Copyright (C) 2001, Geert Vernaeve. All Rights Reserved.
  Created 29-jan-2001 
package gve.calc.formula;

import java.awt.*;

// PROBLEM:
// We want to add a "Cmd: " item to the stack where the user enters commands.
// This command is to be an editable Part tree that is *not* a child of the Stack model.
// Currently, the system is not designed to handle this kind of stuff.

public class StackView extends TabularView {
	public StackView(Tabular model, FormulaView view) {
		super(model,view);
		int h = model.getHeight();
		if (h == 0) checklabels();	// Create "Cmd:" stuff
		else for (int i = 0; i < h; i++) {
			// We use CursorPosLabels because they implement HasBaseline.
			add(new CursorPosLabel((h-i)+":"),i*2);
		}
		TabularLayout layout = (TabularLayout)getLayout();
		layout.setCols(2);
	}

	public void updateView(Object with) {
		super.updateView(with);
		checklabels();
	}

	public void addRow(int row) {
		FormulaView view = FormulaView.get(this);
		Stack model = (Stack)getModel();
		int h = model.getHeight();
		add(new CursorPosLabel((h-row)+":"),2 * row);
		add(view.getView(model.elementAt(row)),1 + 2 * row);
		TabularLayout layout = (TabularLayout)getLayout();
		layout.setRows(h);
	}

	public void remRow(int row) {
		Stack model = (Stack)getModel();
		remove(2*row+1);	// remove stack element
		remove(2*row);	// remove label
		TabularLayout layout = (TabularLayout)getLayout();
		layout.setRows(model.getHeight());
	}

	private void checklabels() {
		Stack model = (Stack)getModel();
		int h = model.getHeight();
		if (h == 0) {	// Special case
			if (getComponentCount() == 2) {
				CursorPosLabel lab = (CursorPosLabel)getComponent(0);
				if (!lab.getText().equals("Cmd:")) {
					lab.setText("Cmd:");
					lab.invalidate();
				}
			} else {
				TabularLayout layout = (TabularLayout)getLayout();
				removeAll();
				add(new CursorPosLabel("Cmd:"));
				add(new FormulaView(new Formula()));
//				add(new CursorPosLabel("???"));	// PENDING: must be an IdentifierView ...
				layout.setRows(1);
			}
			return;
		}
		for (int i = h-1; i>=0; i--) {
			CursorPosLabel lab = (CursorPosLabel)getComponent(i*2);
			String shouldbe = (h-i)+":";
			if (lab.getText().equals(shouldbe)) continue;
			lab.setText(shouldbe);
			lab.invalidate();
		}
	}

	public boolean keydn(int key) {
		switch (key) {
		case '\n': {
			Stack model = (Stack)getModel();
			FormulaView view = FormulaView.get(this);
			int child;
			{	Point p = model.whichOffspring(view.getCursorPart());
				if (p == null) break;
				child = p.y;
			}
//			if (child == model.getHeight()) break;
			model.insertRow(child+1);
			view.setCursorPart(model.elementAt(child+1,0));
			return true;
		}
		}
		return super.keydn(key);
	}
}