NotEnoughItems/src/main/java/codechicken/nei/api/INEIGuiHandler.java

package codechicken.nei.api;

import java.util.Collections;
import java.util.List;

import net.minecraft.client.gui.inventory.GuiContainer;
import net.minecraft.item.ItemStack;

import codechicken.nei.VisiblityData;

/**
 * If this is implemented on a gui, it will be automatically registered
 */
public interface INEIGuiHandler {

    default VisiblityData modifyVisiblity(GuiContainer gui, VisiblityData currentVisibility) {
        return currentVisibility;
    }

    /**
     * NEI will give the specified item to the InventoryRange returned if the player's inventory is full. Should not
     * return null, just an empty list
     */
    default Iterable<Integer> getItemSpawnSlots(GuiContainer gui, ItemStack item) {
        return Collections.emptyList();
    }

    /**
     * @return A list of TaggedInventoryAreas that will be used with the savestates.
     */
    default List<TaggedInventoryArea> getInventoryAreas(GuiContainer gui) {
        return null;
    }

    /**
     * Handles clicks while an itemstack has been dragged from the item panel. Use this to set configurable slots and
     * the like. Changes made to the stackSize of the dragged stack will be kept
     *
     * @param gui          The current gui instance
     * @param mousex       The x position of the mouse
     * @param mousey       The y position of the mouse
     * @param draggedStack The stack being dragged from the item panel
     * @param button       The button presed
     * @return True if the drag n drop was handled. False to resume processing through other routes. The held stack will
     *         be deleted if draggedStack.stackSize == 0
     */
    default boolean handleDragNDrop(GuiContainer gui, int mousex, int mousey, ItemStack draggedStack, int button) {
        return false;
    }

    /**
     * Used to prevent the item panel from drawing on top of other gui elements. This function will also be called with
     * a 1x1 size rectangle on the mouse position for determining if the given coordinate should override item panel
     * functions such as scrolling
     *
     * @param x The x coordinate of the rectangle bounding the slot
     * @param y The y coordinate of the rectangle bounding the slot
     * @param w The w coordinate of the rectangle bounding the slot
     * @param h The h coordinate of the rectangle bounding the slot
     * @return true if the item panel slot within the specified rectangle should not be rendered.
     */
    default boolean hideItemPanelSlot(GuiContainer gui, int x, int y, int w, int h) {
        return false;
    }
}