teapod/app/src/main/java/org/mosad/teapod/ui/activity/main/viewmodel/LibraryFragmentViewModel.kt

131 lines
3.9 KiB
Kotlin

package org.mosad.teapod.ui.activity.main.viewmodel
import androidx.lifecycle.LifecycleCoroutineScope
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import kotlinx.coroutines.Job
import kotlinx.coroutines.async
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.update
import kotlinx.coroutines.launch
import org.mosad.teapod.parser.crunchyroll.Crunchyroll
import org.mosad.teapod.util.ItemMedia
import org.mosad.teapod.util.toItemMediaList
class LibraryFragmentViewModel : ViewModel() {
val PAGESIZE = 50
private val uiState = MutableStateFlow<UiState>(UiState.Loading)
private var oldSearchQuery = ""
private var searchJob: Job? = null
var isLazyLoading = false
internal set
sealed class UiState {
object Loading : UiState()
data class Browse(
val itemList: MutableList<ItemMedia>
) : UiState()
data class Search(
val itemList: List<ItemMedia>
) : UiState()
data class Error(val message: String?) : UiState()
}
init {
load()
}
fun onUiState(scope: LifecycleCoroutineScope, collector: (UiState) -> Unit) {
scope.launch { uiState.collect { collector(it) } }
}
/**
* initially load the first n browsing items
*/
private fun load() {
viewModelScope.launch {
uiState.emit(UiState.Loading)
try {
initBrowse()
} catch (ex: Exception) {
uiState.emit(UiState.Error(ex.message))
}
}
}
/**
* Search for a query string at Crunchyroll and emit the new ui state.
*/
fun search(query: String) {
// return if nothing has changed
if (query == oldSearchQuery) return
// update the old query since it has changed
oldSearchQuery = query
viewModelScope.launch {
// always cancel a running search job
if (searchJob?.isActive == true) searchJob?.cancel()
// handle state change: browse <-> search
if (query.isEmpty()) {
// if the query is empty change back to browse state
initBrowse()
} else {
// TODO handle errors
// if the current ui state is not search, clear the recyclerview
if (uiState.value !is UiState.Search) {
uiState.emit(UiState.Search(emptyList()))
}
// create a new search job
searchJob = viewModelScope.async {
// wait for a few ms: if the user is typing the task will get canceled
delay(250)
val results = Crunchyroll.search(query, 50)
.data.firstOrNull()?.items?.toItemMediaList()
?: listOf()
uiState.emit(UiState.Search(results))
}
}
}
}
fun onLazyLoad() = viewModelScope.launch {
isLazyLoading = true
try {
uiState.update { currentUiState ->
if (currentUiState is UiState.Browse) {
val newBrowseItems = Crunchyroll.browse(start = currentUiState.itemList.size, n = PAGESIZE)
.toItemMediaList()
currentUiState.itemList.addAll(newBrowseItems)
}
currentUiState
}
} catch (ex: Exception) {
uiState.emit(UiState.Error(ex.message))
}
isLazyLoading = false
}
private suspend fun initBrowse() {
try {
val initialBrowseItems = Crunchyroll.browse(n = PAGESIZE)
.toItemMediaList()
.toMutableList()
uiState.emit(UiState.Browse(initialBrowseItems))
} catch (ex: Exception) {
uiState.emit(UiState.Error(ex.message))
}
}
}