package moe.nea.ultranotifier.init;

//#if FORGE
//$$import org.spongepowered.asm.lib.tree.ClassNode;
//#else
import org.objectweb.asm.tree.ClassNode;
//#endif
import org.spongepowered.asm.mixin.extensibility.IMixinConfigPlugin;
import org.spongepowered.asm.mixin.extensibility.IMixinInfo;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.stream.Stream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class NeaMixinConfig implements IMixinConfigPlugin {

	private static final List<NeaMixinConfig> mixinPlugins = new ArrayList<>();

	public static List<NeaMixinConfig> getMixinPlugins() {
		return mixinPlugins;
	}

	private String mixinPackage;

	@Override
	public void onLoad(String mixinPackage) {
		this.mixinPackage = mixinPackage;
		mixinPlugins.add(this);
	}

	/**
	 * Resolves the base class root for a given class URL. This resolves either the JAR root, or the class file root.
	 * In either case the return value of this + the class name will resolve back to the original class url, or to other
	 * class urls for other classes.
	 */
	public URL getBaseUrlForClassUrl(URL classUrl) {
		String string = classUrl.toString();
		if (classUrl.getProtocol().equals("jar")) {
			try {
				return new URL(string.substring(4).split("!")[0]);
			} catch (MalformedURLException e) {
				throw new RuntimeException(e);
			}
		}
		if (string.endsWith(".class")) {
			try {
				return new URL(string.replace("\\", "/")
						.replace(getClass().getCanonicalName()
								.replace(".", "/") + ".class", ""));
			} catch (MalformedURLException e) {
				throw new RuntimeException(e);
			}
		}
		return classUrl;
	}

	/**
	 * Get the package that contains all the mixins. This value is set by mixin itself using {@link #onLoad}.
	 */
	public String getMixinPackage() {
		return mixinPackage;
	}

	/**
	 * Get the path inside the class root to the mixin package
	 */
	public String getMixinBaseDir() {
		return mixinPackage.replace(".", "/");
	}

	/**
	 * A list of all discovered mixins.
	 */
	private List<String> mixins = null;

	/**
	 * Try to add mixin class ot the mixins based on the filepath inside of the class root.
	 * Removes the {@code .class} file suffix, as well as the base mixin package.
	 * <p><b>This method cannot be called after mixin initialization.</p>
	 *
	 * @param className the name or path of a class to be registered as a mixin.
	 */
	public void tryAddMixinClass(String className) {
		String norm = (className.endsWith(".class") ? className.substring(0, className.length() - ".class".length()) : className)
				.replace("\\", "/")
				.replace("/", ".");
		if (norm.startsWith(getMixinPackage() + ".") && !norm.endsWith(".")) {
			mixins.add(norm.substring(getMixinPackage().length() + 1));
		}
	}

	/**
	 * Search through the JAR or class directory to find mixins contained in {@link #getMixinPackage()}
	 */
	@Override
	public List<String> getMixins() {
		if (mixins != null) return mixins;
		System.out.println("Trying to discover mixins");
		mixins = new ArrayList<>();
		URL classUrl = getClass().getProtectionDomain().getCodeSource().getLocation();
		System.out.println("Found classes at " + classUrl);
		Path file;
		try {
			file = Paths.get(getBaseUrlForClassUrl(classUrl).toURI());
		} catch (URISyntaxException e) {
			throw new RuntimeException(e);
		}
		System.out.println("Base directory found at " + file);
		if (Files.isDirectory(file)) {
			walkDir(file);
		} else {
			walkJar(file);
		}
		System.out.println("Found mixins: " + mixins);

		return mixins;
	}

	/**
	 * Search through directory for mixin classes based on {@link #getMixinBaseDir}.
	 *
	 * @param classRoot The root directory in which classes are stored for the default package.
	 */
	private void walkDir(Path classRoot) {
		System.out.println("Trying to find mixins from directory");
		try (Stream<Path> classes = Files.walk(classRoot.resolve(getMixinBaseDir()))) {
			classes.map(it -> classRoot.relativize(it).toString())
					.forEach(this::tryAddMixinClass);
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * Read through a JAR file, trying to find all mixins inside.
	 */
	private void walkJar(Path file) {
		System.out.println("Trying to find mixins from jar file");
		try (ZipInputStream zis = new ZipInputStream(Files.newInputStream(file))) {
			ZipEntry next;
			while ((next = zis.getNextEntry()) != null) {
				tryAddMixinClass(next.getName());
				zis.closeEntry();
			}
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}


	@Override
	public String getRefMapperConfig() {
		return null;
	}

	@Override
	public boolean shouldApplyMixin(String targetClassName, String mixinClassName) {
		return true;
	}

	@Override
	public void acceptTargets(Set<String> myTargets, Set<String> otherTargets) {

	}

	@Override
	public void preApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {

	}

	@Override
	public void postApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {

	}
}