#region License

/* MoonWorks - Game Development Framework
 * Copyright 2021 Evan Hemsley
 */

/* Derived from code by Ethan Lee (Copyright 2009-2021).
 * Released under the Microsoft Public License.
 * See fna.LICENSE for details.

 * Derived from code by the Mono.Xna Team (Copyright 2006).
 * Released under the MIT License. See monoxna.LICENSE for details.
 */

#endregion

#region Using Statements
using System;
using System.Numerics;
#endregion

namespace Nerfed.Runtime.Graphics.PackedVector;

/// <summary>
/// Packed vector type containing unsigned normalized values ranging from 0 to 1.
/// The x and z components use 5 bits, and the y component uses 6 bits.
/// </summary>
public struct Bgra5551 : IPackedVector<ushort>, IEquatable<Bgra5551>, IPackedVector
{
	#region Public Properties

	/// <summary>
	/// Gets and sets the packed value.
	/// </summary>
	public ushort PackedValue
	{
		get
		{
			return packedValue;
		}
		set
		{
			packedValue = value;
		}
	}

	#endregion

	#region Private Variables

	private ushort packedValue;

	#endregion

	#region Public Constructors

	/// <summary>
	/// Creates a new instance of Bgra5551.
	/// </summary>
	/// <param name="x">The x component</param>
	/// <param name="y">The y component</param>
	/// <param name="z">The z component</param>
	/// <param name="w">The w component</param>
	public Bgra5551(float x, float y, float z, float w)
	{
		packedValue = Pack(x, y, z, w);
	}

	/// <summary>
	/// Creates a new instance of Bgra5551.
	/// </summary>
	/// <param name="vector">
	/// Vector containing the components for the packed vector.
	/// </param>
	public Bgra5551(Vector4 vector)
	{
		packedValue = Pack(vector.X, vector.Y, vector.Z, vector.W);
	}

	#endregion

	#region Public Methods

	/// <summary>
	/// Gets the packed vector in Vector4 format.
	/// </summary>
	/// <returns>The packed vector in Vector4 format</returns>
	public Vector4 ToVector4()
	{
		return new Vector4(
			((packedValue >> 10) & 0x1F) / 31.0f,
			((packedValue >> 5) & 0x1F) / 31.0f,
			(packedValue & 0x1F) / 31.0f,
			(float) (packedValue >> 15)
		);
	}

	#endregion

	#region IPackedVector Methods

	/// <summary>
	/// Sets the packed vector from a Vector4.
	/// </summary>
	/// <param name="vector">Vector containing the components.</param>
	void IPackedVector.PackFromVector4(Vector4 vector)
	{
		packedValue = Pack(vector.X, vector.Y, vector.Z, vector.W);
	}

	#endregion

	#region Public Static Operators and Override Methods

	/// <summary>
	/// Compares an object with the packed vector.
	/// </summary>
	/// <param name="obj">The object to compare.</param>
	/// <returns>True if the object is equal to the packed vector.</returns>
	public override bool Equals(object obj)
	{
		return (obj is Bgra5551) && Equals((Bgra5551) obj);
	}

	/// <summary>
	/// Compares another Bgra5551 packed vector with the packed vector.
	/// </summary>
	/// <param name="other">The Bgra5551 packed vector to compare.</param>
	/// <returns>True if the packed vectors are equal.</returns>
	public bool Equals(Bgra5551 other)
	{
		return packedValue == other.packedValue;
	}

	/// <summary>
	/// Gets a string representation of the packed vector.
	/// </summary>
	/// <returns>A string representation of the packed vector.</returns>
	public override string ToString()
	{
		return packedValue.ToString("X");
	}

	/// <summary>
	/// Gets a hash code of the packed vector.
	/// </summary>
	/// <returns>The hash code for the packed vector.</returns>
	public override int GetHashCode()
	{
		return packedValue.GetHashCode();
	}

	public static bool operator ==(Bgra5551 lhs, Bgra5551 rhs)
	{
		return lhs.packedValue == rhs.packedValue;
	}

	public static bool operator !=(Bgra5551 lhs, Bgra5551 rhs)
	{
		return lhs.packedValue != rhs.packedValue;
	}

	#endregion

	#region Private Static Pack Method

	private static ushort Pack(float x, float y, float z, float w)
	{
		return (ushort) (
			(((ushort) System.Math.Round(Math.Clamp(x, 0, 1) * 31.0f)) << 10) |
			(((ushort) System.Math.Round(Math.Clamp(y, 0, 1) * 31.0f)) << 5) |
			((ushort) System.Math.Round(Math.Clamp(z, 0, 1) * 31.0f)) |
			((ushort) System.Math.Round(Math.Clamp(w, 0, 1)) << 15)
		);
	}

	#endregion
}