Copyright (C) 2000, 2001, Geert Vernaeve. All Rights Reserved. 
package gve.calc.formula;

import java.awt.*;

 Controls a binary infix operator. 
public class InfixBinaryOpController extends OperatorController {
	public static HasCursorPos getOperatorView(Container comp) {
		return (HasCursorPos)comp.getComponent(1);
	}

	public static boolean keydn(int key,Container comp) {
		BinaryOp model = (BinaryOp)((View)comp).getModel();
		FormulaView view = FormulaView.get(comp);
		switch (key) {
		case KeydnListener.Key_LEFT:
			if (comp == view.getCursorComp()) {
				// actual cursor pos is stored in middle child
				HasCursorPos operatorComp = getOperatorView(comp);
				int cp = operatorComp.getCursorPos();
				if (cp > 0) {
					operatorComp.setCursorPos(cp - 1);
				} else {
					view.setCursorPart(model.left,HasCursorPos.Somewhere_RIGHT);
				}
				return true;
			} else if (Part.isDescendantOr(view.getCursorPart(),model.right)) {
				// Cannot go more to the left in a (sub)child on the right side
				// so move to the middle
				view.setCursorComp(comp);	// disactivate old cursor
				getOperatorView(comp).setCursorPos(HasCursorPos.Somewhere_RIGHT);
				return true;
			}
			return false;
		case KeydnListener.Key_RIGHT:
			if (comp == view.getCursorComp()) {
				// actual cursor pos is stored in middle child
				HasCursorPos operatorComp = getOperatorView(comp);
				int cp = operatorComp.getCursorPos();
				if (cp < model.getName().length()) {
					operatorComp.setCursorPos(cp + 1);
				} else {
					view.setCursorPart(model.right,HasCursorPos.Somewhere_LEFT);
				}
				return true;
			} else if (Part.isDescendantOr(view.getCursorPart(),model.left)) {
				// Cannot go more to the right in a (sub)child on the left side
				// so move to the middle
				view.cursorOff();	// disactivate old cursor; may cause the child to recognize operator
				Formula f = view.getFormula();
				if (!f.contains(model)) {	// e.g. the child recognized it was an operator upon deactivate()
					if (f.contains(model.right))
						// try at least to showe some cursor
						view.setCursorPart(model.right);
					return true;
				}
				// Next two lines are obsoleted by the introduction of MYLEFT
//				view.setCursorComp(comp);	// disactivate old cursor
//				getOperatorView(comp).setCursorPos(HasCursorPos.Somewhere_LEFT);
				view.setCursorPart(model,HasCursorPos.Somewhere_MYLEFT);
				return true;
			}
			return false;
		case KeydnListener.Key_BS:
			if (comp == view.getCursorComp()) {
				HasCursorPos operatorComp = getOperatorView(comp);
				int cp = operatorComp.getCursorPos();
				if (cp == 0) {	// push backspace when cursor is at leftmost position in operator name
					// => go to left child and push backspace there.
					operatorComp.deactivate();
					view.setCursorPart(model.left,HasCursorPos.Somewhere_RIGHT);
					return ((KeydnListener)view.getCursorComp()).keydn(key);
				}
			}
		}
		return OperatorController.keydn(key,comp);	// dismantle operator
	}
}