From 6e6f09dba011c436b5c4429759b44dfbf3a82a7f Mon Sep 17 00:00:00 2001
From: DecDuck <declanahofmeyr@gmail.com>
Date: Sat, 16 Nov 2024 19:41:19 +1100
Subject: [PATCH] feat(notifications): added notification system w/ interwoven
 refactoring

---
 .../{DocsSidebar.vue => Docs/Sidebar.vue}     |  0
 .../SidebarNavItem.vue}                       |  0
 components/HeaderWidget.vue                   | 17 ----
 components/Notification.vue                   | 57 ++++++++++++
 components/PanelWidget.vue                    |  2 +-
 components/UserHeader.vue                     | 82 +++++++++++------
 .../UserHeader/NotificationWidgetPanel.vue    | 43 +++++++++
 .../UserWidget.vue}                           |  7 +-
 components/UserHeader/Widget.vue              | 37 ++++++++
 composables/notifications.ts                  | 12 +++
 composables/types.d.ts                        |  2 +-
 .../migration.sql                             | 18 ++++
 .../migration.sql                             |  2 +
 prisma/schema/user.prisma                     | 20 ++++-
 .../api/v1/notifications/[id]/index.delete.ts | 28 ++++++
 server/api/v1/notifications/[id]/index.get.ts | 28 ++++++
 server/api/v1/notifications/[id]/read.post.ts | 31 +++++++
 server/api/v1/notifications/index.get.ts      | 17 ++++
 server/api/v1/notifications/readall.post.ts   | 17 ++++
 server/api/v1/notifications/ws.get.ts         | 42 +++++++++
 server/api/v1/task/index.get.ts               |  4 +-
 server/internal/notifications/index.ts        | 88 +++++++++++++++++++
 22 files changed, 498 insertions(+), 56 deletions(-)
 rename components/{DocsSidebar.vue => Docs/Sidebar.vue} (100%)
 rename components/{DocsSidebarNavItem.vue => Docs/SidebarNavItem.vue} (100%)
 delete mode 100644 components/HeaderWidget.vue
 create mode 100644 components/Notification.vue
 create mode 100644 components/UserHeader/NotificationWidgetPanel.vue
 rename components/{HeaderUserWidget.vue => UserHeader/UserWidget.vue} (94%)
 create mode 100644 components/UserHeader/Widget.vue
 create mode 100644 composables/notifications.ts
 create mode 100644 prisma/migrations/20241116053120_add_notifications/migration.sql
 create mode 100644 prisma/migrations/20241116054212_add_created_time_stamp_to_notifications/migration.sql
 create mode 100644 server/api/v1/notifications/[id]/index.delete.ts
 create mode 100644 server/api/v1/notifications/[id]/index.get.ts
 create mode 100644 server/api/v1/notifications/[id]/read.post.ts
 create mode 100644 server/api/v1/notifications/index.get.ts
 create mode 100644 server/api/v1/notifications/readall.post.ts
 create mode 100644 server/api/v1/notifications/ws.get.ts
 create mode 100644 server/internal/notifications/index.ts

diff --git a/components/DocsSidebar.vue b/components/Docs/Sidebar.vue
similarity index 100%
rename from components/DocsSidebar.vue
rename to components/Docs/Sidebar.vue
diff --git a/components/DocsSidebarNavItem.vue b/components/Docs/SidebarNavItem.vue
similarity index 100%
rename from components/DocsSidebarNavItem.vue
rename to components/Docs/SidebarNavItem.vue
diff --git a/components/HeaderWidget.vue b/components/HeaderWidget.vue
deleted file mode 100644
index 861f5d05..00000000
--- a/components/HeaderWidget.vue
+++ /dev/null
@@ -1,17 +0,0 @@
-<template>
-    <div class="transition inline-flex items-center justify-center cursor-pointer rounded-sm px-4 py-2 bg-zinc-900 text-zinc-600 hover:bg-zinc-800 hover:text-zinc-300 relative">
-        <slot />
-        <div v-if="props.notifications !== undefined"
-            class="text-zinc-900 absolute top-0 right-0 translate-x-[30%] translate-y-[-30%] text-xs bg-blue-300 rounded-full w-3.5 h-3.5 text-center">
-            {{ props.notifications }}
-        </div>
-    </div>
-</template>
-
-<script setup lang="ts">
-const props = defineProps<{
-    notifications?: number
-}>();
-
-
-</script>
\ No newline at end of file
diff --git a/components/Notification.vue b/components/Notification.vue
new file mode 100644
index 00000000..6ca05593
--- /dev/null
+++ b/components/Notification.vue
@@ -0,0 +1,57 @@
+<template>
+  <div class="pointer-events-auto w-full bg-zinc-950/40 rounded">
+    <div class="p-4">
+      <div class="flex items-start">
+        <div class="w-0 flex-1 pt-0.5">
+          <p class="text-sm font-medium text-zinc-100">
+            {{ notification.title }}
+          </p>
+          <p class="mt-1 text-sm text-zinc-600 line-clamp-3">
+            {{ notification.description }}
+          </p>
+          <div
+            v-if="notification.actions.length > 0"
+            class="mt-3 flex space-x-7"
+          >
+            <button
+              type="button"
+              class="rounded-md bg-white text-sm font-medium text-blue-600 hover:text-blue-500 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2"
+            >
+              Undo
+            </button>
+            <!-- todo -->
+          </div>
+        </div>
+        <div class="ml-4 flex shrink-0">
+          <button
+            @click="() => deleteMe()"
+            type="button"
+            class="inline-flex rounded-md text-zinc-400 hover:text-zinc-500 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2"
+          >
+            <span class="sr-only">Close</span>
+            <XMarkIcon class="size-5" aria-hidden="true" />
+          </button>
+        </div>
+      </div>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { XMarkIcon } from "@heroicons/vue/24/solid";
+import type { Notification } from "@prisma/client";
+
+const props = defineProps<{ notification: Notification }>();
+
+async function deleteMe() {
+  await $fetch(`/api/v1/notifications/${props.notification.id}`, {
+    method: "DELETE",
+  });
+  const notifications = useNotifications();
+  const indexOfMe = notifications.value.findIndex(
+    (e) => e.id === props.notification.id
+  );
+  // Delete me
+  notifications.value.splice(indexOfMe, 1);
+}
+</script>
diff --git a/components/PanelWidget.vue b/components/PanelWidget.vue
index be7ba0f0..5022563f 100644
--- a/components/PanelWidget.vue
+++ b/components/PanelWidget.vue
@@ -1,5 +1,5 @@
 <template>
-    <div class="flex rounded-sm px-2 py-2 bg-zinc-900 text-zinc-600">
+    <div class="flex rounded px-2 py-2 bg-zinc-900 text-zinc-600">
         <slot />
     </div>
 </template>
\ No newline at end of file
diff --git a/components/UserHeader.vue b/components/UserHeader.vue
index fb13efb7..a8afc0d4 100644
--- a/components/UserHeader.vue
+++ b/components/UserHeader.vue
@@ -21,15 +21,39 @@
     </div>
     <div class="inline-flex items-center">
       <ol class="inline-flex gap-3">
-        <li v-for="(item, itemIdx) in quickActions">
-          <HeaderWidget
-            @click="item.action"
-            :notifications="item.notifications"
-          >
-            <component class="h-5" :is="item.icon" />
-          </HeaderWidget>
+        <li>
+          <UserHeaderWidget>
+            <UserGroupIcon class="h-5" />
+          </UserHeaderWidget>
         </li>
-        <HeaderUserWidget />
+
+        <li>
+          <Menu as="div" class="relative inline-block">
+            <MenuButton>
+              <UserHeaderWidget :notifications="unreadNotifications.length">
+                <BellIcon class="h-5" />
+              </UserHeaderWidget>
+            </MenuButton>
+
+            <transition
+              enter-active-class="transition ease-out duration-100"
+              enter-from-class="transform opacity-0 scale-95"
+              enter-to-class="transform opacity-100 scale-100"
+              leave-active-class="transition ease-in duration-75"
+              leave-from-class="transform opacity-100 scale-100"
+              leave-to-class="transform opacity-0 scale-95"
+            >
+              <MenuItems
+                class="absolute inset-x-0 -translate-x-1/2 top-10 z-50 w-96 focus:outline-none shadow-md"
+              >
+                <UserHeaderNotificationWidgetPanel
+                  :notifications="unreadNotifications"
+                />
+              </MenuItems>
+            </transition>
+          </Menu>
+        </li>
+        <UserHeaderUserWidget />
       </ol>
     </div>
   </div>
@@ -41,7 +65,7 @@
     <div class="flex gap-x-4 lg:gap-x-6">
       <div class="flex items-center gap-x-3">
         <!-- Profile dropdown -->
-        <HeaderUserWidget />
+        <UserHeaderUserWidget />
 
         <button
           type="button"
@@ -111,7 +135,7 @@
                   <Logo class="h-8 w-auto" />
                 </NuxtLink>
 
-                <HeaderUserWidget />
+                <UserHeaderUserWidget />
               </div>
               <nav class="flex flex-1 flex-col gap-y-8">
                 <ol class="flex flex-col gap-y-3">
@@ -130,14 +154,18 @@
                 </ol>
                 <div class="h-px w-full bg-zinc-700" />
                 <div class="flex flex-row gap-x-4 justify-stretch">
-                  <li class="w-full" v-for="(item, itemIdx) in quickActions">
-                    <HeaderWidget
-                    class="w-full"
-                      @click="item.action"
-                      :notifications="item.notifications"
+                  <li class="w-full">
+                    <UserHeaderWidget class="w-full">
+                      <UserGroupIcon class="h-5" />
+                    </UserHeaderWidget>
+                  </li>
+                  <li class="w-full">
+                    <UserHeaderWidget
+                      class="w-full"
+                      :notifications="unreadNotifications.length"
                     >
-                      <component class="h-5" :is="item.icon" />
-                    </HeaderWidget>
+                      <BellIcon class="h-5" />
+                    </UserHeaderWidget>
                   </li>
                 </div>
               </nav>
@@ -156,9 +184,11 @@ import {
   DialogPanel,
   TransitionChild,
   TransitionRoot,
+  Menu,
+  MenuButton,
+  MenuItems,
 } from "@headlessui/vue";
-import type { NavigationItem, QuickActionNav } from "../composables/types";
-import HeaderWidget from "./HeaderWidget.vue";
+import type { NavigationItem } from "../composables/types";
 import { Bars3Icon } from "@heroicons/vue/24/outline";
 import { XMarkIcon } from "@heroicons/vue/24/solid";
 
@@ -189,16 +219,10 @@ const navigation: Array<NavigationItem> = [
 
 const currentPageIndex = useCurrentNavigationIndex(navigation);
 
-const quickActions: Array<QuickActionNav> = [
-  {
-    icon: UserGroupIcon,
-    action: async () => {},
-  },
-  {
-    icon: BellIcon,
-    action: async () => {},
-  },
-];
+const notifications = useNotifications();
+const unreadNotifications = computed(() =>
+  notifications.value.filter((e) => !e.read)
+);
 
 const sidebarOpen = ref(false);
 router.afterEach(() => (sidebarOpen.value = false));
diff --git a/components/UserHeader/NotificationWidgetPanel.vue b/components/UserHeader/NotificationWidgetPanel.vue
new file mode 100644
index 00000000..b0addf4f
--- /dev/null
+++ b/components/UserHeader/NotificationWidgetPanel.vue
@@ -0,0 +1,43 @@
+<template>
+  <PanelWidget class="flex-col gap-y-2">
+    <div class="border-b border-zinc-700 pb-3 p-2">
+      <div
+        class="-ml-4 -mt-2 flex flex-wrap items-center justify-between sm:flex-nowrap"
+      >
+        <div class="ml-4 mt-2">
+          <h3 class="text-base font-semibold text-zinc-100 text-sm">
+            Unread notifications
+          </h3>
+        </div>
+        <div class="ml-4 mt-2 shrink-0">
+          <NuxtLink
+            to="/account/notifications"
+            type="button"
+            class="text-sm text-zinc-500"
+          >
+            View all &rarr;
+          </NuxtLink>
+        </div>
+      </div>
+    </div>
+
+    <div class="flex flex-col gap-y-2 max-h-[300px] overflow-y-scroll">
+      <Notification
+        v-for="notification in props.notifications"
+        :notification="notification"
+      />
+    </div>
+    <div
+      v-if="props.notifications.length == 0"
+      class="text-sm text-zinc-600 p-3 text-center w-full"
+    >
+      No notifications
+    </div>
+  </PanelWidget>
+</template>
+
+<script setup lang="ts">
+import type { Notification } from "@prisma/client";
+
+const props = defineProps<{ notifications: Array<Notification> }>();
+</script>
diff --git a/components/HeaderUserWidget.vue b/components/UserHeader/UserWidget.vue
similarity index 94%
rename from components/HeaderUserWidget.vue
rename to components/UserHeader/UserWidget.vue
index 54cd21eb..de99c97e 100644
--- a/components/HeaderUserWidget.vue
+++ b/components/UserHeader/UserWidget.vue
@@ -1,7 +1,7 @@
 <template>
   <Menu v-if="user" as="div" class="relative inline-block">
     <MenuButton>
-      <HeaderWidget>
+      <UserHeaderWidget>
         <div class="inline-flex items-center text-zinc-300 hover:text-white">
           <img
             :src="useObject(user.profilePicture)"
@@ -10,7 +10,7 @@
           <span class="ml-2 text-sm font-bold">{{ user.displayName }}</span>
           <ChevronDownIcon class="ml-3 h-4" />
         </div>
-      </HeaderWidget>
+      </UserHeaderWidget>
     </MenuButton>
 
     <transition
@@ -60,9 +60,8 @@
 <script setup lang="ts">
 import { Menu, MenuButton, MenuItem, MenuItems } from "@headlessui/vue";
 import { ChevronDownIcon } from "@heroicons/vue/16/solid";
-import type { NavigationItem } from "../composables/types";
-import HeaderWidget from "./HeaderWidget.vue";
 import { useObject } from "~/composables/objects";
+import type { NavigationItem } from "~/composables/types";
 
 const user = useUser();
 
diff --git a/components/UserHeader/Widget.vue b/components/UserHeader/Widget.vue
new file mode 100644
index 00000000..dddec3ad
--- /dev/null
+++ b/components/UserHeader/Widget.vue
@@ -0,0 +1,37 @@
+<template>
+  <div
+    :class="[
+      'transition inline-flex items-center justify-center cursor-pointer rounded-sm px-4 py-2 relative',
+      showNotifications
+        ? 'bg-blue-300 text-zinc-900 hover:bg-blue-200 hover:text-zinc-950'
+        : 'bg-zinc-900 text-zinc-600 hover:bg-zinc-800 hover:text-zinc-300',
+    ]"
+  >
+    <slot />
+    <TransitionRoot
+      :show="showNotifications"
+      enter="ease-out duration-150"
+      enter-from="opacity-0"
+      enter-to="opacity-100"
+      leave="ease-in duration-150"
+      leave-from="opacity-100"
+      leave-to="opacity-0"
+    >
+      <div
+        class="w-4 h-4 absolute top-0 right-0 translate-x-[30%] translate-y-[-30%] rounded-full bg-blue-300 inline-flex items-center justify-center text-xs text-zinc-900 font-bold"
+      >
+        {{ props.notifications }}
+      </div>
+    </TransitionRoot>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { TransitionRoot } from "@headlessui/vue";
+
+const props = defineProps<{
+  notifications?: number;
+}>();
+
+const showNotifications = computed(() => !!props.notifications);
+</script>
diff --git a/composables/notifications.ts b/composables/notifications.ts
new file mode 100644
index 00000000..304a7cd3
--- /dev/null
+++ b/composables/notifications.ts
@@ -0,0 +1,12 @@
+import type { Notification } from "@prisma/client";
+
+const ws = new WebSocketHandler("/api/v1/notifications/ws");
+
+export const useNotifications = () =>
+  useState<Array<Notification>>("notifications", () => []);
+
+ws.listen((e) => {
+  const notification = JSON.parse(e) as Notification;
+  const notifications = useNotifications();
+  notifications.value.push(notification);
+});
diff --git a/composables/types.d.ts b/composables/types.d.ts
index e1102f17..9b5af135 100644
--- a/composables/types.d.ts
+++ b/composables/types.d.ts
@@ -8,6 +8,6 @@ export type NavigationItem = {
 
 export type QuickActionNav = {
     icon: Component,
-    notifications?: number,
+    notifications?: Ref<number>,
     action: () => Promise<void>,
 }
\ No newline at end of file
diff --git a/prisma/migrations/20241116053120_add_notifications/migration.sql b/prisma/migrations/20241116053120_add_notifications/migration.sql
new file mode 100644
index 00000000..230e67cd
--- /dev/null
+++ b/prisma/migrations/20241116053120_add_notifications/migration.sql
@@ -0,0 +1,18 @@
+-- CreateTable
+CREATE TABLE "Notification" (
+    "id" TEXT NOT NULL,
+    "nonce" TEXT,
+    "userId" TEXT NOT NULL,
+    "title" TEXT NOT NULL,
+    "description" TEXT NOT NULL,
+    "actions" TEXT[],
+    "read" BOOLEAN NOT NULL DEFAULT false,
+
+    CONSTRAINT "Notification_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "Notification_nonce_key" ON "Notification"("nonce");
+
+-- AddForeignKey
+ALTER TABLE "Notification" ADD CONSTRAINT "Notification_userId_fkey" FOREIGN KEY ("userId") REFERENCES "User"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
diff --git a/prisma/migrations/20241116054212_add_created_time_stamp_to_notifications/migration.sql b/prisma/migrations/20241116054212_add_created_time_stamp_to_notifications/migration.sql
new file mode 100644
index 00000000..ec5756ce
--- /dev/null
+++ b/prisma/migrations/20241116054212_add_created_time_stamp_to_notifications/migration.sql
@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "Notification" ADD COLUMN     "created" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP;
diff --git a/prisma/schema/user.prisma b/prisma/schema/user.prisma
index d39cb10a..518297bb 100644
--- a/prisma/schema/user.prisma
+++ b/prisma/schema/user.prisma
@@ -9,4 +9,22 @@ model User {
 
     authMecs LinkedAuthMec[]
     clients  Client[]
-}
\ No newline at end of file
+
+    notifications Notification[]
+}
+
+model Notification {
+    id String @id @default(uuid())
+
+    nonce String? @unique
+
+    userId String
+    user   User   @relation(fields: [userId], references: [id])
+
+    created        DateTime @default(now())
+    title       String
+    description String
+    actions     String[]
+
+    read Boolean @default(false)
+}
diff --git a/server/api/v1/notifications/[id]/index.delete.ts b/server/api/v1/notifications/[id]/index.delete.ts
new file mode 100644
index 00000000..c89a147d
--- /dev/null
+++ b/server/api/v1/notifications/[id]/index.delete.ts
@@ -0,0 +1,28 @@
+import prisma from "~/server/internal/db/database";
+
+export default defineEventHandler(async (h3) => {
+  const userId = await h3.context.session.getUserId(h3);
+  if (!userId) throw createError({ statusCode: 403 });
+
+  const notificationId = getRouterParam(h3, "id");
+  if (!notificationId)
+    throw createError({
+      statusCode: 400,
+      statusMessage: "Missing notification ID",
+    });
+
+  const notification = await prisma.notification.delete({
+    where: {
+      id: notificationId,
+      userId,
+    },
+  });
+
+  if (!notification)
+    throw createError({
+      statusCode: 400,
+      statusMessage: "Invalid notification ID",
+    });
+
+  return {};
+});
diff --git a/server/api/v1/notifications/[id]/index.get.ts b/server/api/v1/notifications/[id]/index.get.ts
new file mode 100644
index 00000000..0d9b2c21
--- /dev/null
+++ b/server/api/v1/notifications/[id]/index.get.ts
@@ -0,0 +1,28 @@
+import prisma from "~/server/internal/db/database";
+
+export default defineEventHandler(async (h3) => {
+  const userId = await h3.context.session.getUserId(h3);
+  if (!userId) throw createError({ statusCode: 403 });
+
+  const notificationId = getRouterParam(h3, "id");
+  if (!notificationId)
+    throw createError({
+      statusCode: 400,
+      statusMessage: "Missing notification ID",
+    });
+
+  const notification = await prisma.notification.findFirst({
+    where: {
+      id: notificationId,
+      userId,
+    },
+  });
+
+  if (!notification)
+    throw createError({
+      statusCode: 400,
+      statusMessage: "Invalid notification ID",
+    });
+
+  return notification;
+});
diff --git a/server/api/v1/notifications/[id]/read.post.ts b/server/api/v1/notifications/[id]/read.post.ts
new file mode 100644
index 00000000..ef180c40
--- /dev/null
+++ b/server/api/v1/notifications/[id]/read.post.ts
@@ -0,0 +1,31 @@
+import prisma from "~/server/internal/db/database";
+
+export default defineEventHandler(async (h3) => {
+  const userId = await h3.context.session.getUserId(h3);
+  if (!userId) throw createError({ statusCode: 403 });
+
+  const notificationId = getRouterParam(h3, "id");
+  if (!notificationId)
+    throw createError({
+      statusCode: 400,
+      statusMessage: "Missing notification ID",
+    });
+
+  const notification = await prisma.notification.update({
+    where: {
+      id: notificationId,
+      userId,
+    },
+    data: {
+      read: true,
+    },
+  });
+
+  if (!notification)
+    throw createError({
+      statusCode: 400,
+      statusMessage: "Invalid notification ID",
+    });
+
+  return notification;
+});
diff --git a/server/api/v1/notifications/index.get.ts b/server/api/v1/notifications/index.get.ts
new file mode 100644
index 00000000..65a6cba1
--- /dev/null
+++ b/server/api/v1/notifications/index.get.ts
@@ -0,0 +1,17 @@
+import prisma from "~/server/internal/db/database";
+
+export default defineEventHandler(async (h3) => {
+  const userId = await h3.context.session.getUserId(h3);
+  if (!userId) throw createError({ statusCode: 403 });
+
+  const notifications = await prisma.notification.findMany({
+    where: {
+      userId,
+    },
+    orderBy: {
+      created: "desc", // Newest first
+    },
+  });
+
+  return notifications;
+});
diff --git a/server/api/v1/notifications/readall.post.ts b/server/api/v1/notifications/readall.post.ts
new file mode 100644
index 00000000..9f29bbaf
--- /dev/null
+++ b/server/api/v1/notifications/readall.post.ts
@@ -0,0 +1,17 @@
+import prisma from "~/server/internal/db/database";
+
+export default defineEventHandler(async (h3) => {
+  const userId = await h3.context.session.getUserId(h3);
+  if (!userId) throw createError({ statusCode: 403 });
+
+  await prisma.notification.updateMany({
+    where: {
+      userId,
+    },
+    data: {
+      read: true,
+    },
+  });
+
+  return;
+});
diff --git a/server/api/v1/notifications/ws.get.ts b/server/api/v1/notifications/ws.get.ts
new file mode 100644
index 00000000..13091285
--- /dev/null
+++ b/server/api/v1/notifications/ws.get.ts
@@ -0,0 +1,42 @@
+import notificationSystem from "~/server/internal/notifications";
+import session from "~/server/internal/session";
+import { parse as parseCookies } from "cookie-es";
+
+// TODO add web socket sessions for horizontal scaling
+// Peer ID to user ID
+const socketSessions: { [key: string]: string } = {};
+
+export default defineWebSocketHandler({
+  async open(peer) {
+    const cookies = peer.request?.headers?.get("Cookie");
+    if (!cookies) {
+      peer.send("unauthenticated");
+      return;
+    }
+
+    const parsedCookies = parseCookies(cookies);
+    const token = parsedCookies[session.getDropTokenCookie()];
+
+    const userId = await session.getUserIdRaw(token);
+    if (!userId) {
+      peer.send("unauthenticated");
+      return;
+    }
+
+    socketSessions[peer.id] = userId;
+
+    notificationSystem.listen(userId, peer.id, (notification) => {
+      peer.send(JSON.stringify(notification));
+    });
+  },
+  async close(peer, details) {
+    const userId = socketSessions[peer.id];
+    if (!userId) {
+      console.log(`skipping websocket close for ${peer.id}`);
+      return;
+    }
+
+    notificationSystem.unlisten(userId, peer.id);
+    delete socketSessions[peer.id];
+  },
+});
diff --git a/server/api/v1/task/index.get.ts b/server/api/v1/task/index.get.ts
index 5716c6ed..6cc0295c 100644
--- a/server/api/v1/task/index.get.ts
+++ b/server/api/v1/task/index.get.ts
@@ -1,6 +1,4 @@
-import { H3Event } from "h3";
 import session from "~/server/internal/session";
-import { v4 as uuidv4 } from "uuid";
 import taskHandler, { TaskMessage } from "~/server/internal/tasks";
 import { parse as parseCookies } from "cookie-es";
 
@@ -24,7 +22,7 @@ export default defineWebSocketHandler({
       peer.send("unauthenticated");
       return;
     }
-    
+
     const admin = session.getAdminUser(token);
     adminSocketSessions[peer.id] = admin !== undefined;
 
diff --git a/server/internal/notifications/index.ts b/server/internal/notifications/index.ts
new file mode 100644
index 00000000..e2ec1fe3
--- /dev/null
+++ b/server/internal/notifications/index.ts
@@ -0,0 +1,88 @@
+/*
+The notification system handles the recieving, creation and sending of notifications in Drop
+
+Design goals:
+1. Nonce-based notifications; notifications should only be created once
+2. Real-time; use websocket listeners to keep clients up-to-date
+*/
+
+import { Notification } from "@prisma/client";
+import prisma from "../db/database";
+
+export type NotificationCreateArgs = Pick<
+  Notification,
+  "title" | "description" | "actions" | "nonce"
+>;
+
+class NotificationSystem {
+  private listeners: {
+    [key: string]: Map<string, (notification: Notification) => any>;
+  } = {};
+
+  listen(
+    userId: string,
+    id: string,
+    callback: (notification: Notification) => any
+  ) {
+    this.listeners[userId] ??= new Map();
+    this.listeners[userId].set(id, callback);
+
+    this.catchupListener(userId, id);
+  }
+
+  unlisten(userId: string, id: string) {
+    this.listeners[userId].delete(id);
+  }
+
+  private async catchupListener(userId: string, id: string) {
+    const callback = this.listeners[userId].get(id);
+    if (!callback)
+      throw new Error("Failed to catch-up listener: callback does not exist");
+    const notifications = await prisma.notification.findMany({
+      where: { userId: userId },
+      orderBy: {
+        created: "asc", // Oldest first, because they arrive in reverse order
+      },
+    });
+    for (const notification of notifications) {
+      await callback(notification);
+    }
+  }
+
+  private async pushNotification(userId: string, notification: Notification) {
+    for (const listener of this.listeners[userId] ?? []) {
+      await listener[1](notification);
+    }
+  }
+
+  async push(userId: string, notificationCreateArgs: NotificationCreateArgs) {
+    const notification = await prisma.notification.create({
+      data: {
+        userId: userId,
+        ...notificationCreateArgs,
+      },
+    });
+
+    await this.pushNotification(userId, notification);
+  }
+
+  async pushAll(notificationCreateArgs: NotificationCreateArgs) {
+    const users = await prisma.user.findMany({
+      where: { id: { not: "system" } },
+      select: {
+        id: true,
+      },
+    });
+
+    for (const user of users) {
+      await this.push(user.id, notificationCreateArgs);
+    }
+  }
+
+  async systemPush(notificationCreateArgs: NotificationCreateArgs) {
+    return await this.push("system", notificationCreateArgs);
+  }
+}
+
+export const notificationSystem = new NotificationSystem();
+export default notificationSystem;