feat(P5A.T2): WatchTogetherPayload + wrappers + parseYouTubeUrl + tests

packages/db-types/src/index.ts

@@ -582,6 +582,36 @@ export type Database = {
         }
         Relationships: []
       }
+      conversation_watch_sessions: {
+        Row: {
+          id: string;
+          conversation_id: string;
+          owner_user_id: string;
+          video_id: string;
+          started_at: string;
+          ended_at: string | null;
+          current_state: { playing: boolean; position_seconds: number; updated_at_ms: number };
+        };
+        Insert: {
+          id?: string;
+          conversation_id: string;
+          owner_user_id: string;
+          video_id: string;
+          started_at?: string;
+          ended_at?: string | null;
+          current_state?: { playing: boolean; position_seconds: number; updated_at_ms: number };
+        };
+        Update: {
+          id?: string;
+          conversation_id?: string;
+          owner_user_id?: string;
+          video_id?: string;
+          started_at?: string;
+          ended_at?: string | null;
+          current_state?: { playing: boolean; position_seconds: number; updated_at_ms: number };
+        };
+        Relationships: [];
+      };
     }
     Views: {
       [_ in never]: never

packages/shared/src/chat/attachments.ts

@@ -82,11 +82,18 @@ export interface WhiteboardPayload {
   whiteboard_id: string;
 }
 
+export interface WatchTogetherPayload {
+  v: 1;
+  type: 'watch_together';
+  session_id: string;
+}
+
 export type MessagePayload =
   | TextMessagePayload
   | CallEventPayload
   | PollPayload
-  | WhiteboardPayload;
+  | WhiteboardPayload
+  | WatchTogetherPayload;
 
 export type ParsedMessagePayload =
   | {
@@ -109,6 +116,10 @@ export type ParsedMessagePayload =
   | {
       kind: 'whiteboard';
       whiteboardId: string;
+    }
+  | {
+      kind: 'watch_together';
+      sessionId: string;
     };
 
 export function serializeMessagePayload(payload: MessagePayload): string {
@@ -172,6 +183,13 @@ export function parseMessagePayload(raw: string | null): ParsedMessagePayload {
           : '';
         return { kind: 'whiteboard', whiteboardId: id };
       }
+      if (obj.type === 'watch_together') {
+        const p = obj as Partial<WatchTogetherPayload>;
+        const id = typeof p.session_id === 'string' && p.session_id.length > 0
+          ? p.session_id
+          : '';
+        return { kind: 'watch_together', sessionId: id };
+      }
       const t = obj as TextMessagePayload;
       return {
         kind: 'text',

packages/shared/src/chat/index.ts

@@ -12,6 +12,7 @@ export * from './mentions';
 export * from './viewOnceAttachments';
 export * from './whiteboards';
 export * from './soundboards';
+export * from './watchTogether';
 
 // ----- RPC wrappers ---------------------------------------------------------
 

packages/shared/src/chat/watchTogether.test.ts

@@ -0,0 +1,124 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import {
+  createWatchSession,
+  getWatchSession,
+  parseYouTubeUrl,
+  updateWatchSessionState,
+} from './watchTogether';
+
+describe('parseYouTubeUrl', () => {
+  it.each([
+    ['https://www.youtube.com/watch?v=dQw4w9WgXcQ', 'dQw4w9WgXcQ'],
+    ['https://www.youtube.com/watch?v=dQw4w9WgXcQ&t=42', 'dQw4w9WgXcQ'],
+    ['https://youtu.be/dQw4w9WgXcQ', 'dQw4w9WgXcQ'],
+    ['https://youtu.be/dQw4w9WgXcQ?t=1', 'dQw4w9WgXcQ'],
+    ['https://www.youtube.com/embed/dQw4w9WgXcQ', 'dQw4w9WgXcQ'],
+    ['https://www.youtube.com/shorts/dQw4w9WgXcQ', 'dQw4w9WgXcQ'],
+    ['https://m.youtube.com/watch?v=dQw4w9WgXcQ', 'dQw4w9WgXcQ'],
+    ['dQw4w9WgXcQ', 'dQw4w9WgXcQ'],
+  ])('extracts the id from %s', (url, expected) => {
+    expect(parseYouTubeUrl(url)).toBe(expected);
+  });
+
+  it.each([
+    '',
+    '   ',
+    'https://vimeo.com/123',
+    'not a url',
+    'short_id',
+    'https://www.youtube.com/playlist?list=PL123',
+  ])('returns null for %s', (input) => {
+    expect(parseYouTubeUrl(input)).toBeNull();
+  });
+});
+
+function makeClient(opts: {
+  user?: { id: string } | null;
+  insertReturn?: { data: unknown; error: unknown };
+  selectReturn?: { data: unknown; error: unknown };
+  updateReturn?: { error: unknown };
+}): any {
+  const single = vi.fn().mockResolvedValue(opts.insertReturn ?? { data: {}, error: null });
+  const insertSelect = vi.fn().mockReturnValue({ single });
+  const insertChain = vi.fn().mockReturnValue({ select: insertSelect });
+  const maybeSingle = vi.fn().mockResolvedValue(opts.selectReturn ?? { data: null, error: null });
+  const eqSelect = vi.fn().mockReturnValue({ maybeSingle });
+  const selectChain = vi.fn().mockReturnValue({ eq: eqSelect });
+  const eqUpdate = vi.fn().mockResolvedValue(opts.updateReturn ?? { error: null });
+  const updateChain = vi.fn().mockReturnValue({ eq: eqUpdate });
+  const from = vi.fn().mockReturnValue({
+    insert: insertChain,
+    select: selectChain,
+    update: updateChain,
+  });
+  return {
+    auth: { getUser: vi.fn().mockResolvedValue({ data: { user: opts.user ?? { id: 'u-1' } } }) },
+    from,
+  };
+}
+
+describe('createWatchSession', () => {
+  it('inserts row + maps response to camelCase', async () => {
+    const client = makeClient({
+      insertReturn: {
+        data: {
+          id: 'w-1',
+          conversation_id: 'c-1',
+          owner_user_id: 'u-1',
+          video_id: 'dQw4w9WgXcQ',
+          started_at: '2026-05-16T00:00:00Z',
+          ended_at: null,
+          current_state: { playing: false, position_seconds: 0, updated_at_ms: 0 },
+        },
+        error: null,
+      },
+    });
+    const out = await createWatchSession(client, { conversationId: 'c-1', videoId: 'dQw4w9WgXcQ' });
+    expect(out.id).toBe('w-1');
+    expect(out.ownerUserId).toBe('u-1');
+    expect(out.videoId).toBe('dQw4w9WgXcQ');
+    expect(out.endedAt).toBeNull();
+    expect(out.currentState.playing).toBe(false);
+  });
+});
+
+describe('getWatchSession', () => {
+  it('returns null when row not found', async () => {
+    const client = makeClient({ selectReturn: { data: null, error: null } });
+    const out = await getWatchSession(client, 'w-missing');
+    expect(out).toBeNull();
+  });
+
+  it('coerces missing current_state fields to safe defaults', async () => {
+    const client = makeClient({
+      selectReturn: {
+        data: {
+          id: 'w-1',
+          conversation_id: 'c-1',
+          owner_user_id: 'u-1',
+          video_id: 'dQw4w9WgXcQ',
+          started_at: '2026-05-16T00:00:00Z',
+          ended_at: null,
+          current_state: {},
+        },
+        error: null,
+      },
+    });
+    const out = await getWatchSession(client, 'w-1');
+    expect(out?.currentState).toEqual({ playing: false, positionSeconds: 0, updatedAtMs: 0 });
+  });
+});
+
+describe('updateWatchSessionState', () => {
+  it('does not throw on success', async () => {
+    const client = makeClient({ updateReturn: { error: null } });
+    await expect(
+      updateWatchSessionState(client, 'w-1', {
+        playing: true,
+        positionSeconds: 42.5,
+        updatedAtMs: Date.now(),
+      }),
+    ).resolves.toBeUndefined();
+  });
+});

packages/shared/src/chat/watchTogether.ts

@@ -0,0 +1,124 @@
+import type { AppSupabaseClient } from '../supabase/client';
+
+export interface WatchSessionState {
+  playing: boolean;
+  positionSeconds: number;
+  updatedAtMs: number;
+}
+
+export interface WatchSession {
+  id: string;
+  conversationId: string;
+  ownerUserId: string;
+  videoId: string;
+  startedAt: string;
+  endedAt: string | null;
+  currentState: WatchSessionState;
+}
+
+export function parseYouTubeUrl(input: string): string | null {
+  const s = input.trim();
+  if (!s) return null;
+  if (/^[A-Za-z0-9_-]{11}$/.test(s)) return s;
+  const patterns = [
+    /[?&]v=([A-Za-z0-9_-]{11})/,
+    /youtu\.be\/([A-Za-z0-9_-]{11})/,
+    /youtube\.com\/embed\/([A-Za-z0-9_-]{11})/,
+    /youtube\.com\/shorts\/([A-Za-z0-9_-]{11})/,
+  ];
+  for (const re of patterns) {
+    const m = re.exec(s);
+    if (m && m[1]) return m[1];
+  }
+  return null;
+}
+
+export async function createWatchSession(
+  client: AppSupabaseClient,
+  params: { conversationId: string; videoId: string },
+): Promise<WatchSession> {
+  const { data: session } = await client.auth.getUser();
+  if (!session.user) throw new Error('not authenticated');
+  const { data, error } = await client
+    .from('conversation_watch_sessions')
+    .insert({
+      conversation_id: params.conversationId,
+      owner_user_id: session.user.id,
+      video_id: params.videoId,
+    })
+    .select('id, conversation_id, owner_user_id, video_id, started_at, ended_at, current_state')
+    .single();
+  if (error) throw error;
+  return mapRow(data);
+}
+
+export async function getWatchSession(
+  client: AppSupabaseClient,
+  sessionId: string,
+): Promise<WatchSession | null> {
+  const { data, error } = await client
+    .from('conversation_watch_sessions')
+    .select('id, conversation_id, owner_user_id, video_id, started_at, ended_at, current_state')
+    .eq('id', sessionId)
+    .maybeSingle();
+  if (error) throw error;
+  return data ? mapRow(data) : null;
+}
+
+export async function updateWatchSessionState(
+  client: AppSupabaseClient,
+  sessionId: string,
+  state: WatchSessionState,
+): Promise<void> {
+  const { error } = await client
+    .from('conversation_watch_sessions')
+    .update({
+      current_state: {
+        playing: state.playing,
+        position_seconds: state.positionSeconds,
+        updated_at_ms: state.updatedAtMs,
+      },
+    })
+    .eq('id', sessionId);
+  if (error) throw error;
+}
+
+export async function endWatchSession(
+  client: AppSupabaseClient,
+  sessionId: string,
+): Promise<void> {
+  const { error } = await client
+    .from('conversation_watch_sessions')
+    .update({ ended_at: new Date().toISOString() })
+    .eq('id', sessionId);
+  if (error) throw error;
+}
+
+function mapRow(row: {
+  id: string;
+  conversation_id: string;
+  owner_user_id: string;
+  video_id: string;
+  started_at: string;
+  ended_at: string | null;
+  current_state: unknown;
+}): WatchSession {
+  const raw = (row.current_state ?? {}) as Partial<{
+    playing: boolean;
+    position_seconds: number;
+    updated_at_ms: number;
+  }>;
+  return {
+    id: row.id,
+    conversationId: row.conversation_id,
+    ownerUserId: row.owner_user_id,
+    videoId: row.video_id,
+    startedAt: row.started_at,
+    endedAt: row.ended_at,
+    currentState: {
+      playing: typeof raw.playing === 'boolean' ? raw.playing : false,
+      positionSeconds: typeof raw.position_seconds === 'number' ? raw.position_seconds : 0,
+      updatedAtMs: typeof raw.updated_at_ms === 'number' ? raw.updated_at_ms : 0,
+    },
+  };
+}