snake

1/* @jsx h */
2import type { Register } from 'claude-code'
3import { isBetter } from './games/best.ts'
4
5// Snake above the Claude Code prompt, split out of cc-arcade (https://github.com/sezaakgun/cc-arcade,
6// MIT, by Seza Akgün) as a single-game mod. `/snake` opens it, `/snake stop` closes it. The board in
7// ./boards is a surface module that runs on the drawing thread; this module mounts it, keeps the best
8// score in $.store and pauses the game when Claude finishes a turn. Playing costs no tokens.
9
10const GAME = 'snake' // what the board posts its score under
11const TITLE = 'Snake'
12const LOWER_IS_BETTER = false
13const UNIT = ''
14
15let open = false
16// bumped at each finished turn; the open game pauses when it sees a new value
17let turnsDone = 0
18let best = 0
19
20export const register: Register = on => {
21  on('session.start', async ($, e, next) => {
22    const r = await next(e)
23    // a store that cannot be read costs the best score, never the game
24    const score = Number(await $.store.get('best').catch(() => undefined))
25    if (score) best = score
26    await $.command.register({
27      name: 'snake',
28      description: `$Snake above the prompt, while Claude works (stop closes)`,
29      argumentHint: '[stop]',
30      immediate: true,
31    }).catch(err => $.ui.log(`snake: /snake not registered: ${err}`))
32    return r
33  })
34
35  on('command.run', { command: 'snake' }, async ($, e) => {
36    const arg = e.args.trim().toLowerCase()
37    if (arg === 'stop' || arg === 'close') {
38      open = false
39      $.ui.invalidate('ui.render')
40      return { text: `$Snake closed` }
41    }
42    open = true
43    $.ui.invalidate('ui.render')
44    const score = best ? ` · best ${best}$` : ''
45    return { text: `$Snake · click the board to play · Esc returns to the prompt · /snake stop closes${score}` }
46  })
47
48  on('turn.complete', async ($, e, next) => {
49    const r = await next(e)
50    // a subagent's turn is not the one the person is waiting for
51    if (e.agentId) return r
52    if (open) {
53      turnsDone++
54      $.ui.invalidate('ui.render')
55    }
56    return r
57  })
58
59  // a finished round, posted by the board: keep the best score and hand it back with the next props
60  on('ui.message', async ($, e, next) => {
61    const data = e.data as { game?: unknown; score?: unknown } | null
62    if (data?.game !== GAME || typeof data.score !== 'number') return next(e)
63    if (isBetter(data.score, best || undefined, LOWER_IS_BETTER)) {
64      best = data.score
65      await $.store.set('best', best).catch(err => $.ui.log(`snake: store write failed: ${err}`))
66      $.ui.toast(`$Snake: new best ${best}$`)
67    }
68    return { props: { best, done: turnsDone, safe: false } }
69  })
70
71  on('ui.render', { component: 'AbovePrompt' }, async ($, e, next) => {
72    // the board needs a terminal's keys and mouse; the desktop and mobile surfaces draw their own band
73    if (!open || e.props.hasSurvey || e.surface !== 'terminal') return next(e)
74    const { Box, Button, Client } = $.ui.resolve(e)
75    // the band's own width: the transcript column's while a Pane is docked beside it
76    const cols = e.props.bodyColumns || (e.viewport?.columns ?? 80)
77    // one row for the close button, one for whatever else draws in the band
78    const rows = Math.max(8, e.props.maxRows - 2)
79    const tall = (max: number) => Math.min(rows, max)
80    const close = () => {
81      open = false
82      $.ui.invalidate('ui.render')
83    }
84    return (
85      <Box flexDirection="column">
86        <Box flexDirection="row" columnGap={1}>
87          <Button key="snake:close" label="close" onPress={close} />
88        </Box>
89        <Client key="board:snake" module="./boards/snake.tsx" width={cols} height={rows} props={{ best, done: turnsDone, safe: false }} />
90        {await next(e)}
91      </Box>
92    )
93  })
94}
95

1// Which score counts as a new best. Minesweeper's best is its fastest clear, so lower wins there;
2// everywhere else higher wins. A score of zero or less never counts: a Minesweeper board whose
3// first click clears it takes 0 s and would otherwise lock the best forever, and a Pong match you
4// lost posts a negative margin.
5export function isBetter(score: number, prev: number | undefined, lowerIsBetter = false): boolean {
6  if (!Number.isFinite(score) || score <= 0) return false
7  if (prev === undefined || prev <= 0) return true
8  return lowerIsBetter ? score < prev : score > prev
9}
10

1/* @jsx h */
2import type { ClientSurface } from 'claude-code'
3import { base, claudeDone, grid, statusLine, type Base, type Props } from './common.tsx'
4import { newSnake, step, turn, type SnakeGame } from '../games/snake.ts'
5
6type State = Base & { game?: SnakeGame }
7
8export default function Snake(props: Props, surface: ClientSurface<State>) {
9  const { Box, Text } = surface.elements
10  const size = () => ({ bw: Math.floor((surface.columns - 2) / 2), bh: surface.rows - 3 })
11
12  if (surface.state === undefined) {
13    surface.setState(base(props))
14    surface.every(100, () => {
15      const s = surface.state
16      if (!s?.game || !s.playing || s.game.over) return
17      const game = step(s.game)
18      if (game.over) surface.post({ game: 'snake', score: game.score })
19      surface.setState({ ...s, game })
20    })
21    surface.onKey(({ key }) => {
22      const s = surface.state
23      if (!s) return
24      // the space bar may arrive as the character or by name
25      if (key === ' ' || key === 'space' || key === 'p') {
26        if (s.game && !s.game.over) surface.setState({ ...s, banner: false, playing: !s.playing })
27        return
28      }
29      // no round yet, or the last one ended: an arrow (or r) starts a new one
30      if (!s.game || s.game.over || key === 'r') {
31        const { bw, bh } = size()
32        if (bw < 4 || bh < 3) return
33        surface.setState({ ...s, banner: false, playing: true, game: turn(newSnake(bw, bh), key) })
34        return
35      }
36      surface.setState({ ...s, banner: false, playing: true, game: turn(s.game, key) })
37    })
38  }
39  claudeDone(props, surface)
40
41  const s = surface.state
42  const g = s?.game
43  const { bw, bh } = g ? { bw: g.w, bh: g.h } : size()
44  const head = g?.snake[0]
45  const body = new Set(g?.snake.slice(1).map(p => `${p[0]},${p[1]}`))
46  const rows = grid(Text, bw, bh, (x, y) =>
47    head && head[0] === x && head[1] === y ? ['██', 'greenBright']
48    : body.has(`${x},${y}`) ? ['▓▓', 'green']
49    : g && g.food[0] === x && g.food[1] === y ? ['██', 'red']
50    : ['  '])
51  const text = !g ? 'snake · click here, then an arrow key · wasd works too'
52    : g.over ? `snake · game over · score ${g.score} · an arrow or r plays again`
53    : !s?.playing ? `snake · paused · score ${g.score} · space resumes`
54    : `snake · score ${g.score} · space pauses`
55  return (
56    <Box flexDirection="column">
57      <Box flexDirection="column" borderStyle="round" borderColor={g?.over ? 'red' : 'green'} width={Math.max(0, bw) * 2 + 2}>{rows}</Box>
58      {statusLine(Text, !!s?.banner, `${text} · best ${props?.best ?? 0}`)}
59    </Box>
60  )
61}
62

1/* @jsx h */
2import type { ClientElements, ClientSurface } from 'claude-code'
3
4// Shared by every board. A board is a surface module: it runs on the drawing thread with its own
5// frame clock, keys (after a click gives it focus; Esc gives the prompt back) and mouse.
6//
7// Never name a local `h` in a board file: every JSX tag compiles to a call of `h`.
8
9export type Props = { best?: number; done?: number; safe?: boolean } | undefined
10export type Base = { playing: boolean; banner: boolean; seenDone: number }
11export type Paint = readonly [glyph: string, color?: string, bg?: string]
12type TextTag = ClientElements['Text']
13
14export const base = (props: Props): Base => ({ playing: false, banner: false, seenDone: props?.done ?? 0 })
15
16// the hooks module bumps props.done when Claude finishes a turn: pause and say so, once per turn
17export function claudeDone<S extends Base>(props: Props, surface: ClientSurface<S>) {
18  const s = surface.state
19  const done = props?.done ?? 0
20  if (s && done !== s.seenDone) surface.setState({ ...s, seenDone: done, banner: true, playing: false })
21}
22
23export function statusLine(Text: TextTag, banner: boolean, text: string) {
24  return banner
25    ? <Text color="yellow" bold wrap="truncate-end">{`● Claude is done · ${text}`}</Text>
26    : <Text dimColor wrap="truncate-end">{text}</Text>
27}
28
29export type Run = [text: string, color?: string, bg?: string]
30
31// one run per stretch of cells sharing both colors. A drawing the engine cannot fit in its node
32// budget is worse than a coarser one, so maxRuns folds neighbours together, pair by pair, until
33// the row fits: a merged pair keeps the left one's colors and every glyph.
34export function runs(cols: number, y: number, at: (x: number, y: number) => Paint, maxRuns = Infinity): Run[] {
35  let out: Run[] = []
36  for (let x = 0; x < cols; x++) {
37    const [glyph, color, bg] = at(x, y)
38    const last = out[out.length - 1]
39    if (last && last[1] === color && last[2] === bg) last[0] += glyph
40    else out.push([glyph, color, bg])
41  }
42  while (out.length > Math.max(1, maxRuns)) {
43    const folded: Run[] = []
44    for (let i = 0; i < out.length; i += 2) {
45      const [t, c, b] = out[i]
46      const next = out[i + 1]
47      folded.push(next ? [t + next[0], c, b] : [t, c, b])
48    }
49    out = folded
50  }
51  return out
52}
53
54// a board as rows of two-character cells (a terminal cell is about twice as tall as wide, so two
55// make a square), one styled span per run of the same colors
56export function grid(Text: TextTag, cols: number, rowCount: number, at: (x: number, y: number) => Paint, maxRuns = Infinity) {
57  return Array.from({ length: Math.max(0, rowCount) }, (_, y) => (
58    <Text>{runs(cols, y, at, maxRuns).map(([t, c, b]) => (b ? <Text color={c} backgroundColor={b}>{t}</Text> : <Text color={c}>{t}</Text>))}</Text>
59  ))
60}
61

1// Snake: pure game logic, drawn by the Snake module in ../surface.tsx.
2
3export type Pt = readonly [number, number]
4export type SnakeGame = { snake: Pt[]; dir: Pt; queued: Pt[]; food: Pt; w: number; h: number; score: number; over: boolean }
5
6const DIRS: Record<string, Pt> = { up: [0, -1], down: [0, 1], left: [-1, 0], right: [1, 0], w: [0, -1], s: [0, 1], a: [-1, 0], d: [1, 0] }
7const same = (a: Pt, b: Pt) => a[0] === b[0] && a[1] === b[1]
8
9// a random free cell; [-1, -1] once the snake fills the board
10export function placeFood(snake: Pt[], w: number, h: number, rand = Math.random): Pt {
11  const taken = new Set(snake.map(p => `${p[0]},${p[1]}`))
12  const free: Pt[] = []
13  for (let y = 0; y < h; y++) for (let x = 0; x < w; x++) if (!taken.has(`${x},${y}`)) free.push([x, y])
14  return free.length ? free[Math.floor(rand() * free.length)] : [-1, -1]
15}
16
17export function newSnake(w: number, h: number, rand = Math.random): SnakeGame {
18  const x = Math.floor(w / 4)
19  const y = Math.floor(h / 2)
20  const snake: Pt[] = [[x, y], [x - 1, y], [x - 2, y]]
21  return { snake, dir: [1, 0], queued: [], food: placeFood(snake, w, h, rand), w, h, score: 0, over: false }
22}
23
24// a key queues a turn (two at most, so a quick up-then-left lands on consecutive ticks);
25// turning back into the neck, or the way it already goes, is ignored
26export function turn(g: SnakeGame, key: string): SnakeGame {
27  const d = Object.hasOwn(DIRS, key.toLowerCase()) ? DIRS[key.toLowerCase()] : undefined
28  const last = g.queued[g.queued.length - 1] ?? g.dir
29  if (!d || g.over || same(d, last) || same(d, [-last[0], -last[1]])) return g
30  return { ...g, queued: [...g.queued, d].slice(0, 2) }
31}
32
33// one tick: move the head, grow on food, end on a wall or the body; the tail cell the snake
34// vacates this tick is free to move into
35export function step(g: SnakeGame, rand = Math.random): SnakeGame {
36  if (g.over) return g
37  const [dir = g.dir, ...queued] = g.queued
38  const head: Pt = [g.snake[0][0] + dir[0], g.snake[0][1] + dir[1]]
39  const eats = same(head, g.food)
40  const body = eats ? g.snake : g.snake.slice(0, -1)
41  if (head[0] < 0 || head[1] < 0 || head[0] >= g.w || head[1] >= g.h || body.some(p => same(p, head))) return { ...g, dir, queued, over: true }
42  const snake = [head, ...body]
43  const food = eats ? placeFood(snake, g.w, g.h, rand) : g.food
44  return { ...g, snake, dir, queued, food, score: g.score + (eats ? 1 : 0), over: food[0] < 0 }
45}
46