ditto/packages/ditto/views/mastodon/statuses.ts

import { NostrEvent, NSchema as n, NStore } from '@nostrify/nostrify';
import { nip19 } from 'nostr-tools';

import { Conf } from '@/config.ts';
import { type DittoEvent } from '@/interfaces/DittoEvent.ts';
import { nostrDate } from '@/utils.ts';
import { contentToHtml, getLinks, getMediaLinks, removeTrailingTokens } from '@/utils/note.ts';
import { findReplyTag } from '@/utils/tags.ts';
import { accountFromPubkey, renderAccount } from '@/views/mastodon/accounts.ts';
import { renderAttachment } from '@/views/mastodon/attachments.ts';
import { renderEmojis } from '@/views/mastodon/emojis.ts';

import { MastodonAttachment, MastodonMention, MastodonStatus } from '@ditto/mastoapi/types';

interface RenderStatusOpts {
  viewerPubkey?: string;
  depth?: number;
}

async function renderStatus(
  store: NStore,
  event: DittoEvent,
  opts: RenderStatusOpts,
): Promise<MastodonStatus | undefined> {
  const { viewerPubkey, depth = 1 } = opts;

  if (depth > 2 || depth < 0) return;

  const nevent = nip19.neventEncode({
    id: event.id,
    author: event.pubkey,
    kind: event.kind,
    relays: [Conf.relay],
  });

  const account = event.author
    ? renderAccount({ ...event.author, author_stats: event.author_stats })
    : accountFromPubkey(event.pubkey);

  const replyId = findReplyTag(event.tags)?.[1];

  const links = getLinks(event.content);
  const mentions = event.mentions?.map((event) => renderMention(event)) ?? [];

  const imeta: string[][][] = event.tags
    .filter(([name]) => name === 'imeta')
    .map(([_, ...entries]) =>
      entries.map((entry) => {
        const split = entry.split(' ');
        return [split[0], split.splice(1).join(' ')];
      })
    );

  const media = imeta.length ? imeta : getMediaLinks(links);
  const mediaUrls = new Set<string>();

  for (const tags of media) {
    for (const [name, value] of tags) {
      if (name === 'url') {
        mediaUrls.add(value);
        break;
      }
    }
  }

  const html = contentToHtml(removeTrailingTokens(event.content, mediaUrls), mentions, { conf: Conf });

  const relatedEvents = viewerPubkey
    ? await store.query([
      { kinds: [6], '#e': [event.id], authors: [viewerPubkey], limit: 1 },
      { kinds: [7], '#e': [event.id], authors: [viewerPubkey], limit: 1 },
      { kinds: [9734], '#e': [event.id], authors: [viewerPubkey], limit: 1 },
      { kinds: [10001], '#e': [event.id], authors: [viewerPubkey], limit: 1 },
      { kinds: [10003], '#e': [event.id], authors: [viewerPubkey], limit: 1 },
    ])
    : [];

  const reactionEvent = relatedEvents.find((event) => event.kind === 7);
  const repostEvent = relatedEvents.find((event) => event.kind === 6);
  const pinEvent = relatedEvents.find((event) => event.kind === 10001);
  const bookmarkEvent = relatedEvents.find((event) => event.kind === 10003);
  const zapEvent = relatedEvents.find((event) => event.kind === 9734);

  const compatMentions = buildInlineRecipients(mentions.filter((m) => {
    if (m.id === account.id) return false;
    if (html.includes(m.url)) return false;
    return true;
  }));

  const cw = event.tags.find(([name]) => name === 'content-warning');
  const subject = event.tags.find(([name]) => name === 'subject');

  /** Pleroma emoji reactions object. */
  const reactions = Object.entries(event.event_stats?.reactions ?? {}).reduce((acc, [key, count]) => {
    if (['+', '-'].includes(key)) return acc; // skip basic reactions (treat as likes/dislikes in Mastodon API)

    // Custom emoji reactions: `<shortcode>:<url>`
    try {
      const [shortcode, ...rest] = key.split(':');
      const url = new URL(rest.join(':'));
      const tag = reactionEvent?.tags.find((t) => t[0] === 'emoji' && t[1] === shortcode && t[2] === url.href);

      acc.push({
        name: shortcode,
        me: reactionEvent?.content === `:${shortcode}:` && !!tag,
        url: url.href,
        count,
      });

      return acc;
    } catch {
      // fallthrough
    }

    // Native emojis: `🚀`
    acc.push({ name: key, count, me: reactionEvent?.content === key });

    return acc;
  }, [] as { name: string; count: number; me: boolean; url?: string }[]);

  let application: MastodonStatus['application'] = undefined;

  if (event.client) {
    const result = n.json().pipe(n.metadata()).safeParse(event.client.content);
    if (result.success) {
      const name = result.data.name ?? result.data.display_name ?? event.tags.find(([name]) => name === 'client')?.[1];
      if (name) {
        application = {
          name,
          website: result.data.website ?? null,
        };
      }
    }
  }

  const expiresAt = new Date(Number(event.tags.find(([name]) => name === 'expiration')?.[1]) * 1000);

  return {
    id: event.id,
    account,
    application,
    card: event.event_stats?.link_preview ?? null,
    content: compatMentions + html,
    created_at: nostrDate(event.created_at).toISOString(),
    in_reply_to_id: replyId ?? null,
    in_reply_to_account_id: null,
    sensitive: !!cw,
    spoiler_text: (cw ? cw[1] : subject?.[1]) || '',
    visibility: 'public',
    language: event.language ?? null,
    replies_count: event.event_stats?.replies_count ?? 0,
    reblogs_count: event.event_stats?.reposts_count ?? 0,
    favourites_count: event.event_stats?.reactions['+'] ?? 0,
    zaps_amount: event.event_stats?.zaps_amount ?? 0,
    favourited: reactionEvent?.content === '+',
    reblogged: Boolean(repostEvent),
    muted: false,
    bookmarked: Boolean(bookmarkEvent),
    pinned: Boolean(pinEvent),
    reblog: null,
    media_attachments: media
      .map((m) => renderAttachment({ tags: m }))
      .filter((m): m is MastodonAttachment => Boolean(m)),
    mentions,
    tags: [],
    emojis: renderEmojis(event),
    poll: null,
    quote: !event.quote ? null : await renderStatus(store, event.quote, { depth: depth + 1 }),
    quote_id: event.quote?.id ?? null,
    uri: Conf.local(`/users/${account.acct}/statuses/${event.id}`),
    url: Conf.local(`/@${account.acct}/${event.id}`),
    zapped: Boolean(zapEvent),
    ditto: {
      external_url: Conf.external(nevent),
    },
    pleroma: {
      emoji_reactions: reactions,
      expires_at: !isNaN(expiresAt.getTime()) ? expiresAt.toISOString() : undefined,
      quotes_count: event.event_stats?.quotes_count ?? 0,
    },
  };
}

async function renderReblog(
  store: NStore,
  event: DittoEvent,
  opts: RenderStatusOpts,
): Promise<MastodonStatus | undefined> {
  const { viewerPubkey } = opts;
  if (!event.repost) return;

  const status = await renderStatus(store, event, {}); // omit viewerPubkey intentionally
  if (!status) return;

  const reblog = await renderStatus(store, event.repost, { viewerPubkey }) ?? null;

  return {
    ...status,
    in_reply_to_id: null,
    in_reply_to_account_id: null,
    reblog,
  };
}

function renderMention(event: NostrEvent): MastodonMention {
  const account = renderAccount(event);
  return {
    id: account.id,
    acct: account.acct,
    username: account.username,
    url: account.url,
  };
}

function buildInlineRecipients(mentions: MastodonMention[]): string {
  if (!mentions.length) return '';

  const elements = mentions.reduce<string[]>((acc, { url, username }) => {
    const name = nip19.BECH32_REGEX.test(username) ? username.substring(0, 8) : username;
    acc.push(`<span class="h-card"><a class="u-url mention" href="${url}" rel="ugc">@<span>${name}</span></a></span>`);
    return acc;
  }, []);

  return `<span class="recipients-inline">${elements.join(' ')} </span>`;
}

export { renderReblog, renderStatus };