Add messageNotifier (#515)

* Add messageNotifier

* Refactor message notifier to improve user ID handling

* why did it do ext if I copied it from below and it says id :(

* Add globalName property to User type definition

* Update notification message text and formatting

---------

Co-authored-by: thororen <78185467+thororen1234@users.noreply.github.com>

packages/discord-types/src/common/User.d.ts

@@ -62,4 +62,5 @@ export interface UserJSON {
     id: string;
     publicFlags: number;
     username: string;
+    globalName: string | undefined;
 }

src/plugins/messageNotifier/index.ts

@@ -0,0 +1,63 @@
+/*
+ * Vencord, a Discord client mod
+ * Copyright (c) 2025 Vendicated and contributors
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+import { Notifications } from "@api/index";
+import { definePluginSettings } from "@api/Settings";
+import { EquicordDevs } from "@utils/constants";
+import { getCurrentChannel } from "@utils/discord";
+import definePlugin, { OptionType } from "@utils/types";
+import { MessageJSON } from "@vencord/discord-types";
+import { MessageType } from "@vencord/discord-types/enums";
+import { ChannelStore, GuildStore, NavigationRouter, RelationshipStore } from "@webpack/common";
+
+interface MessageCreatePayload {
+    guildId: string;
+    channelId: string;
+    message: MessageJSON;
+}
+
+const settings = definePluginSettings({
+    users: {
+        type: OptionType.STRING,
+        description: "Comma separated list of user ids to get message toasts for",
+        default: "",
+        isValid(value: string) {
+            if (value === "") return true;
+            const userIds = value.split(",").map(id => id.trim());
+            for (const id of userIds)
+                if (!/\d+/.test(id)) return `${id} isn't a valid user id`;
+            return true;
+        },
+    },
+});
+
+export default definePlugin({
+    authors: [EquicordDevs.cassie, EquicordDevs.mochienya],
+    name: "MessageNotifier",
+    description: "Get toasts for when chosen users send a message",
+    settings,
+    flux: {
+        MESSAGE_CREATE({ message, channelId, guildId }: MessageCreatePayload) {
+            if (message.type !== MessageType.DEFAULT || getCurrentChannel()?.id === channelId) return;
+
+            const userIds = settings.store.users.split(",").map(id => id.trim());
+            if (!userIds.includes(message.author.id)) return;
+
+            const username = RelationshipStore.getNickname(message.author.id) ?? message.author.globalName ?? message.author.username;
+            const guild = GuildStore.getGuild(guildId);
+            const channel = ChannelStore.getChannel(channelId);
+            const locationName = guild ? `${guild.name}#${channel.name}` : channel?.name ?? "their dms";
+
+            Notifications.showNotification({
+                title: `${username} sent a message`,
+                body: `Click to jump to ${locationName}`,
+                onClick() { 
+                    NavigationRouter.transitionTo(`/channels/${guild?.id ?? "@me"}/${channel.id}/${message.id}`);
+                },
+            });
+        },
+    },
+});