import { describe, expect, it } from 'vitest';
import { sortFeed, type FeedItemDTO } from './dto';

function item(username: string, opts: { pinnedAt?: string; isPlaying?: boolean; updatedAt?: string }): FeedItemDTO {
  return {
    user: { id: username, username, displayName: null, avatarUrl: null },
    track: { id: 't', title: 't', artist: 'a', album: null, artworkUrl: null, durationMs: null, isrc: null, links: {} },
    isPlaying: opts.isPlaying ?? false,
    source: 'spotify',
    sourceApp: null,
    progressMs: null,
    updatedAt: opts.updatedAt ?? '2026-01-01T00:00:00.000Z',
    pinnedAt: opts.pinnedAt ?? null,
  };
}

const names = (items: FeedItemDTO[]) => items.map((i) => i.user.username);

describe('sortFeed', () => {
  it('puts pinned friends first, in the order they were pinned', () => {
    const feed = sortFeed([
      item('live', { isPlaying: true }),
      item('pinnedSecond', { pinnedAt: '2026-01-02T00:00:00.000Z' }),
      item('pinnedFirst', { pinnedAt: '2026-01-01T00:00:00.000Z' }),
    ]);
    expect(names(feed)).toEqual(['pinnedFirst', 'pinnedSecond', 'live']);
  });

  it('then live listeners, then most recently updated', () => {
    const feed = sortFeed([
      item('old', { updatedAt: '2026-01-01T00:00:00.000Z' }),
      item('recent', { updatedAt: '2026-01-03T00:00:00.000Z' }),
      item('live', { isPlaying: true, updatedAt: '2025-12-01T00:00:00.000Z' }),
    ]);
    expect(names(feed)).toEqual(['live', 'recent', 'old']);
  });

  it('does not mutate its input', () => {
    const input = [item('b', {}), item('a', { isPlaying: true })];
    sortFeed(input);
    expect(names(input)).toEqual(['b', 'a']);
  });
});