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// SPDX-License-Identifier: MIT
pragma solidity ^0.8.30;

/// @title Love
/// @notice A minimal on-chain counter of love sent between addresses.
contract Love {
    mapping(address sender => mapping(address recipient => uint256 amount)) public sent;
    mapping(address recipient => uint256 amount) public received;

    event LoveSent(address indexed from, address indexed to, uint256 amount);

    error SelfLove();
    error ZeroAmount();

    /// @notice Send `amount` units of love to `to`.
    function send(address to, uint256 amount) external {
        if (to == msg.sender) revert SelfLove();
        if (amount == 0) revert ZeroAmount();

        sent[msg.sender][to] += amount;
        received[to] += amount;

        emit LoveSent(msg.sender, to, amount);
    }
}