/*
 * Created on Nov 26, 2004
 *
 * TODO To change the template for this generated file go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
package webraveler.ravel;

import java.io.File;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

import webraveler.http.HTTPRequest;
import webraveler.http.HTTPResponse;

/**
 * A PluginStack handles running the plugins on 
 * various requests/responses, as well as the 
 * bookkeeping operations such as ordering, etc.
 * 
 * @author martinsa
 */
public class PluginStack {
	private Vector plugins;
	private Raveler ravel;
	private boolean DEBUG = false;
	
	/**
	 * Make a new PluginStack given a Raveler instance 
	 * 
	 * @param ravel
	 */
	public PluginStack(Raveler ravel) {
		plugins = new Vector();
		this.ravel = ravel;
		
		gatherPlugins();
	}//PluginStack(Raveler)
	
	
	/**
	 * Return an Enumeration of all the plugins we know about.
	 *
	 * @return an Enumeration of the loaded plugins
	 */
	public Enumeration getPlugins() {
		return plugins.elements();
	}//Enumeration plugins()

	
	/**
	 * 
	 */
	public void initializePlugins() {
		/* Initialize the plugins */
		boolean success;
		for( Enumeration e=getPlugins() ; e.hasMoreElements() ;  ) {
			RavelerPlugin plugin = (RavelerPlugin) e.nextElement();
			success = plugin.initialize();
		}
	}
	
	/**
	 * Send the request through the applicable plugins, returning the result.
	 *
	 * @param user the RavelerUser making the request
	 * @param request an HTTPRequest object submitted for modifications
	 * @param ravel the Raveler object against which we're matching plugin information
	 * @return        an HTTPRequest object, the result of running the plugins on the request
	 */
	public HTTPRequest passThroughPlugins(RavelerUser user, HTTPRequest request) throws PluginCallbackException {
		/* does the user have Raveler on or off? */
		if (!user.ravelOn) {
			if (DEBUG) System.out.println("PluginStack: Raveler turned off, not raveling page");
			return request;
		} //if
		else {
			/* Send the request to the plugins */
			for (Enumeration e = plugins.elements() ; e.hasMoreElements() ;) {
				RavelerPlugin plugin = (RavelerPlugin) e.nextElement();
				
				/* only execute the user's active plugins */
				if ( !user.activePlugins.contains(plugin.name)) continue;
				
				try {
					request = plugin.execute(request,(Hashtable) user.preferences.get(plugin.name), user.username);
				}
				catch (RavelerWarningException rwe) {
					if ( DEBUG ) System.out.println("PluginStack: plugin "+plugin.name+" generated an warning.  Attempting to pass along modified content.");
					/* Print the warning */
					RavelerWarning warn = rwe.getWarning();
					String message;
					if (warn != null) {}
					else if ((message = rwe.getMessage()) != null)
						warn = new RavelerWarning(message);
					else
						warn = new RavelerWarning(100);
					//ravel.printWarning(plugin.name,warn,request.uriString());
					/* Try to pass along the modified content */
					HTTPRequest errRequest = rwe.getRequest();
					if (errRequest != null) {
						request = errRequest;
					} //if
				} //catch (RavelerWarningException)
				catch(RavelerErrorException ree) {
					if (DEBUG) System.out.println("PluginStack: Plugin "+plugin.name+" generated an error.  Skipping to next plugin.");
					/* Print the error */
					RavelerError err = ree.getError();
					String message;
					if (err != null) {}
					else if (( message = ree.getMessage()) != null)
						err = new RavelerError(message);
					else
						err = new RavelerError(100);
					//ravel.printError(plugin.name,err,request.uriString());
				} //catch
			} // for
		}//else
		return request;
	}//passThroughPlugins(request)
	
	
	

	/**
	 * Send the response through the applicable plugins, returning the result.
	 *
	 * @param currentUser the RavelerUser making the request
	 * @param response an HTTPResponse object submitted for modifications
	 * @param url a String containing the url being raveled
	 * @return        an HTTPResponse object, the result of running the plugins on the response
	 */
	public HTTPResponse passThroughPlugins(RavelerUser currentUser, HTTPResponse response, String url) {
		HTTPResponse modResponse = response; /* change the original */
		modResponse.uriString = url;
		
		/* let's send the response through the plugin vector ... */
		String contentType = modResponse.getHeader("content-type");
		if (contentType != null) contentType = contentType.toLowerCase();
		int pluginNum = currentUser.activePlugins.size();
		for (int i = 0; i < pluginNum ; i++) {
			String pluginName = (String) currentUser.activePlugins.get(i);
			for (Enumeration e = plugins.elements() ; e.hasMoreElements() ;) {
				RavelerPlugin plugin = (RavelerPlugin) e.nextElement();
				//	System.out.println("CONTENT TYPE: "+contentType);
				if ( contentType != null ) {
					int index = contentType.indexOf(";");
					if ( index != -1 ) {
						contentType = contentType.substring(0, index);
					}//if
				}
				if ( pluginName.equals(plugin.name) && contentType != null && plugin.mimeTypes.contains(contentType)) {
					try {
						modResponse = plugin.execute(modResponse,(Hashtable) currentUser.preferences.get(plugin.name), currentUser.username);
					}
					catch (RavelerWarningException rwe) {
						if (DEBUG) System.out.println("GetUnframedDocumentVURL: plugin "+plugin.name+" generated an warning.");
						/* Print the warning */
						RavelerWarning warn = rwe.getWarning();
						String message;
						if (warn != null) {}
						else if ((message = rwe.getMessage()) != null)
							warn = new RavelerWarning(message);
						else
							warn = new RavelerWarning(100);
						//ravel.printWarning(plugin.name,warn,url);
						/* Try to pass along the modified content */
						HTTPResponse errResponse = rwe.getResponse();
						if (errResponse != null) {
							if (DEBUG) System.out.println("GetUnframedDocumentVURL: Attempting to pass along modified content.");
							modResponse = errResponse;
						} //if
					} //catch (RavelerWarningException)
					catch (RavelerErrorException ree) {
						if ( DEBUG ) System.out.println("GetUnframedDocumentVURL: plugin "+plugin.name+" generated an error.  Skipping to next plugin.");
						/* Print the error */
						RavelerError err = ree.getError();
						String message;
						if (err != null) {}
						else if (( message = ree.getMessage()) != null)
							err = new RavelerError(message);
						else
							err = new RavelerError(100);
						//ravel.printError(plugin.name,err,url);
					}//catch (RavelerWarningException)
					catch( PluginCallbackException pce ) {
						if ( DEBUG ) System.out.println("GUDVURL: Plugin generated callback response.");
						return pce.getResponse();
					}//catch
				} //if
			} // for
		}// for
		return modResponse;
	}//passThroughPlugins(response)
	
	
	
	/**
	 * Fill the plugins Vector with plugins from the 
	 * user's plugin directory
	 */
	private void gatherPlugins() {
		File pluginDir = new File(Raveler.WEBRAVELER_HOME + "/bin/webraveler/plugin");
		String pluginFileList[] = pluginDir.list();
		String fileName;
		Class pluginClass;
		boolean added;
		int count = 0;
		if (pluginFileList == null) return;
		
		//instantiate Plugin objects as necessary
		//and add 'em to the plugins Vector
		for ( int i=0,j=pluginFileList.length;   i < j;   i++ ) {
			fileName = pluginFileList[i];
			if (fileName.endsWith("Plugin.class")) {
				try{
					pluginClass = Class.forName("webraveler.plugin."+fileName.substring(0,fileName.length()-6));
					added = plugins.add(pluginClass.newInstance());
					count++;
					System.out.println("Loaded " + fileName);
				}catch(Exception e) { e.printStackTrace(); }
			}//if
		}//for
		
		for (Enumeration e = plugins.elements(); e.hasMoreElements() ;) {
			RavelerPlugin plugin = (RavelerPlugin) e.nextElement();
			plugin.ravel = ravel;
		} //for
		if ( DEBUG ) System.out.println("PluginStack: Found "+count+" plugins in plugin directory");
	}//void gatherPlugins()
}//class PluginStack