CellWithDistance.cs

using System.Collections.Generic;

namespace RT.Coordinates;

/// <summary>
///     Encapsulates a cell and its distance from an origin cell within a structure.</summary>
/// <typeparam name="TCell">
///     Type of cell (e.g., <see cref="Square"/>, <see cref="Hex"/> or <see cref="Tri"/>).</typeparam>
/// <remarks>
///     Used in the return value of <see cref="Structure{TCell}.FindPaths(TCell)"/>.</remarks>
/// <remarks>
///     Constructor.</remarks>
public struct CellWithDistance<TCell>(TCell cell, TCell parent, int distance)
{
    /// <summary>The relevant cell.</summary>
    public TCell Cell { get; private set; } = cell;
    /// <summary>
    ///     The previous cell in the path from the origin cell to this cell.</summary>
    /// <remarks>
    ///     If <see cref="Distance"/> is <c>0</c>, this value is meaningless and must be ignored.</remarks>
    public TCell Parent { get; private set; } = parent;
    /// <summary>
    ///     The amount of steps required to reach this cell from the origin cell. If this is <c>0</c>, this cell is the origin
    ///     cell.</summary>
    public int Distance { get; private set; } = distance;

    /// <inheritdoc/>
    public override readonly bool Equals(object obj) => obj is CellWithDistance<TCell> other && EqualityComparer<TCell>.Default.Equals(Parent, other.Parent) && Distance == other.Distance;

    /// <inheritdoc/>
    public override readonly int GetHashCode() => Parent.GetHashCode() * 1068603923 + Distance;

    /// <summary>Deconstructor.</summary>
    public readonly void Deconstruct(out TCell parent, out int distance)
    {
        parent = Parent;
        distance = Distance;
    }

    /// <summary>Equality operator.</summary>
    public static bool operator ==(CellWithDistance<TCell> left, CellWithDistance<TCell> right) => left.Equals(right);

    /// <summary>Inequality operator.</summary>
    public static bool operator !=(CellWithDistance<TCell> left, CellWithDistance<TCell> right) => !left.Equals(right);
}