export class CameraSession {
  constructor({ enabled = false, grantMinutes = 3, device = '', clock = () => Date.now(), audit } = {}) {
    this.clock = clock;
    this.enabled = Boolean(enabled);
    this.grantMinutes = Math.min(15, Math.max(1, Number(grantMinutes) || 3));
    this.device = String(device || '');
    this.active = false;
    this.expiresAt = null;
    this.backend = 'none';
    this.audit = audit;
  }

  grant() {
    this.active = true;
    this.expiresAt = this.clock() + this.grantMinutes * 60 * 1000;
    return { active: true, grant_expires_at: this.expiresAt, device: this.device };
  }

  setBackend(backend) {
    this.backend = ['portal', 'v4l2', 'grant', 'none'].includes(backend) ? backend : 'none';
    return this.backend;
  }

  revoke() {
    this.active = false;
    this.expiresAt = null;
    this.backend = 'none';
    Promise.resolve(this.audit?.wipeTemp?.('/tmp/jarvis-webcam')).catch(() => {});
  }

  status() {
    if (this.active && this.expiresAt != null && this.clock() >= this.expiresAt) this.revoke();
    return {
      enabled: this.enabled,
      active: this.active,
      device: this.device,
      grant_expires_at: this.expiresAt,
      backend: this.backend,
    };
  }

  assertActive() {
    if (!this.active) throw new Error('webcam grant is inactive');
    if (this.expiresAt && this.clock() >= this.expiresAt) {
      this.revoke();
      throw new Error('webcam grant expired');
    }
  }
}