MessageLinkArgument: Initial commit

arguments/messageLinkArgument.ts

@@ -0,0 +1,25 @@
+import { Channel, Guild, Message } from 'discord.js';
+import { client } from '..';
+import { CommandError } from '../commandError';
+import { SnowflakeBasedArgument } from './base/snowflakeBasedArgument';
+
+export class MessageLinkArgument extends SnowflakeBasedArgument {
+
+    public static async parse(input: string): Promise<Message> {
+        if (!input)
+            throw CommandError.syntax('MessageLinkArgument', 'No input provided');
+
+        const match: RegExpMatchArray = this.regex('MessageLinkArgument', /https:\/\/(?:canary\.|ptb\.)?discord\.com\/channels\/(\d*)\/(\d*)\/(\d*)/, input);
+
+        if (!this.validateSnowflake(match[1]) || !this.validateSnowflake(match[2]) || !this.validateSnowflake(match[3]))
+            throw CommandError.syntax('MessageLinkArgument', 'One or more snowflakes in the link are invalid');
+
+        const guild: Guild = await client.guilds.fetch(match[1]);
+        const channel: Channel = await guild.channels.resolve(match[2]);
+
+        if (!channel.isText())
+            throw CommandError.semantic('MessageLinkArgument', 'Linked channel does not have the type text');
+
+        return channel.messages.fetch(match[3]);
+    }
+}