package at.connyduck.pixelcat.components.profile

import android.graphics.Rect
import android.view.View
import androidx.recyclerview.widget.RecyclerView
import androidx.recyclerview.widget.RecyclerView.ItemDecoration

class GridSpacingItemDecoration(
    private val spanCount: Int,
    private val spacing: Int,
    private val topOffset: Int
) : ItemDecoration() {

    override fun getItemOffsets(
        outRect: Rect,
        view: View,
        parent: RecyclerView,
        state: RecyclerView.State
    ) {
        val position = parent.getChildAdapterPosition(view) // item position
        if (position < topOffset) return

        val column = (position - topOffset) % spanCount // item column

        outRect.left = column * spacing / spanCount // column * ((1f / spanCount) * spacing)
        outRect.right =
            spacing - (column + 1) * spacing / spanCount // spacing - (column + 1) * ((1f /    spanCount) * spacing)
        if (position - topOffset >= spanCount) {
            outRect.top = spacing // item top
        }
    }
}