ledgerr/AGENTS.md

Ledgerr — Agent Instructions

Personal Android expense tracking app. Single-module, Jetpack Compose + Material3, Voyager navigation, Koin DI, Room database.

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Package structure

dev.achmad.ledgerr/
├── core/
│   ├── network/          - OkHttp helpers (not used by expense features)
│   └── preference/       - PreferenceStore, AndroidPreferenceStore, Preference<T>
├── di/
│   ├── util/
│   │   └── KoinExtensions.kt   - inject<T>() and injectLazy<T>() helpers
│   ├── CoreModule.kt
│   ├── DataModule.kt
│   ├── DomainModule.kt
│   └── PreferenceModule.kt     - replaces UiModule.kt (delete UiModule if it exists)
├── domain/
│   ├── preference/
│   │   ├── AppPreference.kt
│   │   └── ExpensePreference.kt
│   ├── expense/
│   │   ├── model/
│   │   └── interactor/
│   ├── category/
│   │   ├── model/
│   │   └── interactor/
│   ├── recurring/
│   │   ├── model/
│   │   └── interactor/
│   ├── bankstatement/
│   │   ├── model/
│   │   └── interactor/
│   └── export/
│       └── interactor/
├── data/
│   └── local/
│       ├── AppDatabase.kt
│       ├── converter/
│       ├── dao/
│       ├── entity/
│       └── mapper/
└── ui/
    ├── base/
    │   ├── MainApplication.kt
    │   └── MainActivity.kt
    ├── components/         - shared Compose components (already copied)
    │   └── preference/     - PreferenceScreen + widgets
    ├── screens/
    │   ├── home/           HomeScreen.kt
    │   ├── expenses/       ExpenseListScreen.kt
    │   ├── add_edit_expense/ AddEditExpenseScreen.kt
    │   ├── category/       CategoryScreen.kt
    │   └── settings/       SettingsScreen.kt
    ├── theme/
    └── util/

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Architecture rules

Domain / interactors

• Each folder in domain/ is a feature with model/ and interactor/ subpackages.
• Interactor classes are named after the action: GetExpenses, UpsertExpense, DeleteCategory, etc.
• Method names follow this convention:
  • await(...) — single suspend result
  • awaitAll(...) — list suspend result
  • awaitOne(id) — fetch one by ID
  • subscribeAll(...) — returns Flow
• Interactors take DAOs (or Context for PDF/export) directly as constructor params — no repository layer.
• Interactors can contain business logic (think use-cases).

Dependency injection (Koin)

• DI modules live in di/, not core/.
• CoreModule provides SharedPreferences and PreferenceStore (as AndroidPreferenceStore). Nothing else.
• Interactors are registered as factory { }, not single.
• Preference classes are registered as single { } in PreferenceModule.
• DAOs are registered as single { get<AppDatabase>().xyzDao() } in DataModule.
• Bank statement importers use named qualifiers: factory<BankStatementImporter>(named("bri")) { ... }.
• ScreenModels are NOT registered in Koin. Never add a ScreenModel to any Koin module.

ScreenModel pattern

Always use rememberScreenModel { } in Screen.Content(). Inject dependencies via inject() as constructor default params:

class HomeScreenModel(
    private val getExpenses: GetExpenses = inject(),
    private val appPreference: AppPreference = inject(),
) : ScreenModel { ... }

// In Screen.Content():
val screenModel = rememberScreenModel { HomeScreenModel() }

inject<T>() is at dev.achmad.ledgerr.di.util.KoinExtensions.

Navigation

• Pure Voyager stack — Navigator, navigator.push(...), navigator.pop().
• No TabNavigator at root level.
• ExpenseListScreen has 2 internal tabs using plain Compose TabRow + HorizontalPager (not Voyager tabs).
• Screen flow:

  HomeScreen (root)
    ├── FAB expand → "Manual"               → AddEditExpenseScreen
    │              → "Import Bank Statement" → ImportBankStatementScreen
    ├── Export icon → date range dialog → SAF CreateDocument → writes CSV
    ├── "See all" → ExpenseListScreen
    │                 ├── Tab: Expenses (search + filter)
    │                 │     └── FAB expand → same as HomeScreen FAB
    │                 └── Tab: Recurring
    ├── "Manage Categories" button (dashboard body) → CategoryScreen
    └── Settings icon → SettingsScreen
  
  AddEditExpenseScreen → CategoryScreen (manage categories button)
  
  ImportBankStatementScreen (1 Voyager Screen, 1 ScreenModel, 2 composable functions)
    ├── ImportBankStatementPickerContent      — state is BankPicker or Processing
    │     select bank → SAF OpenDocument → loading overlay while parsing
    └── ImportBankStatementConfirmationContent — state is Confirmation
          toggle/edit per row → InsertExpenses → navigator.pop()
  

• Export has no dedicated screen. Icon in HomeScreen and ExpenseListScreen top bars; also a TextPreference in SettingsScreen. Tapping shows a date range dialog first, then opens SAF CreateDocument. CSV uses ISO 8601 dates (yyyy-MM-dd) with UTF-8 BOM.
• Import goes through ImportBankStatementScreen — one Voyager Screen, one ScreenModel, two internal composables switched by StateFlow<ImportState>. ImportBankStatementPickerContent handles bank selection and processing; ImportBankStatementConfirmationContent handles review, edit, and confirm. On confirm calls InsertExpenses.awaitAll() then pops.

Settings screen

SettingsScreen uses the PreferenceScreen composable from ui/components/preference/. Pattern:

PreferenceScreen(
    itemsProvider = {
        listOf(
            Preference.PreferenceItem.ListPreference(
                title = "Theme",
                preference = appPreference.appTheme(),
                entries = mapOf(...),
            ),
            Preference.PreferenceItem.TextPreference(
                title = "Export CSV",
                onClick = { /* launch SAF CreateDocument */ }
            ),
            Preference.PreferenceItem.AlertDialogPreference(
                title = "Clear all data",
                onConfirm = { screenModel.clearData() }
            ),
        )
    }
)

Preference classes

Located in domain/preference/. Take PreferenceStore as constructor param. Methods return Preference<T> objects from core/preference/:

class AppPreference(private val store: PreferenceStore) {
    fun appTheme() = store.getEnum("app_theme", defaultValue = AppTheme.SYSTEM)
}

Data layer

• LocalDate stored as Long epoch day via LocalDateConverter (LocalDate.toEpochDay() / LocalDate.ofEpochDay()).
• Use @Upsert Room annotation for insert-or-update operations.
• AppDatabase.Callback.onCreate seeds default categories using CoroutineScope(Dispatchers.IO) — Koin is not ready inside Room callbacks.
• minSdk 26, so java.time.* is available without desugaring.

Bank statement import

• BankStatementImporter interface: val bankName: String + suspend fun await(pdfUri: Uri): Result<List<PendingImportExpense>>.
• Stubs: ImportBRIBankStatement, ImportJagoBankStatement, ImportBNIBankStatement — all return Result.failure(NotImplementedError(...)).
• PDF text extraction: com.tom-roush:pdfbox-android. Requires PDFBoxResourceLoader.init(applicationContext) in MainApplication.onCreate().
• No manifest permissions needed — SAF handles file access.

Export

• ExportExpensesToCsv interactor writes UTF-8 BOM CSV via Okio to a SAF URI.
• SAF launchers (ActivityResultContracts.OpenDocument, ActivityResultContracts.CreateDocument) are registered in the Screen composable; URIs are passed to the ScreenModel.

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Workflow for new features

Follow these steps in order every time. Do not skip ahead to implementation without explicit approval.

1. Define structs — add any new models to the relevant domain/<feature>/model/ package.
2. Define interfaces — add or update interactor class signatures and method stubs in domain/<feature>/interactor/. If a new feature has no existing feature folder, create one.
3. Add TODOs — fill method bodies with TODO("...") comments describing the intended behavior, edge cases, and any invariants.
4. Self-review — think through the full implementation. If anything requires going outside or beyond what was defined in steps 1–3 (new models, new methods, changed signatures), go back to the relevant step and update it before continuing.
5. Prompt for review — stop and present a summary of what was defined. Wait for an explicit go-ahead before writing any real implementation code.
6. Implement — only after approval: replace TODOs with real code, wire up DI in the relevant module, update any callers.

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Key dependencies

Library	Version	Purpose
Jetpack Compose + Material3	(from BOM)	UI
Voyager	—	Navigation + ScreenModel
Koin	4.2.2	DI
Room	2.7.1	Local DB
PDFBox-Android	2.0.27.0	PDF text extraction
Okio	(transitive)	CSV write

No chart library — use Canvas (drawArc for pie, drawRect for bar).

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Git

• Never commit or push unless the user explicitly asks. Do not auto-commit after completing a task, do not squash, amend, or rebase without being told to.
• Never add Co-Authored-By lines to commit messages.

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Things to avoid

• Do not register ScreenModels in Koin.
• Do not create a repository layer between interactors and DAOs.
• Do not add a TabNavigator at the root.
• Do not create a dedicated screen for export — it is a direct action (date range dialog → SAF picker).
• Do not add manifest permissions for file access — SAF handles it.
• Do not use an external chart library.
• Do not rename MainApplication back to LedgerrApp.
• UiModule.kt has been deleted — do not recreate it; the replacement is PreferenceModule.kt.
• Do not use @KoinViewModel or viewModel {} — this project uses Voyager ScreenModel.

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Docs

Full design documentation is in docs/:

• 01-data-model.md — domain models per feature
• 02-interfaces.md — all interactor signatures
• 03-function-todos.md — per-method behavior and edge cases
• 04-implementation-plan.md — package structure, DI wiring, build order