package calculator;

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

public class CalcController implements ActionListener {
 
  /**
   * String for sum command.
   */
  public static final String SUM = "SUM";

  /**
   * String for subtract command.
   */
  public static final String SUBTRACT = "SUBTRACT";

  /**
   * String for multiply command.
   */
  public static final String MULTIPLY = "MULTIPLY";

  /**
   * String for divide command.
   */
  public static final String DIVIDE = "DIVIDE";

  /**
   * String for clear command.
   */
  public static final String CLEAR = "CLEAR";

  private CalcModel model;
  private CalcView view;

  /**
   * Creates a controller with no view and no model.
   * 
   */
  public CalcController() {
    this.model = null;
    this.view = null;
  }

  /**
   * Invoked when an event occurs.
   * 
   * @param event
   *            The event.
   */
  public void actionPerformed(ActionEvent event) {
    // Translates an event into something that the model can do.
    String action = event.getActionCommand();

    if (action.equals(CalcController.CLEAR)) {
      this.getModel().clear();
    } else {
      int userValue = 0;
      try {
        userValue = Integer.parseInt(this.getView().getUserValue());
      } catch (NumberFormatException ex) {
        return;
      }

      if (action.equals(CalcController.SUM)) {
        this.getModel().sum(userValue);
      } else if (action.equals(CalcController.SUBTRACT)) {
        this.getModel().subtract(userValue);
      } else if (action.equals(CalcController.MULTIPLY)) {
        this.getModel().multiply(userValue);
      } else if (action.equals(CalcController.DIVIDE)) {
        if (userValue != 0) {
          this.getModel().divide(userValue);
        }
      }
    }
    int calcValue = this.getModel().getCalcValue();
    this.getView().setCalcValue("" + calcValue);
  }

  /**
   * Returns the view of this controller.
   * 
   * @return the view of this controller.
   */
  public CalcView getView() {
    return this.view;
  }

  /**
   * Sets the view of this controller to the given view.
   * 
   * @param view
   *            the new view of this controller.
   * @pre. view != null
   */
  public void setView(CalcView view) {
    this.view = view;
  }

  /**
   * Returns the model of this controller.
   * 
   * @return the model of this controller.
   */
  public CalcModel getModel() {
    return this.model;
  }

  /**
   * Sets the model of this controller to the given model.
   * 
   * @param model
   *            the new model of this controller.
   * @pre. model != null
   */
  public void setModel(CalcModel model) {
    this.model = model;
  }

}