/*******************************************************************************
 * Copyright (c) 2006, 2015 Wind River Systems and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     Wind River Systems - initial API and implementation
 *     Marc Khouzam (Ericsson) - Added support for multiple selection (bug 330974)
 *******************************************************************************/
package org.eclipse.cdt.dsf.debug.ui.actions;

import java.util.HashSet;
import java.util.Set;

import org.eclipse.cdt.dsf.concurrent.DsfRunnable;
import org.eclipse.cdt.dsf.concurrent.Immutable;
import org.eclipse.cdt.dsf.datamodel.DMContexts;
import org.eclipse.cdt.dsf.debug.service.IProcesses;
import org.eclipse.cdt.dsf.debug.service.IRunControl;
import org.eclipse.cdt.dsf.debug.service.IRunControl.IExecutionDMContext;
import org.eclipse.cdt.dsf.debug.ui.viewmodel.SteppingController;
import org.eclipse.cdt.dsf.internal.ui.DsfUIPlugin;
import org.eclipse.cdt.dsf.service.DsfServicesTracker;
import org.eclipse.cdt.dsf.ui.viewmodel.datamodel.IDMVMContext;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.debug.core.commands.IDebugCommandRequest;

/**
 * @since 1.0
 */
@Immutable
public abstract class DsfCommandRunnable extends DsfRunnable {
	private final IExecutionDMContext[] fContexts;
	private final DsfServicesTracker fTracker;
	private final IDebugCommandRequest fRequest;

	// For backwards compatibility, keep this method that returns the first selection.  This method
	// is meaningful when we only support a single selection.
	public IExecutionDMContext getContext() {
		return (fContexts != null && fContexts.length > 0) ? fContexts[0] : null;
	}

	/**
	 * Return all selected contexts.
	 * @since 2.3
	 */
	public IExecutionDMContext[] getContexts() {
		return fContexts;
	}

	public IRunControl getRunControl() {
		return fTracker.getService(IRunControl.class);
	}

	/**
	 * @since 1.1
	 */
	public SteppingController getSteppingController() {
		if (fContexts != null && fContexts.length > 0) {
			return fContexts[0].getAdapter(SteppingController.class);
		}
		return null;
	}

	/**
	 * @since 1.1
	 */
	public IProcesses getProcessService() {
		return fTracker.getService(IProcesses.class);
	}

	public DsfCommandRunnable(DsfServicesTracker servicesTracker, Object element, IDebugCommandRequest request) {
		this(servicesTracker, new Object[] { element }, request);
	}

	/** @since 2.3 */
	public DsfCommandRunnable(DsfServicesTracker servicesTracker, Object[] elements, IDebugCommandRequest request) {
		fTracker = servicesTracker;
		fRequest = request;

		// Extract all selected execution contexts, using a set to avoid duplicates.  Duplicates will
		// happen if multiple stack frames of the same thread are selected.
		Set<IExecutionDMContext> execDmcSet = new HashSet<>(request.getElements().length);
		for (Object element : request.getElements()) {
			if (element instanceof IDMVMContext) {
				IDMVMContext vmc = (IDMVMContext) element;
				IExecutionDMContext execDmc = DMContexts.getAncestorOfType(vmc.getDMContext(),
						IExecutionDMContext.class);
				if (execDmc != null) {
					// We have a thread or a process
					execDmcSet.add(execDmc);
				}
			}
		}

		if (execDmcSet.size() == 0) {
			fContexts = null;
		} else {
			fContexts = execDmcSet.toArray(new IExecutionDMContext[execDmcSet.size()]);
		}
	}

	@Override
	public final void run() {
		if (fRequest.isCanceled()) {
			fRequest.done();
			return;
		}
		if (getContexts() == null || getContexts().length == 0) {
			fRequest.setStatus(makeError("Selected objects do not support run control.", null)); //$NON-NLS-1$
		} else if (getRunControl() == null || getSteppingController() == null) {
			fRequest.setStatus(makeError("Run Control not available", null)); //$NON-NLS-1$
		} else {
			doExecute();
		}
		fRequest.done();
	}

	/**
	 * Method to perform the actual work.
	 */
	protected abstract void doExecute();

	protected IStatus makeError(String message, Throwable e) {
		return new Status(IStatus.ERROR, DsfUIPlugin.PLUGIN_ID, -1, message, e);
	}

}
