AFKSwitch

1import type { EngineInterface, Register } from 'claude-code'
2
3type Status = 'available' | 'afk'
4type ReadStatus = Status | 'missing' | null
5
6let showOnboarding = false
7type Cache = {
8  initialized: boolean
9  lastGood: ReadStatus
10  readable: boolean
11  pending: boolean
12  awaiting: Status | null
13  started: boolean
14  failed: boolean
15  revision: number
16}
17
18// Mirror parse_since/context_problem/problems_v1/problems_v2 in the state helper.
19function validSince(value: unknown): boolean {
20  if (typeof value !== 'string') return false
21  const parts = /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})(?:\.\d+)?(Z|[+-](\d{2}):(\d{2}))$/.exec(value)
22  if (!parts || parts[0] !== value) return false
23  const [, y, m, d, hour, minute, s, zone, oh, om] = parts
24  const year = Number(y), month = Number(m), day = Number(d)
25  const leap = year % 4 === 0 && (year % 100 !== 0 || year % 400 === 0)
26  const days = [31, leap ? 29 : 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
27  return year >= 1 && month >= 1 && month <= 12 && day >= 1 && day <= days[month - 1] &&
28    Number(hour) < 24 && Number(minute) < 60 && Number(s) < 60 &&
29    (zone === 'Z' || Number(oh) * 60 + Number(om) < 1440)
30}
31
32const validContext = (value: unknown): boolean => value === null ||
33  (typeof value === 'string' && [...value].length <= 2048 &&
34    !/[\u0000-\u0008\u000b-\u001f\u007f-\u009f\ud800-\udfff]/u.test(value))
35
36async function readStatus($: EngineInterface): Promise<ReadStatus> {
37  const override = await $.env.get('AFKSWITCH_STATE_DIR')
38  const home = override ? undefined : (await $.env.get('HOME')) || (await $.env.get('USERPROFILE'))
39  const directory = override || (home ? `${home}/.afkswitch` : undefined)
40  if (!directory) return null
41
42  try {
43    const path = `${directory.replace(/[\\/]+$/, '')}/state.json`
44    if (await $.fs.exists(path) === false) return 'missing'
45    const text = await $.fs.read(path)
46    const value: unknown = JSON.parse(text.replace(/^\uFEFF/, ''))
47    if (value === null || typeof value !== 'object' || Array.isArray(value)) return null
48    const state = value as Record<string, unknown>
49    const keys = state.version === 1
50      ? ['version', 'status', 'since', 'context']
51      : ['version', 'status', 'since', 'context', 'generation']
52    if (Object.keys(state).length !== keys.length || !keys.every(key => Object.hasOwn(state, key))) return null
53    if (state.version !== 1 && state.version !== 2) return null
54    if (state.status !== 'afk' && state.status !== 'available') return null
55    if (!validSince(state.since) || !validContext(state.context)) return null
56    if (state.version === 2 &&
57      (typeof state.generation !== 'number' || !Number.isInteger(state.generation) || state.generation < 1 ||
58        (state.status === 'available' && state.context !== null))) return null
59    return state.status
60  } catch {
61    // Unreadable, malformed and future state are unknown, never present.
62    return null
63  }
64}
65
66async function refresh($: EngineInterface, cache: Cache): Promise<ReadStatus> {
67  const request = ++cache.revision
68  try {
69    const status = await readStatus($)
70    if (request === cache.revision) {
71      cache.initialized = true
72      cache.readable = status !== null
73      if (status !== null) cache.lastGood = status
74      if (cache.awaiting && status === cache.awaiting) {
75        cache.pending = false
76        cache.awaiting = null
77        cache.started = false
78        cache.failed = false
79      }
80    }
81    return status
82  } catch (error) {
83    if (request === cache.revision) {
84      cache.initialized = false
85      cache.readable = false
86    }
87    throw error
88  }
89}
90
91// A drawing cache only: the helper used by the skills remains the single writer.
92// A hook that throws is skipped by the engine and the chain continues without it.
93export const register: Register = on => {
94  const cache: Cache = {
95    initialized: false, lastGood: null, readable: false,
96    pending: false, awaiting: null, started: false, failed: false, revision: 0,
97  }
98
99  on('session.start', async ($, e, next) => {
100    showOnboarding = false
101    try {
102      const seen = await $.store.get('onboardingVersion')
103      if (!(typeof seen === 'number' && seen >= 1)) {
104        showOnboarding = true
105        await $.store.set('onboardingVersion', 1)
106      }
107    } catch { showOnboarding = false }
108    await refresh($, cache)
109    cache.failed = false
110    $.ui.invalidate('ui.render')
111    return next(e)
112  })
113
114  on('prompt.submit', async ($, e, next) => {
115    showOnboarding = false
116    $.ui.invalidate('ui.render')
117    await refresh($, cache)
118    $.ui.invalidate('ui.render')
119    return next(e)
120  })
121
122  on('command.run', ($, e, next) => {
123    if (cache.awaiting && e.origin?.kind === 'plugin' && e.origin.name === 'afkswitch' &&
124      (e.command === 'afkswitch:afk' || e.command === 'afkswitch:back')) cache.started = true
125    return next(e)
126  })
127
128  on('turn.complete', async ($, e, next) => {
129    await refresh($, cache)
130    if (cache.awaiting) {
131      if (cache.started) {
132        cache.pending = false
133        cache.awaiting = null
134        cache.started = false
135        cache.failed = true
136      }
137    } else cache.failed = false
138    $.ui.invalidate('ui.render')
139    return next(e)
140  })
141
142  on('ui.render', { component: 'AbovePrompt' }, async ($, e, next) => {
143    // This release advertises the terminal only; remote paint is not verified.
144    if (e.surface !== 'terminal') return next(e)
145    if (!cache.initialized) await refresh($, cache)
146
147    const status = cache.readable ? cache.lastGood : null
148    const cells = status === 'afk' ? '■□' : status === 'available' ? '□■' : '□□'
149    // Capture explicit intent from this drawing; never toggle a later disk value.
150    const intended: Status | null = status === 'available' || status === 'missing' ? 'afk' : status === 'afk' ? 'available' : null
151    const { Box, Text, Button } = $.ui.resolve(e)
152    const original = await next(e)
153
154    const press = async () => {
155      // The synchronous guard also covers two presses of an old drawing.
156      if (cache.pending || intended === null) return
157      showOnboarding = false
158      cache.pending = true
159      cache.failed = false
160      try {
161        $.ui.invalidate('ui.render')
162        const current = await refresh($, cache)
163        if (current === intended) return
164        // Do not act from a file we cannot currently understand.
165        if (current === null) {
166          cache.failed = true
167          return
168        }
169        // Set before running: an idle session fires command.run inside this call.
170        cache.awaiting = intended
171        cache.started = false
172        intended === 'afk'
173          ? await $.command.run({ command: 'afkswitch:afk' })
174          : await $.command.run({ command: 'afkswitch:back' })
175      } catch {
176        cache.awaiting = null
177        cache.started = false
178        cache.failed = true
179        // Show disk truth even if command dispatch or completion failed.
180        try { await refresh($, cache) } catch { cache.readable = false }
181      } finally {
182        cache.pending = cache.awaiting !== null
183        // A redraw error must not escape a button handler into the host.
184        try { $.ui.invalidate('ui.render') } catch { /* text commands still work */ }
185      }
186    }
187
188    return (
189      <Box flexDirection="column">
190        {original}
191        <Box flexDirection="row" alignSelf="flex-start" borderStyle="single" paddingX={1} flexShrink={0}>
192          <Text color={status === 'afk' ? '#F28C28' : undefined} dimColor={status !== 'afk'}>AFK</Text>
193          <Text>{'  '}</Text>
194          {cache.pending || intended === null
195            ? <Text dimColor={status !== 'afk'}>{cells}</Text>
196            : <Button key="afkswitch-toggle" label={cells} plain onPress={press} />}
197          {cache.pending || cache.failed ? <Text>{' '}</Text> : null}
198          {cache.pending ? <Text dimColor>saving…</Text> : null}
199          {cache.failed ? <Text color="#F28C28">not switched — try /afk or /back</Text> : null}
200        </Box>
201        {showOnboarding ? <Box flexDirection="column">
202          <Text dimColor>{"AFKSwitch is ready — [ AFK □■ ] means you're here."}</Text>
203          <Text dimColor>{"Click it when you leave; click again when you're back."}</Text>
204          <Text dimColor>Use /afk [note] or /back [note] for optional context.</Text>
205        </Box> : null}
206      </Box>
207    )
208  })
209}
210