/*******************************************************************************
 *  Copyright (c) 2007, 2010 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
 *  	Compeople AG (Stefan Liebig) - various ongoing maintenance
 *      Sonatype, Inc. - transport split
 *******************************************************************************/
package org.eclipse.equinox.p2.internal.repository.mirroring;

import java.util.*;
import org.eclipse.core.runtime.*;
import org.eclipse.equinox.internal.p2.artifact.repository.RawMirrorRequest;
import org.eclipse.equinox.internal.p2.core.helpers.CollectionUtils;
import org.eclipse.equinox.internal.p2.repository.Transport;
import org.eclipse.equinox.p2.core.ProvisionException;
import org.eclipse.equinox.p2.internal.repository.tools.Activator;
import org.eclipse.equinox.p2.internal.repository.tools.Messages;
import org.eclipse.equinox.p2.metadata.IArtifactKey;
import org.eclipse.equinox.p2.query.IQuery;
import org.eclipse.equinox.p2.query.IQueryResult;
import org.eclipse.equinox.p2.repository.artifact.*;
import org.eclipse.equinox.p2.repository.artifact.spi.ArtifactDescriptor;
import org.eclipse.equinox.p2.repository.tools.comparator.ArtifactComparatorFactory;
import org.eclipse.equinox.p2.repository.tools.comparator.IArtifactComparator;
import org.eclipse.osgi.util.NLS;

/**
 * A utility class that performs mirroring of artifacts between repositories.
 */
public class Mirroring {
	private IArtifactRepository source;
	private IArtifactRepository destination;
	private IArtifactRepository baseline;
	private boolean raw;
	private boolean compare = false;
	private boolean validate = false;
	private IArtifactComparator comparator;
	private IQuery<IArtifactDescriptor> compareExclusionQuery = null;
	private Set<IArtifactDescriptor> compareExclusions = CollectionUtils.<IArtifactDescriptor> emptySet();
	private String comparatorID;
	private List<IArtifactKey> keysToMirror;
	private IArtifactMirrorLog comparatorLog;
	private Transport transport;

	private IArtifactComparator getComparator() {
		if (comparator == null)
			comparator = ArtifactComparatorFactory.getArtifactComparator(comparatorID);
		return comparator;
	}

	public Mirroring(IArtifactRepository source, IArtifactRepository destination, boolean raw) {
		this.source = source;
		this.destination = destination;
		this.raw = raw;
	}

	public void setCompare(boolean compare) {
		this.compare = compare;
	}

	public void setComparatorId(String id) {
		this.comparatorID = id;
	}

	public void setComparatorLog(IArtifactMirrorLog comparatorLog) {
		this.comparatorLog = comparatorLog;
	}

	public void setBaseline(IArtifactRepository baseline) {
		this.baseline = baseline;
	}

	public void setValidate(boolean validate) {
		this.validate = validate;
	}

	public MultiStatus run(boolean failOnError, boolean verbose) {
		if (!destination.isModifiable())
			throw new IllegalStateException(NLS.bind(Messages.exception_destinationNotModifiable, destination.getLocation()));
		if (compare)
			getComparator(); //initialize the comparator. Only needed if we're comparing. Used to force error if comparatorID is invalid.
		MultiStatus multiStatus = new MultiStatus(Activator.ID, IStatus.OK, Messages.message_mirroringStatus, null);
		Iterator<IArtifactKey> keys = null;
		if (keysToMirror != null)
			keys = keysToMirror.iterator();
		else {
			IQueryResult<IArtifactKey> result = source.query(ArtifactKeyQuery.ALL_KEYS, null);
			keys = result.iterator();
		}

		if (compareExclusionQuery != null) {
			IQueryResult<IArtifactDescriptor> exclusions = source.descriptorQueryable().query(compareExclusionQuery, null);
			compareExclusions = exclusions.toUnmodifiableSet();
		}

		while (keys.hasNext()) {
			IArtifactKey key = keys.next();
			IArtifactDescriptor[] descriptors = source.getArtifactDescriptors(key);
			for (int j = 0; j < descriptors.length; j++) {
				IStatus result = mirror(descriptors[j], verbose);
				//Only log INFO and WARNING if we want verbose logging. Always log ERRORs
				if (!result.isOK() && (verbose || result.getSeverity() == IStatus.ERROR))
					multiStatus.add(result);
				//stop mirroring as soon as we have an error
				if (failOnError && multiStatus.getSeverity() == IStatus.ERROR)
					return multiStatus;
			}
		}
		if (validate) {
			// Simple validation of the mirror
			IStatus validation = validateMirror(verbose);
			if (!validation.isOK() && (verbose || validation.getSeverity() == IStatus.ERROR))
				multiStatus.add(validation);
		}
		return multiStatus;
	}

	private IStatus mirror(IArtifactDescriptor sourceDescriptor, boolean verbose) {
		IArtifactDescriptor targetDescriptor = raw ? sourceDescriptor : new ArtifactDescriptor(sourceDescriptor);
		IArtifactDescriptor baselineDescriptor = getBaselineDescriptor(sourceDescriptor);

		if (verbose)
			System.out.println("Mirroring: " + sourceDescriptor.getArtifactKey() + " (Descriptor: " + sourceDescriptor + ")"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$

		MultiStatus compareStatus = new MultiStatus(Activator.ID, IStatus.OK, null, null);
		boolean comparing = compare && !compareExclusions.contains(sourceDescriptor);
		if (comparing) {
			if (baselineDescriptor != null) {
				//compare source & baseline
				compareStatus.add(compare(baseline, baselineDescriptor, source, sourceDescriptor));
				//compare baseline & destination
				if (destination.contains(baselineDescriptor)) {
					compareStatus.add(compareToDestination(baselineDescriptor));
					return compareStatus;
				}
			} else if (destination.contains(targetDescriptor)) {
				compareStatus.add(compareToDestination(sourceDescriptor));
				return compareStatus;
			}
		}

		//from source or baseline
		IArtifactRepository sourceRepository = baselineDescriptor != null ? baseline : source;
		sourceDescriptor = baselineDescriptor != null ? baselineDescriptor : sourceDescriptor;
		targetDescriptor = baselineDescriptor != null ? baselineDescriptor : targetDescriptor;
		IStatus status = null;
		if (!destination.contains(targetDescriptor))
			//actual download
			status = downloadArtifact(sourceRepository, targetDescriptor, sourceDescriptor);
		else {
			String message = NLS.bind(Messages.mirror_alreadyExists, sourceDescriptor, destination);
			status = new Status(IStatus.INFO, Activator.ID, ProvisionException.ARTIFACT_EXISTS, message, null);
		}

		if (comparing) {
			compareStatus.add(status);
			return compareStatus;
		}
		return status;
	}

	/**
	 * Takes an IArtifactDescriptor descriptor and the ProvisionException that was thrown when destination.getOutputStream(descriptor)
	 * and compares descriptor to the duplicate descriptor in the destination.
	 * 
	 * Callers should verify the ProvisionException was thrown due to the artifact existing in the destination before invoking this method.
	 * @param descriptor
	 * @return the status of the compare
	 */
	private IStatus compareToDestination(IArtifactDescriptor descriptor) {
		IArtifactDescriptor[] destDescriptors = destination.getArtifactDescriptors(descriptor.getArtifactKey());
		IArtifactDescriptor destDescriptor = null;
		for (int i = 0; destDescriptor == null && i < destDescriptors.length; i++) {
			if (destDescriptors[i].equals(descriptor))
				destDescriptor = destDescriptors[i];
		}
		if (destDescriptor == null)
			return new Status(IStatus.INFO, Activator.ID, ProvisionException.ARTIFACT_EXISTS, Messages.Mirroring_noMatchingDescriptor, null);
		return compare(source, descriptor, destination, destDescriptor);
	}

	private IStatus compare(IArtifactRepository sourceRepository, IArtifactDescriptor sourceDescriptor, IArtifactRepository destRepository, IArtifactDescriptor destDescriptor) {
		IStatus comparison = getComparator().compare(sourceRepository, sourceDescriptor, destRepository, destDescriptor);
		if (comparatorLog != null && !comparison.isOK())
			comparatorLog.log(sourceDescriptor, comparison);
		return comparison;
	}

	/*
	 * Create, and execute a MirrorRequest for a given descriptor.
	 */
	private IStatus downloadArtifact(IArtifactRepository sourceRepo, IArtifactDescriptor destDescriptor, IArtifactDescriptor srcDescriptor) {
		RawMirrorRequest request = new RawMirrorRequest(srcDescriptor, destDescriptor, destination, transport);
		request.perform(sourceRepo, new NullProgressMonitor());

		return request.getResult();
	}

	public void setArtifactKeys(IArtifactKey[] keys) {
		this.keysToMirror = Arrays.asList(keys);
	}

	/*
	 *  Get the equivalent descriptor from the baseline repository
	 */
	private IArtifactDescriptor getBaselineDescriptor(IArtifactDescriptor descriptor) {
		if (baseline == null || !baseline.contains(descriptor))
			return null;

		IArtifactDescriptor[] baselineDescriptors = baseline.getArtifactDescriptors(descriptor.getArtifactKey());
		for (int i = 0; i < baselineDescriptors.length; i++) {
			if (baselineDescriptors[i].equals(descriptor))
				return baselineDescriptors[i];
		}
		return null;
	}

	/* 
	 * Simple validation of a mirror to see if all source descriptors are present in the destination
	 */
	private IStatus validateMirror(boolean verbose) {
		MultiStatus status = new MultiStatus(Activator.ID, 0, Messages.Mirroring_ValidationError, null);

		// The keys that were mirrored in this session
		Iterator<IArtifactKey> keys = null;
		if (keysToMirror != null) {
			keys = keysToMirror.iterator();
		} else {
			IQueryResult<IArtifactKey> result = source.query(ArtifactKeyQuery.ALL_KEYS, null);
			keys = result.iterator();
		}
		while (keys.hasNext()) {
			IArtifactKey artifactKey = keys.next();
			IArtifactDescriptor[] srcDescriptors = source.getArtifactDescriptors(artifactKey);
			IArtifactDescriptor[] destDescriptors = destination.getArtifactDescriptors(artifactKey);

			Arrays.sort(srcDescriptors, new ArtifactDescriptorComparator());
			Arrays.sort(destDescriptors, new ArtifactDescriptorComparator());

			int src = 0;
			int dest = 0;
			while (src < srcDescriptors.length && dest < destDescriptors.length) {
				if (!destDescriptors[dest].equals(srcDescriptors[src])) {
					if (destDescriptors[dest].toString().compareTo((srcDescriptors[src].toString())) > 0) {
						// Missing an artifact
						if (verbose)
							System.out.println(NLS.bind(Messages.Mirroring_missingDescriptor, srcDescriptors[src]));
						status.add(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.Mirroring_missingDescriptor, srcDescriptors[src++])));
					} else {
						// Its okay if there are extra descriptors in the destination
						dest++;
					}
				} else {
					// check properties for differences
					Map<String, String> destMap = destDescriptors[dest].getProperties();
					Map<String, String> srcProperties = null;
					if (baseline != null) {
						IArtifactDescriptor baselineDescriptor = getBaselineDescriptor(destDescriptors[dest]);
						if (baselineDescriptor != null)
							srcProperties = baselineDescriptor.getProperties();
					}
					// Baseline not set, or could not find descriptor so we'll use the source descriptor
					if (srcProperties == null)
						srcProperties = srcDescriptors[src].getProperties();

					// Cycle through properties of the originating descriptor & compare
					for (String key : srcProperties.keySet()) {
						if (!srcProperties.get(key).equals(destMap.get(key))) {
							if (verbose)
								System.out.println(NLS.bind(Messages.Mirroring_differentDescriptorProperty, new Object[] {destDescriptors[dest], key, srcProperties.get(key), destMap.get(key)}));
							status.add(new Status(IStatus.WARNING, Activator.ID, NLS.bind(Messages.Mirroring_differentDescriptorProperty, new Object[] {destDescriptors[dest], key, srcProperties.get(key), destMap.get(key)})));
						}
					}
					src++;
					dest++;
				}
			}

			// If there are still source descriptors they're missing from the destination repository 
			while (src < srcDescriptors.length) {
				if (verbose)
					System.out.println(NLS.bind(Messages.Mirroring_missingDescriptor, srcDescriptors[src]));
				status.add(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.Mirroring_missingDescriptor, srcDescriptors[src++])));
			}
		}

		return status;
	}

	// Simple comparator for ArtifactDescriptors
	protected class ArtifactDescriptorComparator implements Comparator<IArtifactDescriptor> {

		public int compare(IArtifactDescriptor arg0, IArtifactDescriptor arg1) {
			if (arg0 != null && arg1 != null)
				return arg0.toString().compareTo(arg1.toString());
			else if (arg1 == null && arg0 == null)
				return 0;
			else if (arg1 == null)
				return 1;
			return -1;
		}
	}

	public void setCompareExclusions(IQuery<IArtifactDescriptor> excludedKeys) {
		compareExclusionQuery = excludedKeys;
	}

	public void setTransport(Transport transport) {
		this.transport = transport;
	}
}
