Synthetic Assets

// Contract configuration options
options {
  server = treasuryPk;
  exit = 144;
}

contract SyntheticAsset(
  // The collateral asset ID
  bytes32 collateralAssetId,
  // The minimum collateralization ratio (e.g., 150% = 15000)
  int minCollateralRatio,
  // The liquidation threshold (e.g., 120% = 12000)
  int liquidationThreshold,
  // The oracle's public key
  pubkey oraclePk,
  // The synthetic asset identifier (e.g., "BTC/USD")
  bytes assetIdentifier,
  // The treasury's public key
  pubkey treasuryPk,
  // The borrower's public key
  pubkey borrowerPk
) {
  // Helper function to verify the collateralization ratio
  function verifyCollateralization(int collateralValue, int syntheticValue, int requiredRatio) internal {
    // Calculate the actual ratio (scaled by 10000 for precision)
    int actualRatio = (collateralValue * 10000) / syntheticValue;
    
    // Verify the ratio meets the requirement
    require(actualRatio >= requiredRatio, "Insufficient collateralization");
  }

  // Mint new synthetic tokens
  function mint(int collateralAmount, int syntheticAmount, int currentPrice, signature oracleSig, signature borrowerSig) {
    // Verify the oracle signature on the price data
    bytes message = sha256(assetIdentifier + int2bytes(tx.time));
    require(checkSigFromStack(oracleSig, oraclePk, message), "Invalid oracle signature");
    
    // Calculate the value of synthetic tokens being minted
    int syntheticValue = syntheticAmount * currentPrice / 10000;
    
    // Verify collateralization ratio
    verifyCollateralization(collateralAmount, syntheticValue, minCollateralRatio);
    
    // Verify the collateral input
    require(tx.inputs[0].asset == collateralAssetId, "Invalid collateral asset");
    require(tx.inputs[0].value >= collateralAmount, "Insufficient collateral");
    
    // Verify the outputs
    // Output 0: Collateral locked in vault
    require(tx.outputs[0].asset == collateralAssetId, "Output 0 asset mismatch");
    require(tx.outputs[0].value == collateralAmount, "Output 0 value mismatch");
    
    // Output 1: Synthetic tokens to borrower
    // Implementation details for synthetic token issuance omitted for brevity
    
    // Verify borrower signature
    require(checkSig(borrowerSig, borrowerPk), "Invalid borrower signature");
  }
  
  // Redeem synthetic tokens for collateral
  function redeem(int collateralAmount, int syntheticAmount, signature borrowerSig) {
    // Verify the synthetic token input
    // Implementation details for synthetic token verification omitted for brevity
    
    // Verify the outputs
    // Output 0: Collateral returned to borrower
    require(tx.outputs[0].asset == collateralAssetId, "Output 0 asset mismatch");
    require(tx.outputs[0].value == collateralAmount, "Output 0 value mismatch");
    bytes borrowerScript = new P2PKH(borrowerPk);
    require(tx.outputs[0].scriptPubKey == borrowerScript, "Output 0 not spendable by borrower");
    
    // Verify borrower signature
    require(checkSig(borrowerSig, borrowerPk), "Invalid borrower signature");
  }
  
  // Liquidate undercollateralized position
  function liquidate(int collateralAmount, int syntheticAmount, int currentPrice, signature oracleSig, signature liquidatorSig, pubkey liquidatorPk) {
    // Verify the oracle signature on the price data
    bytes message = sha256(assetIdentifier + int2bytes(tx.time));
    require(checkSigFromStack(oracleSig, oraclePk, message), "Invalid oracle signature");
    
    // Calculate the value of synthetic tokens
    int syntheticValue = syntheticAmount * currentPrice / 10000;
    
    // Calculate the actual collateralization ratio
    int actualRatio = (collateralAmount * 10000) / syntheticValue;
    
    // Verify the position is undercollateralized
    require(actualRatio < liquidationThreshold, "Position not liquidatable");
    
    // Verify the synthetic token input
    // Implementation details for synthetic token verification omitted for brevity
    
    // Verify the outputs
    // Output 0: Collateral to liquidator (with discount incentive)
    require(tx.outputs[0].asset == collateralAssetId, "Output 0 asset mismatch");
    
    // Calculate liquidation bonus (e.g., 5% discount)
    int liquidationBonus = collateralAmount * 500 / 10000;
    require(tx.outputs[0].value >= collateralAmount - liquidationBonus, "Output 0 value mismatch");
    
    bytes liquidatorScript = new P2PKH(liquidatorPk);
    require(tx.outputs[0].scriptPubKey == liquidatorScript, "Output 0 not spendable by liquidator");
    
    // Verify liquidator signature
    require(checkSig(liquidatorSig, liquidatorPk), "Invalid liquidator signature");
  }
  
  // Emergency shutdown by treasury
  function emergencyShutdown(signature treasurySig) {
    // Verify treasury signature
    require(checkSig(treasurySig, treasuryPk), "Invalid treasury signature");
    
    // Additional emergency shutdown logic omitted for brevity
  }
}

function calculateInterest(int collateralRatio, int baseRate) internal returns (int) {
  // Lower collateralization ratio = higher interest rate
  if (collateralRatio < 20000) { // 200%
    return baseRate + 500; // +5%
  } else if (collateralRatio < 25000) { // 250%
    return baseRate + 300; // +3%
  } else if (collateralRatio < 30000) { // 300%
    return baseRate + 100; // +1%
  } else {
    return baseRate; // Base rate
  }
}

function verifyCollateral(bytes32 assetId, int amount, int riskFactor) internal {
  if (assetId == stableAssetId) {
    // Stablecoins have lower risk, so lower collateral requirement
    require(amount >= requiredAmount * riskFactor / 10000, "Insufficient stable collateral");
  } else if (assetId == volatileAssetId) {
    // Volatile assets have higher risk, so higher collateral requirement
    require(amount >= requiredAmount * (riskFactor + 5000) / 10000, "Insufficient volatile collateral");
  } else {
    // Unsupported collateral type
    require(false, "Unsupported collateral type");
  }
}

function verifyPriceFeeds(int price1, signature oracle1Sig, int price2, signature oracle2Sig, int price3, signature oracle3Sig) internal {
  // Verify all oracle signatures
  require(checkSigFromStack(oracle1Sig, oracle1Pk, message), "Invalid oracle1 signature");
  require(checkSigFromStack(oracle2Sig, oracle2Pk, message), "Invalid oracle2 signature");
  require(checkSigFromStack(oracle3Sig, oracle3Pk, message), "Invalid oracle3 signature");
  
  // Sort prices to find median
  int[] prices = [price1, price2, price3];
  // Sorting logic omitted for brevity
  
  // Use the median price
  int medianPrice = prices[1];
  
  // Verify the price is within acceptable bounds
  require(medianPrice > minPrice, "Price too low");
  require(medianPrice < maxPrice, "Price too high");
  
  return medianPrice;
}