package net.minecraft.client.gui.screens.inventory;

import java.util.List;
import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;
import net.minecraft.client.gui.GuiGraphicsExtractor;
import net.minecraft.client.renderer.RenderPipelines;
import net.minecraft.resources.Identifier;
import net.minecraft.util.ARGB;
import net.minecraft.world.inventory.AbstractContainerMenu;
import net.minecraft.world.inventory.Slot;

@Environment(EnvType.CLIENT)
public class CyclingSlotBackground {
	private static final int ICON_CHANGE_TICK_RATE = 30;
	private static final int ICON_SIZE = 16;
	private static final int ICON_TRANSITION_TICK_DURATION = 4;
	private final int slotIndex;
	private List<Identifier> icons = List.of();
	private int tick;
	private int iconIndex;

	public CyclingSlotBackground(final int slotIndex) {
		this.slotIndex = slotIndex;
	}

	public void tick(final List<Identifier> newIcons) {
		if (!this.icons.equals(newIcons)) {
			this.icons = newIcons;
			this.iconIndex = 0;
		}

		if (!this.icons.isEmpty() && ++this.tick % 30 == 0) {
			this.iconIndex = (this.iconIndex + 1) % this.icons.size();
		}
	}

	public void extractRenderState(final AbstractContainerMenu menu, final GuiGraphicsExtractor graphics, final float a, final int left, final int top) {
		Slot slot = menu.getSlot(this.slotIndex);
		if (!this.icons.isEmpty() && !slot.hasItem()) {
			boolean shouldTransition = this.icons.size() > 1 && this.tick >= 30;
			float alphaProgress = shouldTransition ? this.getIconTransitionTransparency(a) : 1.0F;
			if (alphaProgress < 1.0F) {
				int previousIconIndex = Math.floorMod(this.iconIndex - 1, this.icons.size());
				this.extractIcon(slot, (Identifier)this.icons.get(previousIconIndex), 1.0F - alphaProgress, graphics, left, top);
			}

			this.extractIcon(slot, (Identifier)this.icons.get(this.iconIndex), alphaProgress, graphics, left, top);
		}
	}

	private void extractIcon(
		final Slot slot, final Identifier iconIdentifier, final float alphaProgress, final GuiGraphicsExtractor graphics, final int left, final int top
	) {
		graphics.blitSprite(RenderPipelines.GUI_TEXTURED, iconIdentifier, left + slot.x, top + slot.y, 16, 16, ARGB.white(alphaProgress));
	}

	private float getIconTransitionTransparency(final float a) {
		float elapsedTransitionTime = this.tick % 30 + a;
		return Math.min(elapsedTransitionTime, 4.0F) / 4.0F;
	}
}