package net.minecraft.client.gui.components;

import net.minecraft.client.Minecraft;
import net.minecraft.client.gui.Font;
import net.minecraft.client.gui.GuiGraphicsExtractor;
import net.minecraft.client.input.PreeditEvent;
import net.minecraft.client.renderer.RenderPipelines;
import net.minecraft.network.chat.Component;
import net.minecraft.network.chat.Style;
import net.minecraft.resources.Identifier;
import net.minecraft.util.Util;

public class IMEPreeditOverlay implements Renderable {
	private static final Identifier BACKGROUND = Identifier.withDefaultNamespace("widget/preedit");
	private static final Style FOCUSED_STYLE = Style.EMPTY.withUnderlined(true);
	private static final int SEPARATION_FROM_INPUT = 4;
	private static final int BORDER_MARGIN = 4;
	private static final int BORDER_WIDTH = 1;
	private static final int BORDER_OFFSET = 5;
	private static final int TEXT_COLOR = -16777216;
	private static final int HOT_AREA_MARGIN = 2;
	private final Font font;
	private int inputLeft;
	private int inputTop;
	private final int inputHeight;
	private final long initTimeMs;
	private final Component preEditText;
	private final int preEditTextWidth;
	private final int caretPos;

	public IMEPreeditOverlay(final PreeditEvent contents, final Font font, final int inputHeight) {
		this.font = font;
		this.inputHeight = inputHeight;
		this.initTimeMs = Util.getMillis();
		this.preEditText = contents.toFormattedText(FOCUSED_STYLE).withColor(-16777216);
		this.preEditTextWidth = font.width(this.preEditText);
		String textBeforeCaret = contents.fullText().substring(0, contents.caretPosition());
		this.caretPos = font.width(textBeforeCaret);
	}

	public void updateInputPosition(final int inputLeft, final int inputTop) {
		this.inputLeft = inputLeft;
		this.inputTop = inputTop;
	}

	@Override
	public void extractRenderState(final GuiGraphicsExtractor graphics, final int mouseX, final int mouseY, final float a) {
		int preeditLeft = this.inputLeft;
		int preeditRight = preeditLeft + this.preEditTextWidth;
		if (preeditRight > graphics.guiWidth()) {
			preeditLeft = graphics.guiWidth() - this.preEditTextWidth;
			preeditRight = preeditLeft + this.preEditTextWidth;
		}

		int inputBottom = this.inputTop + this.inputHeight;
		int preeditBottom = inputBottom + 4 + 9;
		if (preeditBottom > graphics.guiHeight()) {
			preeditBottom = this.inputTop - 4 - 9;
		}

		int preeditTop = preeditBottom - 9;
		Minecraft.getInstance()
			.textInputManager()
			.setTextInputArea(
				Math.min(preeditLeft, this.inputLeft) - 2, Math.min(preeditTop, this.inputTop) - 2, preeditRight + 2, Math.max(preeditBottom, inputBottom) + 2
			);
		int backgroundWidth = preeditRight - preeditLeft + 10;
		int backgroundHeight = preeditBottom - preeditTop + 10;
		graphics.blitSprite(RenderPipelines.GUI_TEXTURED, BACKGROUND, preeditLeft - 5, preeditTop - 5, backgroundWidth, backgroundHeight);
		graphics.text(this.font, this.preEditText, preeditLeft, preeditTop, -16777216, false);
		if (TextCursorUtils.isCursorVisible(Util.getMillis() - this.initTimeMs)) {
			TextCursorUtils.extractInsertCursor(graphics, preeditLeft + this.caretPos, preeditTop, -16777216, 9 + 1);
		}
	}
}