package net.minecraft.client.gui.components;

import com.mojang.blaze3d.platform.cursor.CursorTypes;
import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;
import net.minecraft.client.gui.GuiGraphicsExtractor;
import net.minecraft.client.input.MouseButtonEvent;
import net.minecraft.client.renderer.RenderPipelines;
import net.minecraft.network.chat.Component;
import net.minecraft.resources.Identifier;
import net.minecraft.util.Mth;
import org.jspecify.annotations.Nullable;

@Environment(EnvType.CLIENT)
public abstract class AbstractScrollArea extends AbstractWidget {
	public static final int SCROLLBAR_WIDTH = 6;
	private static final int SCROLLBAR_MIN_HEIGHT = 32;
	private static final Identifier SCROLLER_SPRITE = Identifier.withDefaultNamespace("widget/scroller");
	private static final Identifier SCROLLER_BACKGROUND_SPRITE = Identifier.withDefaultNamespace("widget/scroller_background");
	private final AbstractScrollArea.ScrollbarSettings scrollbarSettings;
	private double scrollAmount;
	private boolean scrolling;

	public AbstractScrollArea(
		final int x, final int y, final int width, final int height, final Component message, final AbstractScrollArea.ScrollbarSettings scrollbarSettings
	) {
		super(x, y, width, height, message);
		this.scrollbarSettings = scrollbarSettings;
	}

	@Override
	public boolean mouseScrolled(final double mx, final double my, final double scrollX, final double scrollY) {
		if (!this.visible) {
			return false;
		} else {
			this.setScrollAmount(this.scrollAmount() - scrollY * this.scrollRate());
			return true;
		}
	}

	@Override
	public boolean mouseDragged(final MouseButtonEvent event, final double dx, final double dy) {
		if (this.scrolling) {
			if (event.y() < this.getY()) {
				this.setScrollAmount(0.0);
			} else if (event.y() > this.getBottom()) {
				this.setScrollAmount(this.maxScrollAmount());
			} else {
				double max = Math.max(1, this.maxScrollAmount());
				int barHeight = this.scrollerHeight();
				double yDragScale = Math.max(1.0, max / (this.height - barHeight));
				this.setScrollAmount(this.scrollAmount() + dy * yDragScale);
			}

			return true;
		} else {
			return super.mouseDragged(event, dx, dy);
		}
	}

	@Override
	public void onRelease(final MouseButtonEvent event) {
		this.scrolling = false;
	}

	public double scrollAmount() {
		return this.scrollAmount;
	}

	public void setScrollAmount(final double scrollAmount) {
		this.scrollAmount = Mth.clamp(scrollAmount, 0.0, (double)this.maxScrollAmount());
	}

	public boolean updateScrolling(final MouseButtonEvent event) {
		this.scrolling = this.scrollable() && this.isValidClickButton(event.buttonInfo()) && this.isOverScrollbar(event.x(), event.y());
		return this.scrolling;
	}

	protected boolean isOverScrollbar(final double x, final double y) {
		return x >= this.scrollBarX() && x <= this.scrollBarX() + this.scrollbarWidth() && y >= this.getY() && y < this.getBottom();
	}

	public void refreshScrollAmount() {
		this.setScrollAmount(this.scrollAmount);
	}

	public int maxScrollAmount() {
		return Math.max(0, this.contentHeight() - this.height);
	}

	protected boolean scrollable() {
		return this.maxScrollAmount() > 0;
	}

	public int scrollbarWidth() {
		return this.scrollbarSettings.scrollbarWidth();
	}

	protected int scrollerHeight() {
		return Mth.clamp((int)((float)(this.height * this.height) / this.contentHeight()), 32, this.height - 8);
	}

	protected int scrollBarX() {
		return this.getRight() - this.scrollbarWidth();
	}

	public int scrollBarY() {
		return this.maxScrollAmount() == 0
			? this.getY()
			: Math.max(this.getY(), (int)this.scrollAmount * (this.height - this.scrollerHeight()) / this.maxScrollAmount() + this.getY());
	}

	protected void extractScrollbar(final GuiGraphicsExtractor graphics, final int mouseX, final int mouseY) {
		int scrollbarX = this.scrollBarX();
		int scrollerHeight = this.scrollerHeight();
		int scrollerY = this.scrollBarY();
		if (!this.scrollable() && this.scrollbarSettings.disabledScrollerSprite() != null) {
			graphics.blitSprite(
				RenderPipelines.GUI_TEXTURED, this.scrollbarSettings.backgroundSprite(), scrollbarX, this.getY(), this.scrollbarWidth(), this.getHeight()
			);
			graphics.blitSprite(
				RenderPipelines.GUI_TEXTURED, this.scrollbarSettings.disabledScrollerSprite(), scrollbarX, this.getY(), this.scrollbarWidth(), scrollerHeight
			);
			if (this.isOverScrollbar(mouseX, mouseY)) {
				graphics.requestCursor(CursorTypes.NOT_ALLOWED);
			}
		}

		if (this.scrollable()) {
			graphics.blitSprite(
				RenderPipelines.GUI_TEXTURED, this.scrollbarSettings.backgroundSprite(), scrollbarX, this.getY(), this.scrollbarWidth(), this.getHeight()
			);
			graphics.blitSprite(RenderPipelines.GUI_TEXTURED, this.scrollbarSettings.scrollerSprite(), scrollbarX, scrollerY, this.scrollbarWidth(), scrollerHeight);
			if (this.isOverScrollbar(mouseX, mouseY)) {
				graphics.requestCursor(this.scrolling ? CursorTypes.RESIZE_NS : CursorTypes.POINTING_HAND);
			}
		}
	}

	protected abstract int contentHeight();

	protected double scrollRate() {
		return this.scrollbarSettings.scrollRate();
	}

	public static AbstractScrollArea.ScrollbarSettings defaultSettings(final int scrollRate) {
		return new AbstractScrollArea.ScrollbarSettings(SCROLLER_SPRITE, null, SCROLLER_BACKGROUND_SPRITE, 6, 32, scrollRate, true);
	}

	@Environment(EnvType.CLIENT)
	public record ScrollbarSettings(
		Identifier scrollerSprite,
		@Nullable Identifier disabledScrollerSprite,
		Identifier backgroundSprite,
		int scrollbarWidth,
		int scrollbarMinHeight,
		int scrollRate,
		boolean resizingScrollbar
	) {
	}
}