/*
 * Copyright (C) 2020 Conny Duck
 *
 * This file is part of Pixelcat.
 *
 * Pixelcat is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Pixelcat is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

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
        }
    }
}