ticketchain/contracts/EventManager.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.8.2 <0.9.0;

contract EventManager {

  struct Event {
    string name;
    string description;
    uint256 capacity;
    uint256 ticketsSold;
    uint256 ticketPrice; // in USD cents
    uint256 eventDate;
    string[] images; // array of image URLs
    uint256[] tickets;
    address eventHost;
  }

  struct Ticket {
    address holder;
    uint256 boughtTime;
    uint256 eventId;
  }

  mapping(uint256 => Event) public events;
  mapping(uint256 => Ticket) public tickets;

  mapping(uint256 => mapping(address => bool)) ticketAllowance;

  mapping(address => uint256[]) public userTickets;

  uint256 public eventCounter;
  uint256 public ticketCounter;

  function centsToFlare(uint256 _cents) public view returns (uint256 _flr) {
    return _cents*14/10;
  }

  function power(uint base, int8 exponent) public pure returns (uint) {
    require(exponent >= 0, 'Exponent must be non-negative');
    uint result = 1;
    for (int8 i = 0; i < exponent; i++) {
      result *= base;
    }
    return result;
  }

  function getEventPriceFlare(
    uint256 _eventId
  ) public view returns (uint256 _flr) {
    require(_eventId < eventCounter, 'Invalid event ID');
    return centsToFlare(events[_eventId].ticketPrice);
  }

  function createEvent(
    string memory _name,
    string memory _description,
    uint256 _capacity,
    uint256 _ticketPrice,
    uint256 _eventDate,
    string[] memory _images
  ) public {
    events[eventCounter] = Event(
      _name,
      _description,
      _capacity,
      0,
      _ticketPrice,
      _eventDate,
      _images,
      new uint256[](0),
      msg.sender
    );
    eventCounter++;
  }

  function getEventImages(
    uint256 _eventId
  ) public view returns (string[] memory) {
    require(_eventId < eventCounter, 'Invalid event ID');
    return events[_eventId].images;
  }

  function getEventTickets(
    uint256 _eventId
  ) public view returns (uint256[] memory) {
    require(_eventId < eventCounter, 'Invalid event ID');
    return events[_eventId].tickets;
  }

  //TODO: ADD CURRENCY CONVERSION + CHECK
  function buyTicket(uint256 _eventId) public payable {
    require(_eventId < eventCounter, 'Invalid event ID');
    require(
      events[_eventId].eventDate > block.timestamp,
      'Event has already passed'
    );
    require(
      events[_eventId].tickets.length < events[_eventId].capacity,
      'Event is full'
    );
    require(msg.value == events[_eventId].ticketPrice, 'Invalid ticket price');

    // Create new ticket
    tickets[ticketCounter] = Ticket(msg.sender, block.timestamp, _eventId);

    // Add ticket to user
    userTickets[msg.sender].push(ticketCounter);

    ticketCounter++;

    // Update number of tickets sold
    events[_eventId].ticketsSold++;

    // Transfer FLR to event host
    (bool sent, ) = events[_eventId].eventHost.call{value: msg.value}('');
    require(sent, 'Failed to send FLR to event host');
  }

  function transferTicketForce(uint256 _ticketId, address _to) private {
    require(_ticketId < ticketCounter, 'Invalid ticket ID');
    require(
      events[tickets[_ticketId].eventId].eventDate > block.timestamp,
      'Event has already passed'
    );

    address prevHolder = tickets[_ticketId].holder;

    // Get index of ticket in holder's array
    bool found = false;
    uint256 i = 0;
    for (; i < userTickets[prevHolder].length; i++) {
      if (userTickets[prevHolder][i] == _ticketId) {
        found = true;
        break;
      }
    }

    require(found, "Ticket not found in sender's inventory");

    // Remove ticket from holder's array
    for (; i < userTickets[prevHolder].length; i++) {
      userTickets[prevHolder][i] = userTickets[prevHolder][i + 1];
    }

    // Add ticket to _to's array
    userTickets[_to].push(_ticketId);

    tickets[_ticketId].holder = _to;
  }

  function approveTicket(uint256 _ticketId, address _to, bool _allowed) public {
    require(_ticketId < ticketCounter, 'Invalid ticket ID');
    require(
      tickets[_ticketId].holder == msg.sender,
      'You do not own this ticket'
    );
    ticketAllowance[_ticketId][_to] = _allowed;
  }

  function transferTicket(uint256 _ticketId, address _to) public {
    require(_ticketId < ticketCounter, 'Invalid ticket ID');
    require(
      tickets[_ticketId].holder == msg.sender ||
        tickets[_ticketId].holder == msg.sender,
      'You do not own this ticket'
    );
    require(
      ticketAllowance[_ticketId][msg.sender],
      'You are not allowed to transfer this ticket'
    );
    ticketAllowance[_ticketId][msg.sender] = false;
    transferTicketForce(_ticketId, _to);
  }
}