fix(conversations): preserve two-member groups

src/app/api/conversations/delete/route.js

@@ -84,17 +84,7 @@ export const POST = withAuth(async ({ request, locals }) => {
 			return NextResponse.json({ error: 'Failed to fetch conversation details' }, { status: 500 });
 		}
 
-		const { count: participantCount, error: countError } = await supabase
-			.from('conversation_participants')
-			.select('*', { count: 'exact', head: true })
-			.eq('conversation_id', conversationId);
-
-		if (countError) {
-			console.error('Error counting participants:', countError);
-		}
-
-		// Determine if this is a direct message (2 participants) or group
-		const isDirectMessage = conversation.type === 'direct' || participantCount === 2;
+		const isDirectMessage = conversation.type === 'direct';
 
 		if (isDirectMessage) {
 			// For direct messages, delete everything for all participants
@@ -278,4 +268,4 @@ export const POST = withAuth(async ({ request, locals }) => {
 		console.error('Delete conversation error:', error);
 		return NextResponse.json({ error: 'Internal server error' }, { status: 500 });
 	}
-});
+});

src/app/api/conversations/delete/route.test.js

@@ -0,0 +1,92 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const mocks = vi.hoisted(() => ({
+	from: vi.fn(),
+	getServiceRoleClient: vi.fn()
+}));
+
+vi.mock('@/lib/api/middleware/auth.js', () => ({
+	withAuth: (handler) => (request, context) =>
+		handler({
+			request,
+			locals: {
+				supabase: { from: mocks.from },
+				user: { id: 'auth-user-id' }
+			},
+			context
+		})
+}));
+
+vi.mock('@/lib/supabase/service-role.js', () => ({
+	getServiceRoleClient: mocks.getServiceRoleClient
+}));
+
+function selectSingle(data) {
+	const query = {
+		select: vi.fn(() => query),
+		eq: vi.fn(() => query),
+		single: vi.fn().mockResolvedValue({ data, error: null })
+	};
+	return query;
+}
+
+function participantLookup() {
+	const query = {
+		select: vi.fn(() => query),
+		eq: vi.fn(() => query),
+		is: vi.fn(() => query),
+		maybeSingle: vi.fn().mockResolvedValue({
+			data: { id: 'participant-id', left_at: null, archived_at: null },
+			error: null
+		})
+	};
+	return query;
+}
+
+function deleteQuery() {
+	const query = {
+		error: null,
+		delete: vi.fn(() => query),
+		eq: vi.fn(() => query)
+	};
+	return query;
+}
+
+describe('POST /api/conversations/delete', () => {
+	beforeEach(() => {
+		vi.resetModules();
+		vi.clearAllMocks();
+	});
+
+	it('keeps a two-member group and removes only the requesting participant data', async () => {
+		const messages = deleteQuery();
+		const files = deleteQuery();
+		const participantDelete = deleteQuery();
+		participantDelete.count = 2;
+		participantDelete.select = vi.fn(() => participantDelete);
+		let participantQueries = 0;
+
+		mocks.from.mockImplementation((table) => {
+			if (table === 'users') return selectSingle({ id: 'internal-user-id' });
+			if (table === 'conversations') return selectSingle({ type: 'group' });
+			if (table === 'messages') return messages;
+			if (table === 'file_attachments') return files;
+			if (table === 'conversation_participants') {
+				participantQueries += 1;
+				return participantQueries === 1 ? participantLookup() : participantDelete;
+			}
+			throw new Error(`Unexpected table: ${table}`);
+		});
+
+		const { POST } = await import('./route.js');
+		const response = await POST({
+			json: vi.fn().mockResolvedValue({ conversationId: 'group-1' })
+		});
+
+		expect(response.status).toBe(200);
+		expect(mocks.getServiceRoleClient).not.toHaveBeenCalled();
+		expect(messages.eq).toHaveBeenCalledWith('sender_id', 'internal-user-id');
+		expect(files.eq).toHaveBeenCalledWith('uploaded_by', 'internal-user-id');
+		expect(participantDelete.eq).toHaveBeenCalledWith('user_id', 'internal-user-id');
+	});
+});