package de.geolykt.starloader.launcher;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;

import org.json.JSONException;
import org.json.JSONObject;
import org.slf4j.LoggerFactory;
import org.stianloader.sll.impl.classtransform.SLLCTMixinTransformer;

import net.minestom.server.extras.selfmodification.MinestomRootClassLoader;

import de.geolykt.starloader.mod.DirectoryExtensionPrototypeList;
import de.geolykt.starloader.mod.NamedExtensionPrototype;
import de.geolykt.starloader.util.JavaInterop;

public class CLILauncher {

    private static Set<Path> getPaths(JSONObject jsonConfig) {

        Set<Path> extraPaths = new HashSet<>();

        //
        for (Object o : jsonConfig.getJSONArray("classPath")) {
            extraPaths.add(Paths.get(o.toString()).toAbsolutePath());
        }
        URI launcherURI;
        try {
            launcherURI = CLILauncher.class.getProtectionDomain().getCodeSource().getLocation().toURI();
        } catch (URISyntaxException e) {
            e.printStackTrace();
            return extraPaths;
        }
        Path launcherPath = Paths.get(launcherURI);
        extraPaths.remove(launcherPath);
        return extraPaths;
    }

    public static void main(String[] args) {
        Set<Path> bootPaths = null;
        try {
            String read = new String(Files.readAllBytes(Paths.get("config.json")), StandardCharsets.UTF_8);
            JSONObject json = new JSONObject(read);
            bootPaths = getPaths(json);
        } catch (JSONException | IOException e) {
            e.printStackTrace();
            if (bootPaths == null) {
                bootPaths = new HashSet<>();
            }
        }

        MinestomRootClassLoader cl = MinestomRootClassLoader.getInstance();
        Thread.currentThread().setContextClassLoader(cl);
        bootPaths.forEach(p -> {
            try {
                cl.addURL(p.toUri().toURL());
            } catch (MalformedURLException e) {
                e.printStackTrace();
            }
        });

        // Start mixins & load extensions
        cl.addASMTransformer(new SLLCTMixinTransformer());

        // ensure extensions are loaded when starting the server
        try {
            Class<?> slClass = cl.loadClass("de.geolykt.starloader.Starloader");
            DirectoryExtensionPrototypeList modSource = new DirectoryExtensionPrototypeList(new File("mods"));

            LoggerFactory.getLogger(CLILauncher.class).info("Using prototypes from following sources:");
            modSource.forEach((prototype) -> {
                prototype.enabled = true;
                if (prototype instanceof NamedExtensionPrototype) {
                    NamedExtensionPrototype namedPrototype = (NamedExtensionPrototype) prototype;
                    LoggerFactory.getLogger(CLILauncher.class).info("- {} v{} (loaded from {})", namedPrototype.name, namedPrototype.version, namedPrototype.originURLs);
                } else {
                    LoggerFactory.getLogger(CLILauncher.class).info("- {}", prototype.originURLs);
                }
            });

            MethodHandles.lookup().findStatic(slClass, "start", MethodType.methodType(void.class, DirectoryExtensionPrototypeList.class)).invokeExact(modSource);
        } catch (Throwable t) {
            t.printStackTrace();
            return;
        }

        // Find & launch main class
        String mainClass = System.getProperty("de.geolykt.starloader.launcher.CLILauncher.mainClass");

        findManifest:
        try {
            if (mainClass != null) {
                break findManifest;
            }

            Enumeration<URL> manifests = cl.getResources("META-INF/MANIFEST.MF");

            URL manifest = null;
            while (manifests.hasMoreElements()) {
                manifest = manifests.nextElement();
            }
            if (manifest == null) {
                throw new IOException("Unable to find jar manifest!");
            }
            try (BufferedReader br = new BufferedReader(new InputStreamReader(manifest.openStream(), StandardCharsets.UTF_8))) {
                for (String ln = br.readLine(); ln != null; ln = br.readLine()) {
                    ln = ln.split("#", 2)[0];
                    if (ln.startsWith("Main-Class:")) {
                        mainClass = ln.split(":", 2)[1].trim();
                        break;
                    }
                }
            } catch (IOException e) {
                throw new IOException("Unable to find jar manifest!", e);
            }
        } catch (IOException t) {
            LoggerFactory.getLogger(CLILauncher.class).warn("Unable to find manifest.", t);
        }

        if (mainClass == null) {
            LoggerFactory.getLogger(CLILauncher.class).error("Unable to find main class! Falling back to com.example.Main");
            mainClass = "com.example.Main";
        }

        LoggerFactory.getLogger(CLILauncher.class).info("Starting main class " + mainClass + " with arguments " + Arrays.toString(args));

        try {
            Class<?> mainClassInstance = cl.loadClass(mainClass);
            if (mainClassInstance.getClassLoader() != cl) {
                LoggerFactory.getLogger(IDELauncher.class).warn("Main class '{}' loaded by wrong Classloader '{}', expected it to be loaded by '{}'. Some runtime anomalies are to be expected; Did you set up the classpaths correctly?", mainClass, JavaInterop.getClassloaderName(mainClassInstance.getClassLoader()), JavaInterop.getClassloaderName(cl));
            }
            Utils.startMain(mainClassInstance, args);
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }
}