snapme

1import {
2  ACTION_BY_CATEGORY,
3  CAPTURE_COOLDOWN_MS,
4  GESTURE_SCORE_THRESHOLD,
5  HOLD_DURATION_MS,
6  type GestureAction,
7} from "./thresholds"
8
9/* ARCHITECTURE §6: `holdDetector` adalah fungsi murni. Waktu disuntik pemanggil
10   lewat `push(sample, time)`, jadi seluruh alur bisa diuji tanpa kamera dan
11   tanpa timer (PRD GS-02, GS-04). */
12
13/** Satu keluaran `gestureSource`: kategori teratas dengan skornya, atau null. */
14export interface GestureSample {
15  category: string
16  score: number
17}
18
19export type HoldEvent =
20  | { type: "hold-start"; action: GestureAction }
21  | { type: "hold-progress"; action: GestureAction; progress: number }
22  | { type: "hold-complete"; action: GestureAction }
23  | { type: "hold-cancel" }
24
25export interface HoldDetector {
26  push(sample: GestureSample | null, time: number): HoldEvent[]
27  /** GS-04: jeda setelah satu foto sebelum gesture dibaca lagi. */
28  notifyCapture(time: number): void
29  reset(): void
30}
31
32export function createHoldDetector(): HoldDetector {
33  let active: { action: GestureAction; startedAt: number } | null = null
34  /* Aksi yang sudah selesai ditahan. Satu pose tidak menghasilkan dua pemicu:
35     aksi yang sama diabaikan sampai tangan diturunkan (sampel non-aksi itu). */
36  let satisfied: GestureAction | null = null
37  let cooldownUntil = Number.NEGATIVE_INFINITY
38
39  return {
40    push(sample, time) {
41      if (time < cooldownUntil) {
42        active = null
43        return []
44      }
45
46      const action =
47        sample !== null && sample.score >= GESTURE_SCORE_THRESHOLD
48          ? (ACTION_BY_CATEGORY[sample.category] ?? null)
49          : null
50
51      if (action === null) {
52        satisfied = null
53        if (active === null) {
54          return []
55        }
56        active = null
57        return [{ type: "hold-cancel" }]
58      }
59
60      if (satisfied === action) {
61        return []
62      }
63      satisfied = null
64
65      if (active !== null && active.action !== action) {
66        active = null
67        return [{ type: "hold-cancel" }]
68      }
69
70      if (active === null) {
71        active = { action, startedAt: time }
72        return [{ type: "hold-start", action }]
73      }
74
75      const progress = (time - active.startedAt) / HOLD_DURATION_MS
76      if (progress >= 1) {
77        active = null
78        satisfied = action
79        return [{ type: "hold-complete", action }]
80      }
81      return [{ type: "hold-progress", action, progress }]
82    },
83
84    notifyCapture(time) {
85      active = null
86      satisfied = null
87      cooldownUntil = time + CAPTURE_COOLDOWN_MS
88    },
89
90    reset() {
91      /* Cooldown GS-04 sengaja tidak dihapus: reset dipakai saat loop berhenti
92         dan tidak boleh membatalkan jeda setelah foto. */
93      active = null
94      satisfied = null
95    },
96  }
97}
98