Navigation & Routes Definition

The navigation system is string-based and centralized in the :core:design-system module.

Defining a Route

Add a const val in Routes.kt (located in :core:design-system). This acts as the unique key for the destination.

object Routes {
    const val MAIN = "main"
    const val SETTINGS = "settings"
    const val SETTINGS_DEFAULT_CURRENCY = "settings_default_currency"
}

Registering the Route

1. Feature Module: Create a navigation extension function (e.g., SettingsNavigation.kt).
2. Graph Construction: Add the composable to the graph. For features with multiple screens, we typically wrap them in a navigation block (Nested Graph).

fun NavGraphBuilder.settingsGraph() {
    // Nested navigation graph for the Settings feature
    navigation(startDestination = Routes.SETTINGS_MAIN, route = Routes.SETTINGS) {
        
        composable(Routes.SETTINGS_MAIN) {
            SettingsFeature()
        }

        composable(Routes.SETTINGS_DEFAULT_CURRENCY) {
            DefaultCurrencyFeature()
        }
    }
}

Adding to the App

In the :features module, open AppNavHost.kt and call the feature graph function inside the main NavHost:

NavHost(navController = navController, ...) {
    // ... other graphs
    settingsGraph()
}

Note: For top-level bottom navigation tabs (like Groups or Expenses), we use the NavigationProvider interface instead of manually calling functions in AppNavHost. This allows the Main Screen to discover tabs dynamically via Koin.

---

Non-Tab Feature Modules (TabGraphContributor)

Some features are standalone write-flows extracted into their own modules but navigated to from within an existing tab (not the root AppNavHost). These modules implement TabGraphContributor instead of NavigationProvider.

How it works

1. The non-tab module defines a TabGraphContributor implementation that registers its composables.
2. The module registers it in Koin: factory { ContributionsTabGraphContributorImpl() } bind TabGraphContributor::class.
3. The host tab's NavigationProvider injects all TabGraphContributor instances and calls contributeGraph(builder) inside its buildGraph().

Current non-tab route ownership

Route	Served by	Host Tab
Routes.ADD_CONTRIBUTION	:features:contributions	Balances tab
Routes.ADD_CASH_WITHDRAWAL	:features:withdrawals	Balances tab
Routes.MANAGE_SUBUNITS	:features:subunits	Groups tab
Routes.CREATE_EDIT_SUBUNIT	:features:subunits	Groups tab

The host tab navigates to these routes via LocalTabNavController.current.navigate(Routes.ADD_CONTRIBUTION) — there is no compile-time dependency between the host tab module and the non-tab module. The routes are defined in :core:design-system/Routes.kt (shared by all modules).