From d184f73160765b8bcefbd934dc2448c644fc2fa7 Mon Sep 17 00:00:00 2001
From: syuilo <Syuilotan@yahoo.co.jp>
Date: Sat, 16 Oct 2021 17:42:17 +0900
Subject: [PATCH] feat(api): add users/groups/leave

Resolve #7775
---
 CHANGELOG.md                                  |  1 +
 .../api/endpoints/users/groups/leave.ts       | 50 +++++++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 src/server/api/endpoints/users/groups/leave.ts

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 128c212c0..dbe98f4ae 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@
 - クライアント: 新しいダークテーマを追加
 - クライアント: テーマコンパイラに hue と saturate 関数を追加
 - ActivityPub: HTML -> MFMの変換を強化
+- API: グループから抜ける users/groups/leave エンドポイントを実装
 - API: i/notifications に unreadOnly オプションを追加
 - API: ap系のエンドポイントをログイン必須化+レートリミット追加
 - MFM: Add tag syntaxes of bold <b></b> and strikethrough <s></s>
diff --git a/src/server/api/endpoints/users/groups/leave.ts b/src/server/api/endpoints/users/groups/leave.ts
new file mode 100644
index 000000000..0e52f2abd
--- /dev/null
+++ b/src/server/api/endpoints/users/groups/leave.ts
@@ -0,0 +1,50 @@
+import $ from 'cafy';
+import { ID } from '@/misc/cafy-id';
+import define from '../../../define';
+import { ApiError } from '../../../error';
+import { UserGroups, UserGroupJoinings } from '@/models/index';
+
+export const meta = {
+	tags: ['groups', 'users'],
+
+	requireCredential: true as const,
+
+	kind: 'write:user-groups',
+
+	params: {
+		groupId: {
+			validator: $.type(ID),
+		},
+	},
+
+	errors: {
+		noSuchGroup: {
+			message: 'No such group.',
+			code: 'NO_SUCH_GROUP',
+			id: '62780270-1f67-5dc0-daca-3eb510612e31'
+		},
+
+		youAreOwner: {
+			message: 'Your are the owner.',
+			code: 'YOU_ARE_OWNER',
+			id: 'b6d6e0c2-ef8a-9bb8-653d-79f4a3107c69'
+		},
+	}
+};
+
+export default define(meta, async (ps, me) => {
+	// Fetch the group
+	const userGroup = await UserGroups.findOne({
+		id: ps.groupId,
+	});
+
+	if (userGroup == null) {
+		throw new ApiError(meta.errors.noSuchGroup);
+	}
+
+	if (me.id === userGroup.userId) {
+		throw new ApiError(meta.errors.youAreOwner);
+	}
+
+	await UserGroupJoinings.delete({ userGroupId: userGroup.id, userId: me.id });
+});