news-ticker

1import { atom, read, update } from 'claude-code'
2import type { EngineInterface, Register, Timer } from 'claude-code'
3
4import type { Item } from '../types'
5
6const FEEDS = [
7  ['BBC', 'https://feeds.bbci.co.uk/news/world/rss.xml'],
8  ['Guardian', 'https://www.theguardian.com/world/rss'],
9  ['NPR', 'https://feeds.npr.org/1001/rss.xml'],
10  ['tagesschau', 'https://www.tagesschau.de/index~rss2.xml'],
11  ['Al Jazeera', 'https://www.aljazeera.com/xml/rss/all.xml'],
12  ['DW', 'https://rss.dw.com/rdf/rss-en-all'],
13  ['Euronews', 'https://www.euronews.com/rss'],
14  ['Sky News', 'https://feeds.skynews.com/feeds/rss/world.xml'],
15  ['CBC', 'https://www.cbc.ca/webfeed/rss/rss-topstories'],
16  ['Global News', 'https://globalnews.ca/feed/'],
17] as const
18const SEP = '  •  '
19const TICK_MS = 350
20const REFRESH_MS = 10 * 60 * 1000
21const MAX_AGE_MS = 6 * 60 * 60 * 1000
22const PER_FEED = 4
23
24// Every headline in ticker order; empty until the first fetch lands.
25const items = atom({ plugin: 'news-ticker', key: 'items' } as const, [])
26const offset = atom({ plugin: 'news-ticker', key: 'offset' } as const, 0)
27
28const decode = (s: string) =>
29  s
30    .replace(/<!\[CDATA\[([\s\S]*?)\]\]>/g, '$1')
31    .replace(/&#(x[0-9a-f]+|\d+);/gi, (_, n: string) =>
32      String.fromCodePoint(/^x/i.test(n) ? parseInt(n.slice(1), 16) : Number(n)),
33    )
34    .replace(/&quot;/g, '"').replace(/&apos;/g, "'")
35    .replace(/&lt;/g, '<').replace(/&gt;/g, '>').replace(/&amp;/g, '&')
36    .replace(/\s+/g, ' ')
37    .trim()
38
39// ponytail: regex RSS parsing (<pubDate>, or <dc:date> for DW's RDF); swap for a real parser if Atom feeds are added
40export const itemsOf = (xml: string) =>
41  [...xml.matchAll(/<item[\s>]([\s\S]*?)<\/item>/g)].map(([, body = '']) => ({
42    title: decode(body.match(/<title>([\s\S]*?)<\/title>/)?.[1] ?? ''),
43    published: Date.parse(body.match(/<(?:pubDate|dc:date)>([\s\S]*?)<\//)?.[1] ?? ''),
44  }))
45
46export const ago = (ms: number) => {
47  const minutes = Math.max(0, Math.round(ms / 60_000))
48  if (minutes < 60) return `${minutes} min ago`
49  const hours = Math.round(minutes / 60)
50  if (hours < 48) return hours === 1 ? '1 hour ago' : `${hours} hours ago`
51  return `${Math.round(hours / 24)} days ago`
52}
53
54// One topic per line, `#` starts a comment. Matches whole words or phrases, any case.
55export const topicsOf = (text: string) =>
56  text
57    .split('\n')
58    .map(line => line.replace(/#.*/, '').trim())
59    .filter(Boolean)
60    .map(t => new RegExp(`(?<![\\p{L}\\p{N}])${t.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')}(?![\\p{L}\\p{N}])`, 'iu'))
61
62export const isWanted = (title: string, allow: RegExp[], deny: RegExp[]) =>
63  (allow.length === 0 || allow.some(t => t.test(title))) && !deny.some(t => t.test(title))
64
65// An undated headline can't be judged, so it stays.
66export const isRecent = (published: number, now: number) => Number.isNaN(published) || now - published <= MAX_AGE_MS
67
68// Every headline joined into one loop of text, its age worked out now rather than at fetch time.
69export const stripOf = (list: readonly Item[], now: number) =>
70  list
71    .map(i => `${i.title} [${i.outlet}${i.published === null ? '' : `, ${ago(now - i.published)}`}]${SEP}`)
72    .join('')
73
74let timers: Timer[] = []
75
76// Reads the lists, then starts the scroll and the feed refresh, replacing any earlier run.
77async function start($: EngineInterface) {
78  timers.forEach(t => t.cancel())
79  // Editing either list reloads the plugin, so they're read once per load.
80  const dir = $.plugin.root.replace(/[\\/]\.claude-plugin$/, '')
81  const list = (name: string) => $.fs.read(`${dir}/${name}`).then(topicsOf, () => [])
82  const [allow, deny] = await Promise.all([list('whitelist.txt'), list('blacklist.txt')])
83
84  const refresh = async () => {
85    const now = await $.clock.now()
86    const results = await Promise.all(
87      FEEDS.map(([outlet, url]) =>
88        $.http.fetch(url).then(
89          r =>
90            r.ok
91              ? itemsOf(r.text)
92                  .filter(i => i.title && isWanted(i.title, allow, deny) && isRecent(i.published, now))
93                  .slice(0, PER_FEED)
94                  .map(i => ({
95                    title: i.title,
96                    outlet,
97                    published: Number.isNaN(i.published) ? null : i.published,
98                  }))
99              : [],
100          () => [],
101        ),
102      ),
103    )
104    // Interleave feeds so one source doesn't hog a stretch of the ticker.
105    const fresh: Item[] = []
106    for (let i = 0; i < PER_FEED; i++) for (const r of results) {
107      const item = r[i]
108      if (item) fresh.push(item)
109    }
110    if (fresh.length === 0) return
111    await update($, items, () => fresh)
112  }
113
114  const tick = async () => {
115    const list = await read($, items)
116    if (list.length === 0) return
117    const length = stripOf(list, await $.clock.now()).length
118    await update($, offset, o => (o + 1) % length)
119  }
120
121  timers = [
122    $.clock.every(TICK_MS, tick),
123    $.clock.every(REFRESH_MS, refresh),
124    // A timer, not a direct call: session.end aborts its own in-flight fetches after 1.5 s.
125    $.clock.after(0, refresh),
126  ]
127}
128
129export const register: Register = on => {
130  on('session.start', async ($, e, next) => {
131    await start($)
132    return next(e)
133  })
134
135  // A /clear ends the session and starts no new session.start, so start over here.
136  on('session.end', async ($, e, next) => {
137    const result = await next(e)
138    if (e.reason === 'clear') await start($)
139    return result
140  })
141
142  on('ui.render', { component: 'AbovePrompt' }, async ($, e, next) => {
143    const list = await read($, items)
144    if (e.props.hasSurvey || list.length === 0) return next(e)
145
146    const { Text } = $.ui.resolve(e)
147    const width = Math.max(20, (e.viewport?.columns ?? 80) - 2)
148    const text = stripOf(list, await $.clock.now())
149    const from = (await read($, offset)) % text.length
150    const loop = text.repeat(Math.ceil((from + width) / text.length) + 1)
151
152    // The theme's "subtle" key: a faint gray that sits close to the background in every theme.
153    return (
154      <Text color="subtle" wrap="truncate-end">
155        {loop.slice(from, from + width)}
156      </Text>
157    )
158  })
159}
160

1// `published` is epoch ms, or null when the feed gave no date.
2export type Item = { title: string; outlet: string; published: number | null }
3
4declare module 'claude-code' {
5  interface PluginState {
6    'news-ticker': { items: Item[]; offset: number }
7  }
8}
9