mecenas.cash

pragma cashscript ^0.10.0;

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

        // Check that the first output sends to the recipient
        require(tx.outputs[0].lockingBytecode == new LockingBytecodeP2PKH(recipient));

        int minerFee = 1000;
        int currentValue = tx.inputs[this.activeInputIndex].value;
        int changeValue = currentValue - pledge - minerFee;

        // If there is not enough left for *another* pledge after this one, we send the remainder to the recipient
        // Otherwise we send the remainder to the recipient and the change back to the contract
        if (changeValue <= pledge + minerFee) {
            require(tx.outputs[0].value == currentValue - minerFee);
        } else {
            require(tx.outputs[0].value == pledge);
            require(tx.outputs[1].lockingBytecode == tx.inputs[this.activeInputIndex].lockingBytecode);
            require(tx.outputs[1].value == changeValue);
        }
    }

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