Shogi/Shogi.Contracts/Api/Commands/MovePieceCommand.cs

using Shogi.Contracts.Types;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Text.RegularExpressions;

namespace Shogi.Contracts.Api;

public class MovePieceCommand : IValidatableObject
{
	/// <summary>
	/// For serialization.
	/// </summary>
	public MovePieceCommand()
	{
		this.To = string.Empty;
	}

	/// <summary>
	/// Move a piece on the board.
	/// </summary>
	public MovePieceCommand(string from, string to, bool isPromotion)
	{
		this.From = from;
		this.To = to;
		this.IsPromotion = isPromotion;
	}

	/// <summary>
	/// Add a piece to the board from the hand.
	/// </summary>
	public MovePieceCommand(WhichPiece pieceFromHand, string to)
	{
		this.PieceFromHand = pieceFromHand;
		this.To = to;
	}

	/// <summary>
	/// Mutually exclusive with <see cref="From"/>.
	/// Set this property to indicate moving a piece from the hand onto the board.
	/// </summary>
	public WhichPiece? PieceFromHand { get; set; }
	
	/// <summary>
	/// Board position notation, like A3 or G1
	/// Mutually exclusive with <see cref="PieceFromHand"/>.
	/// Set this property to indicate moving a piece from the board to another position on the board.
	/// </summary>
	public string? From { get; set; }

	/// <summary>
	/// Board position notation, like A3 or G1
	/// </summary>
	[Required]
	public string To { get; set; }
	
	public bool? IsPromotion { get; set; }

	public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
	{
		if (this.PieceFromHand.HasValue && !string.IsNullOrWhiteSpace(this.From))
		{
			yield return new ValidationResult($"{nameof(this.PieceFromHand)} and {nameof(this.From)} are mutually exclusive properties.");
		}
		if (this.PieceFromHand.HasValue && this.IsPromotion.HasValue)
		{
			yield return new ValidationResult($"{nameof(this.PieceFromHand)} and {nameof(this.IsPromotion)} are mutually exclusive properties.");
		}
		if (!Regex.IsMatch(this.To, "[A-I][1-9]"))
		{
			yield return new ValidationResult($"{nameof(this.To)} must be a valid board position, between A1 and I9");
		}
		if (!string.IsNullOrEmpty(this.From) && !Regex.IsMatch(this.From, "[A-I][1-9]"))
		{
			yield return new ValidationResult($"{nameof(this.From)} must be a valid board position, between A1 and I9");
		}
	}
}