#region ================== Copyright (c) 2007 Pascal vd Heiden

/*
 * Copyright (c) 2007 Pascal vd Heiden, www.codeimp.com
 * This program is released under GNU General Public License
 * 
 * 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.
 * 
 */

#endregion

#region ================== Namespaces

using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.Text;

#endregion

namespace CodeImp.DoomBuilder.Geometry
{
	public struct Vector3D
	{
		#region ================== Constants

		private const float TINY_VALUE = 0.0000000001f;
		
		#endregion

		#region ================== Variables

		// Coordinates
		public float x;
		public float y;
		public float z;

		#endregion

		#region ================== Constructors

		// Constructor
		public Vector3D(float x, float y, float z)
		{
			this.x = x;
			this.y = y;
			this.z = z;
		}

		// Constructor
		public Vector3D(Vector2D v)
		{
			this.x = v.x;
			this.y = v.y;
			this.z = 0f;
		}
		
		#endregion

		#region ================== Statics

		// Conversion to Vector2D
		public static implicit operator Vector2D(Vector3D a)
		{
			return new Vector2D(a);
		}

		// This adds two vectors
		public static Vector3D operator +(Vector3D a, Vector3D b)
		{
			return new Vector3D(a.x + b.x, a.y + b.y, a.z + b.z);
		}

		// This subtracts two vectors
		public static Vector3D operator -(Vector3D a, Vector3D b)
		{
			return new Vector3D(a.x - b.x, a.y - b.y, a.z - b.z);
		}

		// This reverses a vector
		public static Vector3D operator -(Vector3D a)
		{
			return new Vector3D(-a.x, -a.y, -a.z);
		}

		// This scales a vector
		public static Vector3D operator *(float s, Vector3D a)
		{
			return new Vector3D(a.x * s, a.y * s, a.z * s);
		}

		// This scales a vector
		public static Vector3D operator *(Vector3D a, float s)
		{
			return new Vector3D(a.x * s, a.y * s, a.z * s);
		}

		// This scales a vector
		public static Vector3D operator *(Vector3D a, Vector3D b)
		{
			return new Vector3D(a.x * b.x, a.y * b.y, a.z * b.z);
		}
		
		// This scales a vector
		public static Vector3D operator /(float s, Vector3D a)
		{
			return new Vector3D(a.x / s, a.y / s, a.z / s);
		}

		// This scales a vector
		public static Vector3D operator /(Vector3D a, float s)
		{
			return new Vector3D(a.x / s, a.y / s, a.z / s);
		}

		// This compares a vector
		public static bool operator ==(Vector3D a, Vector3D b)
		{
			return (a.x == b.x) && (a.y == b.y) && (a.z == b.z);
		}

		// This compares a vector
		public static bool operator !=(Vector3D a, Vector3D b)
		{
			return (a.x != b.x) || (a.y != b.y) || (a.z != b.z);
		}

		// This calculates the cross product
		public static Vector3D CrossProduct(Vector3D a, Vector3D b)
		{
			Vector3D result = new Vector3D();

			// Calculate and return the dot product
			result.x = a.y * b.z - a.z * b.y;
			result.y = a.z * b.x - a.x * b.z;
			result.z = a.x * b.y - a.y * b.x;
			return result;
		}

		// This calculates the dot product
		public static float DotProduct(Vector3D a, Vector3D b)
		{
			// Calculate and return the dot product
			return a.x * b.x + a.y * b.y + a.z * b.z;
		}

		// This reflects the vector v over mirror m
		// Note that mirror m must be normalized!
		public static Vector3D Reflect(Vector3D v, Vector3D m)
		{
			// Get the dot product of v and m
			float dp = Vector3D.DotProduct(v, m);

			// Make the reflected vector
			Vector3D mv = new Vector3D();
			mv.x = -v.x + 2f * m.x * dp;
			mv.y = -v.y + 2f * m.y * dp;
			mv.z = -v.z + 2f * m.z * dp;

			// Return the reflected vector
			return mv;
		}

		// This returns the reversed vector
		public static Vector3D Reversed(Vector3D v)
		{
			// Return reversed vector
			return new Vector3D(-v.x, -v.y, -v.z);
		}

		// This returns a vector from an angle
		public static Vector3D FromAngleXY(float angle)
		{
			// Return vector from angle
			return new Vector3D((float)Math.Sin(angle), -(float)Math.Cos(angle), 0f);
		}
		
		// This returns a vector from an angle with a given legnth
		public static Vector3D FromAngleXY(float angle, float length)
		{
			// Return vector from angle
			return FromAngleXY(angle) * length;
		}

		// This returns a vector from an angle with a given legnth
		public static Vector3D FromAngleXYZ(float anglexy, float anglez)
		{
			// Calculate x y and z
			float ax = (float)Math.Sin(anglexy) * (float)Math.Cos(anglez);
			float ay = -(float)Math.Cos(anglexy) * (float)Math.Cos(anglez);
			float az = (float)Math.Sin(anglez);

			// Return vector
			return new Vector3D(ax, ay, az);
		}
		
		#endregion
		
		#region ================== Methods

		// This calculates the angle
		public float GetAngleXY()
		{
			// Calculate and return the angle
			return -(float)Math.Atan2(-y, x) + (float)Math.PI * 0.5f;
		}

		// This calculates the angle
		public float GetAngleZ()
		{
			Vector2D xy = new Vector2D(x, y);

			// Calculate and return the angle
			return (float)Math.Atan2(xy.GetLength(), z) + (float)Math.PI * 0.5f;
		}

		// This calculates the length
		public float GetLength()
		{
			// Calculate and return the length
			return (float)Math.Sqrt(x * x + y * y + z * z);
		}

		// This calculates the squared length
		public float GetLengthSq()
		{
			// Calculate and return the length
			return x * x + y * y + z * z;
		}

		// This calculates the length
		public float GetManhattanLength()
		{
			// Calculate and return the length
			return Math.Abs(x) + Math.Abs(y) + Math.Abs(z);
		}

		// This normalizes the vector
		public Vector3D GetNormal()
		{
			float lensq = this.GetLengthSq();
			if(lensq > TINY_VALUE)
			{
				// Divide each element by the length
				float mul = 1f / (float)Math.Sqrt(lensq);
				return new Vector3D(x * mul, y * mul, z * mul);
			}
			else
			{
				// Cannot normalize
				return new Vector3D(0f, 0f, 0f);
			}
		}

		// This scales the vector
		public Vector3D GetScaled(float s)
		{
			// Scale the vector
			return new Vector3D(x * s, y * s, z * s);
		}

		// This changes the vector length
		public Vector3D GetFixedLength(float l)
		{
			// Normalize, then scale
			return this.GetNormal().GetScaled(l);
		}
		
		// This checks if the vector is normalized
		public bool IsNormalized()
		{
			return (Math.Abs(GetLengthSq() - 1.0f) < 0.0001f);
		}
		
		// Output
		public override string ToString()
		{
			return x + ", " + y + ", " + z;
		}
		
		#endregion
	}
}