/**
 * Inheritance Example
 * socialnetwork Module
 * Source code file: Post.java
 *
 * This class stores information about a news feed post in a
 * social network. Posts can be stored and displayed. This class
 * serves as a superclass for more specific post types.
 * Javadoc comments are used
 *
 * Source: Objects First with Java
 * @author Michael Koelling and David J. Barnes
 * @version 0.3
 */

import java.util.ArrayList;
public class Post {
    // username of the post's author
    private String _username;
    private long _timestamp;
    private int _likes;
    private ArrayList<String> _comments;

    /**
     * Constructor for objects of class Post.
     *
     * @param author    The username of the author of this post.
     */
    public Post(String author) {
        _username = author;
        _timestamp = System.currentTimeMillis();
        _likes = 0;
        _comments = new ArrayList<String>();
    }

    /**
     * Record one more 'Like' indication from a user.
     */
    public void like() {
        _likes++;
    }

    /**
     * Record that a user has withdrawn his/her 'Like' vote.
     */
    public void unlike() {
        if (_likes > 0) {
            _likes--;
        }
    }

    /**
     * Add a comment to this post.
     *
     * @param text  The new comment to add.
     */
    public void addComment(String text) {
        _comments.add(text);
    }

    /**
     * Return the time of creation of this post.
     *
     * @return The post's creation time, as a system time value.
     */
    public long getTimeStamp() {
        return _timestamp;
    }

    /**
     * Display the details of this post.
     *
     * (Currently: Print to the text terminal. This is simulating display
     * in a web browser for now.)
     */
    public void display() {
        System.out.println(_username);
        System.out.print(timeString(_timestamp));

        if(_likes > 0) {
            System.out.println("  -  " + _likes + " people like this.");
        }
        else {
            System.out.println();
        }

        if(_comments.isEmpty()) {
            System.out.println("   No comments.");
        }
        else {
            System.out.println("   " + _comments.size() +
                    " comment(s). Click here to view.");
        }
    }

    /**
     * Create a string describing a time point in the past in terms
     * relative to current time, such as "30 seconds ago" or "7 minutes ago".
     * Currently, only seconds and minutes are used for the string.
     *
     * @param time  The time value to convert (in system milliseconds)
     * @return      A relative time string for the given time
     */

    private String timeString(long time) {
        long _current = System.currentTimeMillis();
        long _pastMillis = _current - time;      // time passed in milliseconds
        long _seconds = _pastMillis/1000;
        long _minutes = _seconds/60;
        if(_minutes > 0) {
            return _minutes + " minutes ago";
        }
        else {
            return _seconds + " seconds ago";
        }
    }
}