/*******************************************************************************
 * Copyright (c) 2000, 2007 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
 *******************************************************************************/
// Port to the D programming language:
//     Frank Benoit <benoit@tionex.de>
module org.eclipse.core.runtimeSubProgressMonitor;

import java.lang.all;

import org.eclipse.core.runtimeIProgressMonitor; // packageimport
import org.eclipse.core.runtimeProgressMonitorWrapper; // packageimport

/**
 * For new implementations consider using {@link SubMonitor}.
 * 
 * A progress monitor that uses a given amount of work ticks
 * from a parent monitor. It can be used as follows:
 * <pre>
 *     try {
 *         pm.beginTask("Main Task", 100);
 *         doSomeWork(pm, 30);
 *         SubProgressMonitor subMonitor= new SubProgressMonitor(pm, 40);
 *         try {
 *             subMonitor.beginTask("", 300);
 *             doSomeWork(subMonitor, 300);
 *         } finally {
 *             subMonitor.done();
 *         }
 *         doSomeWork(pm, 30);
 *     } finally {
 *         pm.done();
 *     }
 * </pre>
 * <p>
 * This class can be used without OSGi running.
 * </p><p>
 * This class may be instantiated or subclassed by clients.
 * </p>
 * 
 * @see SubMonitor
 */
public class SubProgressMonitor : ProgressMonitorWrapper {

    /**
     * Style constant indicating that calls to <code>subTask</code>
     * should not have any effect.
     *
     * @see #SubProgressMonitor(IProgressMonitor,int,int)
     */
    public static final int SUPPRESS_SUBTASK_LABEL = 1 << 1;
    /**
     * Style constant indicating that the main task label 
     * should be prepended to the subtask label.
     *
     * @see #SubProgressMonitor(IProgressMonitor,int,int)
     */
    public static final int PREPEND_MAIN_LABEL_TO_SUBTASK = 1 << 2;

    private int parentTicks = 0;
    private double sentToParent = 0.0;
    private double scale = 0.0;
    private int nestedBeginTasks = 0;
    private bool usedUp = false;
    private bool hasSubTask = false;
    private int style;
    private String mainTaskLabel;

    /**
     * Creates a new sub-progress monitor for the given monitor. The sub 
     * progress monitor uses the given number of work ticks from its 
     * parent monitor.
     *
     * @param monitor the parent progress monitor
     * @param ticks the number of work ticks allocated from the
     *    parent monitor
     */
    public this(IProgressMonitor monitor, int ticks) {
        this(monitor, ticks, 0);
    }

    /**
     * Creates a new sub-progress monitor for the given monitor. The sub 
     * progress monitor uses the given number of work ticks from its 
     * parent monitor.
     *
     * @param monitor the parent progress monitor
     * @param ticks the number of work ticks allocated from the
     *    parent monitor
     * @param style one of
     *    <ul>
     *    <li> <code>SUPPRESS_SUBTASK_LABEL</code> </li>
     *    <li> <code>PREPEND_MAIN_LABEL_TO_SUBTASK</code> </li>
     *    </ul>
     * @see #SUPPRESS_SUBTASK_LABEL
     * @see #PREPEND_MAIN_LABEL_TO_SUBTASK
     */
    public this(IProgressMonitor monitor, int ticks, int style) {
        super(monitor);
        this.parentTicks = (ticks > 0) ? ticks : 0;
        this.style = style;
    }

    /* (Intentionally not javadoc'd)
     * Implements the method <code>IProgressMonitor.beginTask</code>.
     *
     * Starts a new main task. Since this progress monitor is a sub
     * progress monitor, the given name will NOT be used to update
     * the progress bar's main task label. That means the given 
     * string will be ignored. If style <code>PREPEND_MAIN_LABEL_TO_SUBTASK
     * <code> is specified, then the given string will be prepended to
     * every string passed to <code>subTask(String)</code>.
     */
    public void beginTask(String name, int totalWork) {
        nestedBeginTasks++;
        // Ignore nested begin task calls.
        if (nestedBeginTasks > 1) {
            return;
        }
        // be safe:  if the argument would cause math errors (zero or 
        // negative), just use 0 as the scale.  This disables progress for
        // this submonitor. 
        scale = totalWork <= 0 ? 0 : cast(double) parentTicks / cast(double) totalWork;
        if ((style & PREPEND_MAIN_LABEL_TO_SUBTASK) !is 0) {
            mainTaskLabel = name;
        }
    }

    /* (Intentionally not javadoc'd)
     * Implements the method <code>IProgressMonitor.done</code>.
     */
    public void done() {
        // Ignore if more done calls than beginTask calls or if we are still
        // in some nested beginTasks
        if (nestedBeginTasks is 0 || --nestedBeginTasks > 0)
            return;
        // Send any remaining ticks and clear out the subtask text
        double remaining = parentTicks - sentToParent;
        if (remaining > 0)
            super.internalWorked(remaining);
        //clear the sub task if there was one
        if (hasSubTask)
            subTask(""); //$NON-NLS-1$
        sentToParent = 0;
    }

    /* (Intentionally not javadoc'd)
     * Implements the internal method <code>IProgressMonitor.internalWorked</code>.
     */
    public void internalWorked(double work) {
        if (usedUp || nestedBeginTasks !is 1) {
            return;
        }

        double realWork = (work > 0.0d) ? scale * work : 0.0d;
        super.internalWorked(realWork);
        sentToParent += realWork;
        if (sentToParent >= parentTicks) {
            usedUp = true;
        }
    }

    /* (Intentionally not javadoc'd)
     * Implements the method <code>IProgressMonitor.subTask</code>.
     */
    public void subTask(String name) {
        if ((style & SUPPRESS_SUBTASK_LABEL) !is 0) {
            return;
        }
        hasSubTask = true;
        String label = name;
        if ((style & PREPEND_MAIN_LABEL_TO_SUBTASK) !is 0 && mainTaskLabel !is null && mainTaskLabel.length() > 0) {
            label = mainTaskLabel + ' ' + label;
        }
        super.subTask(label);
    }

    /* (Intentionally not javadoc'd)
     * Implements the method <code>IProgressMonitor.worked</code>.
     */
    public void worked(int work) {
        internalWorked(work);
    }
}