// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.5.2;

import "./Ownable.sol";

contract SelladorFederalTitulos is Ownable {
    address private _owner;

    struct Item {
        uint256 timestamp;
        uint256 blockNumber;
    }

    event ItemAdded(
        bytes32 indexed itemId,
        uint256 timestamp,
        uint256 blockNumber
    );

    mapping(bytes32 => Item) public items;

    constructor() public Ownable() {
    }

    function put(bytes32 key) public onlyOwner {
        if (items[key].timestamp == 0) {
            items[key] = Item(block.timestamp, block.number);
            emit ItemAdded(key, block.timestamp, block.number);
        }
    }

    function exists(bytes32 key) public view returns (bool) {
        return items[key].timestamp > 0;
    }

    function get(bytes32 key) public view returns (uint256 timestamp, uint256 blockNumber) {
        Item storage item = items[key];
        return (item.timestamp, item.blockNumber);
    }

    function verify(bytes32 leafNode, bytes32[] memory proof) public view returns (bool) {
        bytes32 currentHash = leafNode;

        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];

            if (currentHash < proofElement) {
                currentHash = _hash(abi.encodePacked(currentHash, proofElement));
            } else {
                currentHash = _hash(abi.encodePacked(proofElement, currentHash));
            }
        }

        return exists(currentHash);
    }

    function _hash(bytes memory packedData) private pure returns (bytes32) {
        return keccak256(packedData);
    }

}