package com.ts3client.ui;

import javax.swing.UIManager;
import java.awt.Color;
import java.awt.Font;

/**
 * The palette and fonts the client paints with, on top of the active look-and-feel.
 *
 * <p>Surfaces (window, tree, chat background) and fonts come straight from the
 * look-and-feel, so the client follows whatever FlatLaf theme is installed. The
 * status colours TeamSpeak gives meaning to — talking, away, muted, channel and
 * server names — are ours, in a light and a dark variant; {@link #refresh()} picks
 * the variant matching the installed theme.
 */
public final class Theme {

    private static boolean dark;

    private Theme() {
    }

    /** Re-reads the installed look-and-feel; call after changing it. */
    static void refresh() {
        Color bg = UIManager.getColor("Panel.background");
        dark = bg != null && luminance(bg) < 0.5;
    }

    public static boolean isDark() {
        return dark;
    }

    // ---- fonts ----

    public static Font uiFont() {
        Font f = UIManager.getFont("Label.font");
        return f != null ? f : new Font("SansSerif", Font.PLAIN, 12);
    }

    public static Font uiBold() {
        return uiFont().deriveFont(Font.BOLD);
    }

    // ---- surfaces, from the look-and-feel ----

    public static Color windowBg() {
        return ui("Panel.background", 0xF0F0F0, 0x3C3F41);
    }

    public static Color toolbarBg() {
        return ui("ToolBar.background", 0xE6E9ED, 0x3C3F41);
    }

    public static Color statusBg() {
        return windowBg();
    }

    public static Color treeBg() {
        return ui("Tree.background", 0xFFFFFF, 0x2B2B2B);
    }

    public static Color treeText() {
        return ui("Tree.foreground", 0x1E1E1E, 0xDFE1E5);
    }

    public static Color treeSelection() {
        return ui("Tree.selectionBackground", 0xCFE3FB, 0x2F5075);
    }

    /** Outline drawn around the row the pointer is over. */
    public static Color treeHover() {
        return pick(0x9CC4EE, 0x4A6E96);
    }

    public static Color chatBg() {
        return ui("TextPane.background", 0xFAFAFA, 0x2B2B2B);
    }

    public static Color border() {
        return ui("Component.borderColor", 0xD0D0D0, 0x4B4B4B);
    }

    public static Color chatText() {
        return ui("TextPane.foreground", 0x202020, 0xDFE1E5);
    }

    // ---- status colours ----

    public static Color channelText() {
        return pick(0x21486B, 0x8FBCE6);
    }

    public static Color serverText() {
        return pick(0x123456, 0xB9D4F0);
    }

    public static Color talking() {
        return pick(0x33B35A, 0x4CC479);
    }

    public static Color idleClient() {
        return pick(0x6E7B87, 0x9AA6B2);
    }

    public static Color away() {
        return pick(0xC98A1B, 0xE0A83C);
    }

    public static Color muted() {
        return pick(0xC0392B, 0xE05C4C);
    }

    public static Color accent() {
        return pick(0x2C7BE5, 0x5C9BEE);
    }

    public static Color chatSystem() {
        return pick(0x8A8A8A, 0x9A9A9A);
    }

    public static Color chatName() {
        return accent();
    }

    /** Links that leave the client, distinct from the colour used for identities. */
    public static Color link() {
        return pick(0x1A5FB4, 0x6EA8FF);
    }

    private static Color pick(int light, int darkRgb) {
        return new Color(dark ? darkRgb : light);
    }

    private static Color ui(String key, int lightFallback, int darkFallback) {
        // Returned as the look-and-feel's own UIResource colour, so components painted with
        // it are recoloured automatically when the look-and-feel is switched.
        Color c = UIManager.getColor(key);
        return c != null ? c : pick(lightFallback, darkFallback);
    }

    private static double luminance(Color c) {
        return (0.2126 * c.getRed() + 0.7152 * c.getGreen() + 0.0722 * c.getBlue()) / 255.0;
    }
}