# Fluffytrix Agent Guidelines

## Project Overview

Fluffytrix is an Android Matrix chat client with a Discord-like UI. Built with Kotlin, targeting Android 14+ (minSdk 34, targetSdk 36, compileSdk 36).

**Package**: `com.example.fluffytrix`  
**Build system**: Gradle with Kotlin DSL, version catalog at `gradle/libs.versions.toml`  
**Container/DI**: Koin  
**State management**: Jetpack Compose StateFlow, ViewModel  
**UI framework**: Jetpack Compose with Material 3 (Dynamic Colors)  
**Protocol**: Trixnity SDK for Matrix  
**Storage**: Room Database, DataStore Preferences  
**Async**: Kotlin Coroutines  

---

## Build Commands

```bash
./gradlew assembleDebug          # Build debug APK (minified for performance)
./gradlew assembleRelease        # Build release APK
./gradlew test                   # Run unit tests
./gradlew connectedAndroidTest   # Run instrumented tests on device/emulator
./gradlew testDebugUnitTest --tests "com.example.fluffytrix.ExampleUnitTest"  # Run single test
```

**Notes**:
- Debug builds use R8 with `isDebuggable = true` but strip material-icons-extended and optimize Compose for performance
- Use `--tests` with Gradle test tasks to run a single test class
- Instrumented tests require a connected device or emulator

---

## Testing

**Unit tests**: Located in `app/src/test/java/`, run with `./gradlew test`  
**Instrumented tests**: Located in `app/src/androidTest/java/`, run with `./gradlew connectedAndroidTest`

**Single test execution**:
```bash
./gradlew testDebugUnitTest --tests "com.example.fluffytrix.*"
./gradlew app:testDebugUnitTest --tests "ExampleUnitTest"
```

---

## Code Style Guidelines

### Kotlin Conventions

- **Android Official Kotlin style** (`kotlin.code.style=official` in gradle.properties)
- File naming: `PascalCase.kt` (e.g., `MainViewModel.kt`)
- Class naming: `PascalCase` (e.g., `MainViewModel`, `AuthRepository`)
- Function/property naming: `camelCase` (e.g., `sendMessage`, `selectedChannel`)
- Constant naming: `PascalCase` for top-level constants
- **Never use underscores in variable names**

### Imports

- Explicit imports only (no wildcard imports)
- Group imports: Android/X → Kotlin → Javax/Java → Third-party → Same package
- Example:
  ```kotlin
  import android.os.Bundle
  import androidx.compose.material3.Text
  import kotlinx.coroutines.flow.StateFlow
  import net.folivo.trixnity.client.MatrixClient
  import com.example.fluffytrix.ui.theme.FluffytrixTheme
  ```

### Types

- Prefer `val` over `var` (immutable data)
- Use `StateFlow<T>` for observable state in ViewModels
- Use `Flow<T>` for read-only data streams
- Use `suspend` functions for async operations
- Use `Result<T>` for operations that can fail

### Error Handling

- Prefer `try-catch` with silent failure or `?` operators where appropriate
- In ViewModels, use `catch (_: Exception) { }` or `?:` for graceful degradation
- Expose error state via `StateFlow<AuthState>` where users need feedback
- **Never crash the app on recoverable errors**

### Compose UI

- Use `@Composable` for all UI functions
- Follow Discord-like layout: space sidebar → channel list → message area → member list
- Use `MaterialTheme` for consistent theming
- Prefer `Modifier.padding()` over nested `Box` with margins
- Use `wrapContentWidth()` and `fillMaxWidth()` appropriately
- For columnar layouts: `Column(horizontalAlignment = Alignment.CenterHorizontally, verticalArrangement = Arrangement.spacedBy(12.dp))`

### ViewModels

- Inject dependencies via constructor (Koin)
- Use `viewModelScope` for coroutines
- Expose state via `StateFlow` (e.g., `val messages: StateFlow<List<MessageItem>>`)
- Use `MutableStateFlow` for internal state, expose as read-only `StateFlow`

### Coroutines

- Use `Dispatchers.Default` for CPU-intensive work (parsing, filtering)
- Use `Dispatchers.IO` for file/network operations
- Always cancel jobs on ViewModel cleanup: `job?.cancel()`
- Use `withContext(Dispatchers.Default)` to switch threads explicitly

### Data Layer

- Use Room for persistent storage (Trixnity uses Room internally)
- Use DataStore Preferences for small key-value data
- Prefer Flow-based APIs for reactive data streams
- Cache expensive operations in ViewModel (e.g., `messageCache`, `memberCache`)

### Naming Conventions

- State Flow properties: `_name` (private) / `name` (public)
- Repository class: `AuthService`, `AuthRepository`
- ViewModel class: `MainViewModel`, `LoginViewModel`
- UI composable: `MainScreen`, `ChannelList`, `MessageItem`
- Model data class: `MessageItem`, `ChannelItem`, `SpaceItem`
- Use `full` property for Matrix IDs (e.g., `userId.full`, `roomId.full`)

---

## Architecture Patterns

**Layered Architecture**:
```
ui/          — ViewModels, Screens, Navigation
data/        — Repositories, local storage, models
di/          — Koin modules
ui/theme/    — Material 3 Theme (colors, typography)
```

**Dependency Injection**: Koin with two modules:
- `appModule`: ViewModels (`viewModel { MainViewModel(...) }`)
- `dataModule`: singleton services (`single { AuthRepository(...) }`)

**UI Flow**:
1. `FluffytrixNavigation` handles nav graph and session restoration
2. `MainActivity` hosts the NavHost with `FluffytrixTheme`
3. ViewModels expose state via StateFlow
4. Screens observe state with `collectAsState()`

---

## Key Dependencies (from libs.versions.toml)

- **Compose BOM**: `2025.06.00`
- **Kotlin**: `2.2.10`
- **AGP**: `9.0.1`
- **Koin**: `4.1.1`
- **Trixnity**: `4.22.7`
- **Ktor**: `3.3.0`
- **Coroutines**: `1.10.2`
- **DataStore**: `1.1.7`
- **Coil**: `3.2.0`
- **Media3**: `1.6.0`

---

## Special Notes

1. **Matrix IDs**: Use `RoomId`, `UserId` types from Trixnity; access `.full` for string representation

2. **MXC URLs**: Convert with `MxcUrlHelper.mxcToDownloadUrl()` and `mxcToThumbnailUrl()`

3. **Build Performance**: Debug builds use R8 minification with `isDebuggable = true` to balance speed and debuggability

4. **Channel Reordering**: Channel order is saved per-space in DataStore and restored on navigation

5. **Encrypted Rooms**: Handle decryption state—messages may appear as `Unable to decrypt` until keys arrive

6. **Theme**: Material 3 with Discord-inspired color scheme (primary: `#5865F2`)

---

## Running Lint/Checks

```bash
./gradlew lintDebug
./gradlew spotlessCheck
```

## CI/CD

- All builds use Gradle wrapper (`./gradlew`)
- No manual Gradle installation required (project uses Gradle 9.1.0)