deviant/contracts/TermCouponVault.cash

pragma cashscript ^0.12.0;

// TermCouponVault — ADR-0042 term-note / t-bond payout side.
//
// A bounded-term coupon vault. During the term the oracle attests coupon payouts
// (identical to DistributionVault.payout — replay-bound to the vault outpoint).
// The oracle simply stops attesting after maturity (off-chain term policy).
//
// The on-chain term mechanic is the MATURITY SWEEP: after `maturityTime` the issuer
// reclaims the unpaid coupon reserve. This uses CLTV correctly — a LOWER bound
// (`tx.time >= maturityTime`); "coupon only before T" is not directly enforceable
// on BCH (CLTV can't upper-bound), so the term end is expressed as "the reserve
// becomes reclaimable at maturity."
//
// The share's FLOOR (principal) is the self-backed share UTXO, redeemable anytime
// by a plain P2PKH spend — not gated here.

contract TermCouponVault(pubkey oraclePk, bytes sweepLockingBytecode, int maturityTime) {
    // Coupon payout during the term (oracle-attested, replay-bound). 69-byte message:
    // recipientLB(25) ‖ amount(8 LE) ‖ outpointTxHash(32) ‖ outpointIndex(4 LE).
    function payout(bytes recipientLockingBytecode, datasig oracleSig, bytes oracleMessage) {
        require(checkDataSig(oracleSig, oracleMessage, oraclePk));
        require(oracleMessage.length == 69);
        bytes lb, bytes r1 = oracleMessage.split(25);
        bytes amtBytes, bytes r2 = r1.split(8);
        bytes opTx, bytes opIdxBytes = r2.split(32);
        require(lb == recipientLockingBytecode);
        require(opTx == tx.inputs[this.activeInputIndex].outpointTransactionHash);
        require(int(opIdxBytes) == tx.inputs[this.activeInputIndex].outpointIndex);
        int amount = int(amtBytes);
        require(amount >= 546);
        require(tx.outputs[0].lockingBytecode == recipientLockingBytecode);
        require(tx.outputs[0].value == amount);
        require(tx.outputs[0].tokenCategory == 0x);
        int remainder = tx.inputs[this.activeInputIndex].value - amount;
        require(remainder >= 546);
        require(tx.outputs[1].lockingBytecode == tx.inputs[this.activeInputIndex].lockingBytecode);
        require(tx.outputs[1].value == remainder);
        require(tx.outputs[1].tokenCategory == 0x);
    }

    // Maturity sweep — after the term, the issuer reclaims the unpaid reserve.
    // CLTV lower bound: only valid once tx.time (locktime) >= maturityTime.
    // Miner fee is funded by an external input; the full vault value goes to sweepLB.
    function sweep() {
        require(tx.time >= maturityTime);
        require(tx.outputs[0].lockingBytecode == sweepLockingBytecode);
        require(tx.outputs[0].value == tx.inputs[this.activeInputIndex].value);
        require(tx.outputs[0].tokenCategory == 0x);
    }
}