26:18.936Z (about 2 months ago)
• Topics: android, clean-architecture, detekt, firebase-auth, firebase-cloud-functions, firebase-firestore, firebase-storage, github-actions, jetpack-compose, konsist, kotlin, kotlin-flow, material3-expressive, multi-module, mvi, offline-first, room-database
• Language: Kotlin
• Homepage:
• Size: 4.27 MB
• Stars: 0
• Watchers: 0
• Forks: 0
• Open Issues: 28
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Agents: AGENTS.md

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README

          
# SplitTrip

[![Build & Test](https://github.com/pedrazamiguez/split-trip/actions/workflows/build-and-test.yml/badge.svg)](https://github.com/pedrazamiguez/split-trip/actions/workflows/build-and-test.yml)

[![Static Analysis](https://github.com/pedrazamiguez/split-trip/actions/workflows/static-analysis.yml/badge.svg)](https://github.com/pedrazamiguez/split-trip/actions/workflows/static-analysis.yml)

[![Coverage & Architecture](https://github.com/pedrazamiguez/split-trip/actions/workflows/coverage-and-architecture.yml/badge.svg)](https://github.com/pedrazamiguez/split-trip/actions/workflows/coverage-and-architecture.yml)

## Overview

**SplitTrip** is a modular Android application designed for travelers to manage shared

expenses efficiently. It allows users to create expense groups, track spending in multiple

currencies, calculate debts, and sync data across devices.

Built with modern Android practices—including **Jetpack Compose**, **Clean Architecture**, and

**Offline-First** principles—the app serves as a reference for scalable, multi-module Android

development.

### ✨ Key Features

* **User Authentication**: Secure login (Email/Password) via Firebase Authentication.

* **Group Management**: Create and join expense groups with unique invite codes.

* **Smart Expense Tracking**: Support for custom split strategies (Equal, Percentage, Shares).

* **Multi-Currency Support**: Real-time currency conversion using Open Exchange Rates.

* **Debt Simplification**: Automatically calculates "Who owes Whom" balances.

* **Offline-First**: Full functionality without internet; syncs automatically when online.

* **Push Notifications**: Instant updates when members add or modify expenses.

## 🛠️ Tech Stack

* **Language**: [Kotlin](https://kotlinlang.org/) (100%)

* **UI**: [Jetpack Compose](https://developer.android.com/jetpack/compose) (Material 3 Expressive

  Design)

* **Architecture**: Clean Architecture + MVVM + MVI patterns

* **Dependency Injection**: [Koin](https://insert-koin.io/)

* **Asynchronous Programming**: Coroutines & Flow

* **Local Data**: [Room Database](https://developer.android.com/training/data-storage/room) (Single

  Source of Truth)

* **Remote Data**: [Retrofit](https://square.github.io/retrofit/) (Currency APIs)

* **Backend (BaaS)**: Firebase (Auth, Firestore, Cloud Messaging)

* **Navigation**: Jetpack Navigation Compose (Feature-based modular navigation)

* **Code Quality**: Detekt, Ktlint, CPD, JaCoCo, Konsist, CodeQL

## 📂 Project Structure

The app follows a strict **Multi-Module** architecture to ensure separation of concerns and faster

build times:

* **`:app`**: The application entry point. Wiring and DI setup.

* **`:core`**: Shared foundational components.

* **`:core:common`**: Utilities, Constants, and DataStore preferences.

* **`:core:design-system`**: Reusable UI components (`ExpressiveFab`, `DynamicTopAppBar`), Themes,

  and the `ScreenUiProvider` system.

* **`:data`**: The Data Layer implementation.

* **`:data:local`**: Room Database entities and DAOs.

* **`:data:remote`**: Retrofit services for external APIs.

* **`:data:firebase`**: Firestore and Auth implementations.

* **`:domain`**: Pure Kotlin business logic (Use Cases, Models, Repository Interfaces).

* **`:features`**: Standalone feature modules containing UI and ViewModels.

## 🚀 Setup Instructions

### Prerequisites

* Android Studio Ladybug or newer.

* JDK 21.

* A Firebase Project with Authentication (Email) and Firestore enabled.

* An API Key from [Open Exchange Rates](https://openexchangerates.org/) (optional, for currency

  features).

### Steps

1. **Clone the Repository**:

```bash

git clone https://github.com/pedrazamiguez/split-trip.git

cd split-trip

```

2. **Run the bootstrap script** (installs git hooks, scaffolds `local.properties`, and checks prerequisites):

```bash

make setup

```

> Run `make help` to see all available targets.

3. **Firebase Configuration**:

* Go to the [Firebase Console](https://console.firebase.google.com).

* Create a project and add an Android app (package: `es.pedrazamiguez.splittrip`).

* Download `google-services.json` and place it in the `app/` directory.

4. **API Keys (Secrets)**:

* The Open Exchange Rates key is a **Gradle property** read by `data/remote/build.gradle.kts` via `providers.gradleProperty()`. It must be added to your **user-level** `~/.gradle/gradle.properties` (not `local.properties`, which is only for `sdk.dir`):

```properties

# ~/.gradle/gradle.properties

OER_APP_ID_DEBUG=your_debug_key_here

OER_APP_ID_RELEASE=your_release_key_here

```

> For release CI builds, `OER_APP_ID_RELEASE` can also be supplied as an environment variable (env var takes precedence over the Gradle property).

5. **Build & Run**:

* Sync Gradle files in Android Studio.

* Select the `app` configuration and run on an Emulator (API 26+ recommended).

### Verify your setup

```bash

make doctor   # checks JDK, SDK path, google-services.json, API key, and git hook

make check    # runs Konsist architecture tests + unit tests + compilation

```

## 🧪 Testing

The project uses a comprehensive testing strategy:

* **Unit Tests**: JUnit 5 & MockK for Domain and Data layers.

```bash

./gradlew test

```

* **UI Tests**: Compose Testing for Screens and Navigation flows.

```bash

./gradlew connectedAndroidTest

```

## 📐 Architecture & Patterns

This project adheres to the **"Strict Visibility"** principle:

1. **Features** cannot see other **Features** (they communicate via `:domain`).

2. **Features** cannot see **Data** implementation details (only Domain interfaces).

3. **App** module is the only one that sees everything to wire up the Dependency Injection.

**Key Patterns:**

* **Navigation Discovery**: Features expose `NavigationProvider` interfaces so the App module can "

  plug them in" dynamically.

* **Repository Pattern**: Mediates between Local (Room) and Cloud (Firestore) data sources.

* **ScreenUiProvider**: Decouples the Main Activity's Scaffold (TopBar/FAB) from individual screens.

## Licence

This project is proprietary. See the [LICENSE](LICENSE) file for full terms.

© 2026 Andrés Pedraza Míguez. All Rights Reserved.