[feature/editor-code-tabs] Allow tabs when typing code

Allow tabs when typing code in textarea
Keep indentation when typing code in textarea

PHPBB3-11557

phpBB/styles/prosilver/template/editor.js

@@ -394,3 +394,101 @@ function getCaretPosition(txtarea) {
 
 	return caretPos;
 }
+
+/**
+* Allow to use tab character when typing code
+* Keep indentation of last line of code when typing code
+*/
+(function($) {
+	$(document).ready(function() {
+		var doc, textarea, startTags, endTags;
+
+		// find textarea, make sure browser supports necessary functions
+		if (document.forms[form_name]) {
+			doc = document;
+		} else {
+			doc = opener.document;
+		}
+
+		if (!doc.forms[form_name]) {
+			return;
+		}
+
+		textarea = doc.forms[form_name].elements[text_name];
+		if (!textarea || typeof textarea.selectionStart !== 'number') {
+			return;
+		}
+
+		// list of allowed start and end bbcode code tags, in lower case
+		startTags = ['[code]', '[code='];
+		endTags = ['[/code]'];
+
+		function inTag() {
+			var start = textarea.selectionStart,
+				lastEnd = -1,
+				lastStart = -1,
+				i, index, value;
+
+			value = textarea.value.toLowerCase();
+
+			for (i = 0; i < startTags.length; i++) {
+				var tagLength = startTags[i].length;
+				if (start >= tagLength)
+				{
+					index = value.lastIndexOf(startTags[i], start - tagLength);
+					lastStart = Math.max(lastStart, index);
+				}
+			}
+			if (lastStart == -1) return false;
+
+			for (i = 0; i < endTags.length; i++) {
+				index = value.lastIndexOf(endTags[i], start);
+				lastEnd = Math.max(lastEnd, index);
+			}
+
+			return (lastEnd < lastStart);
+		}
+
+		function getLastLine() {
+			var start = textarea.selectionStart,
+				value = textarea.value,
+				index = value.lastIndexOf("\n", start - 1);
+			return value.substring(index + 1, start);
+		}
+
+		function appendCode(code) {
+			var start = textarea.selectionStart,
+				end = textarea.selectionEnd,
+				value = textarea.value;
+			textarea.value = value.substr(0, start) + code + value.substr(end);
+			textarea.selectionStart = textarea.selectionEnd = start + code.length;
+		}
+
+		$(textarea).on('keydown', function(event) {
+			var key = event.keyCode || event.which;
+
+			// intercept tabs
+			if (key == 9) {
+				if (inTag()) {
+					appendCode("\t");
+					event.preventDefault();
+					return;
+				}
+			}
+
+			// intercept new line characters
+			if (key == 13) {
+				if (inTag()) {
+					var lastLine = getLastLine(),
+						code = '' + /^\s*/g.exec(lastLine);
+					if (code.length > 0) {
+						appendCode("\n" + code);
+						event.preventDefault();
+						return;
+					}
+				}
+			}
+		});
+	});
+})(jQuery);
+