/*
 * Util.Random.cs
 * Authors: Adam Nabinger
 * 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 Microsoft.Xna.Framework;

namespace Util
{
	/// <summary>
	/// Static wrapper for randomness
	/// </summary>
	public static class Random
	{
		#region Fields

		// The random number generator
		private static readonly System.Random random = new System.Random();

		#endregion

		#region Next

		/// <summary>
		/// Returns a nonnegative random number (0 to 2,147,483,647).
		/// </summary>
		/// <returns>A 32-bit signed integer greater than or equal to zero and less than MaxValue.</returns>
		public static int Next()
		{
			return random.Next();
		}

		/// <summary>
		/// Returns a nonnegative random number less than the specified maximum.
		/// </summary>
		/// <param name="max">The exclusive upper bound of the random number to be generated. maxValue must be greater than or equal to zero.</param>
		/// <returns>A 32-bit signed integer greater than or equal to zero, and less than maxValue; that is, the range of return values ordinarily includes zero but not maxValue. However, if maxValue equals zero, maxValue is returned.</returns>
		public static int Next(int max)
		{
			return random.Next(max);
		}

		/// <summary>
		/// Returns a random number within a specified range.
		/// </summary>
		/// <param name="min">The inclusive lower bound of the random number returned.</param>
		/// <param name="max">The exclusive upper bound of the random number returned. maxValue must be greater than or equal to minValue.</param>
		/// <returns>A 32-bit signed integer greater than or equal to minValue and less than maxValue; that is, the range of return values includes minValue but not maxValue. If minValue equals maxValue, minValue is returned.</returns>
		public static int Next(int min, int max)
		{
			return random.Next(min, max);
		}

		#endregion

		#region NextDouble

		/// <summary>
		/// Returns a random number between 0.0 and 1.0.
		/// </summary>
		/// <returns>A double-precision floating point number greater than or equal to 0.0, and less than 1.0.</returns>
		public static double NextDouble()
		{
			return random.NextDouble();
		}

		/// <summary>
		/// Returns a random number between 0.0 and max.
		/// </summary>
		/// <param name="max">The exclusive upper bound of the random number to be generated. maxValue must be greater than or equal to zero.</param>
		/// <returns>A double-precision floating point number greater than or equal to zero, and less than maxValue; that is, the range of return values ordinarily includes zero but not maxValue. However, if maxValue equals zero, maxValue is returned.</returns>
		public static double NextDouble(double max)
		{
			return max * random.NextDouble();
		}

		/// <summary>
		/// Returns a random number between min and max.
		/// </summary>
		/// <param name="min">The inclusive lower bound of the random number returned.</param>
		/// <param name="max">The exclusive upper bound of the random number returned. maxValue must be greater than or equal to minValue.</param>
		/// <returns>A double-precision floating point number greater than or equal to minValue and less than maxValue; that is, the range of return values includes minValue but not maxValue. If minValue equals maxValue, minValue is returned.</returns>
		public static double NextDouble(double min, double max)
		{
			return min + ((max - min) * random.NextDouble());
		}

		#endregion

		#region NextFloat

		/// <summary>
		/// Returns a random number between 0.0 and 1.0.
		/// </summary>
		/// <returns>A single-precision floating point number greater than or equal to 0.0, and less than 1.0.</returns>
		public static float NextFloat()
		{
			return (float)random.NextDouble();
		}

		/// <summary>
		/// Returns a random number between 0.0 and max.
		/// </summary>
		/// <param name="max">The exclusive upper bound of the random number to be generated. maxValue must be greater than or equal to zero.</param>
		/// <returns>A single-precision floating point number greater than or equal to zero, and less than maxValue; that is, the range of return values ordinarily includes zero but not maxValue. However, if maxValue equals zero, maxValue is returned.</returns>
		public static float NextFloat(float max)
		{
			return max * ((float)random.NextDouble());
		}

		/// <summary>
		/// Returns a random number between min and max.
		/// </summary>
		/// <param name="min">The inclusive lower bound of the random number returned.</param>
		/// <param name="max">The exclusive upper bound of the random number returned. maxValue must be greater than or equal to minValue.</param>
		/// <returns>A single-precision floating point number greater than or equal to minValue and less than maxValue; that is, the range of return values includes minValue but not maxValue. If minValue equals maxValue, minValue is returned.</returns>
		public static float NextFloat(float min, float max)
		{
			return min + ((max - min) * ((float)random.NextDouble()));
		}

		#endregion

		#region RandomVector3

		/// <summary>
		/// Returns 3 independant, random floats as a vector3.
		/// </summary>
		/// <param name="min">The inclusive lower bound of the random number returned.</param>
		/// <param name="max">The exclusive upper bound of the random number returned. maxValue must be greater than or equal to minValue.</param>
		/// <returns>A vector of 3 single-precision floating point numbers whose values are greater than or equal to minValue and less than maxValue; that is, the range of return values includes minValue but not maxValue. If minValue equals maxValue, minValue is returned.</returns>
		public static Vector3 RandomVector3(Vector3 min, Vector3 max)
		{
			return new Vector3(NextFloat(min.X, max.X), NextFloat(min.Y, max.Y), NextFloat(min.Z, max.Z));
		}

		#endregion

		#region Random Binary

		/// <summary>
		/// Returns -1 or +1 with roughly equal likelyhood.
		/// </summary>
		/// <returns>-1 or +1 with roughly equal likelyhood.</returns>
		public static int Sign()
		{
			unchecked
			{
				return (random.Next(2) << 1) - 1;
			}
		}

		/// <summary>
		/// Returns true or false with roughly equal likelyhood.
		/// </summary>
		/// <returns>True or false with roughly equal likelyhood.</returns>
		public static bool Bool()
		{
			return random.Next(2) > 0;
		}

		#endregion
	}
}