/*******************************************************************************
 * Copyright (c) 2007-2009 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.equinox.p2.cudf.solver;

import java.util.*;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.equinox.p2.cudf.Log;
import org.eclipse.equinox.p2.cudf.metadata.*;
import org.eclipse.equinox.p2.cudf.query.QueryableArray;
import org.sat4j.pb.IPBSolver;

public class SimplePlanner {
	private final static boolean PURGE = true;
	private Projector projector;

	public Object getSolutionFor(ProfileChangeRequest profileChangeRequest, SolverConfiguration configuration) {
		QueryableArray profile = profileChangeRequest.getInitialState();

		InstallableUnit updatedPlan = updatePlannerInfo(profileChangeRequest);

		Slicer slice = new Slicer(profile);
		profile = slice.slice(updatedPlan, configuration.objective.equals("p2") ? null : profileChangeRequest.getExtraRequirements());
		if (PURGE) {
			Log.println("Number of  packages after slice: " + profile.getSize());
			if (profileChangeRequest.getInitialState().getSize() != 0)
				Log.println("Slice efficiency: " + (100 - ((profile.getSize() - 1) * 100) / profileChangeRequest.getInitialState().getSize()) + "%");
			profileChangeRequest.purge();

		}
		projector = new Projector(profile);
		projector.encode(updatedPlan, configuration);
		IStatus s = projector.invokeSolver();
		if (s.getSeverity() == IStatus.ERROR) {
			return s;
		}
		return projector.extractSolution();
	}

	private InstallableUnit updatePlannerInfo(ProfileChangeRequest profileChangeRequest) {
		return createIURepresentingTheProfile(profileChangeRequest.getAllRequests());
	}

	private InstallableUnit createIURepresentingTheProfile(ArrayList allRequirements) {
		InstallableUnit iud = new InstallableUnit();
		String time = Long.toString(System.currentTimeMillis());
		iud.setId(time);
		iud.setVersion(new Version(0, 0, 0, time));
		iud.setRequiredCapabilities((IRequiredCapability[]) allRequirements.toArray(new IRequiredCapability[allRequirements.size()]));
		Log.println("Request size: " + iud.getRequiredCapabilities().length);
		return iud;
	}

	public void stopSolver() {
		if (projector != null) {
			projector.stopSolver();
		}
	}

	public Collection getBestSolutionFoundSoFar() {
		return projector.getBestSolutionFoundSoFar();
	}

	public Set getExplanation() {
		return projector.getExplanation();
	}

	public IPBSolver getSolver() {
		return projector.dependencyHelper.getSolver();
	}

	public Map getMappingToDomain() {
		return projector.dependencyHelper.getMappingToDomain();
	}

	public boolean isSolutionOptimal() {
		return projector.dependencyHelper.isOptimal();
	}
}