가격을 100배 펌핑해서 돈을 빌린
사건을 재현하고, 막는 코드까지 공개합니다

// TWAP(시간가중평균가격) 오라클 — 순간 스팟가격 조작 방어
class PriceOracleGuard {
  constructor({ windowMs = 1200000, maxDeviation = 0.1 } = {}) {
    this.history = []; // {price, time}
    this.windowMs = windowMs; // 기본 20분
    this.maxDeviation = maxDeviation; // TWAP 대비 허용 변동폭 10%
  }

  pushPrice(spotPrice) {
    const now = Date.now();
    this.history.push({ price: spotPrice, time: now });
    this.history = this.history.filter(p => now - p.time < this.windowMs);
  }

  twap() {
    if (!this.history.length) return 0;
    const sum = this.history.reduce((s, p) => s + p.price, 0);
    return sum / this.history.length;
  }

  getSafePrice(spotPrice) {
    this.pushPrice(spotPrice);
    const twap = this.twap();
    const deviation = Math.abs(spotPrice - twap) / (twap || spotPrice);
    if (deviation > this.maxDeviation) {
      return { price: twap, flagged: true, reason: 'spot_deviation_exceeded', spotPrice, twap };
    }
    return { price: spotPrice, flagged: false };
  }
}

// 담보가치평가 + 차입한도 로직 (Tectonic 사건 대응)
class CollateralEngine {
  constructor(getPrice, { ltv = 0.7 } = {}) {
    this.getPrice = getPrice; // 오라클 가격 조회 함수 주입
    this.ltv = ltv; // 담보인정비율 70%
    this.positions = {};
  }

  deposit(user, token, amount) {
    this.positions[user] = this.positions[user] || { collateral: {}, borrowed: 0 };
    this.positions[user].collateral[token] = (this.positions[user].collateral[token] || 0) + amount;
  }

  collateralValue(user) {
    const pos = this.positions[user];
    if (!pos) return 0;
    return Object.entries(pos.collateral)
      .reduce((sum, [token, amt]) => sum + amt * this.getPrice(token), 0);
  }

  borrow(user, amount) {
    const maxBorrow = this.collateralValue(user) * this.ltv;
    const pos = this.positions[user];
    if (pos.borrowed + amount > maxBorrow) {
      return { status: 'rejected', reason: 'insufficient_collateral', maxBorrow };
    }
    pos.borrowed += amount;
    return { status: 'approved', borrowed: pos.borrowed };
  }
}