src/scene/GameClock.js

/**
 * GameClock — continuous game-time cycle (GTA-style).
 *
 *   gameTime: 0..1 represents the full 24-hour cycle.
 *     0.00 / 1.00 → midnight
 *     0.22       → sunrise
 *     0.50       → noon
 *     0.78       → sunset
 *
 * dayDurationSeconds controls how fast time passes (default 120s = 2 minutes per game day,
 * a bit faster than GTA so kids see day → night within one play session).
 *
 * Optional jumpToLevel(t01) snaps the clock to a sensible time-of-day for the current grade:
 *   level low  → bright morning
 *   level mid  → noon → afternoon
 *   level high → sunset → night
 * After a snap, time keeps progressing forward — so the BG never goes static.
 */
export class GameClock {
  constructor({ dayDurationSeconds = 120, startTime = 0.30 } = {}) {
    this.dayDurationSeconds = dayDurationSeconds;
    this.gameTime = startTime;     // 0..1
  }

  update(dt) {
    this.gameTime = (this.gameTime + dt / this.dayDurationSeconds) % 1;
  }

  /**
   * Jump time forward so the look matches the current level intensity.
   * Only nudges forward (no rewind) so the cycle keeps marching.
   */
  jumpToLevel(t01) {
    // Map level intensity to a "preferred" time-of-day:
    //   t=0  → 0.30 (mid-morning), t=0.5 → 0.55 (mid-afternoon), t=1 → 0.92 (deep night)
    const target = 0.30 + t01 * 0.62;
    // Take the shortest forward jump
    let delta = target - this.gameTime;
    if (delta < 0) delta += 1;
    if (delta > 0.02) this.gameTime = target;
  }

  // 50/50 split — 10 minutes of day and 10 minutes of night for a 20-minute cycle.
  // Sunrise is at gameTime 0.25, sunset at 0.75.
  isDay()    { return this.gameTime >= 0.25 && this.gameTime < 0.75; }
  isNight()  { return !this.isDay(); }
  /** Returns 0..1 fraction of the daylight arc (only valid during day). */
  dayPhase() {
    if (!this.isDay()) return -1;
    return (this.gameTime - 0.25) / 0.5;        // 0.25..0.75 → 0..1
  }
  /** Returns 0..1 fraction of the night arc (wraps over midnight). */
  nightPhase() {
    if (this.isDay()) return -1;
    const t = this.gameTime >= 0.75 ? this.gameTime - 0.75 : (1 - 0.75) + this.gameTime;
    return t / 0.5;                              // 0.75..1.25 → 0..1
  }
}