28-Twitter-Interaction-Solution-Main.sol

// SPDX-License-Identifier: MIT

// 2️⃣ Add a getProfile() function to the interface ✅ 
// 3️⃣ Initialize the IProfile in the contructor ✅ 
// HINT: don't forget to include the _profileContract address as a input 
// 4️⃣ Create a modifier called onlyRegistered that require the msg.sender to have a profile ✅
// HINT: use the getProfile() to get the user
// HINT: check if displayName.length > 0 to make sure the user exists
// 5️⃣ ADD the onlyRegistered modified to createTweet, likeTweet, and unlikeTweet function

import "@openzeppelin/contracts/access/Ownable.sol";

pragma solidity ^0.8.0;

interface IProfile {
    struct UserProfile {
        string displayName;
        string bio;
    }
    
    // CODE HERE

    function getProfile (address _user) external view returns (UserProfile memory);
}

contract Twitter is Ownable {

    uint16 public MAX_TWEET_LENGTH = 280;

    struct Tweet {
        uint256 id;
        address author;
        string content;
        uint256 timestamp;
        uint256 likes;
    }
    mapping(address => Tweet[] ) public tweets;
    // profile contract defined here 
    IProfile profileContract;

    // Define the events
    event TweetCreated(uint256 id, address author, string content, uint256 timestamp);
    event TweetLiked(address liker, address tweetAuthor, uint256 tweetId, uint256 newLikeCount);
    event TweetUnliked(address unliker, address tweetAuthor, uint256 tweetId, uint256 newLikeCount);

    modifier onlyRegistered(){
        IProfile.UserProfile memory userProfileTemp = profileContract.getProfile(msg.sender);
        require(bytes(userProfileTemp.displayName).length > 0, "USER NOT REGISTERED");
        _;
    }

    constructor(address _profileContract) {
        profileContract = IProfile(_profileContract);
    }

    function changeTweetLength(uint16 newTweetLength) public onlyOwner {
        MAX_TWEET_LENGTH = newTweetLength;
    }

    function getTotalLikes(address _author) external view returns(uint) {
        uint totalLikes;

        for( uint i = 0; i < tweets[_author].length; i++){
            totalLikes += tweets[_author][i].likes;
        }

        return totalLikes;
    }

    function createTweet(string memory _tweet) public  onlyRegistered {
        require(bytes(_tweet).length <= MAX_TWEET_LENGTH, "Tweet is too long bro!" );

        Tweet memory newTweet = Tweet({
            id: tweets[msg.sender].length,
            author: msg.sender,
            content: _tweet,
            timestamp: block.timestamp,
            likes: 0
        });

        tweets[msg.sender].push(newTweet);

        // Emit the TweetCreated event
        emit TweetCreated(newTweet.id, newTweet.author, newTweet.content, newTweet.timestamp);
    }

    function likeTweet(address author, uint256 id) external  onlyRegistered {  
        require(tweets[author][id].id == id, "TWEET DOES NOT EXIST");

        tweets[author][id].likes++;

        // Emit the TweetLiked event
        emit TweetLiked(msg.sender, author, id, tweets[author][id].likes);
    }

    function unlikeTweet(address author, uint256 id) external  onlyRegistered {
        require(tweets[author][id].id == id, "TWEET DOES NOT EXIST");
        require(tweets[author][id].likes > 0, "TWEET HAS NO LIKES");
        
        tweets[author][id].likes--;

        emit TweetUnliked(msg.sender, author, id, tweets[author][id].likes );
    }

    function getTweet( uint _i) public view returns (Tweet memory) {
        return tweets[msg.sender][_i];
    }

    function getAllTweets(address _owner) public view returns (Tweet[] memory ){
        return tweets[_owner];
    }

}