CommentsViewModel.kt

package org.schabi.newpipe.viewmodels

import androidx.lifecycle.SavedStateHandle
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import androidx.paging.Pager
import androidx.paging.PagingConfig
import androidx.paging.PagingData
import androidx.paging.cachedIn
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.ExperimentalCoroutinesApi
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.SharingStarted
import kotlinx.coroutines.flow.filterIsInstance
import kotlinx.coroutines.flow.flatMapLatest
import kotlinx.coroutines.flow.flowOn
import kotlinx.coroutines.flow.map
import kotlinx.coroutines.flow.stateIn
import org.schabi.newpipe.extractor.comments.CommentsInfo
import org.schabi.newpipe.paging.CommentsSource
import org.schabi.newpipe.ui.components.video.comment.CommentInfo
import org.schabi.newpipe.util.KEY_URL
import org.schabi.newpipe.viewmodels.util.Resource

class CommentsViewModel(savedStateHandle: SavedStateHandle) : ViewModel() {
    val uiState = savedStateHandle.getStateFlow(KEY_URL, "")
        .map {
            try {
                val info = CommentsInfo.getInfo(it)
                Resource.Success(CommentInfo(info))
            } catch (e: Exception) {
                Resource.Error(e)
            }
        }
        .flowOn(Dispatchers.IO)
        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(), Resource.Loading)

    @OptIn(ExperimentalCoroutinesApi::class)
    val comments: Flow<PagingData<org.schabi.newpipe.extractor.comments.CommentsInfoItem>> = uiState
        .filterIsInstance<Resource.Success<CommentInfo>>()
        .flatMapLatest {
            Pager(PagingConfig(pageSize = 20, enablePlaceholders = false)) {
                CommentsSource(it.data)
            }.flow
        }
        .cachedIn(viewModelScope)
}