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pragma solidity >=0.5.4 <0.6.0;
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contract Forum {
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//----------------------------------------USER----------------------------------------
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struct User {
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string username;
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uint[] topicIDs; // IDs of the topics the user created
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uint[] postIDs; // IDs of the posts the user created
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uint timestamp;
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bool signedUp; // Helper variable for hasUserSignedUp()
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}
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mapping (address => User) users;
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mapping (string => address) userAddresses;
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event UserSignedUp(string username, address userAddress);
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event UsernameUpdated(string newName, string oldName,address userAddress);
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function signUp(string memory username) public returns (bool) {
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require (!hasUserSignedUp(msg.sender), "User has already signed up.");
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require(!isUserNameTaken(username), "Username is already taken.");
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users[msg.sender] = User(username,
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new uint[](0), new uint[](0), block.timestamp, true);
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userAddresses[username] = msg.sender;
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emit UserSignedUp(username, msg.sender);
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return true;
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}
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function updateUsername(string memory newUsername) public returns (bool) {
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require (hasUserSignedUp(msg.sender), "User hasn't signed up yet.");
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require(!isUserNameTaken(newUsername), "Username is already taken.");
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string memory oldUsername = getUsername(msg.sender);
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delete userAddresses[users[msg.sender].username];
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users[msg.sender].username = newUsername;
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userAddresses[newUsername] = msg.sender;
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emit UsernameUpdated(newUsername, oldUsername, msg.sender);
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return true;
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}
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function getUsername(address userAddress) public view returns (string memory) {
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require (hasUserSignedUp(userAddress), "User hasn't signed up yet.");
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return users[userAddress].username;
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}
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function getUserAddress(string memory username) public view returns (address) {
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return userAddresses[username];
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}
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function hasUserSignedUp(address userAddress) public view returns (bool) {
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return users[userAddress].signedUp;
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}
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function isUserNameTaken(string memory username) public view returns (bool) {
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if (getUserAddress(username)!=address(0))
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return true;
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return false;
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}
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function getUserDateOfRegister(address userAddress) public view returns (uint) {
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require (hasUserSignedUp(userAddress), "User hasn't signed up yet.");
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return users[userAddress].timestamp;
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}
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}
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