// Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
// Licensed under the Apache License, Version 2.0.

using System;
using System.Globalization;

namespace ImageMagick;

/// <summary>
/// Struct for a point with doubles.
/// </summary>
public struct PointD : IEquatable<PointD>
{
    /// <summary>
    /// Initializes a new instance of the <see cref="PointD"/> struct.
    /// </summary>
    /// <param name="xy">The x and y.</param>
    public PointD(double xy)
    {
        X = xy;
        Y = xy;
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="PointD"/> struct.
    /// </summary>
    /// <param name="x">The x.</param>
    /// <param name="y">The y.</param>
    public PointD(double x, double y)
    {
        X = x;
        Y = y;
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="PointD"/> struct.
    /// </summary>
    /// <param name="value">PointD specifications in the form: &lt;x&gt;x&lt;y&gt; (where x, y are numbers).</param>
    public PointD(string value)
      : this()
    {
        Throw.IfNullOrEmpty(nameof(value), value);

        Initialize(value);
    }

    /// <summary>
    /// Gets the x-coordinate of this <see cref="PointD"/>.
    /// </summary>
    public double X { get; private set; }

    /// <summary>
    /// Gets the y-coordinate of this <see cref="PointD"/>.
    /// </summary>
    public double Y { get; private set; }

    /// <summary>
    /// Determines whether the specified <see cref="PointD"/> instances are considered equal.
    /// </summary>
    /// <param name="left">The first <see cref="PointD"/> to compare.</param>
    /// <param name="right">The second <see cref="PointD"/> to compare.</param>
    public static bool operator ==(PointD left, PointD right)
        => Equals(left, right);

    /// <summary>
    /// Determines whether the specified <see cref="PointD"/> instances are not considered equal.
    /// </summary>
    /// <param name="left">The first <see cref="PointD"/> to compare.</param>
    /// <param name="right">The second <see cref="PointD"/> to compare.</param>
    public static bool operator !=(PointD left, PointD right)
        => !Equals(left, right);

    /// <summary>
    /// Determines whether the specified object is equal to the current <see cref="PointD"/>.
    /// </summary>
    /// <param name="obj">The object to compare this <see cref="PointD"/> with.</param>
    /// <returns>True when the specified object is equal to the current <see cref="PointD"/>.</returns>
    public override bool Equals(object? obj)
    {
        if (obj is not PointD other)
            return false;

        return Equals(other);
    }

    /// <summary>
    /// Determines whether the specified <see cref="PointD"/> is equal to the current <see cref="PointD"/>.
    /// </summary>
    /// <param name="other">The <see cref="PointD"/> to compare this <see cref="PointD"/> with.</param>
    /// <returns>True when the specified <see cref="PointD"/> is equal to the current <see cref="PointD"/>.</returns>
    public bool Equals(PointD other)
        => X == other.X && Y == other.Y;

    /// <summary>
    /// Serves as a hash of this type.
    /// </summary>
    /// <returns>A hash code for the current instance.</returns>
    public override int GetHashCode()
        => X.GetHashCode() ^ Y.GetHashCode();

    /// <summary>
    /// Returns a string that represents the current PointD.
    /// </summary>
    /// <returns>A string that represents the current PointD.</returns>
    public override string ToString()
        => string.Format(CultureInfo.InvariantCulture, "{0}x{1}", X, Y);

    private void Initialize(string value)
    {
        var values = value.Split('x');
        Throw.IfTrue(nameof(value), values.Length > 2, "Invalid point specified.");

        Throw.IfFalse(nameof(value), double.TryParse(values[0], NumberStyles.Number, CultureInfo.InvariantCulture, out var x), "Invalid point specified.");

        double y;
        if (values.Length == 2)
            Throw.IfFalse(nameof(value), double.TryParse(values[1], NumberStyles.Number, CultureInfo.InvariantCulture, out y), "Invalid point specified.");
        else
            y = x;

        X = x;
        Y = y;
    }
}
