What if your heartbeat
was a currency?

/**
 * @title ShakaLoveDemo
 * @notice Demo-only creative smart contract for heartbeat synchronization claims.
 * @dev Preserved as a memorial / technical exhibit artifact.
 *
 * SAFETY NOTICE: not audited, not for production, not a financial product.
 * The LOVE token in this demo has no promised value or utility.
 */

contract ShakaLoveDemo is ERC20, Ownable, Pausable, ReentrancyGuard, EIP712 {

    struct Attestation {
        bytes32 sessionId;
        address subject;
        address partner;
        uint64  startTs;
        uint64  endTs;
        uint16  syncScoreBps;   // 9300 = 93.00%
        uint256 reward;
        uint256 deadline;
    }

    uint16  public constant MIN_SYNC_BPS = 9300;
    uint64  public constant MIN_OVERLAP_SECONDS = 30;
    uint256 public constant MAX_REWARD_PER_SUBJECT = 10 ether;

    function claimCouple(
        Attestation calldata a, bytes calldata sigA,
        Attestation calldata b, bytes calldata sigB
    ) external whenNotPaused nonReentrant {
        // same session, never claimed before
        if (a.sessionId != b.sessionId) revert BadAttestation();
        if (usedSession[a.sessionId]) revert SessionUsed();

        _validateCouple(a, b);
        _validateReward(a, b);
        _validateSync(a, b);          // must clear 93%

        uint64 overlap = _overlapSeconds(a.startTs, a.endTs, b.startTs, b.endTs);
        if (overlap  MIN_OVERLAP_SECONDS) revert NoOverlap();

        _verify(a, sigA);             // oracle signature, EIP-712
        _verify(b, sigB);

        bytes32 pairKey = _pairKey(a.subject, b.subject);
        _checkCooldown(pairKey);      // rate-limit the same pair
        _checkDailyMint(a.reward * 2);

        usedSession[a.sessionId] = true;
        lastClaimByPair[pairKey] = block.timestamp;

        _mint(a.subject, a.reward);
        _mint(b.subject, a.reward);

        emit CoupleClaimed(a.sessionId, pairKey, a.subject, b.subject, a.reward);
    }
}