Shogi/Shogi.UI/Pages/Play/GameBoard/GameBoardPresentation.razor

@using Shogi.Contracts.Types;
@using System.Text.Json;

<article class="game-board">
	@if (IsSpectating)
	{
		<aside class="icons">
			<div title="You are spectating.">
				<span>Camera icon</span>
			</div>
		</aside>
	}
	<!-- Game board -->
	<section class="board" data-perspective="@Perspective">
		@for (var rank = 1; rank < 10; rank++)
		{
			foreach (var file in Files)
			{
				var position = $"{file}{rank}";
				var piece = Session?.BoardState.Board[position];
				var isSelected = piece != null && SelectedPosition == position;
				<div class="tile" @onclick="OnClickTileInternal(position)"
						 data-position="@(position)"
						 data-selected="@(isSelected)"
						 style="grid-area: @position">
					@if (piece != null)
					{
						<GamePiece Piece="piece" Perspective="Perspective" />
					}
				</div>
			}
		}
		<div class="ruler vertical" style="grid-area: rank">
			<span>9</span>
			<span>8</span>
			<span>7</span>
			<span>6</span>
			<span>5</span>
			<span>4</span>
			<span>3</span>
			<span>2</span>
			<span>1</span>
		</div>
		<div class="ruler" style="grid-area: file">
			<span>A</span>
			<span>B</span>
			<span>C</span>
			<span>D</span>
			<span>E</span>
			<span>F</span>
			<span>G</span>
			<span>H</span>
			<span>I</span>
		</div>
	</section>

	<!-- Side board -->
	@if (Session != null && UseSideboard == true)
	{
		<aside class="side-board PrimaryTheme ThemeVariant--Contrast">
			<div class="player-area">
				<div class="hand">
					@if (opponentHand.Any())
					{
						@foreach (var piece in opponentHand)
						{
							<div class="tile">
								<GamePiece Piece="piece" Perspective="Perspective" />
							</div>
						}
					}
				</div>
				<p class="text-center">Opponent's Hand</p>
			</div>

			<div class="place-self-center">
				<PlayerName Name="@opponentName" IsTurn="!IsMyTurn" InCheck="IsOpponentInCheck" />
				<hr />
				<PlayerName Name="@userName" IsTurn="IsMyTurn" InCheck="IsPlayerInCheck" />
			</div>

			<div class="player-area">
				@if (string.IsNullOrEmpty(Session.Player2) && !string.IsNullOrEmpty(Session.Player1))
				{
					<div class="place-self-center">
						<button @onclick="OnClickJoinGameInternal">Join Game</button>
					</div>
				}
				else
				{
					<p class="text-center">Your Hand</p>
					<div class="hand">
						@if (userHand.Any())
						{
							@foreach (var piece in userHand)
							{
								<div @onclick="OnClickHandInternal(piece)"
										 class="tile"
										 data-selected="@(piece.WhichPiece == SelectedPieceFromHand)">
									<GamePiece Piece="piece" Perspective="Perspective" />
								</div>
							}
						}
					</div>
				}
			</div>

		</aside>
	}
</article>

@code {
	static readonly string[] Files = new[] { "A", "B", "C", "D", "E", "F", "G", "H", "I" };

	/// <summary>
	/// When true, an icon is displayed indicating that the user is spectating.
	/// </summary>
	[Parameter] public bool IsSpectating { get; set; } = false;
	[Parameter] public WhichPlayer Perspective { get; set; }
	[Parameter] public Session? Session { get; set; }
	[Parameter] public string? SelectedPosition { get; set; }
	[Parameter] public WhichPiece? SelectedPieceFromHand { get; set; }
	// TODO: Exchange these OnClick actions for events like "SelectionChangedEvent" and "MoveFromBoardEvent" and "MoveFromHandEvent".
	[Parameter] public EventCallback<string> OnClickTile { get; set; }
	[Parameter] public EventCallback<Piece> OnClickHand { get; set; }
	[Parameter] public EventCallback OnClickJoinGame { get; set; }
	[Parameter] public bool UseSideboard { get; set; } = true;

	private IReadOnlyCollection<Piece> opponentHand;
	private IReadOnlyCollection<Piece> userHand;
	private string? userName;
	private string? opponentName;

	public GameBoardPresentation()
	{
		opponentHand = Array.Empty<Piece>();
		userHand = Array.Empty<Piece>();
		userName = string.Empty;
		opponentName = string.Empty;
	}

	protected override void OnParametersSet()
	{
		base.OnParametersSet();
		if (Session == null)
		{
			opponentHand = Array.Empty<Piece>();
			userHand = Array.Empty<Piece>();
			userName = string.Empty;
			opponentName = string.Empty;
		}
		else
		{
			opponentHand = Perspective == WhichPlayer.Player1
					? this.Session.BoardState.Player2Hand
					: this.Session.BoardState.Player1Hand;
			userHand = Perspective == WhichPlayer.Player1
					? this.Session.BoardState.Player1Hand
					: this.Session.BoardState.Player2Hand;
			userName = Perspective == WhichPlayer.Player1
					? this.Session.Player1
					: this.Session.Player2 ?? "Empty Seat";
			opponentName = Perspective == WhichPlayer.Player1
					? this.Session.Player2 ?? "Empty Seat"
					: this.Session.Player1;
		}
	}

	private bool IsMyTurn => Session?.BoardState.WhoseTurn == Perspective;

	private bool IsPlayerInCheck => Session?.BoardState.PlayerInCheck == Perspective;

	private bool IsOpponentInCheck => Session?.BoardState.PlayerInCheck != null && Session.BoardState.PlayerInCheck != Perspective;

	private Func<Task> OnClickTileInternal(string position) => () =>
	{
		if (IsMyTurn)
		{
			return OnClickTile.InvokeAsync(position);
		}
		return Task.CompletedTask;
	};

	private Func<Task> OnClickHandInternal(Piece piece) => () =>
	{
		if (IsMyTurn)
		{
			return OnClickHand.InvokeAsync(piece);
		}
		return Task.CompletedTask;
	};

	private Task OnClickJoinGameInternal() => OnClickJoinGame.InvokeAsync();
}