package net.minecraft.client.gui.spectator;

import com.google.common.base.MoreObjects;
import com.google.common.collect.Lists;
import java.util.List;
import net.minecraft.client.gui.GuiGraphicsExtractor;
import net.minecraft.client.gui.spectator.categories.SpectatorPage;
import net.minecraft.client.renderer.RenderPipelines;
import net.minecraft.network.chat.CommonComponents;
import net.minecraft.network.chat.Component;
import net.minecraft.resources.Identifier;
import net.minecraft.util.ARGB;

public class SpectatorMenu {
	private static final Identifier CLOSE_SPRITE = Identifier.withDefaultNamespace("spectator/close");
	private static final Identifier SCROLL_LEFT_SPRITE = Identifier.withDefaultNamespace("spectator/scroll_left");
	private static final Identifier SCROLL_RIGHT_SPRITE = Identifier.withDefaultNamespace("spectator/scroll_right");
	private static final SpectatorMenuItem CLOSE_ITEM = new SpectatorMenu.CloseSpectatorItem();
	private static final SpectatorMenuItem SCROLL_LEFT = new SpectatorMenu.ScrollMenuItem(-1, true);
	private static final SpectatorMenuItem SCROLL_RIGHT_ENABLED = new SpectatorMenu.ScrollMenuItem(1, true);
	private static final SpectatorMenuItem SCROLL_RIGHT_DISABLED = new SpectatorMenu.ScrollMenuItem(1, false);
	private static final int MAX_PER_PAGE = 8;
	private static final Component CLOSE_MENU_TEXT = Component.translatable("spectatorMenu.close");
	private static final Component PREVIOUS_PAGE_TEXT = Component.translatable("spectatorMenu.previous_page");
	private static final Component NEXT_PAGE_TEXT = Component.translatable("spectatorMenu.next_page");
	public static final SpectatorMenuItem EMPTY_SLOT = new SpectatorMenuItem() {
		@Override
		public void selectItem(final SpectatorMenu menu) {
		}

		@Override
		public Component getName() {
			return CommonComponents.EMPTY;
		}

		@Override
		public void extractIcon(final GuiGraphicsExtractor graphics, final float brightness, final float alpha) {
		}

		@Override
		public boolean isEnabled() {
			return false;
		}
	};
	private final SpectatorMenuListener listener;
	private SpectatorMenuCategory category;
	private int selectedSlot = -1;
	private int page;

	public SpectatorMenu(final SpectatorMenuListener listener) {
		this.category = new RootSpectatorMenuCategory();
		this.listener = listener;
	}

	public SpectatorMenuItem getItem(final int slot) {
		int index = slot + this.page * 6;
		if (this.page > 0 && slot == 0) {
			return SCROLL_LEFT;
		} else if (slot == 7) {
			return index < this.category.getItems().size() ? SCROLL_RIGHT_ENABLED : SCROLL_RIGHT_DISABLED;
		} else if (slot == 8) {
			return CLOSE_ITEM;
		} else {
			return index >= 0 && index < this.category.getItems().size()
				? MoreObjects.firstNonNull((SpectatorMenuItem)this.category.getItems().get(index), EMPTY_SLOT)
				: EMPTY_SLOT;
		}
	}

	public List<SpectatorMenuItem> getItems() {
		List<SpectatorMenuItem> items = Lists.<SpectatorMenuItem>newArrayList();

		for (int i = 0; i <= 8; i++) {
			items.add(this.getItem(i));
		}

		return items;
	}

	public SpectatorMenuItem getSelectedItem() {
		return this.getItem(this.selectedSlot);
	}

	public SpectatorMenuCategory getSelectedCategory() {
		return this.category;
	}

	public void selectSlot(final int slot) {
		SpectatorMenuItem item = this.getItem(slot);
		if (item != EMPTY_SLOT) {
			if (this.selectedSlot == slot && item.isEnabled()) {
				item.selectItem(this);
			} else {
				this.selectedSlot = slot;
			}
		}
	}

	public void exit() {
		this.listener.onSpectatorMenuClosed(this);
	}

	public int getSelectedSlot() {
		return this.selectedSlot;
	}

	public void selectCategory(final SpectatorMenuCategory category) {
		this.category = category;
		this.selectedSlot = -1;
		this.page = 0;
	}

	public SpectatorPage getCurrentPage() {
		return new SpectatorPage(this.getItems(), this.selectedSlot);
	}

	private static class CloseSpectatorItem implements SpectatorMenuItem {
		@Override
		public void selectItem(final SpectatorMenu menu) {
			menu.exit();
		}

		@Override
		public Component getName() {
			return SpectatorMenu.CLOSE_MENU_TEXT;
		}

		@Override
		public void extractIcon(final GuiGraphicsExtractor graphics, final float brightness, final float alpha) {
			graphics.blitSprite(RenderPipelines.GUI_TEXTURED, SpectatorMenu.CLOSE_SPRITE, 0, 0, 16, 16, ARGB.colorFromFloat(alpha, brightness, brightness, brightness));
		}

		@Override
		public boolean isEnabled() {
			return true;
		}
	}

	private static class ScrollMenuItem implements SpectatorMenuItem {
		private final int direction;
		private final boolean enabled;

		public ScrollMenuItem(final int direction, final boolean enabled) {
			this.direction = direction;
			this.enabled = enabled;
		}

		@Override
		public void selectItem(final SpectatorMenu menu) {
			menu.page = menu.page + this.direction;
		}

		@Override
		public Component getName() {
			return this.direction < 0 ? SpectatorMenu.PREVIOUS_PAGE_TEXT : SpectatorMenu.NEXT_PAGE_TEXT;
		}

		@Override
		public void extractIcon(final GuiGraphicsExtractor graphics, final float brightness, final float alpha) {
			int color = ARGB.colorFromFloat(alpha, brightness, brightness, brightness);
			if (this.direction < 0) {
				graphics.blitSprite(RenderPipelines.GUI_TEXTURED, SpectatorMenu.SCROLL_LEFT_SPRITE, 0, 0, 16, 16, color);
			} else {
				graphics.blitSprite(RenderPipelines.GUI_TEXTURED, SpectatorMenu.SCROLL_RIGHT_SPRITE, 0, 0, 16, 16, color);
			}
		}

		@Override
		public boolean isEnabled() {
			return this.enabled;
		}
	}
}