package chess.io.commands;

import chess.io.OutputSystem;
import chess.io.PlayerCommand;
import chess.model.ChessBoard;
import chess.model.Coordinate;
import chess.model.Game;
import chess.model.Move;
import chess.model.Piece;
import chess.model.visitor.PiecePathChecker;

public class MoveCommand extends PlayerCommand {
	
	private final Move move;
	private Piece deadPiece;

	public MoveCommand(Move move) {
		this.move = move;
		this.deadPiece = null;
	}

	public Move getMove() {
		return move;
	}

	@Override
	public CommandResult execute(Game game, OutputSystem outputSystem) {
		final ChessBoard board = game.getBoard();

		// we must promote the pending pawn before
		if (game.pawnShouldBePromoted())
			return CommandResult.NotAllowed;

		Piece piece = board.pieceAt(move.getStart());
		if (piece == null)
			return CommandResult.NotAllowed;

		if (piece.getColor() != game.getPlayerTurn())
			return CommandResult.NotAllowed;

		boolean valid = new PiecePathChecker(board, move).isValid();
		if (!valid)
			return CommandResult.NotAllowed;

		this.deadPiece = board.pieceAt(move.getFinish());
		board.applyMove(move);

		if (board.isKingInCheck(game.getPlayerTurn())) {
			board.undoLastMove();
			return CommandResult.NotAllowed;
		}

		if (game.pawnShouldBePromoted()) 
			return CommandResult.ActionNeeded;

		return CommandResult.Moved;
	}

	@Override
	public void undo(Game game, OutputSystem outputSystem) {
		final ChessBoard board = game.getBoard();

		board.undoMove(move, deadPiece);
	}

	@Override
	public void postExec(Game game, OutputSystem outputSystem) {
		tryPromote(game, outputSystem);
	}

	private void tryPromote(Game game, OutputSystem outputSystem) {
		Coordinate pawnPos = game.pawnPromotePosition();

		if (pawnPos == null)
			return;

		outputSystem.promotePawn(pawnPos);
	}

}