/*******************************************************************************
 * Copyright (c) 2000, 2004 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.jface.action;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.jface.dialogs.ProgressIndicator;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.JFaceColors;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.CLabel;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Cursor;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Layout;
import org.eclipse.swt.widgets.ToolBar;
import org.eclipse.swt.widgets.ToolItem;

/**
 * A StatusLine control is a SWT Composite with a horizontal layout which hosts
 * a number of status indication controls.
 * Typically it is situated below the content area of the window.
 * <p>
 * By default a StatusLine has two predefined status controls: a MessageLine and a
 * ProgressIndicator and it provides API for easy access.
 * </p>
 * <p>
 * This is an internal class, not intended to be used outside the JFace framework.
 * </p>
 */
/* package */class StatusLine extends Composite implements IProgressMonitor {

    /** Horizontal gaps between items. */
    public static final int GAP = 3;

    /** Progress bar creation is delayed by this ms */
    public static final int DELAY_PROGRESS = 500;

    // state
    protected boolean fProgressIsVisible = false;

    protected boolean fCancelButtonIsVisible = false;

    protected boolean fCancelEnabled = false;

    protected String fTaskName;

    protected boolean fIsCanceled;

    protected long fStartTime;

    private Cursor fStopButtonCursor;

    protected String fMessageText;

    protected Image fMessageImage;

    protected String fErrorText;

    protected Image fErrorImage;

    // SWT widgets
    protected CLabel fMessageLabel;

    protected Composite fProgressBarComposite;

    protected ProgressIndicator fProgressBar;

    protected ToolBar fToolBar;

    protected ToolItem fCancelButton;

    protected static ImageDescriptor fgStopImage = ImageDescriptor
            .createFromFile(StatusLine.class, "images/stop.gif");//$NON-NLS-1$
    static {
        JFaceResources.getImageRegistry().put(
                "org.eclipse.jface.parts.StatusLine.stopImage", fgStopImage);//$NON-NLS-1$
    }

    /**
     * Layout the contribution item controls on the status line.
     */
    public class StatusLineLayout extends Layout {
        private final StatusLineLayoutData DEFAULT_DATA = new StatusLineLayoutData();

        public Point computeSize(Composite composite, int wHint, int hHint,
                boolean changed) {

            if (wHint != SWT.DEFAULT && hHint != SWT.DEFAULT)
                return new Point(wHint, hHint);

            Control[] children = composite.getChildren();
            int totalWidth = 0;
            int maxHeight = 0;
            int totalCnt = 0;
            for (int i = 0; i < children.length; i++) {
                boolean useWidth = true;
                Control w = children[i];
                if (w == fProgressBarComposite && !fProgressIsVisible)
                    useWidth = false;
                else if (w == fToolBar && !fCancelButtonIsVisible)
                    useWidth = false;
                StatusLineLayoutData data = (StatusLineLayoutData) w
                        .getLayoutData();
                if (data == null)
                    data = DEFAULT_DATA;
                Point e = w.computeSize(data.widthHint, data.heightHint,
                        changed);
                if (useWidth) {
                    totalWidth += e.x;
                    totalCnt++;
                }
                maxHeight = Math.max(maxHeight, e.y);
            }
            if (totalCnt > 0)
                totalWidth += (totalCnt - 1) * GAP;
            if (totalWidth <= 0)
                totalWidth = maxHeight * 4;
            return new Point(totalWidth, maxHeight);
        }

        public void layout(Composite composite, boolean flushCache) {

            if (composite == null)
                return;

            // StatusLineManager skips over the standard status line widgets 
            // in its update method. There is thus a dependency
            // between the layout of the standard widgets and the update method.

            // Make sure cancel button and progress bar are before contributions.
            fMessageLabel.moveAbove(null);
            fToolBar.moveBelow(fMessageLabel);
            fProgressBarComposite.moveBelow(fToolBar);

            Rectangle rect = composite.getClientArea();
            Control[] children = composite.getChildren();
            int count = children.length;

            int ws[] = new int[count];

            int h = rect.height;
            int totalWidth = -GAP;
            for (int i = 0; i < count; i++) {
                Control w = children[i];
                if (w == fProgressBarComposite && !fProgressIsVisible)
                    continue;
                if (w == fToolBar && !fCancelButtonIsVisible)
                    continue;
                StatusLineLayoutData data = (StatusLineLayoutData) w
                        .getLayoutData();
                if (data == null)
                    data = DEFAULT_DATA;
                int width = w.computeSize(data.widthHint, h, flushCache).x;
                ws[i] = width;
                totalWidth += width + GAP;
            }

            int diff = rect.width - totalWidth;
            ws[0] += diff; // make the first StatusLabel wider

            // Check against minimum recommended width
            final int msgMinWidth = rect.width / 3;
            if (ws[0] < msgMinWidth) {
                diff = ws[0] - msgMinWidth;
                ws[0] = msgMinWidth;
            } else {
                diff = 0;
            }

            // Take space away from the contributions first.
            for (int i = count - 1; i >= 0 && diff < 0; --i) {
                int min = Math.min(ws[i], -diff);
                ws[i] -= min;
                diff += min + GAP;
            }

            int x = rect.x;
            int y = rect.y;
            for (int i = 0; i < count; i++) {
                Control w = children[i];
                /*
                 * Workaround for Linux Motif:
                 * Even if the progress bar and cancel button are
                 * not set to be visible ad of width 0, they still
                 * draw over the first pixel of the editor 
                 * contributions.
                 * 
                 * The fix here is to draw the progress bar and
                 * cancel button off screen if they are not visible.
                 */
                if (w == fProgressBarComposite && !fProgressIsVisible
                        || w == fToolBar && !fCancelButtonIsVisible) {
                    w.setBounds(x + rect.width, y, ws[i], h);
                    continue;
                }
                w.setBounds(x, y, ws[i], h);
                if (ws[i] > 0)
                    x += ws[i] + GAP;
            }
        }
    }

    /**
     * Create a new StatusLine as a child of the given parent.
     */
    public StatusLine(Composite parent, int style) {
        super(parent, style);

        addDisposeListener(new DisposeListener() {
            public void widgetDisposed(DisposeEvent e) {
                handleDispose();
            }
        });

        // StatusLineManager skips over the standard status line widgets 
        // in its update method. There is thus a dependency
        // between this code defining the creation and layout of the standard 
        // widgets and the update method.

        setLayout(new StatusLineLayout());

        fMessageLabel = new CLabel(this, SWT.NONE);//SWT.SHADOW_IN);
        //		Color[] colors = new Color[2];
        //		colors[0] = parent.getDisplay().getSystemColor(SWT.COLOR_WIDGET_LIGHT_SHADOW);
        //		colors[1] = fMessageLabel.getBackground();
        //		int[] gradient = new int[] {JFaceColors.STATUS_PERCENT};
        //		fMessageLabel.setBackground(colors, gradient);

        fProgressIsVisible = false;
        fCancelEnabled = false;

        fToolBar = new ToolBar(this, SWT.FLAT);
        fCancelButton = new ToolItem(fToolBar, SWT.PUSH);
        fCancelButton.setImage(fgStopImage.createImage());
        fCancelButton.setToolTipText(JFaceResources
                .getString("Cancel_Current_Operation")); //$NON-NLS-1$
        fCancelButton.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent e) {
                setCanceled(true);
            }
        });
        fCancelButton.addDisposeListener(new DisposeListener() {
            public void widgetDisposed(DisposeEvent e) {
                Image i = fCancelButton.getImage();
                if ((i != null) && (!i.isDisposed()))
                    i.dispose();
            }
        });

        // We create a composite to create the progress bar in
        // so that it can be centered. See bug #32331
        fProgressBarComposite = new Composite(this, SWT.NONE);
        GridLayout layout = new GridLayout();
        layout.horizontalSpacing = 0;
        layout.verticalSpacing = 0;
        layout.marginHeight = 0;
        layout.marginWidth = 0;
        fProgressBarComposite.setLayout(layout);
        fProgressBar = new ProgressIndicator(fProgressBarComposite);
        fProgressBar.setLayoutData(new GridData(GridData.GRAB_HORIZONTAL
                | GridData.GRAB_VERTICAL));

        fStopButtonCursor = new Cursor(getDisplay(), SWT.CURSOR_ARROW);
    }

    /**
     * Notifies that the main task is beginning.
     * 
     * @param name the name (or description) of the main task
     * @param totalWork the total number of work units into which
     * the main task is been subdivided. If the value is 0 or UNKNOWN the 
     * implemenation is free to indicate progress in a way which doesn't 
     * require the total number of work units in advance. In general users 
     * should use the UNKNOWN value if they don't know the total amount of
     * work units. 
     */
    public void beginTask(String name, int totalWork) {
        final long timestamp = System.currentTimeMillis();
        fStartTime = timestamp;
        final boolean animated = (totalWork == UNKNOWN || totalWork == 0);
        // make sure the progress bar is made visible while
        // the task is running. Fixes bug 32198 for the non-animated case.
        Runnable timer = new Runnable() {
            public void run() {
                StatusLine.this.startTask(timestamp, animated);
            }
        };
        if (fProgressBar == null)
            return;

        fProgressBar.getDisplay().timerExec(DELAY_PROGRESS, timer);
        if (!animated) {
            fProgressBar.beginTask(totalWork);
        }
        if (name == null)
            fTaskName = "";//$NON-NLS-1$
        else
            fTaskName = name;
        setMessage(fTaskName);
    }

    /**
     * Notifies that the work is done; that is, either the main task is completed or the
     * user cancelled it.
     * Done() can be called more than once; an implementation should be prepared to handle
     * this case.
     */
    public void done() {

        fStartTime = 0;

        if (fProgressBar != null) {
            fProgressBar.sendRemainingWork();
            fProgressBar.done();
        }
        setMessage(null);

        hideProgress();
    }

    /**
     * Returns the status line's progress monitor
     */
    public IProgressMonitor getProgressMonitor() {
        return this;
    }

    /**
     * @private
     */
    protected void handleDispose() {
    	if (fStopButtonCursor != null) {
    		fStopButtonCursor.dispose();		
    		fStopButtonCursor = null;
    	}
    	if (fProgressBar != null) {
    		fProgressBar.dispose();
    		fProgressBar = null;
    	}
    }

    /**
     * Hides the Cancel button and ProgressIndicator.
     * @private
     */
    protected void hideProgress() {

        if (fProgressIsVisible && !isDisposed()) {
            fProgressIsVisible = false;
            fCancelEnabled = false;
            fCancelButtonIsVisible = false;
            if (fToolBar != null && !fToolBar.isDisposed())
                fToolBar.setVisible(false);
            if (fProgressBarComposite != null
                    && !fProgressBarComposite.isDisposed())
                fProgressBarComposite.setVisible(false);
            layout();
        }
    }

    /**
     * @see IProgressMonitor#internalWorked(double)
     */
    public void internalWorked(double work) {
        if (!fProgressIsVisible) {
            if (System.currentTimeMillis() - fStartTime > DELAY_PROGRESS)
                showProgress();
        }

        if (fProgressBar != null) {
            fProgressBar.worked(work);
        }
    }

    /**
     * Returns true if the user does some UI action to cancel this operation.
     * (like hitting the Cancel button on the progress dialog).
     * The long running operation typically polls isCanceled().
     */
    public boolean isCanceled() {
        return fIsCanceled;
    }

    /**
     * Returns <code>true</true> if the ProgressIndication provides UI for canceling
     * a long running operation.
     */
    public boolean isCancelEnabled() {
        return fCancelEnabled;
    }

    /**
     * Sets the cancel status. This method is usually called with the 
     * argument false if a client wants to abort a cancel action.
     */
    public void setCanceled(boolean b) {
        fIsCanceled = b;
        if (fCancelButton != null)
            fCancelButton.setEnabled(!b);
    }

    /**
     * Controls whether the ProgressIndication provides UI for canceling
     * a long running operation.
     * If the ProgressIndication is currently visible calling this method may have
     * a direct effect on the layout because it will make a cancel button visible. 
     */
    public void setCancelEnabled(boolean enabled) {
        fCancelEnabled = enabled;
        if (fProgressIsVisible && !fCancelButtonIsVisible && enabled) {
            showButton();
            layout();
        }
        if (fCancelButton != null && !fCancelButton.isDisposed())
            fCancelButton.setEnabled(enabled);
    }

    /**
     * Sets the error message text to be displayed on the status line.
     * The image on the status line is cleared.
     * 
     * @param message the error message, or <code>null</code> for no error message
     */
    public void setErrorMessage(String message) {
        setErrorMessage(null, message);
    }

    /**
     * Sets an image and error message text to be displayed on the status line.
     * 
     * @param image the image to use, or <code>null</code> for no image
     * @param message the error message, or <code>null</code> for no error message
     */
    public void setErrorMessage(Image image, String message) {
        fErrorText = trim(message);
        fErrorImage = image;
        updateMessageLabel();
    }

    /**
     * Applies the given font to this status line.
     */
    public void setFont(Font font) {
        super.setFont(font);
        Control[] children = getChildren();
        for (int i = 0; i < children.length; i++) {
            children[i].setFont(font);
        }
    }

    /**
     * Sets the message text to be displayed on the status line.
     * The image on the status line is cleared.
     * 
     * @param message the error message, or <code>null</code> for no error message
     */
    public void setMessage(String message) {
        setMessage(null, message);
    }

    /**
     * Sets an image and a message text to be displayed on the status line.
     * 
     * @param image the image to use, or <code>null</code> for no image
     * @param message the message, or <code>null</code> for no message
     */
    public void setMessage(Image image, String message) {
        fMessageText = trim(message);
        fMessageImage = image;
        updateMessageLabel();
    }

    /**
     * @see IProgressMonitor#setTaskName(java.lang.String)
     */
    public void setTaskName(String name) {
        fTaskName = name;
    }

    /**
     * Makes the Cancel button visible.
     * @private
     */
    protected void showButton() {
        if (fToolBar != null && !fToolBar.isDisposed()) {
            fToolBar.setVisible(true);
            fToolBar.setEnabled(true);
            fToolBar.setCursor(fStopButtonCursor);
            fCancelButtonIsVisible = true;
        }
    }

    /**
     * Shows the Cancel button and ProgressIndicator.
     * @private
     */
    protected void showProgress() {
        if (!fProgressIsVisible && !isDisposed()) {
            fProgressIsVisible = true;
            if (fCancelEnabled)
                showButton();
            if (fProgressBarComposite != null
                    && !fProgressBarComposite.isDisposed())
                fProgressBarComposite.setVisible(true);
            layout();
        }
    }

    /**
     * @private
     */
    void startTask(final long timestamp, final boolean animated) {
        if (!fProgressIsVisible && fStartTime == timestamp) {
            showProgress();
            if (animated) {
                if (fProgressBar != null && !fProgressBar.isDisposed()) {
                    fProgressBar.beginAnimatedTask();
                }
            }
        }
    }

    /**
     * Notifies that a subtask of the main task is beginning.
     * Subtasks are optional; the main task might not have subtasks.
     * @param name the name (or description) of the subtask
     * @see IProgressMonitor#subTask(String)
     */
    public void subTask(String name) {
        String text;
        if (fTaskName.length() == 0)
            text = name;
        else
            text = JFaceResources.format(
                    "Set_SubTask", new Object[] { fTaskName, name });//$NON-NLS-1$
        setMessage(text);
    }

    /**
     * Trims the message to be displayable in the status line.
     * This just pulls out the first line of the message.
     * Allows null.
     */
    String trim(String message) {
        if (message == null)
            return null;
        int cr = message.indexOf('\r');
        int lf = message.indexOf('\n');
        if (cr == -1 && lf == -1)
            return message;
        int len;
        if (cr == -1)
            len = lf;
        else if (lf == -1)
            len = cr;
        else
            len = Math.min(cr, lf);
        return message.substring(0, len);
    }

    /**
     * Updates the message label widget.
     */
    protected void updateMessageLabel() {
        if (fMessageLabel != null && !fMessageLabel.isDisposed()) {
            Display display = fMessageLabel.getDisplay();
            if ((fErrorText != null && fErrorText.length() > 0)
                    || fErrorImage != null) {
                fMessageLabel.setForeground(JFaceColors.getErrorText(display));
                fMessageLabel.setText(fErrorText);
                fMessageLabel.setImage(fErrorImage);
            } else {
                fMessageLabel.setForeground(display
                        .getSystemColor(SWT.COLOR_WIDGET_FOREGROUND));
                fMessageLabel.setText(fMessageText == null ? "" : fMessageText); //$NON-NLS-1$
                fMessageLabel.setImage(fMessageImage);
            }
        }
    }

    /**
     * @see IProgressMonitor#worked(int)
     */
    public void worked(int work) {
        internalWorked(work);
    }
}