From 09c3bd9e42bb3dcdbbc562a5e5dc504a8def88e6 Mon Sep 17 00:00:00 2001
From: gldrk <me@rarity.fan>
Date: Wed, 29 Nov 2023 08:18:10 +0000
Subject: [PATCH] Improve behavior of formatting buttons

* Synthesize an input event to trigger a preview update.
* Slightly tweak the algorithm.
---
 files/assets/js/formatting.js | 112 +++++++++++++++++-----------------
 1 file changed, 55 insertions(+), 57 deletions(-)

diff --git a/files/assets/js/formatting.js b/files/assets/js/formatting.js
index ca6c4b0af..9605ba61c 100644
--- a/files/assets/js/formatting.js
+++ b/files/assets/js/formatting.js
@@ -1,57 +1,55 @@
-
-function makeBold(form) {
-	var text = document.getElementById(form);
-	var startIndex = text.selectionStart,
-	endIndex = text.selectionEnd;
-	var selectedText = text.value.substring(startIndex, endIndex);
-
-	var format = '**'
-
-	if (selectedText.includes('**')) {
-		text.value = selectedText.replace(/\*/g, '');
-	}
-	else if (selectedText.length == 0) {
-		text.value = text.value.substring(0, startIndex) + selectedText + text.value.substring(endIndex);
-	}
-	else {
-		text.value = text.value.substring(0, startIndex) + format + selectedText + format + text.value.substring(endIndex);
-	}
-}
-
-function makeItalics(form) {
-	var text = document.getElementById(form);
-	var startIndex = text.selectionStart,
-	endIndex = text.selectionEnd;
-	var selectedText = text.value.substring(startIndex, endIndex);
-
-	var format = '*'
-
-	if (selectedText.includes('*')) {
-		text.value = selectedText.replace(/\*/g, '');
-	}
-	else if (selectedText.length == 0) {
-		text.value = text.value.substring(0, startIndex) + selectedText + text.value.substring(endIndex);
-	}
-	else {
-		text.value = text.value.substring(0, startIndex) + format + selectedText + format + text.value.substring(endIndex);
-	}
-}
-
-function makeQuote(form) {
-	var text = document.getElementById(form);
-	var startIndex = text.selectionStart,
-	endIndex = text.selectionEnd;
-	var selectedText = text.value.substring(startIndex, endIndex);
-
-	var format = '>'
-
-	if (selectedText.includes('>')) {
-		text.value = text.value.substring(0, startIndex) + selectedText.replace(/\>/g, '') + text.value.substring(endIndex);
-	}
-	else if (selectedText.length == 0) {
-		text.value = text.value.substring(0, startIndex) + selectedText + text.value.substring(endIndex);
-	}
-	else {
-		text.value = text.value.substring(0, startIndex) + format + selectedText + text.value.substring(endIndex);
-	}
-}
+(function() {
+	var event = InputEvent
+		? function(type, attrs) {
+			return new InputEvent(type, attrs);
+		}
+		: function(type) {
+			e = document.createEvent('event');
+			e.initEvent(type, false, false);
+			return e;
+		};
+	var escape = function(str) {
+		return str.replace(/./g, '[$&]').replace(/[\\^]|]]/g, '\\$&');
+	};
+	var wrap = function(cb) {
+		return function(id) {
+			var form = document.getElementById(id);
+			if (cb(form)) {
+				var e = event('input', { inputType: 'insertReplacementText' });
+				form.dispatchEvent(e);
+			}
+		}
+	};
+	var select = function(cb) {
+		return function(form) {
+			var begin = form.selectionStart, end = form.selectionEnd;
+			if (begin == end)
+				return false;
+			form.value = form.value.substring(0, begin)
+				+ cb(form.value.substring(begin, end))
+				+ form.value.substring(end);
+			return true;
+		};
+	};
+	var enclose = function(mark) {
+		var re = new RegExp(escape(mark) + '(\\S.*?\\S|\\S)' + escape(mark), 'g');
+		return select(function(selection) {
+			var replacement = selection.replace(re, '$1');
+			if (replacement.length == selection.length)
+				replacement = mark + replacement + mark;
+			return replacement;
+		});
+	};
+	var quote = select(function(selection) {
+		var lines = selection.split('\n');
+		if (lines.some(function(line) { return /^\s*[^\s>]/.test(line) }))
+			return '>' + lines.join('\n>');
+		else
+			return lines.map(function(line) {
+				return line.substring(line.indexOf('>') + 1);
+			}).join('\n');
+	});
+	makeItalics = wrap(enclose('*'));
+	makeBold = wrap(enclose('**'));
+	makeQuote = wrap(quote);
+})()