// ReSharper disable MemberCanBePrivate.Global
// ReSharper disable UnusedMember.Global

using System;
using System.Diagnostics;

namespace RGB.NET.Core;

/// <summary>
/// Represents a point consisting of a X- and a Y-position.
/// </summary>
[DebuggerDisplay("[X: {X}, Y: {Y}]")]
public readonly struct Point : IEquatable<Point>
{
    #region Constants

    private static readonly Point INVALID = new(float.NaN, float.NaN);
    /// <summary>
    /// Gets a [NaN,NaN]-Point.
    /// </summary>
    public static ref readonly Point Invalid => ref INVALID;

    #endregion

    #region Properties & Fields

    /// <summary>
    /// Gets the X-position of this <see cref="Point"/>.
    /// </summary>
    public float X { get; }

    /// <summary>
    /// Gets the Y-position of this <see cref="Point"/>.
    /// </summary>
    public float Y { get; }

    #endregion

    #region Constructors

    /// <summary>
    /// Initializes a new instance of the <see cref="Point"/> class using the provided values.
    /// </summary>
    /// <param name="x">The value used for the X-position.</param>
    /// <param name="y">The value used for the Y-position.</param>
    public Point(float x, float y)
    {
        this.X = x;
        this.Y = y;
    }

    #endregion

    #region Methods

    /// <summary>
    /// Converts the <see cref="X"/>- and <see cref="Y"/>-position of this <see cref="Point"/> to a human-readable string.
    /// </summary>
    /// <returns>A string that contains the <see cref="X"/> and <see cref="Y"/>  of this <see cref="Point"/>. For example "[X: 100, Y: 20]".</returns>
    public override string ToString() => $"[X: {X}, Y: {Y}]";

    /// <summary>
    /// Tests whether the specified <see cref="Point" /> is equivalent to this <see cref="Point" />.
    /// </summary>
    /// <param name="other">The point to test.</param>
    /// <returns><c>true</c> if <paramref name="other" /> is equivalent to this <see cref="Point" />; otherwise, <c>false</c>.</returns>
    public bool Equals(Point other) => ((float.IsNaN(X) && float.IsNaN(other.X)) || X.EqualsInTolerance(other.X))
                                    && ((float.IsNaN(Y) && float.IsNaN(other.Y)) || Y.EqualsInTolerance(other.Y));

    /// <summary>
    /// Tests whether the specified object is a <see cref="Point" /> and is equivalent to this <see cref="Point" />.
    /// </summary>
    /// <param name="obj">The object to test.</param>
    /// <returns><c>true</c> if <paramref name="obj" /> is a <see cref="Point" /> equivalent to this <see cref="Point" />; otherwise, <c>false</c>.</returns>
    public override bool Equals(object? obj) => obj is Point other && Equals(other);

    /// <summary>
    /// Returns a hash code for this <see cref="Point" />.
    /// </summary>
    /// <returns>An integer value that specifies the hash code for this <see cref="Point" />.</returns>
    public override int GetHashCode() => HashCode.Combine(X, Y);

    #endregion

    #region Operators

    /// <summary>
    /// Returns a value that indicates whether two specified <see cref="Point" /> are equal.
    /// </summary>
    /// <param name="point1">The first <see cref="Point" /> to compare.</param>
    /// <param name="point2">The second <see cref="Point" /> to compare.</param>
    /// <returns><c>true</c> if <paramref name="point1" /> and <paramref name="point2" /> are equal; otherwise, <c>false</c>.</returns>
    public static bool operator ==(in Point point1, in Point point2) => point1.Equals(point2);

    /// <summary>
    /// Returns a value that indicates whether two specified <see cref="Point" /> are equal.
    /// </summary>
    /// <param name="point1">The first <see cref="Point" /> to compare.</param>
    /// <param name="point2">The second <see cref="Point" /> to compare.</param>
    /// <returns><c>true</c> if <paramref name="point1" /> and <paramref name="point2" /> are not equal; otherwise, <c>false</c>.</returns>
    public static bool operator !=(in Point point1, in Point point2) => !(point1 == point2);

    /// <summary>
    /// Returns a new <see cref="Point"/> representing the addition of the two provided <see cref="Point"/>.
    /// </summary>
    /// <param name="point1">The first <see cref="Point"/>.</param>
    /// <param name="point2">The second <see cref="Point"/>.</param>
    /// <returns>A new <see cref="Point"/> representing the addition of the two provided <see cref="Point"/>.</returns>
    public static Point operator +(in Point point1, in Point point2) => new(point1.X + point2.X, point1.Y + point2.Y);

    /// <summary>
    /// Returns a new <see cref="Rectangle"/> created from the provided <see cref="Point"/> and <see cref="Size"/>.
    /// </summary>
    /// <param name="point">The <see cref="Point"/> of the rectangle.</param>
    /// <param name="size">The <see cref="Size"/> of the rectangle.</param>
    /// <returns>The rectangle created from the provided <see cref="Point"/> and <see cref="Size"/>.</returns>
    public static Rectangle operator +(in Point point, in Size size) => new(point, size);

    /// <summary>
    /// Returns a new <see cref="Point"/> representing the subtraction of the two provided <see cref="Point"/>.
    /// </summary>
    /// <param name="point1">The first <see cref="Point"/>.</param>
    /// <param name="point2">The second <see cref="Point"/>.</param>
    /// <returns>A new <see cref="Point"/> representing the subtraction of the two provided <see cref="Point"/>.</returns>
    public static Point operator -(in Point point1, in Point point2) => new(point1.X - point2.X, point1.Y - point2.Y);

    /// <summary>
    /// Returns a new <see cref="Point"/> representing the multiplication of the two provided <see cref="Point"/>.
    /// </summary>
    /// <param name="point1">The first <see cref="Point"/>.</param>
    /// <param name="point2">The second <see cref="Point"/>.</param>
    /// <returns>A new <see cref="Point"/> representing the multiplication of the two provided <see cref="Point"/>.</returns>
    public static Point operator *(in Point point1, in Point point2) => new(point1.X * point2.X, point1.Y * point2.Y);

    /// <summary>
    /// Returns a new <see cref="Point"/> representing the division of the two provided <see cref="Point"/>.
    /// </summary>
    /// <param name="point1">The first <see cref="Point"/>.</param>
    /// <param name="point2">The second <see cref="Point"/>.</param>
    /// <returns>A new <see cref="Point"/> representing the division of the two provided <see cref="Point"/>.</returns>
    public static Point operator /(in Point point1, in Point point2)
    {
        if (point2.X.EqualsInTolerance(0) || point2.Y.EqualsInTolerance(0)) return Invalid;
        return new Point(point1.X / point2.X, point1.Y / point2.Y);
    }

    /// <summary>
    /// Returns a new <see cref="Point"/> representing the multiplication of the <see cref="Point"/> and the provided <see cref="Scale"/>.
    /// </summary>
    /// <param name="point">The <see cref="Point"/>.</param>
    /// <param name="scale">The <see cref="Scale"/>.</param>
    /// <returns>A new <see cref="Point"/> representing the multiplication of the <see cref="Point"/> and the provided <see cref="Scale"/>.</returns>
    public static Point operator *(in Point point, in Scale scale) => new(point.X * scale.Horizontal, point.Y * scale.Vertical);

    #endregion
}