package com.ts3client.ui;

import com.formdev.flatlaf.util.ScaledEmptyBorder;
import com.formdev.flatlaf.util.UIScale;
import com.ts3client.config.Settings;
import com.ts3client.contacts.Contact;
import com.ts3client.net.ChannelNode;
import com.ts3client.net.ClientEntry;
import com.ts3client.net.Details;
import com.ts3client.net.Group;
import com.ts3client.net.IconRepository;
import com.ts3client.net.PictureDownloads;
import com.ts3client.net.ServerModel;
import com.ts3client.net.avatar.Avatar;
import com.ts3client.text.BBCode;

import javax.swing.BorderFactory;
import javax.swing.JEditorPane;
import javax.swing.JFileChooser;
import javax.swing.JLabel;
import javax.swing.JLayeredPane;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.StyleConstants;
import javax.swing.text.html.HTML;
import javax.swing.text.html.HTMLDocument;
import java.awt.BorderLayout;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Rectangle2D;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.List;
import java.util.function.Consumer;

/**
 * Read-only detail view for the server, channel or client selected, mirroring the
 * TeamSpeak 3 info box; what it says comes from {@link Details}.
 */
public final class InfoPanel extends JPanel {

    /** Moves the whole info panel's content out to a persistent chat tab. */
    public interface DescriptionHandler {
        /** Shows/updates {@code html} in the info chat tab, creating it if needed. */
        void showInfoTab(String html, Runnable onClose);

        /** Closes the info chat tab (the user chose to show details in the panel again). */
        void closeInfoTab();

        /** Hides (or restores) the panel itself, freeing its space, while its content lives in the chat tab. */
        void setPanelHidden(boolean hidden);
    }

    private static final int AVATAR_MIN_SIZE = 64;
    private static final int AVATAR_BOX_STEP = 16;
    /** Pictures in a chat tab have no panel to fit, so they get this much. */
    private static final int CHAT_TAB_PICTURE_WIDTH = 480;
    private static final int PICTURE_WIDTH_STEP = 32;

    private final JEditorPane pane = HtmlStyles.pane("font-family:sans-serif; font-size:11px;");
    private final JScrollPane scroll = new JScrollPane(pane);
    /** Floats over the bottom-right corner of the details, out of the text's way. */
    private final JLabel toggle = new JLabel("Show in chat tab");
    private DescriptionHandler descriptionHandler;
    /** Takes someone else's avatar as ours; null where that cannot be done. */
    private Consumer<Avatar> avatarStealer;
    private ChannelNode shownChannel;
    private ClientEntry shownClient;
    /** The server's address while the server itself is shown. */
    private String shownServer;
    private ServerModel shownModel;
    private IconRepository shownIcons;
    private Contact shownContact;
    private Avatar shownAvatar;
    private boolean inChatTab;
    /** The avatar box the current HTML was built for; a resize that changes it re-renders. */
    private int renderedAvatarBox;
    private final PictureDownloads downloads;
    private final DescriptionPictures pictures;
    /** Whether the description shown has pictures, which re-render it as they come or the panel resizes. */
    private boolean showsPictures;
    private int renderedPictureWidth;
    private final Runnable onPicture = () -> SwingUtilities.invokeLater(() -> {
        if (showsPictures) keepingScroll(this::render);
    });

    public InfoPanel(Settings settings, PictureDownloads downloads) {
        super(new BorderLayout());
        this.downloads = downloads;
        this.pictures = new DescriptionPictures(downloads, settings);
        pane.setBorder(new ScaledEmptyBorder(6, 8, 6, 8));
        pane.addHyperlinkListener(e -> {
            if (e.getEventType() != javax.swing.event.HyperlinkEvent.EventType.ACTIVATED) return;
            Links.open(e.getDescription(), this);
        });
        pane.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                if (e.isPopupTrigger()) showAvatarMenu(e);
            }

            @Override
            public void mouseReleased(MouseEvent e) {
                if (e.isPopupTrigger()) showAvatarMenu(e);
            }
        });
        HtmlStyles.fillViewport(pane);
        scroll.getViewport().addComponentListener(new ComponentAdapter() {
            @Override
            public void componentResized(ComponentEvent e) {
                if (inChatTab) return;
                boolean avatar = shownAvatar != null && avatarBox() != renderedAvatarBox;
                boolean pictures = showsPictures && pictureWidth() != renderedPictureWidth;
                if (avatar || pictures) keepingScroll(InfoPanel.this::render);
            }
        });

        toggle.setFont(Theme.uiSmall());
        toggle.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
        toggle.setToolTipText("Show these details in a chat tab instead");
        toggle.setOpaque(true);
        toggle.setBorder(new ScaledEmptyBorder(1, 4, 1, 4));
        toggle.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                inChatTab = true;
                render();
            }
        });

        // The link floats on top of the text rather than following it, so it stays
        // in the corner however long the description is.
        JLayeredPane layers = new JLayeredPane() {
            @Override
            public void doLayout() {
                scroll.setBounds(0, 0, getWidth(), getHeight());
                // Lay the scroll pane out first: the link goes in the corner of the
                // viewport, which is where the scroll bars have already been taken out.
                scroll.doLayout();
                Rectangle view = scroll.getViewport().getBounds();
                Dimension d = toggle.getPreferredSize();
                toggle.setBounds(view.x + view.width - d.width, view.y + view.height - d.height,
                        d.width, d.height);
            }

            // Without a layout manager we have no size of our own, and the split pane
            // above us sizes the panel from it.
            @Override
            public Dimension getPreferredSize() {
                return scroll.getPreferredSize();
            }

            @Override
            public Dimension getMinimumSize() {
                return scroll.getMinimumSize();
            }
        };
        layers.add(scroll, JLayeredPane.DEFAULT_LAYER);
        layers.add(toggle, JLayeredPane.PALETTE_LAYER);
        add(layers, BorderLayout.CENTER);
        applyTheme();
        clear();
    }

    @Override
    public void addNotify() {
        super.addNotify();
        downloads.addListener(onPicture);
    }

    @Override
    public void removeNotify() {
        downloads.removeListener(onPicture);
        super.removeNotify();
    }

    /** Runs {@code change}, which renders again, without the view jumping back to the top. */
    private void keepingScroll(Runnable change) {
        Point at = scroll.getViewport().getViewPosition();
        change.run();
        SwingUtilities.invokeLater(() -> scroll.getViewport().setViewPosition(at));
    }

    @Override
    public void updateUI() {
        super.updateUI();
        // Runs from the superclass constructor too, before our own fields exist.
        if (scroll != null) applyTheme();
    }

    private void applyTheme() {
        scroll.setBorder(BorderFactory.createLineBorder(Theme.border()));
        toggle.setBackground(pane.getBackground());
        toggle.setForeground(Theme.link());
    }

    public void clear() {
        shownChannel = null;
        shownClient = null;
        shownServer = null;
        inChatTab = false;
        render();
    }

    public void setDescriptionHandler(DescriptionHandler handler) {
        this.descriptionHandler = handler;
    }

    public void setAvatarStealer(Consumer<Avatar> stealer) {
        this.avatarStealer = stealer;
    }

    /** Runs when the user closes the info chat tab; shows details in the panel again. */
    private void onInfoTabClosed() {
        inChatTab = false;
        render();
    }

    public void showServer(ServerModel model, String address) {
        shownServer = address;
        shownModel = model;
        shownChannel = null;
        shownClient = null;
        render();
    }

    public void showChannel(ChannelNode ch) {
        shownChannel = ch;
        shownClient = null;
        shownServer = null;
        render();
    }

    /** @param avatar the client's avatar, or {@code null} while there is none to show */
    public void showClient(ClientEntry cl, ServerModel model, IconRepository icons, Contact contact,
                           Avatar avatar) {
        shownClient = cl;
        shownChannel = null;
        shownServer = null;
        shownModel = model;
        shownIcons = icons;
        shownContact = contact;
        shownAvatar = avatar;
        render();
    }

    private void render() {
        boolean selected = shownChannel != null || shownClient != null || shownServer != null;
        boolean hide = inChatTab && selected;
        if (descriptionHandler != null) descriptionHandler.setPanelHidden(hide);
        toggle.setVisible(selected && !hide);
        if (hide) {
            descriptionHandler.showInfoTab(body(), this::onInfoTabClosed);
        } else {
            setHtml(body());
        }
    }

    private String body() {
        showsPictures = false;
        if (shownServer != null) return html(Details.server(shownModel, shownServer), "", "", null, null);
        if (shownChannel != null) return html(Details.channel(shownChannel), "", "", null, "No description.");
        if (shownClient != null) {
            renderedAvatarBox = inChatTab ? UIScale.scale(AvatarHtml.MAX_SIZE) : avatarBox();
            return clientBody(shownClient, shownModel, shownIcons, shownContact, shownAvatar, renderedAvatarBox);
        }
        return "<i class='muted'>Select the server, a channel or a client to see details.</i>";
    }

    /**
     * How large an avatar may be drawn beside the details: a share of the panel's
     * width, so a narrow panel keeps room for the text. Rounded to steps so that
     * dragging a divider does not rebuild the HTML on every pixel.
     */
    private int avatarBox() {
        int width = scroll.getViewport().getWidth();
        int max = UIScale.scale(AvatarHtml.MAX_SIZE);
        if (width <= 0) return max;
        int step = UIScale.scale(AVATAR_BOX_STEP);
        int box = width * 2 / 5 / step * step;
        return Math.max(UIScale.scale(AVATAR_MIN_SIZE), Math.min(max, box));
    }

    private void showAvatarMenu(MouseEvent e) {
        Avatar avatar = shownClient == null ? null : shownAvatar;
        if (avatar == null || !overAvatar(avatar, e.getPoint())) return;
        JPopupMenu menu = new JPopupMenu();
        JMenuItem save = new JMenuItem("Save…");
        save.addActionListener(a -> saveAvatar(avatar, "avatar_" + shownClient.nickname));
        menu.add(save);
        if (!shownClient.self && avatarStealer != null) {
            JMenuItem steal = new JMenuItem("Steal for avatar");
            steal.addActionListener(a -> avatarStealer.accept(avatar));
            menu.add(steal);
        }
        menu.show(pane, e.getX(), e.getY());
    }

    /** Whether {@code point} falls on the avatar's {@code <img>}. */
    private boolean overAvatar(Avatar avatar, Point point) {
        if (avatar.file() == null) return false;
        String src = avatar.file().toURI().toString();
        int pos = pane.viewToModel2D(point);
        for (int at : new int[]{pos, pos - 1}) {
            if (at < 0) continue;
            var el = ((HTMLDocument) pane.getDocument()).getCharacterElement(at);
            AttributeSet attrs = el.getAttributes();
            if (attrs.getAttribute(StyleConstants.NameAttribute) != HTML.Tag.IMG
                    || !src.equals(attrs.getAttribute(HTML.Attribute.SRC))) continue;
            try {
                Rectangle2D start = pane.modelToView2D(el.getStartOffset());
                Rectangle2D end = pane.modelToView2D(el.getEndOffset());
                if (start != null && end != null && start.createUnion(end).contains(point)) return true;
            } catch (BadLocationException ignored) {
            }
        }
        return false;
    }

    private void saveAvatar(Avatar avatar, String name) {
        JFileChooser chooser = new JFileChooser();
        chooser.setDialogTitle("Save avatar");
        chooser.setSelectedFile(new File(name + "." + avatar.format().extension));
        if (chooser.showSaveDialog(this) != JFileChooser.APPROVE_OPTION) return;
        try {
            Files.write(chooser.getSelectedFile().toPath(), avatar.data());
        } catch (IOException ex) {
            JOptionPane.showMessageDialog(this, "Could not save the avatar: " + ex.getMessage(),
                    "Error", JOptionPane.ERROR_MESSAGE);
        }
    }

    private String clientBody(ClientEntry cl, ServerModel model, IconRepository icons, Contact contact,
                                     Avatar avatar, int avatarBox) {
        String details = clientDetails(cl, model, icons, contact);
        String picture = AvatarHtml.imgTag(avatar, avatarBox);
        if (picture.isEmpty()) return details;
        // The avatar sits top-right beside the details, like the official client's info frame.
        return "<table width='100%' cellpadding='0' cellspacing='0'><tr>"
                + "<td valign='top'>" + details + "</td>"
                + "<td valign='top' align='right' style='padding-left:" + HtmlStyles.px(8) + "'>" + picture + "</td>"
                + "</tr></table>";
    }

    private String clientDetails(ClientEntry cl, ServerModel model, IconRepository icons, Contact contact) {
        String you = cl.self ? " <span class='muted'>(you)</span>" : "";
        // The country's flag goes before the name, as in TeamSpeak's info frame.
        return html(Details.client(cl, model, contact), flagTag(cl.country), you, icons, null);
    }

    /**
     * @param titlePrefix HTML before the title
     * @param titleSuffix HTML after the title
     * @param icons       for the icons of the groups a field names; null for none
     * @param none        what to say when there is no description; null to say nothing
     */
    private String html(Details details, String titlePrefix, String titleSuffix, IconRepository icons, String none) {
        StringBuilder sb = new StringBuilder();
        sb.append(heading(titlePrefix + esc(details.title()) + titleSuffix));
        for (Details.Field f : details.fields()) row(sb, esc(f.label()), value(f, icons));
        if (!details.description().isEmpty()) {
            sb.append("<hr><div>").append(description(details.description())).append("</div>");
        } else if (details.pending()) {
            sb.append("<hr><i class='muted'>Loading description…</i>");
        } else if (none != null) {
            sb.append("<hr><i class='muted'>").append(none).append("</i>");
        }
        return sb.toString();
    }

    private static String value(Details.Field field, IconRepository icons) {
        if (field.groups().isEmpty() || icons == null) return esc(field.value());
        StringBuilder sb = new StringBuilder();
        for (Group g : field.groups()) {
            if (sb.length() > 0) sb.append(", ");
            sb.append(iconTag(g, icons)).append(esc(g.name));
        }
        return sb.toString();
    }

    private void setHtml(String body) {
        pane.setText("<html><body>" + body + "</body></html>");
        pane.setCaretPosition(0);
    }

    /**
     * An inline {@code <img>} for a group's icon, or nothing while the icon is missing
     * or still downloading. Swing's HTML renderer only loads images by URL, so the icon
     * is served from the repository's on-disk cache.
     */
    private static String iconTag(Group group, IconRepository icons) {
        if (group.iconId == 0) return "";
        File file = icons.file(group.iconId);
        if (file == null) return "";
        return "<img src='" + file.toURI() + "' width='" + UIScale.scale(14) + "' height='" + UIScale.scale(14) + "'> ";
    }

    /** An inline {@code <img>} for a country's flag, or nothing for no country. */
    private static String flagTag(String country) {
        File file = IconFiles.flag(country);
        if (file == null) return "";
        return "<img src='" + file.toURI() + "' width='" + UIScale.scale(16) + "' height='" + UIScale.scale(11) + "'>&nbsp;";
    }

    private static String heading(String text) {
        return "<div style='font-weight:bold;font-size:13px;margin-bottom:" + HtmlStyles.px(4) + "'>" + text + "</div>";
    }

    private static void row(StringBuilder sb, String label, String value) {
        sb.append("<div style='margin:1px 0'><span class='muted'>")
                .append(label).append(":</span> ").append(value).append("</div>");
    }

    /** Descriptions may carry BBCode markup, pictures included. */
    private String description(String bbcode) {
        String html = BBCode.toHtml(bbcode, true);
        if (!DescriptionPictures.hasPictures(html)) return html;
        showsPictures = true;
        renderedPictureWidth = pictureWidth();
        return pictures.html(html, renderedPictureWidth);
    }

    /**
     * How wide a picture may be: the panel's width inside its padding, in steps so that
     * dragging a divider does not rebuild the HTML on every pixel.
     */
    private int pictureWidth() {
        if (inChatTab) return UIScale.scale(CHAT_TAB_PICTURE_WIDTH);
        int step = UIScale.scale(PICTURE_WIDTH_STEP);
        int width = scroll.getViewport().getWidth() - UIScale.scale(24);
        return Math.max(step, width / step * step);
    }

    private static String esc(String s) {
        return BBCode.escape(s);
    }

}