package chess.controller.commands;

import chess.controller.PlayerCommand;
import chess.controller.event.GameListener;
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;
	}

	public Piece getDeadPiece() {
		return deadPiece;
	}

	@Override
	public CommandResult execute(Game game, GameListener outputSystem) {
		CommandResult result = processMove(game, outputSystem);

		switch (result) {
			case NotAllowed:
				outputSystem.onMoveNotAllowed(this.move);
				return result;

			case Moved:
				outputSystem.onMove(this.move);
				game.saveTraitPiecesPos();
				return result;

			case ActionNeeded:
			case NotMoved:
				return result;
		}

		return null;
	}

	private CommandResult processMove(Game game, GameListener outputSystem) {
		final ChessBoard board = game.getBoard();

		// we must promote the pending pawn before
		if (board.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.getDeadPieceCoords());
		board.applyMove(move);

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

		if (tryPromote(game, outputSystem)) {
			return CommandResult.ActionNeeded;
		}

		board.setLastMove(this.move);

		return CommandResult.Moved;
	}

	@Override
	protected CommandResult undoImpl(Game game, GameListener outputSystem) {
		final ChessBoard board = game.getBoard();

		game.undoTraitPiecesPos();
		board.undoMove(move, deadPiece);
		return CommandResult.Moved;
	}

	private boolean tryPromote(Game game, GameListener outputSystem) {
		Coordinate pawnPos = game.getBoard().pawnPromotePosition();

		if (pawnPos == null)
			return false;

		outputSystem.onPromotePawn(pawnPos);
		return true;
	}
}