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;
    }
}