From c8a72d262c9110f3cb92457cf918df1a455b9d0a Mon Sep 17 00:00:00 2001
From: Guangcong Luo <guangcongluo@gmail.com>
Date: Mon, 30 Nov 2015 18:05:32 -0500
Subject: [PATCH] Improve tab completion

Usernames with spaces can now be completed.

Special characters in front of the username will now be preserved.
This requires usernames to start with an alphanumeric character,
which fortunately we already enforce.
---
 js/client-chat.js | 51 +++++++++++++++++++++++++++++++----------------
 1 file changed, 34 insertions(+), 17 deletions(-)

diff --git a/js/client-chat.js b/js/client-chat.js
index c6237d901..6a2100f2a 100644
--- a/js/client-chat.js
+++ b/js/client-chat.js
@@ -224,9 +224,9 @@
 				candidates: null,
 				index: 0,
 				prefix: null,
-				cursor: -1,
+				cursor: null,
 				reset: function () {
-					this.cursor = -1;
+					this.cursor = null;
 				}
 			};
 			this.userActivity = [];
@@ -253,7 +253,7 @@
 
 			var text = $textbox.val();
 
-			if (idx === this.tabComplete.cursor) {
+			if (this.tabComplete.cursor !== null && text.substr(0, idx) === this.tabComplete.cursor) {
 				// The user is cycling through the candidate names.
 				if (++this.tabComplete.index >= this.tabComplete.candidates.length) {
 					this.tabComplete.index = 0;
@@ -262,16 +262,23 @@
 				// This is a new tab completion.
 
 				// There needs to be non-whitespace to the left of the cursor.
-				var m = /^(.*?)([^ ]*)$/.exec(text.substr(0, idx));
-				if (!m) return true;
+				var m1 = /^(.*?)([A-Za-z0-9][^, ]*)$/.exec(text.substr(0, idx));
+				var m2 = /^(.*?)([A-Za-z0-9][^, ]* [^, ]*)$/.exec(text.substr(0, idx));
+				if (!m1 && !m2) return true;
 
-				this.tabComplete.prefix = m[1];
-				var idprefix = toId(m[2]);
-				var candidates = [];
+				this.tabComplete.prefix = text;
+				var idprefix = (m1 ? toId(m1[2]) : '');
+				var spaceprefix = (m2 ? m2[2].replace(/[^A-Za-z0-9 ]+/g, '').toLowerCase() : '');
+				var candidates = []; // array of [candidate userid, prefix length]
+
+				// don't include command names in autocomplete
+				if (m2 && (m2[0] === '/' || m2[0] === '!')) spaceprefix = '';
 
 				for (var i in users) {
-					if (i.substr(0, idprefix.length) === idprefix) {
-						candidates.push(i);
+					if (spaceprefix && users[i].substr(1).replace(/[^A-Za-z0-9 ]+/g, '').toLowerCase().substr(0, spaceprefix.length) === spaceprefix) {
+						candidates.push([i, m2[1].length]);
+					} else if (idprefix && i.substr(0, idprefix.length) === idprefix) {
+						candidates.push([i, m1[1].length]);
 					}
 				}
 
@@ -279,8 +286,12 @@
 				// in alphabetical order.
 				var self = this;
 				candidates.sort(function (a, b) {
-					var aidx = self.userActivity.indexOf(a);
-					var bidx = self.userActivity.indexOf(b);
+					if (a[1] !== b[1]) {
+						// shorter prefix length comes first
+						return a[1] - b[1];
+					}
+					var aidx = self.userActivity.indexOf(a[0]);
+					var bidx = self.userActivity.indexOf(b[0]);
 					if (aidx !== -1) {
 						if (bidx !== -1) {
 							return bidx - aidx;
@@ -289,20 +300,26 @@
 					} else if (bidx != -1) {
 						return 1;  // b comes first
 					}
-					return (a < b) ? -1 : 1;  // alphabetical order
+					return (a[0] < b[0]) ? -1 : 1;  // alphabetical order
 				});
 				this.tabComplete.candidates = candidates;
 				this.tabComplete.index = 0;
+				if (!candidates.length) {
+					this.tabComplete.cursor = null;
+					return true;
+				}
 			}
 
 			// Substitute in the tab-completed name.
-			var substituteUserId = this.tabComplete.candidates[this.tabComplete.index];
+			var candidate = this.tabComplete.candidates[this.tabComplete.index];
+			var substituteUserId = candidate[0];
 			if (!users[substituteUserId]) return true;
 			var name = users[substituteUserId].substr(1);
-			$textbox.val(this.tabComplete.prefix + name + text.substr(idx));
-			var pos = this.tabComplete.prefix.length + name.length;
+			var fullPrefix = this.tabComplete.prefix.substr(0, candidate[1]) + name;
+			$textbox.val(fullPrefix + text.substr(idx));
+			var pos = fullPrefix.length;
 			$textbox[0].setSelectionRange(pos, pos);
-			this.tabComplete.cursor = pos;
+			this.tabComplete.cursor = fullPrefix;
 			return true;
 		},