package com.ts3client.ui;

import com.ts3client.net.Group;
import com.ts3client.net.IconRepository;

import javax.swing.Icon;
import javax.swing.ImageIcon;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Image;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Turns the {@link IconRepository}'s icon bytes into Swing icons for one server's
 * groups, caching the decoded images. Icons that still have to be downloaded simply
 * do not render yet; the repository repaints the view once they arrive.
 */
public final class GroupIcons {

    /** Tree rows are 16×16 like TeamSpeak's own icon set. */
    private static final int SIZE = 16;

    private final IconRepository repository;
    private final Map<Long, ImageIcon> decoded = new ConcurrentHashMap<>();

    public GroupIcons(IconRepository repository) {
        this.repository = repository;
    }

    /** @return the group's icon, or {@code null} if it has none or it is not loaded yet */
    public ImageIcon iconOf(Group group) {
        if (group == null || group.iconId == 0) return null;
        return icon(group.iconId);
    }

    public ImageIcon icon(long iconId) {
        ImageIcon cached = decoded.get(iconId);
        if (cached != null) return cached;

        byte[] data = repository.get(iconId);
        if (data == null) return null;

        ImageIcon icon = new ImageIcon(data);
        if (icon.getIconWidth() <= 0) return null;
        if (icon.getIconWidth() != SIZE || icon.getIconHeight() != SIZE) {
            icon = new ImageIcon(icon.getImage().getScaledInstance(SIZE, SIZE, Image.SCALE_SMOOTH));
        }
        decoded.put(iconId, icon);
        return icon;
    }

    /** Collects the icons of a client's server groups plus its channel group, in display order. */
    public List<Icon> iconsOf(List<Group> serverGroups, Group channelGroup) {
        List<Icon> icons = new ArrayList<>();
        for (Group g : serverGroups) {
            ImageIcon icon = iconOf(g);
            if (icon != null) icons.add(icon);
        }
        ImageIcon channelIcon = iconOf(channelGroup);
        if (channelIcon != null) icons.add(channelIcon);
        return icons;
    }

    /** Lays several icons out in a row, so a single tree cell can show a badge strip. */
    public static final class Row implements Icon {

        private static final int GAP = 2;

        private final List<Icon> icons;

        public Row(List<Icon> icons) {
            this.icons = icons;
        }

        @Override
        public void paintIcon(Component c, Graphics g, int x, int y) {
            int offset = x;
            for (Icon icon : icons) {
                icon.paintIcon(c, g, offset, y + (getIconHeight() - icon.getIconHeight()) / 2);
                offset += icon.getIconWidth() + GAP;
            }
        }

        @Override
        public int getIconWidth() {
            int width = 0;
            for (Icon icon : icons) width += icon.getIconWidth() + GAP;
            return Math.max(0, width - GAP);
        }

        @Override
        public int getIconHeight() {
            int height = 0;
            for (Icon icon : icons) height = Math.max(height, icon.getIconHeight());
            return height;
        }
    }
}