ALTAPPS-506: Shared load gems and streak on the Track screen

[ivan-magda]

YouTrack Issues:
#ALTAPPS-506, #ALTAPPS-518

Checklist

Before Code Review:

• Fields "Assignees, Labels, Milestone" are filled in the pull request;
• Sentry Performance Monitoring of screen loading is added for new screens;
• View analytics events are added for new screens;
• New analytics events are documented;
• All checks have been passed;
• Changes have been checked locally.

Description

Miscellaneous changes:

• Adds StreaksDataComponent that provides StreaksInteractor. It helps to avoid code duplication on the injection level.
• Refactors user streaks loading in the StreaksRemoteDataSourceImpl, no need to load all pages, because we are using only the first Streak element.
• Extracts getRepetitionsState into helper function in HomeActionDispatcher, which makes code more readable.
• Fixes incorrect forceUpdate value parameter for HomeFeature.Message.Initialize message on tryAgain in HomeFragment
• Optimizes imports

Primary changes:

• Adds GamificationToolbarFeature that encapsulates loading of the streak and hypercoins balance. It also moves analytic events to this feature and ViewActions.
• Migrates HomeFeature to using the GamificationToolbarFeature on iOS and Android.
• Connects TrackFeature with the GamificationToolbarFeature on iOS only. Android implementation has remote data loading, and messages that trigger remote data loading are marked with TODO, we should implement UI or delete those messages before merging this PR.

Also, we could send messages to the GamificationToolbarFeature from the parent feature directly. For example Message.Initialize. The current implementation sends 2 messages: one for the parent feature (home or track) and the second for the toolbar:

homeViewModel.onNewMessage(HomeFeature.Message.Initialize(forceUpdate = false))

homeViewModel.onNewMessage(
    HomeFeature.Message.GamificationToolbarMessage(
        GamificationToolbarFeature.Message.Initialize(
            screen = GamificationToolbarScreen.HOME,
            forceUpdate = false
        )
    )
)

we could update our HomeReducer to initialize home and toolbar in one place:

is Message.Initialize -> {
    val (homeState, homeActions) = if (state.homeState is HomeState.Idle ||
        (message.forceUpdate && (state.homeState is HomeState.Content || state.homeState is HomeState.NetworkError))
    ) {
        HomeState.Loading to setOf(Action.FetchHomeScreenData)
    } else {
        state.homeState to emptySet()
    }

    val (toolbarState, toolbarActions) = reduceGamificationToolbarMessage(
        state.toolbarState,
        GamificationToolbarFeature.Message.Initialize(GamificationToolbarScreen.HOME, message.forceUpdate)
    )

    state.copy(
        homeState = homeState,
        toolbarState = toolbarState
    ) to homeActions + toolbarActions
}

/**
 * Reduces [Message.GamificationToolbarMessage] to [GamificationToolbarFeature.State] and set of [HomeFeature.Action]
 * Avoids code duplication when reducing [Message.GamificationToolbarMessage]
 */
private fun reduceGamificationToolbarMessage(
    state: GamificationToolbarFeature.State,
    message: GamificationToolbarFeature.Message
): Pair<GamificationToolbarFeature.State, Set<HomeFeature.Action>> {
    val (gamificationToolbarState, gamificationToolbarActions) = gamificationToolbarReducer.reduce(state, message)

    val actions = gamificationToolbarActions
        .map {
            if (it is GamificationToolbarFeature.Action.ViewAction) {
                HomeFeature.Action.ViewAction.GamificationToolbarViewAction(it)
            } else {
                HomeFeature.Action.GamificationToolbarAction(it)
            }
        }
        .toSet()

    return gamificationToolbarState to actions
}

I tried this approach in the HomeReducer and it's become harder to read/understand code and more complicated than just sending messages from the Fragment on Android or ViewModel on iOS.

I think there is no silver bullet - the above approach adds the ability to send only one message to initialize parent and child features, but the source code gets more complicated in the reducer and the other approach with sending distinct messages (first for home or track and second for toolbar) leaves reducer simpler, but we could forget to send some message from Fragment/ViewModel.

So, to be discussed...

[XanderZhu]

GamificationToolbarFeature - Nice naming

[XanderZhu]

Also, we could send messages to the GamificationToolbarFeature from the parent feature directly.

I think it would be useful to follow this approach.