リモートのピン留め投稿取得対応 (#2798)

* Fetch featured

* Handle featured change

* Fix typo

src/services/i/pin.ts

@@ -1,12 +1,83 @@
 import config from '../../config';
 import * as mongo from 'mongodb';
-import User, { isLocalUser, isRemoteUser, ILocalUser } from '../../models/user';
+import User, { isLocalUser, isRemoteUser, ILocalUser, IUser } from '../../models/user';
+import Note from '../../models/note';
 import Following from '../../models/following';
 import renderAdd from '../../remote/activitypub/renderer/add';
 import renderRemove from '../../remote/activitypub/renderer/remove';
 import packAp from '../../remote/activitypub/renderer';
 import { deliver } from '../../queue';
 
+/**
+ * 指定した投稿をピン留めします
+ * @param user
+ * @param noteId
+ */
+export async function addPinned(user: IUser, noteId: mongo.ObjectID) {
+	// Fetch pinee
+	const note = await Note.findOne({
+		_id: noteId,
+		userId: user._id
+	});
+
+	if (note === null) {
+		throw new Error('note not found');
+	}
+
+	const pinnedNoteIds = user.pinnedNoteIds || [];
+
+	if (pinnedNoteIds.length > 5) {
+		throw new Error('cannot pin more notes');
+	}
+
+	if (pinnedNoteIds.some(id => id.equals(note._id))) {
+		throw new Error('already exists');
+	}
+
+	pinnedNoteIds.unshift(note._id);
+
+	await User.update(user._id, {
+		$set: {
+			pinnedNoteIds: pinnedNoteIds
+		}
+	});
+
+	// Deliver to remote followers
+	if (isLocalUser(user)) {
+		deliverPinnedChange(user._id, note._id, true);
+	}
+}
+
+/**
+ * 指定した投稿のピン留めを解除します
+ * @param user
+ * @param noteId
+ */
+export async function removePinned(user: IUser, noteId: mongo.ObjectID) {
+	// Fetch unpinee
+	const note = await Note.findOne({
+		_id: noteId,
+		userId: user._id
+	});
+
+	if (note === null) {
+		throw new Error('note not found');
+	}
+
+	const pinnedNoteIds = (user.pinnedNoteIds || []).filter(id => !id.equals(note._id));
+
+	await User.update(user._id, {
+		$set: {
+			pinnedNoteIds: pinnedNoteIds
+		}
+	});
+
+	// Deliver to remote followers
+	if (isLocalUser(user)) {
+		deliverPinnedChange(user._id, noteId, false);
+	}
+}
+
 export async function deliverPinnedChange(userId: mongo.ObjectID, noteId: mongo.ObjectID, isAddition: boolean) {
 	const user = await User.findOne({
 		_id: userId