antisocial/test/reddit.test.ts

import assert from 'node:assert/strict';
import { test } from 'node:test';
import { commentsFrom, mediaFromLink, resolveInlineImages, toPost, treeFromDepths } from '../src/platforms/reddit.ts';
import { reddit } from '../src/platforms/reddit.ts';
import { originalUrlFor } from '../src/platforms/index.ts';
import { fixture } from './helpers.ts';

const URL_ = 'https://www.reddit.com/r/aww/comments/abc123/a_post/';

test('a text post is its title, and carries no media', () => {
  const post = toPost(fixture('reddit/self.json'), URL_);
  assert.equal(post.platform, 'reddit');
  assert.equal(post.author.handle, 'r/AskReddit');
  assert.match(post.author.displayName ?? '', /^u\//);
  assert.equal(post.segments[0]?.title, "What's a healthy food that pleases the taste buds too?");
  assert.deepEqual(post.segments[0]?.media, []);
  assert.ok(post.segments[0]?.postedAt);
});

test('a gallery keeps every picture, in the order the post arranged them', () => {
  const link = fixture<[{ data: { children: Array<{ data: Record<string, unknown> }> } }]>(
    'reddit/gallery.json',
  )[0].data.children[0]?.data as Parameters<typeof mediaFromLink>[0];
  const media = mediaFromLink(link);
  const ids = (link.gallery_data?.items ?? []).map((item) => item.media_id);

  assert.equal(media.length, ids.length);
  assert.ok(media.every((m) => m.kind === 'image'));
  // The pictures live in `media_metadata`, keyed and unordered; the order is
  // only in `gallery_data`, so joining the two is the whole job.
  media.forEach((item, index) => assert.ok(item.url.includes(String(ids[index]))));
  assert.ok(media.every((m) => m.width && m.height));
});

test('a silent video is served as the plain MP4, with a real image for a poster', () => {
  const media = toPost(fixture('reddit/video.json'), URL_).segments[0]?.media ?? [];
  assert.equal(media.length, 1);
  const video = media[0];
  assert.equal(video?.kind, 'video');
  assert.match(video?.url ?? '', /\.mp4/);
  assert.ok(video?.kind === 'video' && video.poster);
  // Not the scrubber file, which is itself an MP4 and would render nothing.
  assert.ok(video?.kind === 'video' && !video.poster?.url.endsWith('.mp4'));
  assert.equal(video?.kind === 'video' ? video.hls : undefined, undefined);
});

test('a video with sound is the HLS playlist, because the MP4 has no audio track', () => {
  const media = mediaFromLink({
    secure_media: {
      reddit_video: {
        fallback_url: 'https://v.redd.it/abc/CMAF_720.mp4?source=fallback',
        hls_url: 'https://v.redd.it/abc/HLSPlaylist.m3u8',
        has_audio: true,
        width: 1920,
        height: 1080,
        duration: 42,
      },
    },
  });

  assert.deepEqual(media, [
    {
      kind: 'video',
      url: 'https://v.redd.it/abc/HLSPlaylist.m3u8',
      hls: true,
      direct: true,
      width: 1920,
      height: 1080,
      durationSec: 42,
    },
  ]);
});

test('a link post keeps the destination, since it is the whole content of the post', () => {
  const post = toPost(fixture('reddit/link.json'), URL_);
  assert.match(post.segments[0]?.text ?? '', /^https:\/\/www\.nytimes\.com\//);
});

test('a crosspost shows what it is crossposting', () => {
  const media = mediaFromLink({
    is_self: false,
    crosspost_parent_list: [
      { url_overridden_by_dest: 'https://i.redd.it/inner.jpg', post_hint: 'image' },
    ],
  });
  assert.deepEqual(media, [{ kind: 'image', url: 'https://i.redd.it/inner.jpg' }]);
});

test('comments come back as a tree, with the counts of what is missing', () => {
  const post = toPost(fixture('reddit/gallery.json'), URL_);

  assert.equal(post.comments?.length, 3);
  assert.ok((post.moreComments ?? 0) > 0, 'the "more comments" node should be counted, not dropped');
  assert.equal(post.commentCount, 443);

  const first = post.comments?.[0];
  assert.equal(first?.author, 'u/Background_Round_853');
  assert.equal(first?.isAuthor, true, 'the poster replying under their own post');
  assert.equal(first?.score, 6583);
  assert.ok((first?.replies.length ?? 0) > 0);
  assert.ok(first?.replies.every((reply) => Array.isArray(reply.replies)));
});

test('a score the platform is still hiding is left off rather than guessed at', () => {
  const { comments } = commentsFrom({
    data: {
      children: [
        { kind: 't1', data: { author: 'a', body: 'new', score: 1, score_hidden: true, replies: '' } },
        { kind: 't1', data: { author: 'b', body: 'older', score: 42, score_hidden: false, replies: '' } },
      ],
    },
  });

  assert.equal(comments[0]?.score, undefined);
  assert.equal(comments[1]?.score, 42);
});

test('a deleted commenter keeps the platform\'s own word for it', () => {
  const { comments } = commentsFrom({
    data: { children: [{ kind: 't1', data: { author: '[deleted]', body: '[removed]', replies: '' } }] },
  });
  assert.equal(comments[0]?.author, '[deleted]');
});

test('an empty reply listing is the string "", not an object', () => {
  // Reddit says "no replies" with an empty string, which is the shape most
  // likely to be read as a listing and crash the walk.
  const { comments } = commentsFrom({
    data: { children: [{ kind: 't1', data: { author: 'a', body: 'x', replies: '' } }] },
  });
  assert.deepEqual(comments[0]?.replies, []);
});

test('a redd.it share code is rebuilt, since the rewrite drops the host', () => {
  assert.equal(originalUrlFor(reddit, 'abc123', ''), 'https://redd.it/abc123');
  assert.equal(
    originalUrlFor(reddit, 'r/aww/comments/abc123/a_post/', '?share_id=xyz&utm_source=share'),
    'https://www.reddit.com/r/aww/comments/abc123/a_post/',
  );
});

test('reddit links route to the adapter, and its media hosts do not', () => {
  assert.ok(reddit.matchesHost('www.reddit.com'));
  assert.ok(reddit.matchesHost('old.reddit.com'));
  assert.ok(reddit.matchesHost('redd.it'));
  assert.ok(!reddit.matchesHost('bsky.app'));
});

test('the page fallback rebuilds nesting from the depth on each comment', () => {
  // Reddit renders the tree flat, so depth is the only thing saying what
  // replies to what.
  const tree = treeFromDepths([
    { depth: 0, author: 'a', score: 5, created: '', text: 'first' },
    { depth: 1, author: 'b', score: 4, created: '', text: 'under first' },
    { depth: 2, author: 'c', score: 3, created: '', text: 'under b' },
    // Back up two levels: this belongs to `first`, not to `c`.
    { depth: 1, author: 'd', score: 2, created: '', text: 'also under first' },
    { depth: 0, author: 'e', score: 1, created: '', text: 'second' },
  ]);

  assert.equal(tree.length, 2);
  assert.equal(tree[0]?.replies.length, 2);
  assert.equal(tree[0]?.replies[0]?.replies[0]?.text, 'under b');
  assert.equal(tree[0]?.replies[1]?.text, 'also under first');
  assert.deepEqual(tree[1]?.replies, []);
});

test('a comment the page gave no text for is dropped rather than shown empty', () => {
  assert.deepEqual(treeFromDepths([{ depth: 0, author: 'a', score: 1, created: '', text: '' }]), []);
});

// Real shapes, captured from comments carrying each kind.
const GIPHY = {
  'giphy|Ve7wX45gaOFmw8eeEM': {
    status: 'valid',
    e: 'AnimatedImage',
    m: 'image/gif',
    s: {
      y: 200,
      x: 304,
      gif: 'https://external-preview.redd.it/CTp8.gif?width=304&height=200&s=b0e9',
      mp4: 'https://external-preview.redd.it/CTp8.gif?width=304&height=200&format=mp4&s=a389',
    },
  },
};

const UPLOAD = {
  jo8gf0ca92zd1: {
    status: 'valid',
    e: 'Image',
    m: 'image/jpeg',
    s: { y: 1270, x: 1274, u: 'https://preview.redd.it/jo8gf0ca92zd1.jpeg?width=1274&s=c226' },
  },
};

test('a giphy comment points at the gif rather than at a token', () => {
  // `![gif](giphy|ID)` is not an address, and renders as nothing at all until
  // it is looked up in the comment's own media_metadata.
  assert.equal(
    resolveInlineImages('![gif](giphy|Ve7wX45gaOFmw8eeEM)', GIPHY),
    '![gif](https://external-preview.redd.it/CTp8.gif?width=304&height=200&s=b0e9)',
  );
});

test('the animated form takes the gif, which plays on its own', () => {
  const out = resolveInlineImages('![gif](giphy|Ve7wX45gaOFmw8eeEM)', GIPHY);
  assert.ok(out.includes('.gif?'), out);
  assert.ok(!out.includes('format=mp4'), 'an mp4 would need a player to move');
});

test('an uploaded image resolves through the same lookup', () => {
  // Giphy, emotes and uploads are all a token that is a key in the same map,
  // so none of them needs naming.
  assert.equal(
    resolveInlineImages('![img](jo8gf0ca92zd1)', UPLOAD),
    '![img](https://preview.redd.it/jo8gf0ca92zd1.jpeg?width=1274&s=c226)',
  );
});

test('a target that is already an address is left alone', () => {
  const already = '![a](https://i.redd.it/x.jpg)';
  assert.equal(resolveInlineImages(already, UPLOAD), already);
  assert.equal(resolveInlineImages(already, undefined), already);
});

test('a token with no entry, or a broken one, is not invented', () => {
  assert.equal(resolveInlineImages('![gif](giphy|missing)', GIPHY), '![gif](giphy|missing)');
  assert.equal(
    resolveInlineImages('![img](gone)', { gone: { status: 'failed', e: 'Image' } }),
    '![img](gone)',
  );
});

test('inline images survive the walk into the comment tree', () => {
  const { comments } = commentsFrom({
    data: {
      children: [{
        kind: 't1',
        data: {
          author: 'a',
          body: 'ha ![gif](giphy|Ve7wX45gaOFmw8eeEM)',
          media_metadata: GIPHY,
          replies: '',
        },
      }],
    },
  });
  assert.match(comments[0]?.text ?? '', /external-preview\.redd\.it/);
});