package com.aiosman.ravenow.entity

import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.setValue
import com.aiosman.ravenow.data.ListContainer

abstract class DataLoader<T,ET> {
    var list: MutableList<T> = mutableListOf()
    var page by mutableStateOf(1)
    var total by mutableStateOf(0)
    var pageSize by mutableStateOf(10)
    var hasNext by mutableStateOf(true)
    var onListChanged: ((List<T>) -> Unit)? = null
    private var firstLoad = true


    abstract suspend fun fetchData(
        page: Int, pageSize: Int, extra: ET
    ): ListContainer<T>

    suspend fun loadData(
        extra: ET
    ) {
        if (!firstLoad) {
            return
        }
        firstLoad = false
        val result = fetchData(page, pageSize, extra)
        list = result.list.toMutableList()
        this.page = page
        this.total = result.total
        this.pageSize = pageSize
        this.hasNext = result.list.size == pageSize
        onListChanged?.invoke(list)
    }

    suspend fun loadMore(extra: ET) {
        if (firstLoad) {
            return
        }
        if (!hasNext) {
            return
        }
        val result = fetchData(page + 1, pageSize, extra)
        list.addAll(result.list)
        page += 1
        hasNext = result.list.size == pageSize
        onListChanged?.invoke(list)
    }

    fun clear() {
        list.clear()
        page = 1
        total = 0
        pageSize = 10
        hasNext = true
        firstLoad = true
    }
}