Membership Pass

1// SPDX-License-Identifier: MIT
2pragma solidity ^0.8.20;
3 
4contract MembershipPass {
5    string public name;
6    string public symbol;
7    address public owner;
8    uint256 public durationSeconds;
9 
10    mapping(address => uint256) public expiresAt;
11 
12    event PassIssued(address indexed holder, uint256 expiresAt);
13    event PassRevoked(address indexed holder);
14    event OwnerChanged(address indexed newOwner);
15 
16    constructor(string memory name_, string memory symbol_, uint256 durationSeconds_, address initialOwner_) {
17        require(initialOwner_ != address(0), "ZERO_OWNER");
18        require(durationSeconds_ > 0, "ZERO_DURATION");
19        name = name_;
20        symbol = symbol_;
21        durationSeconds = durationSeconds_;
22        owner = initialOwner_;
23    }
24 
25    modifier onlyOwner() {
26        require(msg.sender == owner, "NOT_OWNER");
27        _;
28    }
29 
30    function issue(address holder) external onlyOwner returns (uint256) {
31        require(holder != address(0), "ZERO_HOLDER");
32        uint256 base = expiresAt[holder] > block.timestamp ? expiresAt[holder] : block.timestamp;
33        uint256 newExpiry = base + durationSeconds;
34        expiresAt[holder] = newExpiry;
35        emit PassIssued(holder, newExpiry);
36        return newExpiry;
37    }
38 
39    function revoke(address holder) external onlyOwner {
40        expiresAt[holder] = 0;
41        emit PassRevoked(holder);
42    }
43 
44    function isValid(address holder) external view returns (bool) {
45        return expiresAt[holder] > block.timestamp;
46    }
47 
48    function transferOwnership(address newOwner) external onlyOwner {
49        require(newOwner != address(0), "ZERO_OWNER");
50        owner = newOwner;
51        emit OwnerChanged(newOwner);
52    }
53}
54