From c096d8fac0dfdb27d4fdca7100e5c2253910b358 Mon Sep 17 00:00:00 2001
From: bdistin <bdistin@gmail.com>
Date: Fri, 10 Nov 2017 12:47:36 -0600
Subject: [PATCH] Command handler improvements (#81)

* Command Handler Speed Improvments

startsWith is slower than regex.test with a ^, and especially so when cached, instead of recreated every time a message is run (also eliminates regex.exec to get the prefix length)

* forgot to save

* yeah duh
---
 src/lib/Client.js              |  2 --
 src/monitors/commandHandler.js | 29 +++++++++++++++++++++++------
 typings/index.d.ts             |  1 -
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/src/lib/Client.js b/src/lib/Client.js
index a8b2291776..201070d2e9 100644
--- a/src/lib/Client.js
+++ b/src/lib/Client.js
@@ -37,7 +37,6 @@ class KlasaClient extends Discord.Client {
 	 * @property {KlasaConsoleEvents} [consoleEvents={}] Config options to pass to the client console
 	 * @property {boolean} [ignoreBots=true] Whether or not this bot should ignore other bots
 	 * @property {boolean} [ignoreSelf=true] Whether or not this bot should ignore itself
-	 * @property {RegExp} [prefixMention] The prefix mention for your bot (Automatically Generated)
 	 * @property {boolean} [cmdPrompt=false] Whether the bot should prompt missing parameters
 	 * @property {boolean} [cmdEditing=false] Whether the bot should update responses if the command is edited
 	 * @property {boolean} [cmdLogging=false] Whether the bot should log command usage
@@ -382,7 +381,6 @@ class KlasaClient extends Discord.Client {
 	 * @private
 	 */
 	async _ready() {
-		this.config.prefixMention = new RegExp(`^<@!?${this.user.id}>`);
 		if (this.config.ignoreBots === undefined) this.config.ignoreBots = true;
 		if (this.config.ignoreSelf === undefined) this.config.ignoreSelf = this.user.bot;
 		if (this.user.bot) this.application = await super.fetchApplication();
diff --git a/src/monitors/commandHandler.js b/src/monitors/commandHandler.js
index a975805146..0042fbae0b 100644
--- a/src/monitors/commandHandler.js
+++ b/src/monitors/commandHandler.js
@@ -2,6 +2,14 @@ const { Monitor, CommandMessage, Stopwatch, util: { regExpEsc, newError } } = re
 
 module.exports = class extends Monitor {
 
+	constructor(...args) {
+		super(...args);
+		this.prefixes = new Map();
+		this.prefixMention = null;
+		this.prefixMentionLength = null;
+		this.nick = new RegExp('^<@!');
+	}
+
 	async run(msg) {
 		// Ignore other users if selfbot
 		if (!this.client.user.bot && msg.author.id !== this.client.user.id) return;
@@ -23,9 +31,8 @@ module.exports = class extends Monitor {
 	}
 
 	parseCommand(msg) {
-		const prefix = this.getPrefix(msg);
+		const { regex: prefix, length: prefixLength } = this.getPrefix(msg);
 		if (!prefix) return { command: false };
-		const prefixLength = prefix.exec(msg.content)[0].length;
 		return {
 			command: msg.content.slice(prefixLength).trim().split(' ')[0].toLowerCase(),
 			prefix,
@@ -34,18 +41,26 @@ module.exports = class extends Monitor {
 	}
 
 	getPrefix(msg) {
-		if (this.client.config.prefixMention.test(msg.content)) return this.client.config.prefixMention;
+		if (this.prefixMention.test(msg.content)) return { length: this.nick.test(msg.content) ? this.prefixMentionLength + 1 : this.prefixMentionLength, regex: this.prefixMention };
 		const prefix = msg.guildSettings.prefix || this.client.config.prefix;
 		if (prefix instanceof Array) {
 			for (let i = prefix.length - 1; i >= 0; i--) {
-				if (msg.content.startsWith(prefix[i])) return new RegExp(`^${regExpEsc(prefix[i])}`);
+				const testingPrefix = this.prefixes.get(prefix[i]) || this.generateNewPrefix(prefix[i]);
+				if (testingPrefix.regex.test(msg.content)) return testingPrefix;
 			}
-		} else if (prefix && msg.content.startsWith(prefix)) {
-			return new RegExp(`^${regExpEsc(prefix)}`);
+		} else if (prefix) {
+			const testingPrefix = this.prefixes.get(prefix) || this.generateNewPrefix(prefix);
+			if (testingPrefix.regex.test(msg.content)) return testingPrefix;
 		}
 		return false;
 	}
 
+	generateNewPrefix(prefix) {
+		const prefixObject = { length: prefix.length, regex: new RegExp(`^${regExpEsc(prefix)}`) };
+		this.prefixes.set(prefix, prefixObject);
+		return prefixObject;
+	}
+
 	makeProxy(msg, cmdMsg) {
 		return new Proxy(msg, {
 			get: function handler(target, param) {
@@ -100,6 +115,8 @@ module.exports = class extends Monitor {
 
 	init() {
 		this.ignoreSelf = this.client.user.bot;
+		this.prefixMention = new RegExp(`^<@!?${this.client.user.id}>`);
+		this.prefixMentionLength = this.client.user.id.length + 3;
 	}
 
 };
diff --git a/typings/index.d.ts b/typings/index.d.ts
index 4fbdece361..0864d7dfca 100644
--- a/typings/index.d.ts
+++ b/typings/index.d.ts
@@ -959,7 +959,6 @@ declare module 'klasa' {
 		consoleEvents?: KlasaConsoleEvents;
 		ignoreBots?: boolean;
 		ignoreSelf?: boolean;
-		prefixMention?: RegExp;
 		cmdPrompt?: boolean;
 		cmdEditing?: boolean;
 		cmdLogging?: boolean;