/*******************************************************************************
 * Copyright (c) 2010, 2013 Ericsson 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:
 *     Ericsson - initial API and implementation
 *     Marc Khouzam (Ericsson) - Disable button when no trace record is selected
 *******************************************************************************/
package org.eclipse.cdt.dsf.gdb.internal.ui.commands;

import java.util.Hashtable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.RejectedExecutionException;

import org.eclipse.cdt.dsf.concurrent.DataRequestMonitor;
import org.eclipse.cdt.dsf.concurrent.DsfExecutor;
import org.eclipse.cdt.dsf.concurrent.ImmediateRequestMonitor;
import org.eclipse.cdt.dsf.concurrent.Query;
import org.eclipse.cdt.dsf.datamodel.DMContexts;
import org.eclipse.cdt.dsf.gdb.internal.commands.ISelectPrevTraceRecordHandler;
import org.eclipse.cdt.dsf.gdb.internal.ui.GdbUIPlugin;
import org.eclipse.cdt.dsf.gdb.service.GDBTraceControl_7_2.TraceRecordSelectedChangedEvent;
import org.eclipse.cdt.dsf.gdb.service.IGDBTraceControl;
import org.eclipse.cdt.dsf.gdb.service.IGDBTraceControl.ITraceRecordDMContext;
import org.eclipse.cdt.dsf.gdb.service.IGDBTraceControl.ITraceStatusDMData;
import org.eclipse.cdt.dsf.gdb.service.IGDBTraceControl.ITraceStatusDMData2;
import org.eclipse.cdt.dsf.gdb.service.IGDBTraceControl.ITraceTargetDMContext;
import org.eclipse.cdt.dsf.service.DsfServicesTracker;
import org.eclipse.cdt.dsf.service.DsfSession;
import org.eclipse.cdt.dsf.ui.viewmodel.datamodel.IDMVMContext;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.debug.core.IRequest;
import org.eclipse.debug.core.commands.AbstractDebugCommand;
import org.eclipse.debug.core.commands.IDebugCommandRequest;
import org.eclipse.debug.core.commands.IEnabledStateRequest;

/**
 * Command to select the previous trace record
 * 
 * @since 2.1
 */
public class GdbSelectPrevTraceRecordCommand extends AbstractDebugCommand implements ISelectPrevTraceRecordHandler {
	private final DsfExecutor fExecutor;
	private final DsfServicesTracker fTracker;
	private final DsfSession fSession;

	public GdbSelectPrevTraceRecordCommand(DsfSession session) {
		fExecutor = session.getExecutor();
		fTracker = new DsfServicesTracker(GdbUIPlugin.getBundleContext(), session.getId());
		fSession = session;
	}    

	public void dispose() {
		fTracker.dispose();
	}

	@Override
	protected void doExecute(Object[] targets, IProgressMonitor monitor, IRequest request) throws CoreException {
		if (targets.length != 1) {
			return;
		}

		final ITraceTargetDMContext dmc = DMContexts.getAncestorOfType(((IDMVMContext)targets[0]).getDMContext(), ITraceTargetDMContext.class);
		if (dmc == null) {
			return;
		}

      	Query<Object> selectRecordQuery = new Query<Object>() {
            @Override
            public void execute(final DataRequestMonitor<Object> rm) {
        		final IGDBTraceControl traceControl = fTracker.getService(IGDBTraceControl.class);

       			if (traceControl != null) {
       				traceControl.getCurrentTraceRecordContext(
       					    dmc,
       						new DataRequestMonitor<ITraceRecordDMContext>(fExecutor, rm) {
       							@Override
       							protected void handleSuccess() {
       							 final ITraceRecordDMContext prevDmc = traceControl.createPrevRecordContext(getData());
       							 traceControl.selectTraceRecord(prevDmc, new ImmediateRequestMonitor(rm) {
       							     @Override
       							     protected void handleSuccess() {
       							         fSession.dispatchEvent(new TraceRecordSelectedChangedEvent(prevDmc), new Hashtable<String, String>());
       							         rm.done();
       							     }
       							 });
       							};
       						});
       			} else {
       				rm.done();
       			}
       		}
       	};
    	try {
    		fExecutor.execute(selectRecordQuery);
    		selectRecordQuery.get();
		} catch (InterruptedException e) {
		} catch (ExecutionException e) {
        } catch (RejectedExecutionException e) {
        	// Can be thrown if the session is shutdown
        }
	}

	@Override
	protected boolean isExecutable(Object[] targets, IProgressMonitor monitor, IEnabledStateRequest request)
	throws CoreException 
	{
		if (targets.length != 1) {
			return false;
		}

		final ITraceTargetDMContext dmc = DMContexts.getAncestorOfType(((IDMVMContext)targets[0]).getDMContext(), ITraceTargetDMContext.class);
		if (dmc == null) {
			return false;
		}

        Query<Boolean> canSelectRecordQuery = new Query<Boolean>() {
        	@Override
        	public void execute(final DataRequestMonitor<Boolean> rm) {
        		final IGDBTraceControl traceControl = fTracker.getService(IGDBTraceControl.class);

        		if (traceControl != null) {
        			traceControl.getTraceStatus(dmc, new DataRequestMonitor<ITraceStatusDMData>(fExecutor, rm) {
        				@Override
        				protected void handleSuccess() {
        					if (getData().getNumberOfCollectedFrame() <= 0) {
        						// No frames to look at.
        						rm.done(false);
        						return;
        					}
        					
        					if (getData() instanceof ITraceStatusDMData2) {
        						if (((ITraceStatusDMData2)getData()).getCurrentTraceFrameId() == null) {
        							// Haven't started looking at frames, so don't enable the "Previous" button
        							rm.done(false);
            						return;
        						}
        					}

        					traceControl.isTracing(dmc, new DataRequestMonitor<Boolean>(fExecutor, rm) {
        						@Override
        						protected void handleSuccess() {
        							// Can do visualization if we are tracing.
        							rm.done(!getData());
        						};
        					});        					
        				};
        			});
        		} else {
        			rm.done(false);
        		}
        	}
        };
		try {
			fExecutor.execute(canSelectRecordQuery);
			return canSelectRecordQuery.get();
		} catch (InterruptedException e) {
		} catch (ExecutionException e) {
		} catch (RejectedExecutionException e) {
			// Can be thrown if the session is shutdown
		}

		return false;
	}

	@Override
	protected Object getTarget(Object element) {
		if (element instanceof IDMVMContext) {
			return element;
		}
		return null;
	}

	@Override
	protected boolean isRemainEnabled(IDebugCommandRequest request) {
		return true;
	}
}
