/*******************************************************************************
 * Copyright (c) 2000, 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
 *******************************************************************************/
package org.eclipse.ui.wizards.datatransfer;

import java.io.File;
import java.io.FileFilter;
import java.lang.reflect.InvocationTargetException;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IProjectDescription;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceStatus;
import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.SubProgressMonitor;
import org.eclipse.jface.dialogs.ErrorDialog;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.wizard.WizardPage;
import org.eclipse.osgi.util.NLS;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.DirectoryDialog;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Text;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.actions.WorkspaceModifyOperation;
import org.eclipse.ui.internal.ide.IDEWorkbenchPlugin;
import org.eclipse.ui.internal.ide.IIDEHelpContextIds;
import org.eclipse.ui.internal.wizards.datatransfer.DataTransferMessages;

/**
 * Standard main page for a wizard that creates a project resource from
 * whose location already contains a project.
 * <p>
 * This page may be used by clients as-is; it may be also be subclassed to suit.
 * </p>
 * <p>
 * Example usage:
 * <pre>
 * mainPage = new WizardExternalProjectImportPage("basicNewProjectPage");
 * mainPage.setTitle("Project");
 * mainPage.setDescription("Create a new project resource.");
 * </pre>
 * </p>
 */
public class WizardExternalProjectImportPage extends WizardPage {

    private FileFilter projectFilter = new FileFilter() {
        //Only accept those files that are .project
        public boolean accept(File pathName) {
            return pathName.getName().equals(
                    IProjectDescription.DESCRIPTION_FILE_NAME);
        }
    };

    //Keep track of the directory that we browsed to last time
    //the wizard was invoked.
    private static String previouslyBrowsedDirectory = ""; //$NON-NLS-1$

    // widgets
    private Text projectNameField;

    private Text locationPathField;

    private Button browseButton;

    private IProjectDescription description;

    private Listener locationModifyListener = new Listener() {
        public void handleEvent(Event e) {
            setPageComplete(validatePage());
        }
    };

    // constants
    private static final int SIZING_TEXT_FIELD_WIDTH = 250;

    /**
     * Creates a new project creation wizard page.
     *
     */
    public WizardExternalProjectImportPage() {
        super("wizardExternalProjectPage"); //$NON-NLS-1$
        setPageComplete(false);
        setTitle(DataTransferMessages.WizardExternalProjectImportPage_title);
        setDescription(DataTransferMessages.WizardExternalProjectImportPage_description);

    }

    /** (non-Javadoc)
     * Method declared on IDialogPage.
     */
    public void createControl(Composite parent) {

        initializeDialogUnits(parent);

        Composite composite = new Composite(parent, SWT.NULL);

        PlatformUI.getWorkbench().getHelpSystem().setHelp(composite,
                IIDEHelpContextIds.NEW_PROJECT_WIZARD_PAGE);

        composite.setLayout(new GridLayout());
        composite.setLayoutData(new GridData(GridData.FILL_BOTH));
        composite.setFont(parent.getFont());

        createProjectNameGroup(composite);
        createProjectLocationGroup(composite);
        validatePage();
        // Show description on opening
        setErrorMessage(null);
        setMessage(null);
        setControl(composite);
    }

    /**
     * Creates the project location specification controls.
     *
     * @param parent the parent composite
     */
    private final void createProjectLocationGroup(Composite parent) {

        // project specification group
        Composite projectGroup = new Composite(parent, SWT.NONE);
        GridLayout layout = new GridLayout();
        layout.numColumns = 3;
        projectGroup.setLayout(layout);
        projectGroup.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
        projectGroup.setFont(parent.getFont());

        // new project label
        Label projectContentsLabel = new Label(projectGroup, SWT.NONE);
        projectContentsLabel.setText(DataTransferMessages.WizardExternalProjectImportPage_projectContentsLabel);
        projectContentsLabel.setFont(parent.getFont());

        createUserSpecifiedProjectLocationGroup(projectGroup);
    }

    /**
     * Creates the project name specification controls.
     *
     * @param parent the parent composite
     */
    private final void createProjectNameGroup(Composite parent) {

        Font dialogFont = parent.getFont();

        // project specification group
        Composite projectGroup = new Composite(parent, SWT.NONE);
        GridLayout layout = new GridLayout();
        layout.numColumns = 2;
        projectGroup.setFont(dialogFont);
        projectGroup.setLayout(layout);
        projectGroup.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));

        // new project label
        Label projectLabel = new Label(projectGroup, SWT.NONE);
        projectLabel.setText(DataTransferMessages.WizardExternalProjectImportPage_nameLabel);
        projectLabel.setFont(dialogFont);

        // new project name entry field
        projectNameField = new Text(projectGroup, SWT.BORDER | SWT.READ_ONLY);
        GridData data = new GridData(GridData.FILL_HORIZONTAL);
        data.widthHint = SIZING_TEXT_FIELD_WIDTH;
        projectNameField.setLayoutData(data);
        projectNameField.setFont(dialogFont);
        projectNameField.setBackground(parent.getDisplay().getSystemColor(
                SWT.COLOR_WIDGET_BACKGROUND));
    }

    /**
     * Creates the project location specification controls.
     *
     * @param projectGroup the parent composite
     */
    private void createUserSpecifiedProjectLocationGroup(Composite projectGroup) {

        Font dialogFont = projectGroup.getFont();

        // project location entry field
        this.locationPathField = new Text(projectGroup, SWT.BORDER);
        GridData data = new GridData(GridData.FILL_HORIZONTAL);
        data.widthHint = SIZING_TEXT_FIELD_WIDTH;
        this.locationPathField.setLayoutData(data);
        this.locationPathField.setFont(dialogFont);

        // browse button
        this.browseButton = new Button(projectGroup, SWT.PUSH);
        this.browseButton.setText(DataTransferMessages.DataTransfer_browse);
        this.browseButton.setFont(dialogFont);
        setButtonLayoutData(this.browseButton);

        this.browseButton.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent event) {
                handleLocationBrowseButtonPressed();
            }
        });

        locationPathField.addListener(SWT.Modify, locationModifyListener);
    }

    /**
     * Returns the current project location path as entered by 
     * the user, or its anticipated initial value.
     *
     * @return the project location path, its anticipated initial value, or <code>null</code>
     *   if no project location path is known
     */
    public IPath getLocationPath() {

        return new Path(getProjectLocationFieldValue());
    }

    /**
     * Creates a project resource handle for the current project name field value.
     * <p>
     * This method does not create the project resource; this is the responsibility
     * of <code>IProject::create</code> invoked by the new project resource wizard.
     * </p>
     *
     * @return the new project resource handle
     */
    public IProject getProjectHandle() {
        return ResourcesPlugin.getWorkspace().getRoot().getProject(
                getProjectName());
    }

    /**
     * Returns the current project name as entered by the user, or its anticipated
     * initial value.
     *
     * @return the project name, its anticipated initial value, or <code>null</code>
     *   if no project name is known
     */
    public String getProjectName() {
        return getProjectNameFieldValue();
    }

    /**
     * Returns the value of the project name field
     * with leading and trailing spaces removed.
     * 
     * @return the project name in the field
     */
    private String getProjectNameFieldValue() {
        if (projectNameField == null)
            return ""; //$NON-NLS-1$

        return projectNameField.getText().trim();
    }

    /**
     * Returns the value of the project location field
     * with leading and trailing spaces removed.
     * 
     * @return the project location directory in the field
     */
    private String getProjectLocationFieldValue() {
        return locationPathField.getText().trim();
    }

    /**
     *	Open an appropriate directory browser
     */
    private void handleLocationBrowseButtonPressed() {
        DirectoryDialog dialog = new DirectoryDialog(locationPathField
                .getShell());
        dialog.setMessage(DataTransferMessages.WizardExternalProjectImportPage_directoryLabel);

        String dirName = getProjectLocationFieldValue();
        if (dirName.length() == 0)
            dirName = previouslyBrowsedDirectory;

        if (dirName.length() == 0)
            dialog.setFilterPath(getWorkspace().getRoot().getLocation()
                    .toOSString());
        else {
            File path = new File(dirName);
            if (path.exists())
                dialog.setFilterPath(new Path(dirName).toOSString());
        }

        String selectedDirectory = dialog.open();
        if (selectedDirectory != null) {
            previouslyBrowsedDirectory = selectedDirectory;
            locationPathField.setText(previouslyBrowsedDirectory);
            setProjectName(projectFile(previouslyBrowsedDirectory));
        }
    }

    /**
     * Returns whether this page's controls currently all contain valid 
     * values.
     *
     * @return <code>true</code> if all controls are valid, and
     *   <code>false</code> if at least one is invalid
     */
    private boolean validatePage() {

        String locationFieldContents = getProjectLocationFieldValue();

        if (locationFieldContents.equals("")) { //$NON-NLS-1$
            setErrorMessage(null);
            setMessage(DataTransferMessages.WizardExternalProjectImportPage_projectLocationEmpty);
            return false;
        }

        IPath path = new Path(""); //$NON-NLS-1$
        if (!path.isValidPath(locationFieldContents)) {
            setErrorMessage(DataTransferMessages.WizardExternalProjectImportPage_locationError);
            return false;
        }

        File projectFile = projectFile(locationFieldContents);
        if (projectFile == null) {
            setErrorMessage(NLS.bind(DataTransferMessages.WizardExternalProjectImportPage_notAProject, locationFieldContents));
            return false;
        }
        setProjectName(projectFile);

        if (getProjectHandle().exists()) {
            setErrorMessage(DataTransferMessages.WizardExternalProjectImportPage_projectExistsMessage);
            return false;
        }

        setErrorMessage(null);
        setMessage(null);
        return true;
    }

    private IWorkspace getWorkspace() {
        IWorkspace workspace = IDEWorkbenchPlugin.getPluginWorkspace();
        return workspace;
    }

    /**
     * Return whether or not the specifed location is a prefix
     * of the root.
     */
    private boolean isPrefixOfRoot(IPath locationPath) {
        return Platform.getLocation().isPrefixOf(locationPath);
    }

    /**
     * Set the project name using either the name of the
     * parent of the file or the name entry in the xml for 
     * the file
     */
    private void setProjectName(File projectFile) {

        //If there is no file or the user has already specified forget it
        if (projectFile == null)
            return;

        IPath path = new Path(projectFile.getPath());

        IProjectDescription newDescription = null;

        try {
            newDescription = getWorkspace().loadProjectDescription(path);
        } catch (CoreException exception) {
            //no good couldn't get the name
        }

        if (newDescription == null) {
            this.description = null;
            this.projectNameField.setText(""); //$NON-NLS-1$
        } else {
            this.description = newDescription;
            this.projectNameField.setText(this.description.getName());
        }
    }

    /**
     * Return a.project file from the specified location.
     * If there isn't one return null.
     */
    private File projectFile(String locationFieldContents) {
        File directory = new File(locationFieldContents);
        if (directory.isFile())
            return null;

        File[] files = directory.listFiles(this.projectFilter);
        if (files != null && files.length == 1)
            return files[0];

        return null;
    }

    /**
     * Creates a new project resource with the selected name.
     * <p>
     * In normal usage, this method is invoked after the user has pressed Finish on
     * the wizard; the enablement of the Finish button implies that all controls
     * on the pages currently contain valid values.
     * </p>
     *
     * @return the created project resource, or <code>null</code> if the project
     *    was not created
     */
    IProject createExistingProject() {

        String projectName = projectNameField.getText();
        final IWorkspace workspace = ResourcesPlugin.getWorkspace();
        final IProject project = workspace.getRoot().getProject(projectName);
        if (this.description == null) {
            this.description = workspace.newProjectDescription(projectName);
            IPath locationPath = getLocationPath();
            //If it is under the root use the default location
            if (isPrefixOfRoot(locationPath))
                this.description.setLocation(null);
            else
                this.description.setLocation(locationPath);
        } else
            this.description.setName(projectName);

        // create the new project operation
        WorkspaceModifyOperation op = new WorkspaceModifyOperation() {
            protected void execute(IProgressMonitor monitor)
                    throws CoreException {
                monitor.beginTask("", 2000); //$NON-NLS-1$
                project.create(description, new SubProgressMonitor(monitor,
                        1000));
                if (monitor.isCanceled())
                    throw new OperationCanceledException();
                project.open(IResource.BACKGROUND_REFRESH, new SubProgressMonitor(monitor, 1000));

            }
        };

        // run the new project creation operation
        try {
            getContainer().run(true, true, op);
        } catch (InterruptedException e) {
            return null;
        } catch (InvocationTargetException e) {
            // ie.- one of the steps resulted in a core exception	
            Throwable t = e.getTargetException();
            if (t instanceof CoreException) {
                if (((CoreException) t).getStatus().getCode() == IResourceStatus.CASE_VARIANT_EXISTS) {
                    MessageDialog
                            .openError(
                                    getShell(),
                                    DataTransferMessages.WizardExternalProjectImportPage_errorMessage,
                                    NLS.bind(
                                    		DataTransferMessages.WizardExternalProjectImportPage_caseVariantExistsError,
                                    		projectName)
                            );
                } else {
                    ErrorDialog
                            .openError(
                                    getShell(),
                                    DataTransferMessages.WizardExternalProjectImportPage_errorMessage,
                                    null, ((CoreException) t).getStatus());
                }
            }
            return null;
        }

        return project;
    }

    /*
     * see @DialogPage.setVisible(boolean)
     */
    public void setVisible(boolean visible) {
        super.setVisible(visible);
        if (visible)
            this.locationPathField.setFocus();
    }

}