:data

Purpose: Repository implementations that sit between ViewModels and storage/auth sources: Room, JSON DataStore, Firebase Auth and Firestore, with an optional REST source available for extensions. Observable data uses Flow; one-time operations return Result<T>.

Key APIs

API	What it does
`HomeRepository` / `HomeRepositoryImpl`	Offline-first repo for `Jetpack` — Room is the only thing read by the UI, Firestore is a sync target only, implements `Syncable`
`AuthRepository` / `AuthRepositoryImpl`	Saved-credential, email/password and Google authentication; successful auth updates local profile preferences
`ProfileRepositoryImpl`, `SettingsRepositoryImpl`	Local-only repos — DataStore (+ Firebase Auth for sign-out), no Room, no sync
`SyncManager`, `Syncable`, `SyncProgress` (`utils/SyncUtils.kt`)	Scheduler interface (`SyncManager`), repository contract (`Syncable`), and progress model; `:sync` implements the manager, `HomeRepositoryImpl` implements `Syncable`
`RepositoryModule`	One `@Binds` per repository, `@Singleton`

Interface excerpt; the inherited sync() contract is defined by Syncable.

// data/src/main/kotlin/dev/atick/data/repository/home/HomeRepository.kt
interface HomeRepository : Syncable {
    fun getJetpacks(): Flow<List<Jetpack>>
    fun getJetpack(id: String): Flow<Jetpack>
    suspend fun createOrUpdateJetpack(jetpack: Jetpack): Result<Unit>
    suspend fun markJetpackAsDeleted(jetpack: Jetpack): Result<Unit>
}

Gotchas

HomeRepositoryImpl.sync() returns a cold progress flow; collection executes the push/pull. SyncWorker in :sync collects it. Calling the suspend method alone does not execute the phases.
SyncAction (core/room) is NONE, UPSERT, DELETE. There is no CREATE/UPDATE.
Home writes update Room before requesting work. Local persistence/requesting work can fail; a successful Result does not acknowledge remote delivery. A failed enqueue can leave a local change committed. See repository behavior.
Sync takes one pending snapshot, then pushes and pulls. It does not protect concurrent edits or guarantee a follow-up pass after a dropped request. See delivery limitations.