package chess.io;

import chess.io.Command.CommandResult;
import chess.model.Game;
import chess.model.Game.GameStatus;

public class CommandExecutor {

	private Game game;
	private OutputSystem outputSystem;

	public CommandExecutor() {
		this.game = null;
		this.outputSystem = null;
	}

	public CommandResult executeCommand(Command command) {
		assert this.game != null : "No input game specified !";
		assert this.outputSystem != null : "No output system specified !";

		CommandResult result = command.execute(this.game, this.outputSystem);

		// non player commands are not supposed to return move result
		assert result != CommandResult.Moved || command instanceof PlayerCommand;

		processResult(command, result);
		return result;
	}

	private void processResult(Command command, CommandResult result) {
		switch (result) {
			case NotAllowed:
			case NotMoved:
				return;

			case ActionNeeded:
				this.outputSystem.updateDisplay();
				return;

			case Moved:
				if (checkGameStatus())
					return;
				switchPlayerTurn();
				this.outputSystem.updateDisplay();
				return;
		}
	}

	private void switchPlayerTurn() {
		this.game.switchPlayerTurn();
		this.outputSystem.playerTurn(this.game.getPlayerTurn());
	}

	/**
	 * 
	 * @return True if the game is over
	 */
	private boolean checkGameStatus() {
		GameStatus gameStatus = this.game.checkGameStatus();

		switch (gameStatus) {
			case Check:
				this.outputSystem.kingIsInCheck();
				return false;

			case CheckMate:
				this.outputSystem.kingIsInMat();
				this.outputSystem.winnerIs(this.game.getPlayerTurn());
				return true;

			case OnGoing:
				return false;

			case Pat:
				this.outputSystem.patSituation();
				return true;
		}

		return false;
	}

	public void setOutputSystem(OutputSystem outputSystem) {
		this.outputSystem = outputSystem;
	}

	public void setGame(Game game) {
		this.game = game;
	}

}