feat: notifications (#1947)

* feat: notifications
* feat: watchers

* improvements

* handle page move for watchers

* make watchers non-blocking

* more

apps/server/src/database/migrations/20260213T085259-notifications.ts

@@ -0,0 +1,53 @@
+import { type Kysely, sql } from 'kysely';
+
+export async function up(db: Kysely<any>): Promise<void> {
+  await db.schema
+    .createTable('notifications')
+    .addColumn('id', 'uuid', (col) =>
+      col.primaryKey().defaultTo(sql`gen_uuid_v7()`),
+    )
+    .addColumn('user_id', 'uuid', (col) =>
+      col.references('users.id').onDelete('cascade').notNull(),
+    )
+    .addColumn('workspace_id', 'uuid', (col) =>
+      col.references('workspaces.id').onDelete('cascade').notNull(),
+    )
+    .addColumn('type', 'text', (col) => col.notNull())
+    .addColumn('actor_id', 'uuid', (col) =>
+      col.references('users.id').onDelete('set null'),
+    )
+    .addColumn('page_id', 'uuid', (col) =>
+      col.references('pages.id').onDelete('cascade'),
+    )
+    .addColumn('space_id', 'uuid', (col) =>
+      col.references('spaces.id').onDelete('cascade'),
+    )
+    .addColumn('comment_id', 'uuid', (col) =>
+      col.references('comments.id').onDelete('cascade'),
+    )
+    .addColumn('data', 'jsonb')
+    .addColumn('read_at', 'timestamptz')
+    .addColumn('emailed_at', 'timestamptz')
+    .addColumn('archived_at', 'timestamptz')
+    .addColumn('created_at', 'timestamptz', (col) =>
+      col.notNull().defaultTo(sql`now()`),
+    )
+    .execute();
+
+  await db.schema
+    .createIndex('idx_notifications_user_id')
+    .on('notifications')
+    .columns(['user_id', 'id desc'])
+    .execute();
+
+  await db.schema
+    .createIndex('idx_notifications_user_unread')
+    .on('notifications')
+    .column('user_id')
+    .where(sql.ref('read_at'), 'is', null)
+    .execute();
+}
+
+export async function down(db: Kysely<any>): Promise<void> {
+  await db.schema.dropTable('notifications').execute();
+}

apps/server/src/database/migrations/20260213T085320-watchers.ts

@@ -0,0 +1,57 @@
+import { type Kysely, sql } from 'kysely';
+
+export async function up(db: Kysely<any>): Promise<void> {
+  await db.schema
+    .createTable('watchers')
+    .addColumn('id', 'uuid', (col) =>
+      col.primaryKey().defaultTo(sql`gen_uuid_v7()`),
+    )
+    .addColumn('user_id', 'uuid', (col) =>
+      col.references('users.id').onDelete('cascade').notNull(),
+    )
+    .addColumn('page_id', 'uuid', (col) =>
+      col.references('pages.id').onDelete('cascade'),
+    )
+    .addColumn('space_id', 'uuid', (col) =>
+      col.references('spaces.id').onDelete('cascade').notNull(),
+    )
+    .addColumn('workspace_id', 'uuid', (col) =>
+      col.references('workspaces.id').onDelete('cascade').notNull(),
+    )
+    .addColumn('type', 'text', (col) => col.notNull())
+    .addColumn('added_by_id', 'uuid', (col) =>
+      col.references('users.id').onDelete('set null'),
+    )
+    .addColumn('muted_at', 'timestamptz')
+    .addColumn('created_at', 'timestamptz', (col) =>
+      col.notNull().defaultTo(sql`now()`),
+    )
+    .execute();
+
+  await db.schema
+    .createIndex('idx_watchers_user_page')
+    .on('watchers')
+    .columns(['user_id', 'page_id'])
+    .unique()
+    .where('page_id', 'is not', null)
+    .execute();
+
+  await db.schema
+    .createIndex('idx_watchers_user_space')
+    .on('watchers')
+    .columns(['user_id', 'space_id'])
+    .unique()
+    .where(sql.ref('page_id'), 'is', null)
+    .execute();
+
+  // Query index for fetching watchers by page
+  await db.schema
+    .createIndex('idx_watchers_page_id')
+    .on('watchers')
+    .column('page_id')
+    .execute();
+}
+
+export async function down(db: Kysely<any>): Promise<void> {
+  await db.schema.dropTable('watchers').execute();
+}

apps/server/src/database/migrations/20260213T085337-backfill-watchers.ts

@@ -0,0 +1,29 @@
+import { type Kysely, sql } from 'kysely';
+
+export async function up(db: Kysely<any>): Promise<void> {
+  // Backfill watchers from pages.contributorIds and pages.creatorId
+  // This inserts unique user-page combinations from both sources
+  await sql`
+    INSERT INTO watchers (user_id, page_id, space_id, workspace_id, type, added_by_id)
+    SELECT DISTINCT
+      u.user_id,
+      p.id as page_id,
+      p.space_id,
+      p.workspace_id,
+      'page' as type,
+      u.user_id as added_by_id
+    FROM pages p
+    CROSS JOIN LATERAL (
+      SELECT unnest(p.contributor_ids) as user_id
+      UNION
+      SELECT p.creator_id as user_id WHERE p.creator_id IS NOT NULL
+    ) u
+    WHERE p.deleted_at IS NULL
+      AND u.user_id IS NOT NULL
+    ON CONFLICT DO NOTHING
+  `.execute(db);
+}
+
+export async function down(db: Kysely<any>): Promise<void> {
+  await sql`DELETE FROM watchers WHERE type = 'page'`.execute(db);
+}