@using Shogi.Contracts.Api;
@using Shogi.Contracts.Types;
@using System.Text.RegularExpressions;
@using System.Net;
@inject ShogiApi ShogiApi;

<div style="position: relative;">
	<GameBoardPresentation Session="Session"
												 Perspective="Perspective"
												 OnClickHand="OnClickHand"
												 OnClickTile="OnClickTile"
												 SelectedPosition="@selectedBoardPosition"
												 SelectedPieceFromHand="@selectedPieceFromHand"
												 IsMyTurn="IsMyTurn" />

	@if (showPromotePrompt)
	{
		<!-- Promote prompt -->
		<!-- TODO: Add a background div which prevents mouse inputs to the board while this decision is being made. -->
		<section class="promote-prompt">
			<p>Do you wish to promote?</p>
			<div>
				<button type="button" @onclick="() => OnClickPromotionChoice(true)">Yes</button>
				<button type="button" @onclick="() => OnClickPromotionChoice(false)">No</button>
				<button type="button" @onclick="() => showPromotePrompt = false">Cancel</button>
			</div>
		</section>
	}
</div>

@code {
	[Parameter, EditorRequired]
	public WhichPlayer Perspective { get; set; }
	[Parameter, EditorRequired]
	public Session Session { get; set; } = default!;
	private bool IsMyTurn => Session?.BoardState.WhoseTurn == Perspective;
	private string? selectedBoardPosition;
	private WhichPiece? selectedPieceFromHand;
	private bool showPromotePrompt;
	private string? moveTo;

	protected override void OnParametersSet()
	{
		base.OnParametersSet();
		selectedBoardPosition = null;
		selectedPieceFromHand = null;
		if (Session == null)
		{
			throw new ArgumentException($"{nameof(Session)} cannot be null.", nameof(Session));
		}
	}

	bool ShouldPromptForPromotion(string position)
	{
		if (Perspective == WhichPlayer.Player1 && Regex.IsMatch(position, ".[7-9]"))
		{
			return true;
		}
		if (Perspective == WhichPlayer.Player2 && Regex.IsMatch(position, ".[1-3]"))
		{
			return true;
		}
		return false;
	}

	async Task OnClickTile(Piece? pieceAtPosition, string position)
	{
		if (!IsMyTurn) return;


		if (selectedBoardPosition == position)
		{
			// Deselect the selected position.
			selectedBoardPosition = null;
			StateHasChanged();
			return;
		}

		if (selectedBoardPosition == null && pieceAtPosition?.Owner == Perspective)
		{
			// Select an owned piece.
			selectedBoardPosition = position;
			// Prevent selecting pieces from the hand and board at the same time.
			selectedPieceFromHand = null;
			StateHasChanged();
			return;
		}

		if (selectedPieceFromHand is not null)
		{
			if (pieceAtPosition is null)
			{
				// Placing a piece from the hand to an empty space.
				var success = await ShogiApi.Move(
						Session.SessionId,
						new MovePieceCommand(selectedPieceFromHand.Value, position));
				if (!success)
				{
					selectedPieceFromHand = null;
				}
			}
			StateHasChanged();
			return;
		}

		if (selectedBoardPosition != null)
		{
			Console.WriteLine("pieceAtPosition is null? {0}", pieceAtPosition == null);

			if (pieceAtPosition == null || pieceAtPosition?.Owner != Perspective)
			{
				// Moving to an empty space or capturing an opponent's piece.
				if (ShouldPromptForPromotion(position) || ShouldPromptForPromotion(selectedBoardPosition))
				{
					Console.WriteLine("Prompt!");
					moveTo = position;
					showPromotePrompt = true;
				}
				else
				{

					Console.WriteLine("OnClick to move to {0}", position);
					var success = await ShogiApi.Move(Session.SessionId, new MovePieceCommand(selectedBoardPosition, position, false));

					Console.WriteLine("Success? {0}", success);
					if (!success)
					{
						selectedBoardPosition = null;
					}
				}
				StateHasChanged();
				return;
			}
		}
	}

	async Task OnClickHand(Piece piece)
	{
		if (!IsMyTurn) return;

		// Prevent selecting from both the hand and the board.
		selectedBoardPosition = null;

		selectedPieceFromHand = piece.WhichPiece == selectedPieceFromHand
				// Deselecting the already-selected piece
				? selectedPieceFromHand = null
				: selectedPieceFromHand = piece.WhichPiece;

		StateHasChanged();
	}

	private Task OnClickPromotionChoice(bool shouldPromote)
	{
		if (selectedBoardPosition == null && selectedPieceFromHand.HasValue && moveTo != null)
		{
			return ShogiApi.Move(Session.SessionId, new MovePieceCommand(selectedPieceFromHand.Value, moveTo));
		}

		throw new InvalidOperationException("Unexpected scenario during OnClickPromotionChoice.");
	}
}