/*******************************************************************************
 * Copyright (c) 2006 IBM Corporation.
 * 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 - Jeff Briggs, Henry Hughes, Ryan Morse
 *******************************************************************************/

package org.eclipse.linuxtools.internal.systemtap.ui.ide;

import java.text.MessageFormat;
import java.util.LinkedList;
import java.util.List;

import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.viewers.ArrayContentProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.window.Window;
import org.eclipse.linuxtools.internal.systemtap.ui.ide.editors.stp.STPEditor;
import org.eclipse.linuxtools.systemtap.ui.editor.actions.file.NewFileAction;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IEditorReference;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.dialogs.ListDialog;

/**
 * A simple class that contains information about the current session of the IDE, such as
 * the path to the tapset libraries, and the active SystemTap Script Editor.
 * @author Ryan Morse
 */
public class IDESessionSettings {
	public static String tapsetLocation = ""; //$NON-NLS-1$

	/**
	 * Use {@link IDESessionSettings#setActiveSTPEditor(STPEditor)} and
	 * {@link IDESessionSettings#getActiveSTPEditor()}
	 */
	private static STPEditor activeSTPEditor = null;

	/**
	 * Returns the most recent active {@link STPEditor} script editor if one was
	 * set. If one was not set and there is only one {@link STPEditor} script editor
	 * open then that one is returned. Otherwise returns null.
	 * @return The most recent active {@link STPEditor}
	 * @since 1.2
	 */
	public static STPEditor getActiveSTPEditor() {
		if (activeSTPEditor == null) {
			// If no active editor is et and there is only one
			// opened stap script editor, set it to be the active editor.
			IEditorReference[] editors = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().getEditorReferences();
			STPEditor stpEditor = null;
			for (IEditorReference editor: editors) {
				if (editor.getId().equals(STPEditor.ID)) {
					if (stpEditor == null) {
						stpEditor = (STPEditor) editor.getEditor(true);
					} else {
						return null;
					}
				}
			}
			activeSTPEditor = stpEditor;
		}
		return activeSTPEditor;
	}

	/**
	 * Sets the current active editor.
	 * @param editor the active editor.
	 * @since 1.2
	 */
	public static void setActiveSTPEditor(STPEditor editor) {
		activeSTPEditor = editor;
	}

	/**
	 * Restore and return an STPEditor based on the user's choice.
	 * @param checkCurrent Set to <code>true</code> if the currently active editor may be returned
	 * if it is an {@link STPEditor}.
	 * @return
	 */
	public static STPEditor getOrAskForActiveSTPEditor(boolean checkCurrent) {
		STPEditor stpEditor;
		IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
		IWorkbenchPage page = window.getActivePage();
		if (checkCurrent) {
			IEditorPart editor = page.getActiveEditor();
			stpEditor = editor instanceof STPEditor ? (STPEditor) editor : askForSTPEditor(window);
		} else {
			stpEditor = askForSTPEditor(window);
		}
		if (stpEditor != null) {
			page.activate(stpEditor);
		}
		return stpEditor;
	}

	private static STPEditor askForSTPEditor(IWorkbenchWindow window) {
		final List<STPEditor> allEditors = new LinkedList<>();
		for (IEditorReference editor : window.getActivePage().getEditorReferences()) {
			if (editor.getId().equals(STPEditor.ID)) {
				allEditors.add((STPEditor) editor.getEditor(true));
			}
		}

		switch (allEditors.size()) {
		// If only one file is found, open it. Give user the option to open another file.
		case 1:
			MessageDialog messageDialog = new MessageDialog(window.getShell(),
					Localization.getString("GetEditorAction.DialogTitle"), null, //$NON-NLS-1$
					MessageFormat.format(Localization.getString("GetEditorAction.AskBeforeOpenMessage"), //$NON-NLS-1$
							allEditors.get(0).getEditorInput().getName() ),
							MessageDialog.QUESTION,
							new String[]{Localization.getString("GetEditorAction.AskBeforeOpenCancel"), //$NON-NLS-1$
				Localization.getString("GetEditorAction.AskBeforeOpenAnother"), //$NON-NLS-1$
				Localization.getString("GetEditorAction.AskBeforeOpenYes")}, 2); //$NON-NLS-1$

			switch (messageDialog.open()) {
			case 2:
				return allEditors.get(0);

			case 1:
				return openNewFile(window);

			default:
				return null;
			}

		// If no files found, prompt user to open a new file
		case 0:
			return openNewFile(window);

		// If multiple files found, prompt user to select one of them
		default:
			return openNewFileFromMultiple(window, allEditors);
		}
	}

	private static STPEditor openNewFileFromMultiple(IWorkbenchWindow window, final List<STPEditor> allEditors) {
		ListDialog listDialog = new ListDialog(window.getShell());
		listDialog.setTitle(Localization.getString("GetEditorAction.DialogTitle")); //$NON-NLS-1$
		listDialog.setContentProvider(new ArrayContentProvider());

		listDialog.setLabelProvider(new LabelProvider() {
			@Override
			public String getText(Object element) {
				int i = (Integer) element;
				return i != -1 ? allEditors.get(i).getEditorInput().getName()
						: Localization.getString("GetEditorAction.OtherFile"); //$NON-NLS-1$
			}
		});

		Integer[] editorIndexes = new Integer[allEditors.size() + 1];
		for (int i = 0; i < editorIndexes.length - 1; i++) {
			editorIndexes[i] = i;
		}
		editorIndexes[editorIndexes.length - 1] = -1;
		listDialog.setInput(editorIndexes);
		listDialog.setMessage(Localization.getString("GetEditorAction.SelectEditor")); //$NON-NLS-1$
		if (listDialog.open() == Window.OK) {
			int result = (Integer) listDialog.getResult()[0];
			return result != -1 ? allEditors.get(result) : openNewFile(window);
		}
		// Abort if user cancels
		return null;
	}

	private static STPEditor openNewFile(IWorkbenchWindow window) {
		NewFileAction action = new NewFileAction();
		action.run();
		if (action.isSuccessful()) {
			return (STPEditor) window.getActivePage().getActiveEditor();
		}
		return null;
	}
}