import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JMenuBar;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.Box;
import javax.swing.BorderFactory;
import java.awt.Graphics;
import java.awt.FontMetrics;
import java.awt.Dimension;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.util.List;
import java.util.ArrayList;

class
PostWindow extends JFrame
implements ActionListener {

    private Post
    post;

//   -  -%-  -

    private PostComponent
    postDisplay;

    private RepliesComponent
    repliesDisplay;

//  ---%-@-%---

    public void
    setPost(Post post)
    {
        if (post == null)
        {
            post = new Post();
            post.text = "This is a sample post.";
            post.authorId = "snowyfox@biskuteri.cafe";
            post.authorName = "snowyfox";
            post.date = "0712hrs, 17 July";
            post.visibility = PostVisibility.MENTIONED;
            post.postId = "000000000";
            post.boosted = false;
            post.favourited = true;
        }

        this.post = post;

        postDisplay.setAuthor(post.authorName);
        postDisplay.setTime(post.date);
        postDisplay.setText(post.text);

        // And, reply display too, later.
    }

//   -  -%-  -

    public void
    actionPerformed(ActionEvent eA)
    {
        Object src = eA.getSource();
        if (!(src instanceof JMenuItem)) return;
        String text = ((JMenuItem)src).getText();

        if (text.equals("Post"))
        {
            setContentPane(postDisplay);
            revalidate();
            /*
            * (知) Setting a content pane in itself doesn't
            * do anything to the content pane. Validation
            * of the validate root does. Which happens on
            * window realisation, or by manual call.
            */
        }
        else if (text.equals("Replies"))
        {
            setContentPane(repliesDisplay);
            revalidate();
        }
    }

//  ---%-@-%---

    PostWindow()
    {
        getContentPane().setPreferredSize(new Dimension(360, 270));
        pack();
        setDefaultCloseOperation(DISPOSE_ON_CLOSE);
        setLocationByPlatform(true);

        postDisplay = new PostComponent();

        repliesDisplay = new RepliesComponent();
        {
            List<String> authors = new ArrayList<>();
            List<String> texts = new ArrayList<>();
            authors.add("Black tea");
            authors.add("Green tea");
            authors.add("White tea");
            texts.add("Rich..");
            texts.add("Clean!");
            texts.add("Myu..");
            repliesDisplay.setReplies(authors, texts);
        }

        setPost(null);

        JMenu postMenu = new JMenu("Post");
        addToMenu(postMenu, "Favourite");
        addToMenu(postMenu, "Reply");
        JMenu displayMenu = new JMenu("Display");
        addToMenu(displayMenu, "Post");
        addToMenu(displayMenu, "Replies");
        JMenuBar menuBar = new JMenuBar();
        menuBar.add(postMenu);
        menuBar.add(displayMenu);
        setJMenuBar(menuBar);

        setContentPane(postDisplay);
    }

    private void
    addToMenu(JMenu menu, String text)
    {
        JMenuItem item = new JMenuItem(text);
        item.addActionListener(this);
        menu.add(item);
    }

}



class
PostComponent extends JPanel {

    private String
    author, time, text;

//  ---%-@-%---

    public void
    setAuthor(String author)
    {
        assert author != null;
        this.author = author;
    }

    public void
    setTime(String time)
    {
        assert time != null;
        this.time = time;
    }

    public void
    setText(String text)
    {
        assert text != null;
        this.text = text;
    }

//   -  -%-  -

    protected void
    paintComponent(Graphics g)
    {
        int lineHeight = 20;

        FontMetrics met = g.getFontMetrics();

        g.drawString(author, 0, lineHeight);
        int t1 = getWidth() - met.stringWidth(time);
        g.drawString(time, t1, lineHeight);

        int t2 = lineHeight;
        for (String line: split(text, 48)) {
            t2 += lineHeight;
            g.drawString(line, 0, t2);
        }
    }

    private List<String>
    split(String string, int lineLength)
    {
        List<String> returnee = new ArrayList<>();

        int start, max = string.length();
        for (start = 0; start < max; start += lineLength) {
            returnee.add(string.substring(
                start,
                Math.min(max, start + lineLength)
            ));
        }

        return returnee;
    }

//  ---%-@-%---

    PostComponent()
    {
        author = time = text = "";

        setFont(getFont().deriveFont(14f));
    }

}



class
RepliesComponent extends JPanel {

    private List<String>
    authors, texts;

    private JButton
    prevPage, nextPage;

    private JLabel
    pageLabel;

    private ReplyPreviewComponent[]
    previews;

//  ---%-@-%---

    public void
    setReplies(List<String> authors, List<String> texts)
    {
        assert authors != null;
        assert texts != null;
        assert authors.size() == texts.size();

        this.authors.clear();
        this.authors.addAll(authors);
        this.texts.clear();
        this.texts.addAll(texts);

        displayPage(1);
        int currentPage = authors.isEmpty() ? 0 : 1;
        int pages = (7 + authors.size()) / 8;
        // (0 + 7) / 8 = 0
        // (1 + 7) / 8 = 1
        // (8 + 7) / 8 = 1
        // (9 + 7) / 8 = 2
        // (32 + 7) / 8 = 4
        pageLabel.setText(currentPage + "/" + pages);
    }

//   -  -%-  -

    private void
    displayPage(int pageNumber)
    {
        int oS = (pageNumber - 1) * 8;
        if (oS >= authors.size()) return;
        // (悪) Quietly fail?
        int oE = Math.min(oS + 8, authors.size());
        List<String> authors = this.authors.subList(oS, oE);
        List<String> texts = this.texts.subList(oS, oE);
        int l = oE - oS;

        for (int o = 0; o < 8; ++o)
        {
            ReplyPreviewComponent preview = previews[o];

            if (o >= l)  // That doesn't seem right..
            {
                preview.setVisible(false);
            }
            else
            {
                preview.setAuthor(authors.get(oS + o));
                preview.setText(texts.get(oS + o));
                preview.setVisible(true);
            }
        }
    }

//  ---%-@-%---

    RepliesComponent()
    {
        authors = new ArrayList<>();
        texts = new ArrayList<>();

        prevPage = new JButton("<");
        nextPage = new JButton(">");
        prevPage.setEnabled(false);
        nextPage.setEnabled(false);

        pageLabel = new JLabel("0 / 0");

        Box bottom = Box.createHorizontalBox();
        bottom.add(Box.createGlue());
        bottom.add(prevPage);
        bottom.add(Box.createHorizontalStrut(8));
        bottom.add(pageLabel);
        bottom.add(Box.createHorizontalStrut(8));
        bottom.add(nextPage);

        JPanel centre = new JPanel();
        centre.setOpaque(false);
        centre.setLayout(new GridLayout(0, 1, 0, 2));

        previews = new ReplyPreviewComponent[8];
        for (int o = 0; o < previews.length; ++o)
        {
            previews[o] = new ReplyPreviewComponent();
            previews[o].setVisible(false);
            centre.add(previews[o]);
        }

        setLayout(new BorderLayout(0, 8));
        add(centre, BorderLayout.CENTER);
        add(bottom, BorderLayout.SOUTH);

        setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
    }

}



class
ReplyPreviewComponent extends JButton {

    private String
    author;

    private String
    text;

//  ---%-@-%---

    @Override
    public void
    setText(String text)
    {
        assert text != null;
        this.text = text;
        setText();
    }

    public void
    setAuthor(String author)
    {
        assert author != null;
        this.author = author;
        setText();
    }

//   -  -%-  -

    private void
    setText()
    {
        StringBuilder text = new StringBuilder();
        text.append(this.author);
        text.append(" @ ");
        text.append(this.text);
        super.setText(text.toString());
    }

    protected void
    paintComponent(Graphics g)
    {
        g.drawString(getText(), 8, 2 * getHeight() / 3);
    }

//  ---%-@-%---

    ReplyPreviewComponent() { }

}