package com.aiosman.riderpro.data

import androidx.paging.PagingSource
import androidx.paging.PagingState
import com.aiosman.riderpro.R
import com.aiosman.riderpro.model.MomentItem
import com.aiosman.riderpro.test.TestDatabase
import java.io.IOException

class MomentPagingSource(
    private val remoteDataSource: MomentRemoteDataSource,
) : PagingSource<Int, MomentItem>() {
    override suspend fun load(params: LoadParams<Int>): LoadResult<Int, MomentItem> {
        return try {
            val currentPage = params.key ?: 1
            val moments = remoteDataSource.getMoments(
                pageNumber = currentPage
            )

            LoadResult.Page(
                data = moments.list,
                prevKey = if (currentPage == 1) null else currentPage - 1,
                nextKey = if (moments.list.isEmpty()) null else moments.page + 1
            )
        } catch (exception: IOException) {
            return LoadResult.Error(exception)
        }
    }

    override fun getRefreshKey(state: PagingState<Int, MomentItem>): Int? {
        return state.anchorPosition
    }

}

class MomentRemoteDataSource(
    private val momentService: MomentService,
) {
    suspend fun getMoments(pageNumber: Int): ListContainer<MomentItem> {
        return momentService.getMoments(pageNumber)
    }
}

interface MomentService {
    suspend fun getMoments(pageNumber: Int): ListContainer<MomentItem>
    suspend fun getMomentById(id: Int): MomentItem
    suspend fun likeMoment(id: Int)
}

class TestMomentServiceImpl() : MomentService {
    var imageList = listOf(
        "https://img.freepik.com/free-photo/white-billboard-template_23-2147726635.jpg?t=st=1722150015~exp=1722153615~hmac=5540620196d7898215d822be26353c87a63d51bbfb2b814e032626e1948a1583&w=740",
        "https://img.freepik.com/free-photo/minimal-clothing-label-fashion-brands_53876-111053.jpg?w=1060&t=st=1722150122~exp=1722150722~hmac=67f8a2b6abfe3d08714cf0cc0085485c3221e1ba00dda14378b03753dce39153",
        "https://img.freepik.com/free-photo/marketing-strategy-planning-strategy-concept_53876-42950.jpg"
    )
    var mockData = TestDatabase.momentData
    val testMomentBackend = TestMomentBackend(mockData)
    override suspend fun getMoments(pageNumber: Int): ListContainer<MomentItem> {
        return testMomentBackend.fetchMomentItems(pageNumber)
    }

    override suspend fun getMomentById(id: Int): MomentItem {
        return mockData[id]
    }

    override suspend fun likeMoment(id: Int) {
//        mockData = mockData.map {
//            if (it.id == id) {
//                it.copy(likeCount = it.likeCount + 1)
//            } else {
//                it
//            }
//        }
//        mockData
    }

}

class TestMomentBackend(
    private val mockData: List<MomentItem>,
    private val loadDelay: Long = 500,
) {
    val DataBatchSize = 5
    suspend fun fetchMomentItems(pageNumber: Int): ListContainer<MomentItem> {
        val from = pageNumber * DataBatchSize
        val to = (pageNumber + 1) * DataBatchSize
        val currentSublist = mockData.subList(from, to)
        // delay
        kotlinx.coroutines.delay(loadDelay)
        return ListContainer(
            total = mockData.size,
            page = pageNumber,
            pageSize = DataBatchSize,
            list = currentSublist
        )
    }

}