📈 CryptoTester

An offline cryptocurrency trading simulator for Android. Practice spot trading decisions on real historical candlestick data — no real money, no internet connection, and no hindsight bias thanks to price obfuscation.

✨ Features

• RSI Indicator — 14-period Relative Strength Index (Wilder's smoothing) with overbought/oversold thresholds (70/30)
• Step-by-Step Simulation — candles revealed one at a time, simulating real-time market progression
• Spot Trading — place BUY and SELL orders using a percentage slider (0–100% of available funds)
• Realistic Execution — trades always execute at the close price of the latest 15-minute candle, regardless of the chart timeframe being viewed
• Exchange Fees — 0.1% fee applied to every trade, matching real exchange conditions
• Price Obfuscation — random session multiplier (0.1×–10×) prevents recognizing real chart patterns and dates
• Portfolio Tracking — monitor USDT balance and crypto holdings across multiple assets in real time
• Session Results — detailed summary after each session: final balance, P&L%, duration, date range
• Historical Statistics — track all past simulation runs with color-coded profit/loss cards
• 3 Crypto Pairs — BTC, ETH, SOL (against USDT)
• 3 Timeframes — 15-minute, 1-hour, and 1-day candle intervals
• Fully Offline — all historical data is pre-bundled (~38.5 MB); zero network permissions
• Dark Theme — crypto trading-style dark UI with edge-to-edge support

📸 Screenshots

     

Start Screen                       Trading Simulator                    Session Results

🏗️ Architecture

The project follows Clean Architecture with MVVM and Unidirectional Data Flow (UDF):

app/src/main/java/com/example/cryptotester/
├── data/                        # Data Layer
│   ├── local/                   # Room database, DAOs, entities
│   │   ├── dao/                 # CandleDao, SimulationResultDao
│   │   └── entity/              # CandleEntity (15m/1h/1d), SimulationResultEntity
│   ├── mapper/                  # Entity ↔ Domain model mappers
│   └── repository/              # Repository implementations
├── di/                          # Hilt DI modules
├── domain/                      # Domain Layer (framework-independent)
│   ├── model/                   # Candle, CryptoSymbol, Portfolio, TradeOrder, etc.
│   ├── repository/              # Repository interfaces
│   ├── simulation/              # SessionManager & SimulationTimeManager
│   └── usecase/                 # CalculateRsiUseCase, ExecuteTradeUseCase
└── ui/                          # Presentation Layer
    ├── navigation/              # Type-safe routes & NavHost
    ├── simulator/               # Simulator screen, ViewModel, ResultDialog
    │   └── chart/               # CandlestickChart & RsiChart composables
    ├── start/                   # Start screen & ViewModel
    ├── stats/                   # Stats screen & ViewModel
    └── theme/                   # Material 3 dark theme

🔄 How Simulation Works

1. Configure — enter a starting balance (default: 200 USDT) on the Start screen
2. Random start — a random point in history is selected (at least 30 days before the end of available data), and a price multiplier is generated to prevent pattern recognition
3. Trade — switch between BTC, ETH, and SOL; choose 15m, 1h, or 1D timeframes; use the percentage slider to buy or sell
4. Advance — tap "Next Candle ▶" to move forward in time by the selected timeframe interval
5. Finish — end the session manually or reach the end of historical data; all crypto is evaluated at current prices
6. Review — see your P&L%, duration, and date range in the result dialog; results are saved to the local database

Anti-peeking guarantee: every database query enforces WHERE timestamp <= currentTime, making it impossible to access future data.

🛠️ Tech Stack

Component	Technology	Version
Language	Kotlin	2.2.10
UI Framework	Jetpack Compose + Material 3	BOM 2026.02.01
Charts	Custom Canvas rendering	—
Architecture	MVVM + Clean Architecture + UDF	—
Dependency Injection	Dagger Hilt	2.59.2
Database	Room (pre-bundled + runtime)	2.7.1
Navigation	Jetpack Navigation Compose (type-safe)	2.9.0
Serialization	kotlinx-serialization-json	1.8.1
Build System	Gradle + Version Catalogs	AGP 9.2.1
Min / Target / Compile SDK	36	—

🗄️ Database

Single Room database (crypto_tester.db) built from a pre-bundled history.db asset:

Table	Purpose
candle_15m	15-minute OHLC candle data (symbol, timestamp, open, high, low, close)
candle_1h	1-hour OHLC candle data
candle_1d	1-day OHLC candle data
simulation_results	Completed session records (balance, P&L%, duration, dates)

The simulation_results table is created on first launch via a PrepackagedDatabaseCallback.

📱 Screens

Screen	Description
Start	Enter starting balance, launch a new simulation, or view past stats
Simulator	Candlestick & RSI charts, asset/timeframe selectors, trading controls, portfolio bar
Result Dialog	Post-session summary with P&L, duration, and date range
Stats	Scrollable list of all past simulation runs with color-coded results

🚀 Getting Started

Prerequisites

• Android Studio (latest stable)
• JDK 17+
• Android SDK 36

Build & Run

git clone https://github.com/<your-username>/crypto-trading-simulator.git
cd crypto-trading-simulator
./gradlew assembleDebug

Or open the project in Android Studio and run on an emulator or device (API 36+).

📄 License

This project is provided as-is for educational and personal use.