feat: expanding discord links

src/index.ts

@@ -10,6 +10,7 @@ import { reuploadCommands } from './_reupload';
 import * as BuildConfig from './constants';
 import { parseLog } from './logs';
 import { getLatestMinecraftVersion } from './utils/remoteVersions';
+import { expandDiscordLink } from "./utils/resolveMessage";
 
 import { membersCommand } from './commands/members';
 import { starsCommand } from './commands/stars';
@@ -87,12 +88,12 @@ client.once('ready', async () => {
         `${random(BuildConfig.ETA_MESSAGES)} <:pofat:1031701005559144458>`
       );
     }
-
     const log = await parseLog(e.content);
     if (log != null) {
       e.reply({ embeds: [log] });
       return;
     }
+    await expandDiscordLink(e);
   });
 });
 

src/utils/resolveMessage.ts

@@ -0,0 +1,72 @@
+import { Colors, EmbedBuilder, Message, ThreadChannel } from "discord.js";
+
+function findFirstImage(message: Message): string | undefined {
+  const result = message.attachments.find((attach) => {
+    return attach.contentType?.startsWith("image/");
+  });
+  if (result == undefined) {
+    return undefined;
+  } else {
+    return result.url;
+  }
+}
+
+export async function expandDiscordLink(message: Message): Promise<void> {
+  const re =
+    /(https?:\/\/)?(?:canary\.|ptb\.)?discord(?:app)?\.com\/channels\/(?<server_id>\d+)\/(?<channel_id>\d+)\/(?<message_id>\d+)/g;
+  let execResult = re.exec(message.content);
+  while (!(execResult == null || execResult.groups == undefined)) {
+    if (execResult.groups.server_id != message.guildId) {
+      continue; // do not let the bot leak messages from one server to another
+    }
+    const channel = await message.guild?.channels.fetch(
+      execResult.groups.channel_id
+    );
+    if (channel == undefined || channel == null || !channel.isTextBased()) {
+      continue;
+    }
+    if (channel instanceof ThreadChannel) {
+      if (
+        !channel.parent?.members?.some((user) => user.id == message.author.id)
+      ) {
+        continue; // do not reveal a message to a user who can't see it
+      }
+    } else {
+      if (!channel.members?.some((user) => user.id == message.author.id)) {
+        continue; // do not reveal a message to a user who can't see it
+      }
+    }
+    try {
+      const messageToShow = await channel.messages.fetch(
+        execResult.groups.message_id
+      );
+      const builder = new EmbedBuilder()
+        .setAuthor({
+          name: `${messageToShow.author.username}#${messageToShow.author.discriminator}`,
+          iconURL: messageToShow.author.displayAvatarURL(),
+        })
+        .setDescription(messageToShow.content)
+        .setColor(Colors.Aqua);
+      if (messageToShow.attachments.size > 0) {
+        let attachmentsString = "";
+        messageToShow.attachments.forEach((value) => {
+          attachmentsString += `[${value.name}](${value.url}) `;
+        });
+        builder.addFields({ name: "Attachments", value: attachmentsString });
+        const firstImage = findFirstImage(messageToShow);
+        if (firstImage != undefined) {
+          builder.setImage(firstImage);
+        }
+      }
+      builder.addFields({
+        name: "Source",
+        value: `[Jump to original message](${messageToShow.url})`,
+      });
+      message.channel.send({ embeds: [builder] });
+    } catch (e) {
+      console.error(e);
+      continue;
+    }
+    execResult = re.exec(message.content);
+  }
+}