/*
 * Created on Feb 13, 2005
 *
 * TODO To change the template for this generated file go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
package webraveler.ravel;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Hashtable;

/**
 * @author schmitzc
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class UserStack {
	private Hashtable users;
	private Hashtable userPassHash;
	private Raveler ravel;
	
	/**
	 * 
	 * @param ravel
	 */
	public UserStack (Raveler ravel){
		this.ravel = ravel;
		users = new Hashtable();
		userPassHash = new Hashtable();
		
		gatherUsers();
	}
	
	/**
	 * Gets the password for the given username
	 * 
	 * @param username a string containing the username
	 * @return a string containing the password
	 */
	public String getUserPassword(String username) {
		return (String) userPassHash.get(username);
	}
	
	/**
	 * Returns an Enumeration of all the current users
	 * 
	 * @return
	 */
	public Enumeration getUsers(){
		return users.keys();
	}
	/**
	 * Detemines whether a RavelerUser with the given username 
	 * is in the UserStack
	 * 
	 * @param username a string containing the username
	 * @return a boolean existence value 
	 */
	public boolean userExists(String username) {
		return users.containsKey(username);
	} //userExists(String)
	
	/**
	 * Gets the RavelerUser associated with the given username
	 * 
	 * @param username a string containing the username
	 * @return a RavelerUser associated with the given username
	 */
	public RavelerUser getUser(String username) throws RavelerException{
		RavelerUser user = null;
		if (userExists(username)) {
			user = (RavelerUser) users.get(username);
			return user;
		} else
			throw new RavelerException("Unable to get the user: A RavelerUser with the given username does not exist.");
	}  //getUser(String)
	
	/**
	 * Creates a RavelerUser for the given username and adds it to the
	 * Users vector
	 *
	 * @param username a string containing the username
	 */
	public void addUser(RavelerUser user) throws RavelerException {
		if (!users.containsKey(user.username)) {
			users.put(user.username,user);
		} // if
		else
			throw new RavelerException("UserStack: Unable to create a new user: A RavelerUser with the given username already exists.");
		
	} //createUser(String)
	
	/**
	 * Deletes a user from the Users vector
	 *
	 * @param username a string containing the username
	 */
	public void deleteUser(String username) throws RavelerException {
		if (!users.containsKey(username)) {
			users.remove(username);
		} // if
		else
			throw new RavelerException("UserStack: Unable to delete the user: A RavelerUser with the given username does not exist.");
		
	} //deleteUser(String)
	
	/**
	 * Fills the users hashtable with users from the users.txt file, 
	 * sets up the username/password hashtable, and
	 * loads the plugin attributes for each user
	 *
	 */
	private void gatherUsers() {
		// populate the users vector from the users.txt file (for now) ... then try
		// to load the attributes files for those users and the plugins we found
		// (so we don't have to do it later)... if we don't find an attributes file
		// for a plugin and a given user, load the default attributes for the user.
		// then, when the plugin runs, it merely has to fetch the latest attributes
		// from the user, not from the disk
		
		FileReader userFileReader = null;
		FileWriter userFileWriter;
		BufferedReader userFileBuffReader;
		
		try {
			userFileReader = new FileReader(Raveler.WEBRAVELER_HOME + "/data/users.txt");
		} catch (FileNotFoundException fnfe) {
			try{
				System.out.println("UserStack: No users.txt found. . . Attempting to create one.");
				userFileWriter = new FileWriter("users.txt");
				userFileWriter.close(); /* not going to need this one for a while... just creating the file */
				userFileReader = new FileReader("users.txt");
				System.out.println("UserStack: Successfully created users.txt");
			} catch(IOException ioe) {
				System.out.println("UserStack: Could neither open nor create users.txt in your WebRaveler2 directory. Exiting.");
				System.exit(1);
			}
		}
		
		// read in the usernames and passwords from the disk, and put 'em in [yet another] hash
		// table
		
		System.out.println("UserStack: Reading username/password file and populating hash table.");
		
		int colonIndex;
		String username;
		String password;
		String line;
		userFileBuffReader = new BufferedReader(userFileReader);
		
		try {
			while ((line = userFileBuffReader.readLine()) != null) {
				colonIndex = line.indexOf(":");
				username = line.substring(0,colonIndex);
				password = line.substring(colonIndex+1,line.length());
				userPassHash.put(username,password);
				RavelerUser currentUser = new RavelerUser(username);
				try {
				  this.addUser(currentUser); /* add a new user object with this username to the hash table */
				} catch (RavelerException re) {
					System.out.println(re.getMessage());
				}
				try {
					currentUser.readPreferences();
				} catch (RavelerException re) {
					// System.out.println("Raveler: Loading "+username+"'s preferences. Success? " + loaded);
					// save the empty preferences hash table to disk 
					try {
						currentUser.savePreferences();
					} catch (RavelerException rave) {
						System.out.println("UserStack: Couldn't save user preferences file to disk. Exiting.");
						System.exit(1);
					} //catch
					//   System.out.println("Raveler: Saved blank user preferences to disk for user "+username+".");
				} //catch
				// set up plugin attributes (using defaults as necessary) for each plugin in this
				// user's prefs hash 
				for( Enumeration e=ravel.getPlugins() ; e.hasMoreElements() ;  ) {
					RavelerPlugin plugin = (RavelerPlugin) e.nextElement();
					/* if the plugin doesn't have an entry in the user's prefs hash, add the defaults
					 * and set the default status of the plugin */
					if ( ! currentUser.preferences.containsKey(plugin.name) ) {
						//System.out.println("Raveler: Adding defaults for "+plugin.name+" to preferences for user "+username+".");
						plugin.setDefaultAttributes();
						plugin.setDefaultStatus();
						currentUser.preferences.put(plugin.name,plugin.attributes);
					} //if
					//   System.out.println("Raveler: User "+username+" already has preferences for "+plugin.name+".  Continuing.");
				} //for
				// System.out.print("Raveler: User "+username+"'s preferences loaded successfully. Saving any modifications. . . ");
				try {
					currentUser.savePreferences();
					// System.out.println("["+saved+"]");
				}  catch (RavelerException re) {
					System.out.println("UserStack: Couldn't save user preferences file to disk. Exiting.");
					System.exit(1);
				} //catch
			}//while
			userFileReader.close();
		} catch(IOException ioe) {
			ioe.printStackTrace();
		}
	} //gatherUsers()
	
	/**
	 * Saves a user's settings to disk
	 *
	 * @param username A string containing the username
	 */
	public void saveUserSettings(String username) throws RavelerException {
		/* Save the user preferences for the RavelerUser with the given username */
		if (userExists(username)) {    
			RavelerUser user = getUser(username);
			try {
				user.savePreferences();
			} catch (RavelerException re) {
				throw new RavelerException(re.getMessage());
			} //catch
		} // if
		else 
			throw new RavelerException("Unable to save the user's preferences.");
	} //saveUserSettings(String)

}