/*******************************************************************************
 * Copyright (c) 2001, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Jens Lukowski/Innoopract - initial renaming/restructuring
 *     
 *******************************************************************************/
package org.eclipse.wst.sse.ui.internal.preferences.ui;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IMessageProvider;
import org.eclipse.jface.preference.PreferencePage;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Text;
import org.eclipse.wst.sse.ui.internal.SSEUIMessages;
import org.eclipse.wst.sse.ui.internal.preferences.OverlayPreferenceStore;

/**
 * Generic preference tab page that contains helpful methods
 * 
 * @author amywu
 */
abstract public class AbstractPreferenceTab implements IPreferenceTab {

	Map fCheckBoxes = new HashMap();
	private SelectionListener fCheckBoxListener = new SelectionListener() {
		public void widgetDefaultSelected(SelectionEvent e) {
		}

		public void widgetSelected(SelectionEvent e) {
			Button button = (Button) e.widget;
			fOverlayStore.setValue((String) fCheckBoxes.get(button), button.getSelection());
		}
	};
	private PreferencePage fMainPreferencePage;
	private ModifyListener fNumberFieldListener = new ModifyListener() {
		public void modifyText(ModifyEvent e) {
			numberFieldChanged((Text) e.widget);
		}
	};
	private ArrayList fNumberFields = new ArrayList();
	OverlayPreferenceStore fOverlayStore;
	private ModifyListener fTextFieldListener = new ModifyListener() {
		public void modifyText(ModifyEvent e) {
			Text text = (Text) e.widget;
			fOverlayStore.setValue((String) fTextFields.get(text), text.getText());
		}
	};
	Map fTextFields = new HashMap();

	protected Button addCheckBox(Composite parent, String label, String key, int indentation) {
		Button checkBox = new Button(parent, SWT.CHECK);
		checkBox.setText(label);

		GridData gd = new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING);
		gd.horizontalIndent = indentation;
		gd.horizontalSpan = 2;
		checkBox.setLayoutData(gd);
		checkBox.addSelectionListener(fCheckBoxListener);

		fCheckBoxes.put(checkBox, key);

		return checkBox;
	}

	/**
	 * Returns an array of size 2: - first element is of type
	 * <code>Label</code>- second element is of type <code>Text</code>
	 * Use <code>getLabelControl</code> and <code>getTextControl</code> to
	 * get the 2 controls.
	 */
	private Control[] addLabelledTextField(Composite composite, String label, String key, int textLimit, int indentation, boolean isNumber) {
		Label labelControl = new Label(composite, SWT.NONE);
		labelControl.setText(label);
		GridData gd = new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING);
		gd.horizontalIndent = indentation;
		labelControl.setLayoutData(gd);

		Text textControl = new Text(composite, SWT.BORDER | SWT.SINGLE);
		gd = new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING);
		gd.widthHint = convertWidthInCharsToPixels(textControl, textLimit + 1);
		textControl.setLayoutData(gd);
		textControl.setTextLimit(textLimit);
		fTextFields.put(textControl, key);
		if (isNumber) {
			fNumberFields.add(textControl);
			textControl.addModifyListener(fNumberFieldListener);
		} else {
			textControl.addModifyListener(fTextFieldListener);
		}

		return new Control[]{labelControl, textControl};
	}

	protected Text addTextField(Composite composite, String label, String key, int textLimit, int indentation, boolean isNumber) {
		return getTextControl(addLabelledTextField(composite, label, key, textLimit, indentation, isNumber));
	}

	/**
	 * Applies the status to the status line of a dialog page.
	 */
	private void applyToStatusLine(IStatus status) {
		String message = status.getMessage();
		switch (status.getSeverity()) {
			case IStatus.OK :
				fMainPreferencePage.setMessage(message, IMessageProvider.NONE);
				fMainPreferencePage.setErrorMessage(null);
				break;
			case IStatus.WARNING :
				fMainPreferencePage.setMessage(message, IMessageProvider.WARNING);
				fMainPreferencePage.setErrorMessage(null);
				break;
			case IStatus.INFO :
				fMainPreferencePage.setMessage(message, IMessageProvider.INFORMATION);
				fMainPreferencePage.setErrorMessage(null);
				break;
			default :
				if (message.length() == 0) {
					message = null;
				}
				fMainPreferencePage.setMessage(null);
				fMainPreferencePage.setErrorMessage(message);
				break;
		}
	}

	/**
	 * Returns the number of pixels corresponding to the width of the given
	 * number of characters. This method was copied from
	 * org.eclipse.jface.dialogs.DialogPage
	 * <p>
	 * 
	 * @param a
	 *            control in the page
	 * @param chars
	 *            the number of characters
	 * @return the number of pixels
	 */
	private int convertWidthInCharsToPixels(Control testControl, int chars) {
		// Compute and store a font metric
		GC gc = new GC(testControl);
		gc.setFont(JFaceResources.getDialogFont());
		FontMetrics fontMetrics = gc.getFontMetrics();
		gc.dispose();

		// test for failure to initialize for backward compatibility
		if (fontMetrics == null)
			return 0;
		return Dialog.convertWidthInCharsToPixels(fontMetrics, chars);
	}

	/**
	 * @return Returns the fMainPreferencePage.
	 */
	protected PreferencePage getMainPreferencePage() {
		return fMainPreferencePage;
	}

	/**
	 * @return Returns the fOverlayStore.
	 */
	protected OverlayPreferenceStore getOverlayStore() {
		return fOverlayStore;
	}

	private Text getTextControl(Control[] labelledTextField) {
		return (Text) labelledTextField[1];
	}

	protected void initializeFields() {
		Iterator e = fCheckBoxes.keySet().iterator();
		while (e.hasNext()) {
			Button b = (Button) e.next();
			String key = (String) fCheckBoxes.get(b);
			b.setSelection(fOverlayStore.getBoolean(key));
		}

		e = fTextFields.keySet().iterator();
		while (e.hasNext()) {
			Text t = (Text) e.next();
			String key = (String) fTextFields.get(t);
			t.setText(fOverlayStore.getString(key));
		}
	}

	void numberFieldChanged(Text textControl) {
		String number = textControl.getText();
		IStatus status = validatePositiveNumber(number);
		if (!status.matches(IStatus.ERROR))
			fOverlayStore.setValue((String) fTextFields.get(textControl), number);
		updateStatus(status);
	}

	/**
	 * @param mainPreferencePage
	 *            The fMainPreferencePage to set.
	 */
	protected void setMainPreferencePage(PreferencePage mainPreferencePage) {
		fMainPreferencePage = mainPreferencePage;
	}

	/**
	 * @param overlayStore
	 *            The fOverlayStore to set.
	 */
	protected void setOverlayStore(OverlayPreferenceStore overlayStore) {
		fOverlayStore = overlayStore;
	}

	/**
	 * Update status of main preference page
	 * 
	 * @param status
	 */
	protected void updateStatus(IStatus status) {
		if (!status.matches(IStatus.ERROR)) {
			for (int i = 0; i < fNumberFields.size(); i++) {
				Text text = (Text) fNumberFields.get(i);
				IStatus s = validatePositiveNumber(text.getText());
				status = s.getSeverity() > status.getSeverity() ? s : status;
			}
		}

		fMainPreferencePage.setValid(!status.matches(IStatus.ERROR));
		applyToStatusLine(status);
	}

	private IStatus validatePositiveNumber(String number) {
		StatusInfo status = new StatusInfo();
		if (number.length() == 0) {
			status.setError(SSEUIMessages.StructuredTextEditorPreferencePage_37);
		} else {
			try {
				int value = Integer.parseInt(number);
				if (value < 0)
					status.setError(number + SSEUIMessages.StructuredTextEditorPreferencePage_38);
			} catch (NumberFormatException e) {
				status.setError(number + SSEUIMessages.StructuredTextEditorPreferencePage_38);
			}
		}
		return status;
	}
}
