1import {useEffect, useState, type CSSProperties} from 'react'
2import {RegionView, type Segment, type Pt} from './render/RegionView'
3import {useNetwork} from './useNetwork'
4import {runIceTest, type IceTestResult} from './p2p/iceTest'
5import type {Points} from './types'
7// Discrete sample-count choices; the slider indexes into the active array.
8// Capped at 100k: every resample fans the samples out from the central peer to
9// every viewer over WebRTC (~800 KB as Float32 at 100k).
10const SAMPLE_CHOICES = [10, 100, 1000, 10000, 100000]
11// Non-convex sampling runs in the interpreter (no JIT), so cap it lower.
12const SAMPLE_CHOICES_NONCONVEX = [10, 100, 1000, 10000]
14/** The in-region segment(s) hit-and-run samples along: the line through
15 * (px,py) with direction (dx,dy), intersected with the polygon. One segment
16 * for a convex region, possibly several for a non-convex one. With `localOnly`
17 * it keeps just the segment containing the current point (t = 0) — matching the
18 * sampler's local-segment mode. Mirrors the sampler's geometry, so it
19 * reproduces each step exactly. */
20function regionSegments(
21 region: Points,
22 px: number,
23 py: number,
24 dx: number,
25 dy: number,
26 localOnly: boolean
27): Segment[] {
28 if (Math.hypot(dx, dy) < 1e-12) return []
29 const m = region.x.length
30 const ts: number[] = []
31 for (let i = 0; i < m; i++) {
32 const j = (i + 1) % m
33 const ex = region.x[j] - region.x[i]
34 const ey = region.y[j] - region.y[i]
35 const denom = dy * ex - dx * ey
36 if (Math.abs(denom) < 1e-12) continue
37 const wx = region.x[i] - px
38 const wy = region.y[i] - py
39 const s = (dx * wy - dy * wx) / denom // position along the edge
40 if (s >= 0 && s < 1) ts.push((wy * ex - wx * ey) / denom)
41 }
42 ts.sort((a, b) => a - b)
43 const segs: Segment[] = []
44 for (let k = 0; k < ts.length - 1; k++) {
45 const tm = (ts[k] + ts[k + 1]) / 2
46 if (!pointInPolygon(region, px + tm * dx, py + tm * dy)) continue
47 // Local mode: keep only the in-region interval straddling t = 0.
48 if (localOnly && !(ts[k] <= 0 && ts[k + 1] >= 0)) continue
49 segs.push({
50 x0: px + ts[k] * dx,
51 y0: py + ts[k] * dy,
52 x1: px + ts[k + 1] * dx,
53 y1: py + ts[k + 1] * dy
54 })
55 }
56 return segs
57}
59function pointInPolygon(region: Points, x: number, y: number): boolean {
60 const n = region.x.length
61 let inside = false
62 for (let i = 0, j = n - 1; i < n; j = i++) {
63 const xi = region.x[i]
64 const yi = region.y[i]
65 const xj = region.x[j]
66 const yj = region.y[j]
67 if (yi > y !== yj > y && x < ((xj - xi) * (y - yi)) / (yj - yi) + xi) {
68 inside = !inside
69 }
70 }
71 return inside
72}
74const prefixPoints = (p: Points, k: number): Points => ({
75 x: p.x.slice(0, k),
76 y: p.y.slice(0, k)
77})
79const short = (id: string) => id.slice(0, 8) + '…'
81export default function App() {
82 const {snapshot, dispatch} = useNetwork()
83 const {view, samples, samplesSynced, roster, amCentral, centralId, selfId} =
84 snapshot
85 const {params, region, busy, engine, engineError, movieStep} = view
87 // Slider position: local while dragging, following the shared value
88 // otherwise (a remote viewer may move it).
89 const [n, setN] = useState(params.n)
90 useEffect(() => setN(params.n), [params.n])
92 // One-shot WebRTC self-test, so a browser that blocks ICE says so instead of
93 // silently never finding peers.
94 const [ice, setIce] = useState<IceTestResult | null>(null)
95 useEffect(() => {
96 let alive = true
97 void runIceTest().then(r => {
98 if (alive) setIce(r)
99 })
100 return () => {
101 alive = false
102 }
103 }, [])
105 const nonConvex = !params.convex
106 const choices = nonConvex ? SAMPLE_CHOICES_NONCONVEX : SAMPLE_CHOICES
107 const useLocal = nonConvex && params.local
108 const moviePlaying = movieStep !== null
110 const controlsDisabled = !region || busy || moviePlaying || engine !== 'ready'
112 const resample = (count: number, localMode: boolean = params.local) => {
113 dispatch({op: 'resample', n: count, local: localMode})
114 }
116 const newRegion = (count: number, convex: boolean) => {
117 dispatch({op: 'newRegion', n: count, convex, local: params.local})
118 }
120 // Checkbox: switch region type. Clamp N to the active set's max first.
121 const setNonConvex = (makeNonConvex: boolean) => {
122 const c = makeNonConvex ? SAMPLE_CHOICES_NONCONVEX : SAMPLE_CHOICES
123 const clamped = Math.min(n, c[c.length - 1])
124 setN(clamped)
125 newRegion(clamped, !makeNonConvex)
126 }
128 // Overlay for the current movie frame (settled points + segments + marks).
129 // movieStep is shared state driven by the central peer's clock, so every
130 // viewer sees the same frame; the geometry is recomputed locally from the
131 // same samples, so it is identical everywhere.
132 let cloud: Points = samples ?? {x: [], y: []}
133 let segments: Segment[] | null = null
134 let from: Pt | null = null
135 let newPoint: Pt | null = null
136 if (moviePlaying && samples && region && movieStep >= 2) {
137 const i = Math.min(movieStep, samples.x.length - 1) // point being sampled
138 const f = i - 1 // point the step starts from
139 const {x, y} = samples
140 cloud = prefixPoints(samples, i) // settled points 0..i-1
141 from = {x: x[f], y: y[f]}
142 segments = regionSegments(region, x[f], y[f], x[i] - x[f], y[i] - y[f], useLocal)
143 newPoint = {x: x[i], y: y[i]}
144 }
146 const canPlay = !!samples && samples.x.length >= 3 && engine === 'ready'
148 const status = busy
149 ? 'sampling…'
150 : moviePlaying
151 ? `movie · point ${movieStep + 1}`
152 : !samplesSynced && samples
153 ? 'syncing samples…'
154 : `${params.n.toLocaleString()} points`
156 const engineLabel =
157 engine === 'ready'
158 ? amCentral
159 ? 'engine running here'
160 : 'engine on central peer'
161 : engine === 'starting'
162 ? 'starting engine…'
163 : engine === 'error'
164 ? 'engine failed'
165 : 'waiting for a central peer…'
167 const waitingMessage =
168 engine === 'starting'
169 ? 'The central peer is starting the sampling engine…'
170 : engine === 'error'
171 ? `Engine failed: ${engineError ?? 'unknown error'}`
172 : 'Connecting to the room…'
174 return (
175 <div style={rootStyle}>
176 {region && samples ? (
177 <RegionView
178 region={region}
179 samples={cloud}
180 segments={segments}
181 from={from}
182 newPoint={newPoint}
183 />
184 ) : (
185 <div style={waitingStyle}>{waitingMessage}</div>
186 )}
188 <div style={panelStyle}>
189 <label style={labelStyle}>
190 Samples: <b>{n.toLocaleString()}</b>
191 <input
192 type="range"
193 min={0}
194 max={choices.length - 1}
195 step={1}
196 value={Math.max(0, choices.indexOf(n))}
197 disabled={controlsDisabled}
198 // Drag updates the label live; the round-trip to the central
199 // peer's engine fires on release to avoid flooding it.
200 onChange={e => setN(choices[Number(e.target.value)])}
201 onPointerUp={e => resample(choices[Number(e.currentTarget.value)])}
202 onKeyUp={e => {
203 if (e.key.startsWith('Arrow')) {
204 resample(choices[Number(e.currentTarget.value)])
205 }
206 }}
207 style={sliderStyle}
208 />
209 </label>
211 <div style={{display: 'flex', gap: 6, marginTop: 6}}>
212 <button
213 style={btnStyle}
214 disabled={controlsDisabled}
215 onClick={() => resample(n)}
216 title="Draw a fresh set of samples in the same region (for everyone)"
217 >
218 Resample
219 </button>
220 <button
221 style={btnStyle}
222 disabled={busy || moviePlaying || engine !== 'ready'}
223 onClick={() => newRegion(n, !nonConvex)}
224 title="Generate a new region and sample it (for everyone)"
225 >
226 New region
227 </button>
228 </div>
230 <label style={checkLabelStyle}>
231 <input
232 type="checkbox"
233 checked={nonConvex}
234 disabled={controlsDisabled}
235 onChange={e => setNonConvex(e.target.checked)}
236 />
237 non-convex region
238 </label>
240 {nonConvex && (
241 <label
242 style={subCheckLabelStyle}
243 title="Sample only the segment through the current point instead of every segment the line crosses"
244 >
245 <input
246 type="checkbox"
247 checked={params.local}
248 disabled={controlsDisabled}
249 onChange={e => resample(n, e.target.checked)}
250 />
251 local segment only
252 </label>
253 )}
255 <button
256 style={playBtnStyle}
257 disabled={(!canPlay || busy) && !moviePlaying}
258 onClick={() => dispatch({op: 'movie', play: !moviePlaying})}
259 title="Animate the hit-and-run steps for every viewer at once"
260 >
261 {moviePlaying ? '■ Stop movie' : '▶ Play movie'}
262 </button>
264 <div style={{fontSize: 10, color: '#64748b', marginTop: 6}}>{status}</div>
265 </div>
267 <div style={presenceStyle}>
268 <div style={{fontWeight: 600, marginBottom: 2}}>
269 {roster.length} viewer{roster.length === 1 ? '' : 's'} · shared view
270 </div>
271 <div>
272 you: <code>{short(selfId)}</code>
273 {amCentral ? ' (central)' : ''}
274 </div>
275 <div>
276 central: <code>{centralId ? short(centralId) : '(none)'}</code>
277 </div>
278 <div style={{color: engine === 'error' ? '#b91c1c' : '#475569'}}>
279 {engineLabel}
280 </div>
281 {engine === 'error' && engineError && (
282 <div style={{color: '#b91c1c', marginTop: 2}}>{engineError}</div>
283 )}
284 {ice &&
285 (ice.total === 0 ? (
286 <div style={{color: '#b91c1c', marginTop: 2}}>
287 ⚠ this browser is blocking WebRTC (no ICE candidates) — check
288 privacy extensions/settings
289 </div>
290 ) : (
291 <div style={{color: '#94a3b8'}}>
292 webrtc: {ice.total} candidate{ice.total === 1 ? '' : 's'} (
293 {[
294 ice.host && 'host',
295 ice.srflx && 'srflx',
296 ice.relay && 'relay'
297 ]
298 .filter(Boolean)
299 .join(', ') || 'other'}
300 )
301 </div>
302 ))}
303 </div>
304 </div>
305 )
306}
308const rootStyle: CSSProperties = {
309 position: 'absolute',
310 inset: 0,
311 overflow: 'hidden',
312 background: '#ffffff',
313 fontFamily: 'system-ui, -apple-system, Arial, sans-serif'
314}
316const waitingStyle: CSSProperties = {
317 position: 'absolute',
318 inset: 0,
319 display: 'flex',
320 alignItems: 'center',
321 justifyContent: 'center',
322 color: '#94a3b8',
323 padding: '0 2rem',
324 textAlign: 'center'
325}
327const panelStyle: CSSProperties = {
328 position: 'absolute',
329 top: 8,
330 left: 8,
331 width: 150,
332 padding: '7px 9px',
333 background: 'rgba(255,255,255,0.9)',
334 border: '1px solid #e2e8f0',
335 borderRadius: 6,
336 boxShadow: '0 1px 3px rgba(0,0,0,0.1)',
337 color: '#0f172a'
338}
340const presenceStyle: CSSProperties = {
341 position: 'absolute',
342 bottom: 8,
343 left: 8,
344 padding: '6px 9px',
345 background: 'rgba(255,255,255,0.9)',
346 border: '1px solid #e2e8f0',
347 borderRadius: 6,
348 boxShadow: '0 1px 3px rgba(0,0,0,0.1)',
349 color: '#0f172a',
350 fontSize: 10,
351 lineHeight: 1.5,
352 maxWidth: 260
353}
355const labelStyle: CSSProperties = {
356 display: 'block',
357 fontSize: 11
358}
360const checkLabelStyle: CSSProperties = {
361 display: 'flex',
362 alignItems: 'center',
363 gap: 5,
364 fontSize: 11,
365 marginTop: 8,
366 cursor: 'pointer'
367}
369const subCheckLabelStyle: CSSProperties = {
370 display: 'flex',
371 alignItems: 'center',
372 gap: 5,
373 fontSize: 10,
374 marginTop: 4,
375 marginLeft: 14,
376 color: '#475569',
377 cursor: 'pointer'
378}
380const sliderStyle: CSSProperties = {
381 width: '100%',
382 marginTop: 2
383}
385const btnStyle: CSSProperties = {
386 flex: 1,
387 padding: '3px 4px',
388 fontSize: 10,
389 whiteSpace: 'nowrap',
390 cursor: 'pointer',
391 background: '#f8fafc',
392 border: '1px solid #cbd5e1',
393 borderRadius: 5,
394 color: '#0f172a'
395}
397const playBtnStyle: CSSProperties = {
398 width: '100%',
399 marginTop: 6,
400 padding: '4px 6px',
401 fontSize: 10,
402 cursor: 'pointer',
403 background: '#eff6ff',
404 border: '1px solid #bfdbfe',
405 borderRadius: 5,
406 color: '#1e3a8a'
407}