package gve.calc.formula;

import java.awt.*;

 Controls an operator. 
public class OperatorController {
	
 Note that this method has much in common with IdentifierView.keydn() 
	public static boolean keydn(int key,Container comp) {
		Operator model = (Operator)((View)comp).getModel();
		FormulaView view = FormulaView.get(comp);
		int cp = ((HasCursorPos)comp).getCursorPos();

		String str = model.getName();
		switch (key) {
		case KeydnListener.Key_BS:
			if (comp == view.getCursorComp()) {
				if (comp instanceof HasCursorPos) {
					str = str.substring(0,cp-1) + str.substring(cp);
					Identifier ident;
					view.setCursorPart(ident = model.dismantle(str,view.getFormula()),cp-1);
					if (ident.getParent() instanceof OperatorSpace) {
						OperatorSpace spat = (OperatorSpace)ident.getParent();
						spat.recognizeOp(view);
					}
				}
			}
			return true;
		case KeydnListener.Key_DEL:
			if (cp != str.length()) {
				str = str.substring(0,cp) + str.substring(cp+1);
				view.setCursorPart(model.dismantle(str,view.getFormula()),cp);
			}
			return true;
		default:
			if (key < 32) return false;
			str = new String(new StringBuffer(str).insert(cp,(char)key));
			if (str.equals("  ")) {
				if (key == ' ') str = " ";	/* e.g. typed "x y", cursor on OperatorSpace, then press Space again (6-dec-2000 bug) */
				else str = "";
				cp = -1;
			}
			// Dismantle operator
			Identifier ident;
			view.setCursorPart(ident = model.dismantle(str,view.getFormula()),cp+1);
			// Maybe a new operator name has been formed; recognize
			// In case of a n-ary operator, dismantle() has added
			// n OperatorSpaces as parent, parent's parent, ... of
			// the Identifier. We suppose that n==1 or n==2
			Part par = ident.getParent();
			Part parpar = ident.getParent();
			if (par instanceof OperatorSpace) {
				OperatorSpace spat = (OperatorSpace)par;
				if (spat.recognizeOp(view.getFormula(),view))
					parpar = null;
			}
			if (parpar instanceof OperatorSpace) {
				OperatorSpace spat = (OperatorSpace)parpar;
				spat.recognizeOp(view.getFormula(),view);
			}
			return true;
		}
	}
}