/src/PluginLoader.java

import java.io.File;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.net.MalformedURLException;

import java.net.URL;

import java.net.URLClassLoader;

import java.util.ArrayList;

import java.util.EnumMap;

import java.util.HashMap;

import java.util.List;

import java.util.logging.Level;

import java.util.logging.Logger;

import net.minecraft.server.MinecraftServer;



/**

 * PluginLoader.java - Used to load plugins, toggle them, etc.

 * @author James

 */

public class PluginLoader {



    public enum Hook {

        LOGINCHECK,

        LOGIN,

        CHAT,

        COMMAND,

        BAN,

        IPBAN,

        KICK,

        BLOCK_CREATED,

        BLOCK_DESTROYED,

        DISCONNECT,

    }

    private static final Logger log = Logger.getLogger("Minecraft");

    private static final Object lock = new Object();

    private List<Plugin> plugins = new ArrayList<Plugin>();

    private Server server;

    private PropertiesFile properties;



    /**

     * Creates a plugin loader

     * @param server

     */

    public PluginLoader(MinecraftServer server) {

        properties = new PropertiesFile("server.properties");

        this.server = new Server(server);

    }



    /**

     * Loads all plugins.

     */

    public void load() {

        String[] classes = properties.getString("plugins", "").split(",");

        for (String sclass : classes) {

            if (sclass.equals(""))

                continue;

            loadPlugin(sclass);

        }

    }



    private void loadPlugin(String fileName) {

        if (getPlugin(fileName) != null)

            return; //Already exists.



        try {

            File file = new File("plugins/" + fileName + ".jar");

            URLClassLoader child = null;

            try {

                child = new MyClassLoader(new URL[]{file.toURL()}, this.getClass().getClassLoader());

            } catch (MalformedURLException ex) {

                log.log(Level.SEVERE, "Exception while loading class", ex);

            }

            Class c = Class.forName(fileName, true, child);



            try {

                Plugin plugin = (Plugin) c.newInstance();

                plugin.setName(fileName);

                plugin.enable();

                synchronized (lock) {

                    plugins.add(plugin);

                }

            } catch (InstantiationException ex) {

                log.log(Level.SEVERE, "Exception while loading plugin", ex);

            } catch (IllegalAccessException ex) {

                log.log(Level.SEVERE, "Exception while loading plugin", ex);

            }

        } catch (ClassNotFoundException ex) {

            log.log(Level.SEVERE, "Exception while loading plugin", ex);

        }

    }



    /**

     * Reloads the specified plugin

     */

    public void reload(String fileName) {

        /* Not sure exactly how much of this is necessary */

        Plugin toNull = getPlugin(fileName);

        if (toNull.isEnabled())

            toNull.disable();

        plugins.remove(toNull);

        toNull = null;



        try {

            File file = new File("plugins/" + fileName + ".jar");

            URLClassLoader child = null;

            try {

                child = new MyClassLoader(new URL[]{file.toURL()}, this.getClass().getClassLoader());

            } catch (MalformedURLException ex) {

                log.log(Level.SEVERE, "Exception while loading class", ex);

            }

            Class c = Class.forName(fileName, true, child);



            try {

                Plugin plugin = (Plugin) c.newInstance();

                plugin.setName(fileName);

                plugin.enable();

                synchronized (lock) {

                    plugins.add(plugin);

                }

            } catch (InstantiationException ex) {

                log.log(Level.SEVERE, "Exception while reloading plugin", ex);

            } catch (IllegalAccessException ex) {

                log.log(Level.SEVERE, "Exception while reloading plugin", ex);

            }

        } catch (ClassNotFoundException ex) {

            log.log(Level.SEVERE, "Exception while reloading plugin", ex);

        }

    }



    /**

     * Returns the specified plugin

     * @param name

     * @return

     */

    public Plugin getPlugin(String name) {

        synchronized (lock) {

            for (Plugin plugin : plugins) {

                if (plugin.getName().equalsIgnoreCase(name)) {

                    return plugin;

                }

            }

        }

        return null;

    }



    /**

     * Returns a string list of plugins

     * @return

     */

    public String getPluginList() {

        StringBuilder sb = new StringBuilder();

        synchronized (lock) {

            for (Plugin plugin : plugins) {

                sb.append(plugin.getName());

                sb.append(" ");

                sb.append(plugin.isEnabled() ? "(E)" : "(D)");

                sb.append(",");

            }

        }

        String str = sb.toString();

        if (str.length() > 1)

            return str.substring(0, str.length() - 1);

        else

            return "Empty";

    }



    /**

     * Enables the specified plugin (Or adds and enables it)

     * @param name

     * @return

     */

    public boolean enablePlugin(String name) {

        Plugin plugin = getPlugin(name);

        if (plugin != null) {

            if (!plugin.isEnabled()) {

                plugin.toggleEnabled();

                plugin.enable();

            }

        } else { //New plugin, perhaps?

            File file = new File("plugins/" + name + ".jar");

            if (file.exists())

                loadPlugin(name);

            else

                return false;

        }

        return true;

    }



    /**

     * Disables specified plugin

     * @param name

     */

    public void disablePlugin(String name) {

        Plugin plugin = getPlugin(name);

        if (plugin != null) {

            if (plugin.isEnabled()) {

                plugin.toggleEnabled();

                plugin.disable();

            }

        }

    }



    /**

     * Returns the server

     * @return

     */

    public Server getServer() {

        return server;

    }



    /**

     * Calls a plugin hook.

     * @param h

     * @param parameters

     * @return

     */

    public Object callHook(Hook h, Object[] parameters) {

        Object toRet = false;

        synchronized (lock) {

            try {

                for (Plugin plugin : plugins) {

                    if (!plugin.isEnabled())

                        continue;

                    

                    try {

                        switch (h) {

                            case LOGINCHECK:

                                String result = (String)plugin.onLoginChecks((String) parameters[0]);

                                if (result != null)

                                    toRet = result;

                                break;

                            case LOGIN:

                                plugin.onLogin(new Player((ea) parameters[0]));

                                break;

                            case DISCONNECT:

                                plugin.onDisconnect(new Player((ea) parameters[0]));

                                break;

                            case CHAT:

                                if (plugin.onChat(new Player((ea) parameters[0]), (String)parameters[1]))

                                    toRet = true;

                                break;

                            case COMMAND:

                                if (plugin.onCommand(new Player((ea) parameters[0]), (String[])parameters[1]))

                                    toRet = true;

                                break;

                            case BAN:

                                plugin.onBan(new Player((ea) parameters[0]), (String)parameters[1]);

                                break;

                            case IPBAN:

                                plugin.onIpBan(new Player((ea) parameters[0]), (String)parameters[1]);

                                break;

                            case KICK:

                                plugin.onKick(new Player((ea) parameters[0]), (String)parameters[1]);

                                break;

                            case BLOCK_CREATED:

                                if (plugin.onBlockCreate(new Player((ea) parameters[0]), (Block)parameters[1], (Block)parameters[2], (Integer)parameters[3]))

                                    toRet = true;

                                break;

                            case BLOCK_DESTROYED:

                                if (plugin.onBlockDestroy(new Player((ea) parameters[0]), (Block)parameters[1]))

                                    toRet = true;

                                break;

                        }

                    } catch (UnsupportedOperationException ex) {

                    }

                }

            } catch (Throwable ex) {

                log.log(Level.SEVERE, "Exception while calling plugin function (Outdated plugin?)", ex);

            }

        }



        return toRet;

    }

}