package net.sourceforge.pain.plugin;


import net.sourceforge.pain.util.*;

import java.io.*;


final class PluginClassLoader extends ClassLoader {

    /**
     * in this release every plugin should have it's own package (1pack to 1plug) inside net.sf.pain.plugins
     * we need this info during plugins load (to separate classloaders for different plugins using it classnames)
     */
    final String pluginDir;

    private Plugin plugin;
    public final PluginManager plm;
    private int number;//for debug

    protected PluginClassLoader(PluginManager plm, String pluginName) throws Exception {
        number = plm.counter++;
        Log.debug("PlugCL[" + number + "]:creating:" + pluginName);
        this.plm = plm;
        int i = pluginName.indexOf('.');
        pluginDir = pluginName.substring(0, i + 1);
        Class pluginClass = _loadClass(plm.PLUGINS_HOME_PREFIX + pluginName);
        plugin = (Plugin) pluginClass.newInstance();
        //plugin.loader = this;
        plugin.pluginName = pluginName;
        plugin.init();
    }

    public Class loadClass(String className) throws ClassNotFoundException {
        if (!className.startsWith(plm.PLUGINS_HOME_PREFIX) || className.indexOf('.', plm.PLUGINS_HOME_PREFIX_LENGTH) == -1) {
            return Class.forName(className);
        }
        // this class is from plugins package->check if this package is for this classloader
        if (!className.substring(plm.PLUGINS_HOME_PREFIX_LENGTH).startsWith(pluginDir)) {
            // this is class with different class loader
            return plm.loadClassByPluginClassloader(plugin.pluginName, className);
        }
        return _loadClass(className);
    }

    private Class _loadClass(String className) throws ClassNotFoundException {
        Log.debug("PlugCL[" + number + "] Classloader: _loadClass:" + className);
        Class c = findLoadedClass(className);
        if (c == null) {
            c = defineClassFromFile(className);
        } else {
            Log.debug("[" + number + "]PLM Classloader: _loadClass: found loaded:" + className);
        }
        return c;
    }

    public Plugin getPlugin() {
        return plugin;
    }

    protected Class defineClassFromFile(String className) throws ClassNotFoundException {
        Log.debug("PlugCL[" + number + "] Classloader: defineClass:" + className);
        try {
            byte[] data = IOUtils.getFileData(plm.classesDir + "/" + className.replace('.', '/') + ".class");
            return super.defineClass(className, data, 0, data.length);
        } catch (IOException e) {
            Log.error(e.getMessage(), e);
            throw new ClassNotFoundException("Class File Not Found:" + plm.classesDir + "/" + className + ".class");
        }
    }

}