StateMachine

state_machine.kt

/**
 * Keeps track of current and prior application state.
 *
 * @param dataStore storage
 */
@Singleton
class StateMachine(private val dataStore: DataStore) {
    /**
     * Storage implementation for our state machine.
     *
     * @param currentState the current state of the application
     * @param lastKnownError the last error that occurred
     * @param lastActionPerformed the last action the user performed
     */
    @DataStore.Key(key = "StateMachine")
    private data class StateStorage(
        var currentState: Int,
        var lastKnownError: String?,
        var lastActionPerformed: String?
    )

    // Restore our storage from DataStore or create a new instance if one hasn't been created
    private val stateStorage: StateStorage = dataStore.restore(StateStorage::class.java,
        GsonUtils::deserialize) ?: StateStorage(0, null, null)

    private fun saveChanges() {
        // Call this any time a change is made to a variable within StateStorage
        dataStore.save(stateStorage, GsonUtils::serialize)
    }
    // Add methods to access/update data in stateStorage
}