/*
  neon - Embeddable HTTP Server based on jdk.httpserver
  Copyright (C) 2024  Ulrich Hilger

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU Affero General Public License as
  published by the Free Software Foundation, either version 3 of the
  License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License
  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
package de.uhilger.neon;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Enumeration;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

/**
 * Die Klasse JarScanner enthaelt Methoden, um fuer eine Klasse zu bestimmen, in 
 * welcher JAR-Datei sie liegt und diese JAR-Datei nach Klassen zu durchsuchen.
 * 
 * @author Ulrich Hilger
 * @version 0.1, 30.11.2024
 */
public class JarScanner {
  
  
  public void processZipContent(ClassLoader urlCL, File archive, String packageName, JarScannerListener l, Handler h, String contextName) {
    try {
      ZipFile zipfile = new ZipFile(archive);
      Enumeration en = zipfile.entries();
      while (en.hasMoreElements()) {
        ZipEntry zipentry = (ZipEntry) en.nextElement();
        if (!zipentry.isDirectory()) {
          processZipEntry(urlCL, zipentry, packageName, l, h, contextName);
        } else {
          // ZIP-Dir muss nicht bearbeitet werden
        }
      }
      zipfile.close();
    } catch (IOException ex) {
      log(Level.SEVERE, ex.getLocalizedMessage());
    }
  }

  private void processZipEntry(ClassLoader urlCL, ZipEntry zipentry, String packageName, JarScannerListener l, Handler h, String contextName) {
    log(Level.FINEST, zipentry.getName());
    String zName = zipentry.getName();
    if (zName.toLowerCase().endsWith(".class")) {
      int pos = zName.indexOf(".class");
      String fullClassName = zName.substring(0, pos);
      log(Level.FINEST, "full class name: " + zName);
      String fullClassNameDots = fullClassName.replace('/', '.');
      log(Level.FINEST, "full class name dots: " + fullClassNameDots);
      String pkgName = getPackageName(fullClassNameDots);
      log(Level.FINEST, " -- package name: " + pkgName);
      if (null != urlCL && pkgName.toLowerCase().startsWith(packageName)) {
        Class c = null;
        try {
          c = urlCL.loadClass(fullClassNameDots);
          if (c != null) {
            if (c.isAnnotationPresent(Actor.class)) {
              log(Level.FINER, " ---- ACTOR ---- " + fullClassNameDots);
              l.actorFound(c, h, contextName);
            } else {
              log(Level.FINER, "kein Actor " + fullClassNameDots);
            }
          } else {
            log(Level.FINER, "class NOT loaded: " + zName);
          }
        } catch (ClassNotFoundException ex) {
          log(Level.FINER, " +++++ Class not found: " + ex.getMessage());
        }
      }
    }
  }
  
  private String getPackageName(String fullClassName) {
    String packageName;
    int pos = fullClassName.lastIndexOf(".");
    if (pos > 0) {
      packageName = fullClassName.substring(0, pos);
    } else {
      packageName = fullClassName;
    }
    return packageName;
  }
  
  public ClassLoader getUrlClassLoader(Class c) {
    URL url;
    ClassLoader urlCL = null;
    try {
      url = getPath(c).toURL();
      log(Level.FINER, "url: " + url.getPath());
      urlCL = new URLClassLoader(new URL[]{url});
    } catch (URISyntaxException ex) {
      log(Level.SEVERE, ex.getMessage());
    } catch (MalformedURLException ex) {
      log(Level.SEVERE, ex.getMessage());
    } finally {
      return urlCL;
    }
  }
  
  public URI getPath(Class c) throws URISyntaxException {
    //Class c = this.getClass();
    String className = c.getName();
    finer("this name: " + className);
    
    int pos = className.indexOf(".class");
    if(pos > -1) {
      String classNameWoExt = className.substring(0, pos);
    }
    String classNameWoPkg = className.substring(className.lastIndexOf(".") + 1);
    finer("Class name: " + classNameWoPkg);
    String classPath = c.getResource(classNameWoPkg + ".class").getPath();
    pos = classPath.indexOf("!");
    String jarPath;
    if(pos > -1) {
      jarPath = /*"jar:" + */ classPath.substring(0, pos);
    } else {
      jarPath = classPath;
    }
    finer("path: " + jarPath);
    return new URI(jarPath);
  }
  
  private void finer(String msg) {
    log(Level.FINER, msg);
  }
  
  private void log(Level l, String msg) {
    Logger.getLogger(JarScanner.class.getName()).log(l, msg);
  }
  
  
  public interface JarScannerListener {
    public void actorFound(Class actorClass, Handler h, String contextName);
  }
  
}