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yatiksihag01/AllNewsRemoteMediator.kt

Created November 28, 2024 20:14
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  1. yatiksihag01 created this gist Nov 28, 2024.
    61 changes: 61 additions & 0 deletions AllNewsRemoteMediator.kt
    View file
    Original file line number Diff line number Diff line change
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    package com.meproject.newsstream.data.remote.dto.mediator

    import androidx.paging.ExperimentalPagingApi
    import androidx.paging.LoadType
    import androidx.paging.PagingState
    import androidx.paging.RemoteMediator
    import androidx.room.withTransaction
    import com.meproject.newsstream.data.local.NewsDatabase
    import com.meproject.newsstream.data.local.explore.AllNewsItemEntity
    import com.meproject.newsstream.data.mappers.toAllNewsItemEntity
    import com.meproject.newsstream.data.remote.api.NewsApi
    import retrofit2.HttpException
    import java.io.IOException
    import javax.inject.Inject

    @OptIn(ExperimentalPagingApi::class)
    class AllNewsRemoteMediator @Inject constructor(
    private val newsApi: NewsApi, private val newsDatabase: NewsDatabase
    ) : RemoteMediator<Int, AllNewsItemEntity>() {
    override suspend fun load(
    loadType: LoadType, state: PagingState<Int, AllNewsItemEntity>
    ): MediatorResult {
    return try {
    val loadKey = when (loadType) {
    LoadType.REFRESH -> 1
    // We are only appending pages
    LoadType.PREPEND -> return MediatorResult.Success(endOfPaginationReached = true)

    LoadType.APPEND -> {
    // If lastItem is null it means no items were loaded after the initial REFRESH
    // and there are no more items to load.
    val lastItem = state.lastItemOrNull() ?: return MediatorResult.Success(
    endOfPaginationReached = true
    )
    (lastItem.index / state.config.pageSize) + 1
    }
    }
    val allNewsItems = newsApi.getAllNews(
    page = loadKey,
    pageSize = state.config.pageSize
    )
    newsDatabase.withTransaction {
    if (loadType == LoadType.REFRESH) {
    newsDatabase.allNewsItemDao().clearAll()
    }
    val lastItemIndex = state.lastItemOrNull()?.index ?: 0
    val allNewsItemEntities = allNewsItems.mapIndexed { index, allNewsItem ->
    allNewsItem.toAllNewsItemEntity(index + lastItemIndex + 1)
    }
    newsDatabase.allNewsItemDao().upsertAll(allNewsItemEntities)
    }
    MediatorResult.Success(
    endOfPaginationReached = allNewsItems.size < state.config.pageSize
    )
    } catch (e: IOException) {
    MediatorResult.Error(e)
    } catch (e: HttpException) {
    MediatorResult.Error(e)
    }
    }
    }