package envoy.client.util;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.*;
import java.util.logging.Level;

import javax.imageio.ImageIO;

import javafx.scene.image.Image;

import envoy.util.EnvoyLog;

import envoy.client.data.Settings;

/**
 * Provides static utility methods for loading icons from the resource folder.
 *
 * @author Kai S. K. Engelbart
 * @since Envoy Client v0.1-beta
 */
public final class IconUtil {

	private static final HashMap<String, Image>			cache		= new HashMap<>();
	private static final HashMap<String, Image>			scaledCache	= new HashMap<>();
	private static final HashMap<String, BufferedImage>	awtCache	= new HashMap<>();

	private IconUtil() {}

	/**
	 * Loads an image from the resource folder.
	 *
	 * @param path the path to the icon inside the resource folder
	 * @return the loaded image
	 * @since Envoy Client v0.1-beta
	 */
	public static Image load(String path) {
		return cache.computeIfAbsent(path,
			p -> new Image(IconUtil.class.getResource(p).toExternalForm()));
	}

	/**
	 * Loads an image from the resource folder and scales it to the given size.
	 *
	 * @param path the path to the icon inside the resource folder
	 * @param size the size to scale the icon to
	 * @return the scaled image
	 * @since Envoy Client v0.1-beta
	 */
	public static Image load(String path, int size) {
		return scaledCache.computeIfAbsent(path + size,
			p -> new Image(IconUtil.class.getResource(path).toExternalForm(), size, size, true,
				true));
	}

	/**
	 * Loads a {@code .png} image from the sub-folder {@code /icons/} of the resource folder.
	 * <p>
	 * The suffix {@code .png} is automatically appended.
	 *
	 * @param name the image name without the .png suffix
	 * @return the loaded image
	 * @since Envoy Client v0.1-beta
	 * @apiNote let's load a sample image {@code /icons/abc.png}.<br>
	 *          To do that, we only have to call {@code IconUtil.loadIcon("abc")}
	 */
	public static Image loadIcon(String name) {
		return load("/icons/" + name + ".png");
	}

	/**
	 * Loads a {@code .png} image from the sub-folder {@code /icons/} of the resource folder and
	 * scales it to the given size.<br>
	 * The suffix {@code .png} is automatically appended.
	 *
	 * @param name the image name without the .png suffix
	 * @param size the size of the image to scale to
	 * @return the loaded image
	 * @since Envoy Client v0.1-beta
	 * @apiNote let's load a sample image {@code /icons/abc.png} in size 16.<br>
	 *          To do that, we only have to call {@code IconUtil.loadIcon("abc", 16)}
	 */
	public static Image loadIcon(String name, int size) {
		return load("/icons/" + name + ".png", size);
	}

	/**
	 * Loads a {@code .png} image whose design depends on the currently active theme from the
	 * sub-folder {@code /icons/dark/} or {@code /icons/light/} of the resource folder.
	 * <p>
	 * The suffix {@code .png} is automatically appended.
	 *
	 * @param name the image name without the "black" or "white" suffix and without the .png suffix
	 * @return the loaded image
	 * @since Envoy Client v0.1-beta
	 * @apiNote let's take two sample images {@code /icons/dark/abc.png} and
	 *          {@code /icons/light/abc.png}, and load one of them.<br>
	 *          To do that theme sensitive, we only have to call
	 *          {@code IconUtil.loadIconThemeSensitive("abc")}
	 */
	public static Image loadIconThemeSensitive(String name) {
		return loadIcon(themeSpecificSubFolder() + name);
	}

	/**
	 * Loads a {@code .png} image whose design depends on the currently active theme from the
	 * sub-folder {@code /icons/dark/} or {@code /icons/light/} of the resource folder and scales it
	 * to the given size.
	 * <p>
	 * The suffix {@code .png} is automatically appended.
	 *
	 * @param name the image name without the .png suffix
	 * @param size the size of the image to scale to
	 * @return the loaded image
	 * @since Envoy Client v0.1-beta
	 * @apiNote let's take two sample images {@code /icons/dark/abc.png} and
	 *          {@code /icons/light/abc.png}, and load one of them in size 16.<br>
	 *          To do that theme sensitive, we only have to call
	 *          {@code IconUtil.loadIconThemeSensitive("abc", 16)}
	 */
	public static Image loadIconThemeSensitive(String name, int size) {
		return loadIcon(themeSpecificSubFolder() + name, size);
	}

	/**
	 * Loads images specified by an enum. The images have to be named like the lowercase enum
	 * constants with {@code .png} extension and be located inside a folder with the lowercase name
	 * of the enum, which must be contained inside the {@code /icons/} folder.
	 *
	 * @param <T>       the enum that specifies the images to load
	 * @param enumClass the class of the enum
	 * @param size      the size to scale the images to
	 * @return a map containing the loaded images with the corresponding enum constants as keys
	 * @since Envoy Client v0.1-beta
	 */
	public static <T extends Enum<T>> EnumMap<T, Image> loadByEnum(Class<T> enumClass, int size) {
		final var	icons	= new EnumMap<T, Image>(enumClass);
		final var	path	= "/icons/" + enumClass.getSimpleName().toLowerCase() + "/";
		for (final var e : EnumSet.allOf(enumClass))
			icons.put(e, load(path + e.toString().toLowerCase() + ".png", size));
		return icons;
	}

	/**
	 * Loads a buffered image from the resource folder which is compatible with AWT.
	 *
	 * @param path the path to the icon inside the resource folder
	 * @return the loaded image
	 * @since Envoy Client v0.2-beta
	 */
	public static BufferedImage loadAWTCompatible(String path) {
		return awtCache.computeIfAbsent(path, p -> {
			try {
				return ImageIO.read(IconUtil.class.getResource(path));
			} catch (IOException e) {
				EnvoyLog.getLogger(IconUtil.class).log(Level.WARNING,
					String.format("Could not load image at path %s: ", path), e);
				return null;
			}
		});
	}

	/**
	 * This method should be called if the display of an image depends upon the currently active
	 * theme.<br>
	 * In case of a default theme, the string returned will be ({@code dark/} or {@code light/}),
	 * otherwise it will be empty.
	 *
	 * @return the theme specific folder
	 * @since Envoy Client v0.1-beta
	 */
	private static String themeSpecificSubFolder() {
		return Settings.getInstance().isUsingDefaultTheme()
			? Settings.getInstance().getCurrentTheme() + "/"
			: "";
	}
}