/*
 * UserProfileUtility.cs
 * Authors: Mike DeMauro
 * Copyright (c) 2007-2008 Cornell University

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; either version 2
 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 General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;

namespace Util
{
    /// <summary>
    /// Loads and tracks users and the current user.
    /// </summary>
    public static class UserProfileUtility
    {
        #region Constants

        /// <summary>
		/// The default directory for writing log files.
		/// </summary>
		public const string DefaultLogDirectory = @"LogFiles\";

		/// <summary>
		/// The default log file.
		/// </summary>
		public const string DefaultLogFile = DefaultLogDirectory + @"ExperimentLog.txt";

        /// <summary>
        /// Directory for save files.
        /// </summary>
        public const string SaveDirectory = @"Saves\";

        /// <summary>
        /// Path of the users directory.
        /// </summary>
        public const string UsersDir = "Users";

        // Path seperator character
        private const char PathSeparator = '\\';

        #endregion

        #region Fields

        // The current user for any game
        private static string mCurrentUser = string.Empty;

        // The event logger
        private static Logger mCurrentLogger;

        // List of user names that profiles exist for
        private static readonly List<string> mUserNames = new List<string>();

        #endregion

        #region Properties

        /// <summary>
        /// Gets/Sets the current user.
        /// </summary>
        /// <exception cref="System.ArgumentException">Cannot be set to null or empty string</exception>
        public static string CurrentUser
        {
            get { return mCurrentUser; }
            set
            {
                if (string.IsNullOrEmpty(value))
                    throw new System.ArgumentException("Cannot set user to null or empty string");
                mCurrentUser = value;
                createLogger();
            }
        }

        /// <summary>
        /// Logs the current user out and disposes of the user's logger.
        /// </summary>
        public static void CurrentUserLogOut()
        {
            mCurrentUser = null;
            DisposeLogger();
        }

        /// <summary>
        /// Gets the current event logger
        /// </summary>
        public static Logger CurrentLogger
        {
            get
            {
                if (mCurrentLogger == null)
                {
                    createLogger();
                }
                return mCurrentLogger;
            }
        }

        private static void createLogger()
        {
            if (mCurrentLogger != null)
            {
                mCurrentLogger.Dispose();
            }
            if (!Directory.Exists(GameScreen.GlobalRootStorageDirectory + OutputDirectory + DefaultLogDirectory))
            {
                Directory.CreateDirectory(GameScreen.GlobalRootStorageDirectory + OutputDirectory + DefaultLogDirectory);
            }
            mCurrentLogger = new Logger(GameScreen.GlobalRootStorageDirectory + OutputDirectory + DefaultLogFile);
            mCurrentLogger.Initialize();
        }

        public static void DisposeLogger()
        {
            if (mCurrentLogger != null)
                mCurrentLogger.Dispose();
        }

        /// <summary>
        /// Gets the current output directory
        /// </summary>
        public static string OutputDirectory
        {
            get
            {
                if (string.IsNullOrEmpty(mCurrentUser))
                {
                    return string.Empty;
                }
				return UsersDir + PathSeparator + mCurrentUser + PathSeparator;
            }
        }

        /// <summary>
        /// Gets the list of users names
        /// </summary>
        public static ReadOnlyCollection<string> UserNames { get { return new ReadOnlyCollection<string>(mUserNames); } }

        #endregion

        #region Methods

        /// <summary>
        /// Load all user names
        /// </summary>
        public static void LoadUserNames()
        {
            if (!Directory.Exists(GameScreen.GlobalRootStorageDirectory + UsersDir))
            {
                Directory.CreateDirectory(GameScreen.GlobalRootStorageDirectory + UsersDir);

            }
            string[] names = Directory.GetDirectories(GameScreen.GlobalRootStorageDirectory + UsersDir);
            foreach (string name in names)
            {
                mUserNames.Add(name.Substring(name.LastIndexOf(PathSeparator) + 1));
            }
        }

        /// <summary>
        /// Creates a new user if one does not exist with the same name.
        /// </summary>
        /// <param name="userName">The name of the user profile to create</param>
        /// <returns>True if the user was created successfully, False if a user with the given name already exists.</returns>
        public static bool CreateUser(string userName)
        {
			if (mUserNames.Contains(userName))
			{
				return false;
			}
            Directory.CreateDirectory(GameScreen.GlobalRootStorageDirectory + UsersDir + PathSeparator + userName);
            mUserNames.Add(userName);
            return true;
        }

        /// <summary>
        /// Deletes a user.
        /// </summary>
        /// <param name="userName">Then name of the user profile to delete</param>
        /// <returns>True if the user was deleted</returns>
        public static bool DeleteUser(string userName)
        {
            // Need to cleanup current user if it is to be deleted
            if (CurrentUser == userName)
            {
                CurrentUserLogOut();
            }

            // Assume something went wrong or nothing happened until finished with delete operation
            bool isSuccessful = false;

            // Location of the user's directory
            string directory = GameScreen.GlobalRootStorageDirectory + UsersDir + PathSeparator + userName;

            if (Directory.Exists(directory))
            {
                try
                {
                    // Delete the directory and the username, remembering the result
                    Directory.Delete(directory, true);
                    isSuccessful = mUserNames.Remove(userName);
                }
                catch (IOException e)
                {
                    // Delete was unsuccessful
                    mCurrentLogger.Write((int)EventCode.Error, "Could not delete directory '" + directory + "'.\n" + e.ToString());
                }
            }

            return isSuccessful;
        }

        #endregion
    }
}