[1.15] Help with multi-row text field

I'm trying to make a coding game, for players to start learning Java. I created a post yesterday about the multi-row textfield(I need it for the actual in-game Java IDE). Since then I started to work on a multi-row text filed. I added the basics:

https://streamable.com/buse32

As you can see from the video it works, but there are some things missing(cursor, navigating trough code with arrow keys, CTRL+A, select, CTRL+C, CTRL+V, etc). I have no idea how to imlement theese things. Here is may code(GUI class):

Console console = new Console();

	@Override
	public void drawScreen(int x, int y, float ticks) {
		returns[0] = 0;
		int guiX = (width - guiWidth) / 2;
		int guiY = (height - guiHeight) / 2;
		
		//GL11.glColor4f(1, 1, 1, 1);
	
		mc.renderEngine.bindTexture(new ResourceLocation("jp", "textures/gui/java_final.png"));
		drawTexturedModalRect(guiX, guiY, 0, 0, guiWidth, guiHeight);
		
		
		
		for(int j = 1; j <= rows; j++) {
			String row = "nothing yet";
			int i;
			for(i = 1, row = ""; i <= letterCount; i++) {
				if(returns[j] != 0) {
					if(i < returns[j] && i >= returns[j-1]) {
					
						row += Keys[i];
						fontRendererObj.drawString(row, guiX + 10, guiY + 40 + (j - 1) * 10, 0x5e757d);
					
					}
				}
				if(returns[j] == 0) {
					if(i >= returns[j-1]) {
						row += Keys[i];
						fontRendererObj.drawString(row, guiX + 10, guiY + 40 + (j - 1) * 10, 0x5e757d);
						
					}
				}
				
				
				
			}
			
			
		}
		super.drawScreen(x, y, ticks);
				
		
		
	}
	
	
	
	@Override
	protected void keyTyped(char c, int key) {
		//change the "fontRendererObj.drawString("String before any key", guiX + 10, guiY + 40, 0x5e757d);" text to the key tapped
		switch(key) {
		case Keyboard.KEY_BACK:
			if(letterCount >= 1) {
				Keys[letterCount] = null;
				letterCount--;
				if(returns[returnCount] == letterCount + 1) {
					returns[returnCount] = 0;
					returnCount--;
					rows--;
				}
				
			}
			console.log("Returns: ");
			for(int cnt = 1;cnt <= returnCount; cnt++) {
				console.log(returns[cnt] + " ");
				
			}
			console.newline();
			console.log("Keys: ");
			for(int cnt = 1;cnt <= letterCount; cnt++) {
				console.log(Keys[cnt] + " ");
				
			}
			console.newline();
			console.log("Retrun Count: " + returnCount);
			console.newline();
			console.log("Rows: " + rows);
			console.newline();
			console.log("Letter Count: " + letterCount);
			console.newline();
			break;
		case Keyboard.KEY_ESCAPE:
			mc.displayGuiScreen(null);
			break;
		case Keyboard.KEY_RETURN:
			rows++;
			returnCount++;
			returns[returnCount]=letterCount + 1;
			console.log("Returns: ");
			for(int cnt = 1;cnt <= returnCount; cnt++) {
				console.log(returns[cnt] + " ");
				
			}
			console.newline();
			console.log("Keys: ");
			for(int cnt = 1;cnt <= letterCount; cnt++) {
				console.log(Keys[cnt] + " ");
				
			}
			console.newline();
			console.log("Retrun Count: " + returnCount);
			console.newline();
			console.log("Rows: " + rows);
			console.newline();
			console.log("Letter Count: " + letterCount);
			console.newline();
			break;
			
		default:
			if(c >= 32 && c <= 127) {
				letterCount++;
				Keys[letterCount] = c + "";
				console.log("Returns: ");
				for(int cnt = 1;cnt <= returnCount; cnt++) {
					console.log(returns[cnt] + " ");
					
				}
				console.newline();
				console.log("Keys: ");
				for(int cnt = 1;cnt <= letterCount; cnt++) {
					console.log(Keys[cnt] + " ");
					
				}
				console.newline();
				console.log("Retrun Count: " + returnCount);
				console.newline();
				console.log("Rows: " + rows);
				console.newline();
				console.log("Letter Count: " + letterCount);
				console.newline();
				
			}
			break;
		
		}
		
		
		
	}

 The console class is just a class I made to avoid writing "System.out.println" every time I want to print in console something:

package com.mikeyjy.methods;

public class Console {

	public void log(Object obj) {
		System.out.print(obj);
	}
	public void newline() {
		System.out.println();
	}
}

Edited November 6, 20204 yr by MikeyJY