CustomNPC-Plus/src/main/java/tconstruct/client/tabs/TabRegistry.java

package tconstruct.client.tabs;

import cpw.mods.fml.client.FMLClientHandler;
import cpw.mods.fml.common.Loader;
import cpw.mods.fml.common.eventhandler.SubscribeEvent;
import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;
import net.minecraft.client.Minecraft;
import net.minecraft.client.gui.inventory.GuiInventory;
import net.minecraft.network.play.client.C0DPacketCloseWindow;
import net.minecraftforge.client.event.GuiScreenEvent;

import java.util.ArrayList;
import java.util.List;

public class TabRegistry {
	private static ArrayList<AbstractTab> tabList = new ArrayList<AbstractTab>();

	public static void registerTab(AbstractTab tab) {
		tabList.add(tab);
	}

	public static ArrayList<AbstractTab> getTabList() {
		return tabList;
	}

	@SideOnly(Side.CLIENT)
	@SubscribeEvent
	public void guiPostInit(GuiScreenEvent.InitGuiEvent.Post event) {
		if ((event.gui instanceof GuiInventory)) {
			int xSize = 176;
			int ySize = 166;
			int guiLeft = (event.gui.width - xSize) / 2;
			int guiTop = (event.gui.height - ySize) / 2;
			guiLeft += getPotionOffset();
			updateTabValues(guiLeft, guiTop, InventoryTabVanilla.class);
			addTabsToList(event.buttonList);
		}
	}

	private static Minecraft mc = FMLClientHandler.instance().getClient();

	public static void openInventoryGui() {
		mc.thePlayer.sendQueue.addToSendQueue(new C0DPacketCloseWindow(
				mc.thePlayer.openContainer.windowId));
		GuiInventory inventory = new GuiInventory(mc.thePlayer);
		mc.displayGuiScreen(inventory);
	}

	public static void updateTabValues(int cornerX, int cornerY,
			Class<?> selectedButton) {
		int count = 2;
		for (int i = 0; i < tabList.size(); i++) {
			AbstractTab t = tabList.get(i);
			if (t.shouldAddToList()) {
				t.id = count;
				t.xPosition = cornerX + (count - 2) * 28;
				t.yPosition = cornerY - 28;
				t.enabled = !t.getClass().equals(selectedButton);
				count++;
			}
		}
	}

	public static void addTabsToList(List buttonList) {
		for (AbstractTab tab : tabList) {
			if (tab.shouldAddToList()) {
				buttonList.add(tab);
			}
		}
	}

	public static int getPotionOffset() {
		// If at least one potion is active...
		if (!mc.thePlayer.getActivePotionEffects().isEmpty()) {
			if (Loader.isModLoaded("NotEnoughItems")) {
				try {
					// Check whether NEI is hidden and enabled
					Class<?> c = Class
							.forName("codechicken.nei.NEIClientConfig");
					Object hidden = c.getMethod("isHidden").invoke(null);
					Object enabled = c.getMethod("isEnabled").invoke(null);
					if (hidden != null && hidden instanceof Boolean
							&& enabled != null && enabled instanceof Boolean) {
						if ((Boolean) hidden || !((Boolean) enabled)) {
							// If NEI is disabled or hidden, offset the tabs by
							// 60
							return 60;
						}
					}
				} catch (Exception e) {
				}
			} else {
				// If NEI is not installed, offset the tabs
				return 60;
			}
		}
		// No potions, no offset needed
		return 0;
	}
}