UIKit delegates and protocols

import UIKit

// MARK: - Custom Delegate Protocol
protocol PostCellDelegate: AnyObject {
    func postCell(_ cell: PostTableViewCell, didTapLike post: Post)
    func postCell(_ cell: PostTableViewCell, didTapComment post: Post)
    func postCell(_ cell: PostTableViewCell, didTapShare post: Post)
}

class PostTableViewCell: UITableViewCell {
    weak var delegate: PostCellDelegate?
    private var post: Post?

    private let likeButton: UIButton = {
        let button = UIButton(type: .system)
        button.setImage(UIImage(systemName: "heart"), for: .normal)
        button.translatesAutoresizingMaskIntoConstraints = false
        return button
    }()

    private let commentButton: UIButton = {
        let button = UIButton(type: .system)
        button.setImage(UIImage(systemName: "bubble.left"), for: .normal)
        button.translatesAutoresizingMaskIntoConstraints = false
        return button
    }()

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        setupUI()
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    private func setupUI() {
        contentView.addSubview(likeButton)
        contentView.addSubview(commentButton)

        likeButton.addTarget(self, action: #selector(likeTapped), for: .touchUpInside)
        commentButton.addTarget(self, action: #selector(commentTapped), for: .touchUpInside)

        NSLayoutConstraint.activate([
            likeButton.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -12),
            likeButton.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 16),

            commentButton.centerYAnchor.constraint(equalTo: likeButton.centerYAnchor),
            commentButton.leadingAnchor.constraint(equalTo: likeButton.trailingAnchor, constant: 20)
        ])
    }

    func configure(with post: Post) {
        self.post = post
    }

    @objc private func likeTapped() {
        guard let post = post else { return }
        delegate?.postCell(self, didTapLike: post)
    }

    @objc private func commentTapped() {
        guard let post = post else { return }
        delegate?.postCell(self, didTapComment: post)
    }
}

// MARK: - View Controller Implementing Delegate
class FeedViewController: UIViewController {
    private let tableView = UITableView()
    private var posts: [Post] = []

    override func viewDidLoad() {
        super.viewDidLoad()
        setupTableView()
    }

    private func setupTableView() {
        tableView.delegate = self
        tableView.dataSource = self
        tableView.register(PostTableViewCell.self, forCellReuseIdentifier: "PostCell")
    }
}

extension FeedViewController: UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return posts.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "PostCell", for: indexPath) as! PostTableViewCell
        cell.configure(with: posts[indexPath.row])
        cell.delegate = self
        return cell
    }
}

extension FeedViewController: UITableViewDelegate {
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        tableView.deselectRow(at: indexPath, animated: true)
        let post = posts[indexPath.row]
        // Navigate to detail
    }
}

extension FeedViewController: PostCellDelegate {
    func postCell(_ cell: PostTableViewCell, didTapLike post: Post) {
        print("Like tapped for post \(post.id)")
        // Handle like action
    }

    func postCell(_ cell: PostTableViewCell, didTapComment post: Post) {
        print("Comment tapped for post \(post.id)")
        // Navigate to comments
    }

    func postCell(_ cell: PostTableViewCell, didTapShare post: Post) {
        print("Share tapped for post \(post.id)")
        // Show share sheet
    }
}

// MARK: - Protocol with Associated Type
protocol DataProvider {
    associatedtype Item
    func fetchItems(completion: @escaping ([Item]) -> Void)
}

class PostsDataProvider: DataProvider {
    typealias Item = Post

    func fetchItems(completion: @escaping ([Post]) -> Void) {
        // Fetch posts from API
        completion([])
    }
}