gui design is my passion

src/main/java/com/hbm/inventory/gui/GUICalculator.java

@@ -1,23 +1,29 @@
 package com.hbm.inventory.gui;
 
-import com.hbm.lib.RefStrings;
+import com.hbm.util.Tuple;
+
 import net.minecraft.client.gui.GuiScreen;
 import net.minecraft.client.gui.GuiTextField;
-import net.minecraft.util.ResourceLocation;
 import org.lwjgl.input.Keyboard;
 import org.lwjgl.opengl.GL11;
 
 import java.math.BigDecimal;
 import java.math.MathContext;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Deque;
 import java.util.Locale;
 import java.util.Stack;
 
 public class GUICalculator extends GuiScreen {
-	private static final ResourceLocation texture = new ResourceLocation(RefStrings.MODID, "textures/gui/calculator.png");
 	private int xSize = 220;
 	private int ySize = 50;
+	private int borderWidth = 2;
 	private GuiTextField inputField;
 
+	private int selectedHist = -1;
+	private static final int maxHistory = 6;
+	private static Deque<Tuple.Pair<String, Double>> history = new ArrayDeque<>();
 	private String latestResult = "?";
 
 	@Override
@@ -46,15 +52,31 @@ public class GUICalculator extends GuiScreen {
 		String input = inputField.getText().replaceAll("[^\\d+\\-*/^!.()\\sA-Za-z]+", "");
 
 		if (p_73869_1_ == 13 || p_73869_1_ == 10) { // when pressing enter (CR or LF)
-			try {
-				double result = evaluateExpression(input);
-				String plainStringRepresentation = (new BigDecimal(result, MathContext.DECIMAL64)).toPlainString();
-				GuiScreen.setClipboardString(plainStringRepresentation);
-				inputField.setText(plainStringRepresentation);
-				inputField.setCursorPositionEnd();
-				inputField.setSelectionPos(0);
-			} catch (Exception ignored) {}
-			return;
+			if (selectedHist != -1) {
+				input = new ArrayList<>(history).get(selectedHist).key;
+				inputField.setText(input);
+				selectedHist = -1;
+			} else {
+				try {
+					double result = evaluateExpression(input);
+					history.addFirst(new Tuple.Pair<String,Double>(input, result));
+					if (history.size() > maxHistory) history.removeLast();
+					String plainStringRepresentation = (new BigDecimal(result, MathContext.DECIMAL64)).toPlainString();
+					GuiScreen.setClipboardString(plainStringRepresentation);
+					inputField.setText(plainStringRepresentation);
+					inputField.setCursorPositionEnd();
+					inputField.setSelectionPos(0);
+				} catch (Exception ignored) {}
+				return;
+			}
+		}
+
+		if (p_73869_2_ == 200) { // up arrow
+			selectedHist = Math.max(selectedHist - 1, -1);
+		} else if (p_73869_2_ == 208) { // down arrow
+			selectedHist = Math.min(selectedHist + 1, history.size() - 1);
+		} else {
+			selectedHist = -1;
 		}
 
 		if (input.isEmpty()) {
@@ -72,14 +94,27 @@ public class GUICalculator extends GuiScreen {
 		super.drawScreen(mouseX, mouseY, partialTicks);
 
 		GL11.glColor4f(1F, 1F, 1F, 1F);
-		mc.getTextureManager().bindTexture(texture);
 		int x = (width - xSize) / 2;
 		int y = (height - ySize) / 2;
+		int histHeight = (fontRendererObj.FONT_HEIGHT + 2) * maxHistory;
+		int histStart = y + 30 + fontRendererObj.FONT_HEIGHT + 8;
 
-		drawTexturedModalRect(x, y, 0, 0, xSize, ySize);
+		drawRect(x, y, x+xSize, y+ySize+histHeight, 0xFF2d2d2d);
+		drawRect(x+borderWidth, y+borderWidth, x+xSize-borderWidth, y+ySize-borderWidth+histHeight, 0xFF3d3d3d);
+		drawRect(x, histStart - 5, x+xSize, histStart - 3, 0xFF2d2d2d);
 
 		inputField.drawTextBox();
 		fontRendererObj.drawString("=" + latestResult, x + 5, y + 30, -1);
+
+		int i = 0;
+		for (Tuple.Pair<String, Double> prevInput : history) {
+			int hy = y + 50 + (fontRendererObj.FONT_HEIGHT+1)*i;
+			if (i == selectedHist) {
+				drawRect(x + 4, hy - 1, x + 4 + xSize - 9, hy + fontRendererObj.FONT_HEIGHT, 0xFF111111);
+			}
+			fontRendererObj.drawString(prevInput.key + " = " + prevInput.value, x + 5, hy, -1);
+			i++;
+		}
 	}
 
 	/**