From 5d004370e3b394f25bdadc6e4d0727f74c127184 Mon Sep 17 00:00:00 2001
From: filifa <filifa.breath652@8alias.com>
Date: Thu, 11 Dec 2025 23:49:34 -0500
Subject: [PATCH] insert at last cursor position when pressing button

---
 main.js | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/main.js b/main.js
index e3f91d1..25f0667 100644
--- a/main.js
+++ b/main.js
@@ -153,9 +153,13 @@ function calculate() {
 }
 
 let currentInput = null;
+let selectionStart = null;
+let selectionEnd = null;
 
 function setCurrentInput() {
 	currentInput = this;
+	selectionStart = this.selectionStart;
+	selectionEnd = this.selectionEnd;
 }
 
 function clear() {
@@ -164,8 +168,14 @@ function clear() {
 }
 
 function keyPress(c) {
-	currentInput.value += c;
+	// FIXME not working with modulus
+	// errors in logs on each key press
+	// wonder if it's an issue with it being a number type
 	currentInput.focus();
+	const begin = currentInput.value.slice(0, selectionStart);
+	const end = currentInput.value.slice(selectionEnd);
+	currentInput.value = begin + c + end;
+	currentInput.setSelectionRange(selectionEnd+1, selectionEnd+1);
 }
 
 document.querySelector("#expr").addEventListener("focus", setCurrentInput);
@@ -195,5 +205,5 @@ document.querySelector("#pow").addEventListener("click", () => keyPress("^"));
 document.querySelector("#clear").addEventListener("click", clear);
 document.querySelector("#enter").addEventListener("click", calculate);
 
-// FIXME buttons don't work if you try to insert in the middle of the text
-// TODO backspace is probably going to be tricky
+// TODO backspace might be tricky
+// TODO implement square root and inverse keys