RecyclerView with DiffUtil for efficient lists

package com.example.myapp.ui.adapters

import android.view.LayoutInflater
import android.view.ViewGroup
import androidx.recyclerview.widget.DiffUtil
import androidx.recyclerview.widget.ListAdapter
import androidx.recyclerview.widget.RecyclerView
import com.example.myapp.databinding.ItemPostBinding
import com.example.myapp.models.Post

class PostsAdapter(
    private val onPostClick: (Post) -> Unit,
    private val onLikeClick: (Post) -> Unit = {}
) : ListAdapter<Post, PostsAdapter.PostViewHolder>(PostDiffCallback()) {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PostViewHolder {
        val binding = ItemPostBinding.inflate(
            LayoutInflater.from(parent.context),
            parent,
            false
        )
        return PostViewHolder(binding, onPostClick, onLikeClick)
    }

    override fun onBindViewHolder(holder: PostViewHolder, position: Int) {
        holder.bind(getItem(position))
    }

    class PostViewHolder(
        private val binding: ItemPostBinding,
        private val onPostClick: (Post) -> Unit,
        private val onLikeClick: (Post) -> Unit
    ) : RecyclerView.ViewHolder(binding.root) {

        fun bind(post: Post) {
            binding.apply {
                titleText.text = post.title
                bodyText.text = post.body
                authorText.text = post.author
                likesText.text = "${post.likesCount} likes"
                timestampText.text = formatTimestamp(post.createdAt)

                likeButton.setImageResource(
                    if (post.isLiked) R.drawable.ic_liked else R.drawable.ic_like
                )

                root.setOnClickListener { onPostClick(post) }
                likeButton.setOnClickListener { onLikeClick(post) }
            }
        }

        private fun formatTimestamp(timestamp: Long): String {
            val now = System.currentTimeMillis()
            val diff = now - timestamp
            val seconds = diff / 1000
            val minutes = seconds / 60
            val hours = minutes / 60
            val days = hours / 24

            return when {
                days > 0 -> "$days days ago"
                hours > 0 -> "$hours hours ago"
                minutes > 0 -> "$minutes minutes ago"
                else -> "Just now"
            }
        }
    }

    class PostDiffCallback : DiffUtil.ItemCallback<Post>() {
        override fun areItemsTheSame(oldItem: Post, newItem: Post): Boolean {
            return oldItem.id == newItem.id
        }

        override fun areContentsTheSame(oldItem: Post, newItem: Post): Boolean {
            return oldItem == newItem
        }

        override fun getChangePayload(oldItem: Post, newItem: Post): Any? {
            return if (oldItem.likesCount != newItem.likesCount ||
                       oldItem.isLiked != newItem.isLiked) {
                "LIKES_CHANGED"
            } else {
                null
            }
        }
    }
}