/*******************************************************************************

 * Copyright (c) 2007, 2008 Wind River 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:

 *     Wind River - Initial API and implementation

 *     Ericsson   - Low-level breakpoints integration  

 *******************************************************************************/

package org.eclipse.cdt.dsf.debug.service;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Hashtable;

import java.util.LinkedList;

import java.util.List;

import java.util.Map;

import java.util.Set;

import java.util.concurrent.RejectedExecutionException;

import org.eclipse.cdt.dsf.concurrent.CountingRequestMonitor;

import org.eclipse.cdt.dsf.concurrent.DataRequestMonitor;

import org.eclipse.cdt.dsf.concurrent.DsfRunnable;

import org.eclipse.cdt.dsf.concurrent.RequestMonitor;

import org.eclipse.cdt.dsf.concurrent.ThreadSafe;

import org.eclipse.cdt.dsf.datamodel.DMContexts;

import org.eclipse.cdt.dsf.datamodel.IDMContext;

import org.eclipse.cdt.dsf.debug.service.IBreakpoints.IBreakpointDMContext;

import org.eclipse.cdt.dsf.debug.service.IBreakpoints.IBreakpointsTargetDMContext;

import org.eclipse.cdt.dsf.internal.DsfPlugin;

import org.eclipse.cdt.dsf.service.AbstractDsfService;

import org.eclipse.cdt.dsf.service.DsfSession;

import org.eclipse.core.resources.IMarkerDelta;

import org.eclipse.core.runtime.CoreException;

import org.eclipse.core.runtime.IProgressMonitor;

import org.eclipse.core.runtime.IStatus;

import org.eclipse.core.runtime.Status;

import org.eclipse.core.runtime.jobs.Job;

import org.eclipse.debug.core.DebugPlugin;

import org.eclipse.debug.core.IBreakpointListener;

import org.eclipse.debug.core.IBreakpointManager;

import org.eclipse.debug.core.IBreakpointManagerListener;

import org.eclipse.debug.core.model.IBreakpoint;

import org.osgi.framework.BundleContext;

/**

 * 

 */

public class BreakpointsMediator extends AbstractDsfService implements IBreakpointManagerListener, IBreakpointListener

{

    /**

     * The attribute translator that this service will use to map the platform

     * breakpiont attributes to the corresponding target attributes, and vice

     * versa.

     */

    private IBreakpointAttributeTranslator fAttributeTranslator;

    /**

     * DSF Debug service for creating breakpoints.

     */

    IBreakpoints fBreakpoints;

    /**

     * Platform breakpoint manager

     */

    IBreakpointManager fBreakpointManager;

    ///////////////////////////////////////////////////////////////////////////

    // Breakpoints tracking

    ///////////////////////////////////////////////////////////////////////////

    /**

     * Holds the set of platform breakpoints with their corresponding back-end

     * breakpoint attributes, per context (i.e. each platform breakpoint is

     * replicated for each execution context).

     * - Context entry added/removed on start/stopTrackingBreakpoints()

     * - Augmented on breakpointAdded()

     * - Modified on breakpointChanged()

     * - Diminished on breakpointRemoved()

     */

	private Map<IBreakpointsTargetDMContext, Map<IBreakpoint, List<Map<String, Object>>>> fPlatformBPs = 

		new HashMap<IBreakpointsTargetDMContext, Map<IBreakpoint, List<Map<String, Object>>>>();

    /**

     * Holds the mapping from platform breakpoint to the corresponding target

     * breakpoint(s), per context. There can be multiple back-end BPs for a 

     * single platform BP in the case of [1] multiple target contexts, and/or

     * [2] thread filtering.

     * Updated when:

     * - We start/stop tracking an execution context

     * - A platform breakpoint is added/removed

     * - A thread filter is applied/removed

     */

	private Map<IBreakpointsTargetDMContext, Map<IBreakpoint, List<IBreakpointDMContext>>> fBreakpointDMContexts = 

		new HashMap<IBreakpointsTargetDMContext, Map<IBreakpoint, List<IBreakpointDMContext>>>();

    /**

     * Due to the very asynchronous nature of DSF, a new breakpoint request can

     * pop up at any time before an ongoing one is completed. The following set

     * is used to store requests until the ongoing operation completes.

     */

	private Set<IBreakpoint> fPendingRequests    = new HashSet<IBreakpoint>();

	/**

	 * @see fPendingRequests

	 */

	private Set<IBreakpoint> fPendingBreakpoints = new HashSet<IBreakpoint>();

    ///////////////////////////////////////////////////////////////////////////

    // AbstractDsfService    

    ///////////////////////////////////////////////////////////////////////////

	/**

	 * The service constructor

	 * 

	 * @param session

	 * @param debugModelId

	 */

	public BreakpointsMediator(DsfSession session, IBreakpointAttributeTranslator attributeTranslator) {

        super(session);

        fAttributeTranslator = attributeTranslator;

	}

    @Override

    public void initialize(final RequestMonitor rm) {

        // - Collect references for the services we interact with

        // - Register to interesting events

        // - Obtain the list of platform breakpoints   

        // - Register the service for interested parties

        super.initialize(

            new RequestMonitor(getExecutor(), rm) { 

                @Override

                protected void handleSuccess() {

                    doInitialize(rm);

                }});

    }

    /**

     * Asynchronous service initialization 

     * 

     * @param requestMonitor

     */

    private void doInitialize(RequestMonitor rm) {

    	// Get the services references

        fBreakpoints  = getServicesTracker().getService(IBreakpoints.class);

        fBreakpointManager = DebugPlugin.getDefault().getBreakpointManager();

        fAttributeTranslator.initialize(this);

        // Register to the useful events

        fBreakpointManager.addBreakpointListener(this);

        fBreakpointManager.addBreakpointManagerListener( this );

        // Register this service

        register(new String[] { BreakpointsMediator.class.getName() },

				 new Hashtable<String, String>());

        rm.done();

    }

    @Override

    public void shutdown(final RequestMonitor rm) {

        // - Un-register the service

        // - Stop listening to events

        // - Remove the breakpoints installed by this service

        // 

        //  Since we are shutting down, there is no overwhelming need

        //  to keep the maps coherent...

        // Stop accepting requests and events

    	unregister();

        fBreakpointManager.removeBreakpointListener(this);

        fBreakpointManager.removeBreakpointManagerListener( this );

        fAttributeTranslator.dispose();

        // Cleanup the breakpoints that are still installed by the service.

        // Use a counting monitor which will call mom to complete the shutdown

        // after the breakpoints are un-installed (successfully or not).

        CountingRequestMonitor countingRm = new CountingRequestMonitor(getExecutor(), rm) {

            @Override

            protected void handleCompleted() {

                BreakpointsMediator.super.shutdown(rm);

            }

        };

        // We have to make a copy of the fPlatformBPs keys because uninstallBreakpoints()

        // modifies the map as it walks through it.

        List<IBreakpointsTargetDMContext> platformBPKeysCopy = new ArrayList<IBreakpointsTargetDMContext>(fPlatformBPs.size());

        platformBPKeysCopy.addAll(0, fPlatformBPs.keySet());

        for (IBreakpointsTargetDMContext dmc : platformBPKeysCopy) {

            stopTrackingBreakpoints(dmc, countingRm);

        }

        countingRm.setDoneCount(platformBPKeysCopy.size());

    }

	@Override

    protected BundleContext getBundleContext() {

        return DsfPlugin.getBundleContext();

    }

    ///////////////////////////////////////////////////////////////////////////

    // IBreakpointsManager

    ///////////////////////////////////////////////////////////////////////////

	/**

     * Install and begin tracking breakpoints for given context.  The service 

     * will keep installing new breakpoints that appear in the IDE for this 

     * context until {@link #uninstallBreakpoints(IDMContext)} is called for that

     * context.

     * @param dmc Context to start tracking breakpoints for.

     * @param rm Completion callback.

     */

    public void startTrackingBreakpoints(IBreakpointsTargetDMContext dmc, final RequestMonitor rm) {

        // - Augment the maps with the new execution context

        // - Install the platform breakpoints on the selected target

    	// Validate the context

        final IBreakpointsTargetDMContext breakpointsDmc = DMContexts.getAncestorOfType(dmc, IBreakpointsTargetDMContext.class);

        if (breakpointsDmc == null) {

            rm.setStatus(new Status(IStatus.ERROR, DsfPlugin.PLUGIN_ID, INTERNAL_ERROR, "Invalid context type", null)); //$NON-NLS-1$

            rm.done();            

            return;

        }

        // Make sure a mapping for this execution context does not already exist

		Map<IBreakpoint, List<Map<String, Object>>> platformBPs = fPlatformBPs.get(dmc);

		if (platformBPs != null) {

            rm.setStatus(new Status(IStatus.ERROR, DsfPlugin.PLUGIN_ID, INTERNAL_ERROR, "Context already initialized", null)); //$NON-NLS-1$

            rm.done();            

            return;

		}

        // Create entries in the breakpoint tables for the new context. These entries should only

        // be removed when this service stops tracking breakpoints for the given context.

        fPlatformBPs.put(breakpointsDmc, new HashMap<IBreakpoint, List<Map<String, Object>>>());

		fBreakpointDMContexts.put(breakpointsDmc, new HashMap<IBreakpoint, List<IBreakpointDMContext>>());

        // Install the platform breakpoints (stored in fPlatformBPs) on the target.

		// We need to use a background thread for this operation because we are 

		// accessing the resources system to retrieve the breakpoint attributes.

		// Accessing the resources system potentially requires using global locks.

		// Also we will be calling IBreakpointAttributeTranslator which is prohibited

		// from being called on the session executor thread.

		new Job("MI Debugger: Install initial breakpoint list.") { //$NON-NLS-1$

            { setSystem(true); }

			// Get the stored breakpoints from the platform BreakpointManager

			// and install them on the target

        	@Override

            protected IStatus run(IProgressMonitor monitor) {

                // Read initial breakpoints from platform.  Copy the breakpoint attributes into a local map.

                // Note that we cannot write data into fPlatformBPs table here directly because we are not

                // executing on the dispatch thread.

                final Map<IBreakpoint, List<Map<String, Object>>> initialPlatformBPs = 

                    new HashMap<IBreakpoint, List<Map<String, Object>>>();

                try {

                	// Get the stored breakpoint list from the platform BreakpointManager

                    IBreakpoint[] bps = DebugPlugin.getDefault().getBreakpointManager().getBreakpoints();

                    // Single out the installable breakpoints...

                    for (IBreakpoint bp : bps) {

                    	if (fAttributeTranslator.supportsBreakpoint(bp)) {

	                        // Retrieve the breakpoint attributes

                    		List<Map<String, Object>> attrsArray = 

                    		    fAttributeTranslator.getBreakpointAttributes(bp, fBreakpointManager.isEnabled());

	                        // Store it for now (will be installed on the dispatcher thread)

                            initialPlatformBPs.put(bp, attrsArray);

                        }

                    }

                } catch (CoreException e) {

                    IStatus status = new Status(

                        IStatus.ERROR, DsfPlugin.PLUGIN_ID, REQUEST_FAILED, "Unable to read initial breakpoint attributes", e); //$NON-NLS-1$

                    rm.setStatus(status);

                    rm.done();

                    return status;

                }

                // Submit the runnable to plant the breakpoints on dispatch thread.

                getExecutor().submit(new Runnable() {

                	public void run() {

                		installInitialBreakpoints(breakpointsDmc, initialPlatformBPs, rm);

                	}

                });

                return Status.OK_STATUS;

            }

        }.schedule();    

    }

    /**

     * Installs the breakpoints that existed prior to the activation of this

     * breakpoints context.

     */

    private void installInitialBreakpoints(final IBreakpointsTargetDMContext dmc,

            Map<IBreakpoint, List<Map<String, Object>>> initialPlatformBPs,

            RequestMonitor rm)

    {

        // Retrieve the set of platform breakpoints for this context

        Map<IBreakpoint, List<Map<String, Object>>> platformBPs = fPlatformBPs.get(dmc);

        if (platformBPs == null) {

            rm.setStatus(new Status(IStatus.ERROR, DsfPlugin.PLUGIN_ID, INVALID_HANDLE, "Invalid context", null)); //$NON-NLS-1$

            rm.done();

            return;

        }

        // Install the individual breakpoints on the executor thread

        // Requires a counting monitor to know when we're done

        final CountingRequestMonitor countingRm = new CountingRequestMonitor(getExecutor(), rm);

        countingRm.setDoneCount(initialPlatformBPs.size());

        for (final IBreakpoint bp : initialPlatformBPs.keySet()) {

            final List<Map<String, Object>> attrs = initialPlatformBPs.get(bp);

            // Upon determining the debuggerPath, the breakpoint is installed

            installBreakpoint(dmc, bp, attrs, new RequestMonitor(getExecutor(), countingRm));

        }

    }

    public void stopTrackingBreakpoints(final IBreakpointsTargetDMContext dmc, final RequestMonitor rm) {

        // - Remove the target breakpoints for the given execution context

        // - Update the maps

    	// Remove the breakpoints for given DMC from the internal maps.

        Map<IBreakpoint, List<Map<String, Object>>> platformBPs = fPlatformBPs.get(dmc);

        if (platformBPs == null) {

            rm.setStatus(new Status(IStatus.ERROR, DsfPlugin.PLUGIN_ID, INTERNAL_ERROR, "Breakpoints not installed for given context", null)); //$NON-NLS-1$

            rm.done();

            return;

        }

        // Uninstall the individual breakpoints on the executor thread

        // Requires a counting monitor to know when we're done

        final CountingRequestMonitor countingRm = new CountingRequestMonitor(getExecutor(), rm);

        countingRm.setDoneCount(platformBPs.size());

        for (final IBreakpoint bp : platformBPs.keySet()) {

            uninstallBreakpoint(dmc, bp, 

                new RequestMonitor(getExecutor(), countingRm) {

                    @Override

                    protected void handleCompleted() {

                        // After the breakpoint is removed from target.  Call the attribute 

                        // translator to refresh breakpoint status based on the new target 

                        // breakpoint status. 

                        new Job("Breakpoint status update") { //$NON-NLS-1$

                            { setSystem(true); }

                            @Override

                            protected IStatus run(IProgressMonitor monitor) {

                                fAttributeTranslator.updateBreakpointStatus(bp);

                                return Status.OK_STATUS;

                            };

                        }.schedule();

                        countingRm.done();

                    }

                });

        }

    }

    ///////////////////////////////////////////////////////////////////////////

    // Back-end interface functions

    ///////////////////////////////////////////////////////////////////////////

	/**

	 * Install a new platform breakpoint on the back-end. A platform breakpoint

	 * can resolve into multiple back-end breakpoints when threads are taken

	 * into account.

	 *  

	 * @param dmc

	 * @param breakpoint

	 * @param attrsList

	 * @param rm

	 */

	private void installBreakpoint(IBreakpointsTargetDMContext dmc, final IBreakpoint breakpoint,

			final List<Map<String, Object>> attrsList, final RequestMonitor rm)

	{

    	// Retrieve the set of breakpoints for this context

        final Map<IBreakpoint, List<Map<String, Object>>> platformBPs = fPlatformBPs.get(dmc);

        assert platformBPs != null;

        final Map<IBreakpoint, List<IBreakpointDMContext>> breakpointIDs = fBreakpointDMContexts.get(dmc);

        assert breakpointIDs != null; // fBreakpointIds should be updated in parallel with fPlatformBPs 

        // Ensure the breakpoint is not already installed

        if (platformBPs.containsKey(breakpoint)) {

            rm.setStatus(new Status(IStatus.ERROR, DsfPlugin.PLUGIN_ID, INVALID_STATE, "Breakpoint already installed", null)); //$NON-NLS-1$

            rm.done();

            return;

        }

        // Update the breakpoint status when all back-end breakpoints have been installed

    	final CountingRequestMonitor installRM = new CountingRequestMonitor(getExecutor(), rm) {

			@Override

			protected void handleCompleted() {

				// Store the platform breakpoint

				platformBPs.put(breakpoint, attrsList);

                new Job("Breakpoint status update") { //$NON-NLS-1$

                    { setSystem(true); }

                    @Override

                    protected IStatus run(IProgressMonitor monitor) {

                        fAttributeTranslator.updateBreakpointStatus(breakpoint);

                        return Status.OK_STATUS;

                    };

                }.schedule();

		        rm.done();

			}

		};

        // A back-end breakpoint needs to be installed for each specified attributes map.

		installRM.setDoneCount(attrsList.size());

		// Install the back-end breakpoint(s)

		for (Map<String, Object> attrs : attrsList) {

            fBreakpoints.insertBreakpoint(

                dmc, attrs, 

				new DataRequestMonitor<IBreakpointDMContext>(getExecutor(), installRM) {

				@Override

                protected void handleCompleted() {

                    List<IBreakpointDMContext> list = breakpointIDs.get(breakpoint);

                    if (list == null) {

                        list = new LinkedList<IBreakpointDMContext>();

                        breakpointIDs.put(breakpoint, list);

                    }

                    if (isSuccess()) {

						// Add the breakpoint back-end mapping

						list.add(getData());

					} else {

                        // TODO (bug 219841): need to add breakpoint error status tracking

                        // in addition to fBreakpointDMContexts.

					}

					installRM.done();

                }

            });

		}

	}

    /**

     * Un-install an individual breakpoint on the back-end. For one platform

     * breakpoint, there could be multiple corresponding back-end breakpoints.

     * 

     * @param dmc

     * @param breakpoint

     * @param rm

     */

    private void uninstallBreakpoint(final IBreakpointsTargetDMContext dmc, final IBreakpoint breakpoint, 

        final RequestMonitor rm)

    {

  		// Remove completion monitor

    	CountingRequestMonitor removeRM = new CountingRequestMonitor(getExecutor(), rm) {

			@Override

			protected void handleCompleted() {

		    	// Remove the attributes mapping 

		        Map<IBreakpoint, List<Map<String, Object>>> platformBPs = fPlatformBPs.get(dmc);

		        if (platformBPs == null) {

		            rm.setStatus(new Status(IStatus.ERROR, DsfPlugin.PLUGIN_ID, INVALID_HANDLE, "Invalid context", null)); //$NON-NLS-1$

		            rm.done();

		            return;

		        }

		        platformBPs.remove(breakpoint);

				// Remove the back-end mapping

		        Map<IBreakpoint, List<IBreakpointDMContext>> breakpointIDs = fBreakpointDMContexts.get(dmc);

		        if (breakpointIDs == null) {

		            rm.setStatus(new Status(IStatus.ERROR, DsfPlugin.PLUGIN_ID, INVALID_HANDLE, "Invalid breakpoint", null)); //$NON-NLS-1$

		            rm.done();

		            return;

		        }

		        breakpointIDs.get(breakpoint).clear();

		        breakpointIDs.remove(breakpoint);

		        // Update breakpoint status

                new Job("Breakpoint status update") { //$NON-NLS-1$

                    { setSystem(true); }

                    @Override

                    protected IStatus run(IProgressMonitor monitor) {

                        fAttributeTranslator.updateBreakpointStatus(breakpoint);

                        return Status.OK_STATUS;

                    };

                }.schedule();

		        rm.done();

			}

		};

		// Remove the back-end breakpoints

		Map<IBreakpoint, List<IBreakpointDMContext>> breakpointIDs = fBreakpointDMContexts.get(dmc);

        if (breakpointIDs == null) {

            rm.setStatus(new Status(IStatus.ERROR, DsfPlugin.PLUGIN_ID, INVALID_HANDLE, "Invalid breakpoint", null)); //$NON-NLS-1$

            rm.done();

            return;

        }

        List<IBreakpointDMContext> list = breakpointIDs.get(breakpoint);

        int count = 0;

        if (list != null) {

            for (IBreakpointDMContext bp : list) {

                fBreakpoints.removeBreakpoint(bp, removeRM);

            }

            count = list.size();

        }

        removeRM.setDoneCount(count);

    }

	/**

	 * Modify an individual breakpoint

	 * 

	 * @param context

	 * @param breakpoint

	 * @param attributes

	 * @param rm

	 * @throws CoreException

	 */

	private void modifyBreakpoint(final IBreakpointsTargetDMContext context, final IBreakpoint breakpoint,

			final List<Map<String, Object>> newAttrsList0, final IMarkerDelta oldValues, final RequestMonitor rm)

	{

	    // This method uses several lists to track the changed breakpoints:

	    // commonAttrsList - attributes which have not changed 

	    // oldAttrsList - attributes for the breakpoint before the change

	    // newAttrsList - attributes for the breakpoint after the change

	    // oldBpContexts - target-side breakpoints from before the change

	    // newBpContexts - target-side breakpoints after the change

	    // attrDeltasList - changes in the attributes for each attribute map in