심리적 공포의 신경생물학: 편도체 경보 회로, 음향 놀람 반사 및 서스테인드 코르티솔 공포

// Computational Affective Neuroscience: Survival Horror Limbic Simulator
export interface HorrorStimulusEvent {
  acousticDecibels: number; // e.g. 45dB whisper to 95dB glass shatter
  isNonLinearAcoustic: boolean;
  visualThreatDistanceStuds: number;
  ammoRemainingPercent: number; // 0.0 to 1.0 (resource scarcity)
  secondsInDarkness: number;
}

export interface AutonomicState {
  heartRateEstimatedBpm: number;
  amygdalaActivation: number; // 0.0 to 1.0
  cortisolSaturation: number; // sustained stress index
  behavioralFreezeProbability: number;
  threatEvaluationMode: 'SUSTAINED_DREAD' | 'ACUTE_STARTLE_SHOCK' | 'DESENSITIZED_CALM';
}

export class SurvivalHorrorEvaluator {
  private static RESTING_BPM = 72;
  private static STARTLE_THRESHOLD_DB = 80;

  public static evaluateLimbicArousal(
    currentStress: number,
    event: HorrorStimulusEvent,
    exposureHistoryCount: number
  ): AutonomicState {
    // Habituation dampening from repeated exposure (speedrunner effect)
    const habituationFactor = 1 / (1 + Math.log(1 + exposureHistoryCount * 0.15));

    // Fast-path amygdala threat score
    const soundSpike = Math.max(0, event.acousticDecibels - this.STARTLE_THRESHOLD_DB);
    const nonLinearMultiplier = event.isNonLinearAcoustic ? 1.45 : 1.0;
    const proximityThreat = Math.max(0, (30 - event.visualThreatDistanceStuds) / 30);
    const scarcityAnxiety = (1.0 - event.ammoRemainingPercent) * 0.35;

    const rawAmygdala = ((soundSpike * 0.04 * nonLinearMultiplier) + proximityThreat + scarcityAnxiety) * habituationFactor;
    const amygdalaActivation = Math.min(1.0, Math.max(0.05, rawAmygdala));

    // Sustained cortisol accumulation from continuous darkness and resource depletion
    const darknessDrain = Math.min(0.4, event.secondsInDarkness * 0.002);
    const updatedStress = Math.min(1.0, currentStress * 0.95 + (amygdalaActivation * 0.3) + darknessDrain);

    // Heart rate elevation (sympathetic overdrive)
    const estimatedBpm = Math.round(this.RESTING_BPM + (amygdalaActivation * 48) + (updatedStress * 22));

    // Freezing response triggered when high dread combines with zero resources
    const freezeProb = (updatedStress > 0.75 && event.ammoRemainingPercent < 0.15)
      ? Math.min(0.85, (updatedStress - 0.5) * 1.5)
      : 0.05;

    let mode: AutonomicState['threatEvaluationMode'] = 'SUSTAINED_DREAD';
    if (soundSpike > 10 && event.isNonLinearAcoustic) {
      mode = 'ACUTE_STARTLE_SHOCK';
    } else if (habituationFactor < 0.45) {
      mode = 'DESENSITIZED_CALM';
    }

    return {
      heartRateEstimatedBpm: estimatedBpm,
      amygdalaActivation: parseFloat(amygdalaActivation.toFixed(3)),
      cortisolSaturation: parseFloat(updatedStress.toFixed(3)),
      behavioralFreezeProbability: parseFloat(freezeProb.toFixed(3)),
      threatEvaluationMode: mode
    };
  }
}