mecenas.cash

pragma cashscript ^0.6.0;

/* This is an unofficial CashScript port of Licho's Mecenas contract. It is
 * not compatible with Licho's EC plugin, but rather meant as a demonstration
 * of covenants in CashScript.
 * The time checking has been removed so it can be tested without time requirements.
 */
contract Mecenas(bytes20 recipient, bytes20 funder, int pledge/*, int period*/) {
    function receive(pubkey pk, sig s) {
        require(checkSig(s, pk));

        // require(tx.age >= period);

        int minerFee = 1000;
        int intValue = int(bytes(tx.value));

        if (intValue <= pledge + minerFee) {
            /* The contract has less value than the pledge, or equal.
             * The recipient must claim all of of it. */

            bytes8 amount1 = bytes8(intValue - minerFee);
            bytes34 out1 = new OutputP2PKH(amount1, recipient);
            require(hash256(out1) == tx.hashOutputs);
        } else {
            /* The contract has more value than the pledge. The recipient must
             * also add one change output sending the remaining coins back
             * to the contract.
             */

            bytes8 amount1 = bytes8(pledge);
            bytes8 amount2 = bytes8(intValue - pledge - minerFee);
            bytes34 out1 = new OutputP2PKH(amount1, recipient);
            bytes32 out2 = new OutputP2SH(amount2, hash160(tx.bytecode));
            require(hash256(out1 + out2) == tx.hashOutputs);
        }
    }

    function reclaim(pubkey pk, sig s) {
        require(hash160(pk) == funder);
        require(checkSig(s, pk));
    }
}