import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;

/**
 * This is the controller for the Unit Converter application.
 */
public class UnitConvController
{
	private UnitConvModel model;
	private UnitConvView view;
	
	/**
	 * Initialises this controller with the passed model and view.
	 * @param model the model to associate with this controller
	 * @param view the view to associate with this controller
	 */
	public UnitConvController(UnitConvModel model, UnitConvView view)
	{
		this.model = model;
		this.view = view;
		
		this.view.addSaveListener(new SaveListener());
		this.view.addCtoFListener(new CToFListener());
		// TODO: Add listeners for reset and the 5 remaining buttons.
		;
	}

	/**
	 * Returns the model associated with this controller.
	 * @return the model
	 */
	public UnitConvModel getModel()
	{
		return model;
	}

	/**
	 * Returns the view associated with this controller.
	 * @return the view
	 */
	public UnitConvView getView()
	{
		return view;
	}


	/**
	 * Abstract base class for classes that listen for conversion events.
	 */
	private abstract class ConversionListener implements ActionListener
	{
		/**
		 * Defines how to perform the conversion.
		 * @param inputValue the value to convert
		 */
		protected abstract void doOperation(double inputValue);
	
		/**
		 * Parses the user's input, delegates to doOperation, then updates
		 * the result value. If the user's input is not parsable as a double,
		 * use Double.NaN instead.		  
		 */
		@Override
		public void actionPerformed(ActionEvent action)
		{
			double userValue = Double.NaN;
			try
			{
				userValue = Double.parseDouble(getView().getInputValue());
			}
			catch(NumberFormatException ex)
			{}
			doOperation(userValue);
			getView().setResultValue("" + getModel().getResultValue());
		}
	}

	private class CToFListener extends ConversionListener
	{
		@Override
		protected void doOperation(double userValue)
		{
			getModel().cToF(userValue);
		}
	}
	
	private class FToCListener extends ConversionListener
	{
		@Override
		protected void doOperation(double userValue)
		{
			// TODO (1 line of code): Delegate conversion to the model.
			// Use CToFListener as a guide.
			;
		}
	}
	
	private class CmToInchesListener extends ConversionListener
	{
		@Override
		protected void doOperation(double userValue)
		{
			// TODO (1 line of code): Delegate conversion to the model.
			// Use CToFListener as a guide.
			;
		}
	}
	
	private class InchesToCmListener extends ConversionListener
	{
		@Override
		protected void doOperation(double userValue)
		{
			// TODO (1 line of code): Delegate conversion to the model.
			// Use CToFListener as a guide.
			;
		}
	}
	
	private class KgToLbsListener extends ConversionListener
	{
		@Override
		protected void doOperation(double userValue)
		{
			// TODO (1 line of code): Delegate conversion to the model.
			// Use CToFListener as a guide.
			;
		}
	}
	
	private class LbsToKgListener extends ConversionListener
	{
		@Override
		protected void doOperation(double userValue)
		{
			// TODO (1 line of code): Delegate conversion to the model.
			// Use CToFListener as a guide.
			;
		}
	}
	
	/**
	 * Abstract base class for classes that listen for menu events
	 */
	private abstract class MenuListener implements ActionListener
	{
		;
	}
	
	private class SaveListener extends MenuListener
	{
		@Override
		public void actionPerformed(ActionEvent action)
		{
			File f = getView().getSaveFile();
			getModel().save(f);
		}
	}

	private class ResetListener extends MenuListener
	{
		@Override
		public void actionPerformed(ActionEvent action)
		{
			// TODO (3 lines of code):
			// 1) Clear the model
			// 2) Set the input value view based on the model's current state
			// 3) Set the result value view based on the model's current state
			;
		}
	}
}