class SearchStoresMapViewModel(
    private val storeCache: StoreCache,
    private val mapper: StoreUiMapper
) : ViewModel() {

    private val appliedFilters: MutableSet<OpenStatus> = mutableSetOf()

    private val filtersChannel = BroadcastChannel<Set<OpenStatus>>(Channel.CONFLATED)
    private val queryChannel = BroadcastChannel<String>(Channel.CONFLATED)

    private val _stores: LiveData<List<StoreUI>> = filtersChannel.asFlow()
        .combine(queryChannel.asFlow().onEach { delay(400) }) { text, filters -> text to filters }
        .map { (filters: Set<OpenStatus>, text: String) -> searchStores(text, filters) }
        .map { stores: List<Store> -> mapper.map(stores) }
        .asLiveData()

    private fun searchStores(text: String, filters: Set<OpenStatus>): List<Store> =
        storeCache.getByStatus(filters).filter { store ->
            filterStoresByText(text, store)
        }

    private fun filterStoresByText(
        text: String,
        store: Store
    ): Boolean = if (text.isBlank()) {
        true
    } else {
        store.name.contains(text, true)
    }

    val stores: LiveData<List<StoreUI>>
        get() = _stores

    init {
        viewModelScope.launch {
            queryChannel.send("")
            filtersChannel.send(appliedFilters)
        }
    }

    fun search(text: String? = "") {
        viewModelScope.launch { queryChannel.send(text.orEmpty()) }
    }

    fun onFilterChanged(status: OpenStatus, checked: Boolean) {
        if (checked) {
            appliedFilters.add(status)
        } else {
            appliedFilters.remove(status)
        }

        viewModelScope.launch { filtersChannel.send(appliedFilters) }
    }
}