/*******************************************************************************
 * Copyright (c) 2007, 2008 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.internal.p2.metadata.repository;

import java.io.IOException;
import java.io.OutputStream;
import org.eclipse.core.runtime.*;
import org.eclipse.ecf.core.*;
import org.eclipse.ecf.filetransfer.*;
import org.eclipse.ecf.filetransfer.events.*;
import org.eclipse.ecf.filetransfer.identity.FileCreateException;
import org.eclipse.ecf.filetransfer.identity.FileIDFactory;
import org.eclipse.ecf.filetransfer.service.IRetrieveFileTransferFactory;
import org.eclipse.equinox.internal.p2.core.helpers.LogHelper;
import org.osgi.util.tracker.ServiceTracker;

public class ECFMetadataTransport {

	/**
	 * The singleton transport instance.
	 */
	private static ECFMetadataTransport instance;

	private final ServiceTracker retrievalFactoryTracker;

	public static synchronized ECFMetadataTransport getInstance() {
		if (instance == null) {
			instance = new ECFMetadataTransport();
		}
		return instance;
	}

	private ECFMetadataTransport() {
		retrievalFactoryTracker = new ServiceTracker(Activator.getContext(), IRetrieveFileTransferFactory.class.getName(), null);
		retrievalFactoryTracker.open();
	}

	public IStatus download(String toDownload, OutputStream target, IProgressMonitor monitor) {
		IRetrieveFileTransferFactory factory = (IRetrieveFileTransferFactory) retrievalFactoryTracker.getService();
		if (factory == null)
			return new Status(IStatus.ERROR, Activator.ID, "ECF Transfer manager not available");

		return transfer(factory.newInstance(), toDownload, target, monitor);
	}

	/**
	 * Gets the last modified date for the specified file.
	 * @param location - The URL location of the file.
	 * @return A <code>long</code> representing the date. Returns <code>0</code> if the file is not found or an error occurred.
	 */
	public long getLastModified(String location) {
		IContainer container;
		try {
			container = ContainerFactory.getDefault().createContainer();
		} catch (ContainerCreateException e) {
			return 0;
		}
		IRemoteFileSystemBrowserContainerAdapter adapter = (IRemoteFileSystemBrowserContainerAdapter) container.getAdapter(IRemoteFileSystemBrowserContainerAdapter.class);
		if (adapter == null) {
			return 0;
		}
		IRemoteFile remoteFile = checkFile(adapter, location);
		if (remoteFile == null) {
			return 0;
		}
		return remoteFile.getInfo().getLastModified();
	}

	private IRemoteFile checkFile(final IRemoteFileSystemBrowserContainerAdapter retrievalContainer, final String location) {
		final Object[] result = new Object[1];
		final Boolean[] done = new Boolean[1];
		done[0] = new Boolean(false);
		IRemoteFileSystemListener listener = new IRemoteFileSystemListener() {
			public void handleRemoteFileEvent(IRemoteFileSystemEvent event) {
				if (event instanceof IRemoteFileSystemBrowseEvent) {
					IRemoteFileSystemBrowseEvent fsbe = (IRemoteFileSystemBrowseEvent) event;
					IRemoteFile[] remoteFiles = fsbe.getRemoteFiles();
					if (remoteFiles != null && remoteFiles.length > 0) {
						synchronized (result) {
							result[0] = remoteFiles[0];
							done[0] = new Boolean(true);
							result.notify();
						}
					} else {
						synchronized (result) {
							result[0] = null;
							done[0] = new Boolean(true);
							result.notify();
						}
					}
				}
			}
		};
		try {
			retrievalContainer.sendBrowseRequest(FileIDFactory.getDefault().createFileID(retrievalContainer.getBrowseNamespace(), location), listener);
		} catch (RemoteFileSystemException e) {
			return null;
		} catch (FileCreateException e) {
			return null;
		}
		synchronized (result) {
			while (!done[0].booleanValue()) {
				boolean logged = false;
				try {
					result.wait();
				} catch (InterruptedException e) {
					if (!logged)
						LogHelper.log(new Status(IStatus.WARNING, Activator.ID, "Unexpected interrupt while waiting on ECF browse", e)); //$NON-NLS-1$
				}
			}
		}
		return (IRemoteFile) result[0];
	}

	private IStatus transfer(final IRetrieveFileTransferContainerAdapter retrievalContainer, final String toDownload, final OutputStream target, final IProgressMonitor monitor) {
		final IStatus[] result = new IStatus[1];
		IFileTransferListener listener = new IFileTransferListener() {

			public void handleTransferEvent(IFileTransferEvent event) {
				if (event instanceof IIncomingFileTransferReceiveStartEvent) {
					IIncomingFileTransferReceiveStartEvent rse = (IIncomingFileTransferReceiveStartEvent) event;
					if (target != null) {
						try {
							rse.receive(target);
						} catch (IOException e) {
							IStatus status = convertToStatus(e);
							synchronized (result) {
								result[0] = status;
								result.notify();
							}
						}
					}
				}
				if (event instanceof IIncomingFileTransferReceiveDataEvent) {
					IIncomingFileTransfer source = ((IIncomingFileTransferReceiveDataEvent) event).getSource();
					if (monitor != null) {
						if (monitor.isCanceled())
							source.cancel();
					}
				}
				if (event instanceof IIncomingFileTransferReceiveDoneEvent) {
					IStatus status = convertToStatus(((IIncomingFileTransferReceiveDoneEvent) event).getException());
					synchronized (result) {
						result[0] = status;
						result.notify();
					}
				}
			}
		};

		try {
			retrievalContainer.sendRetrieveRequest(FileIDFactory.getDefault().createFileID(retrievalContainer.getRetrieveNamespace(), toDownload), listener, null);
		} catch (IncomingFileTransferException e) {
			return e.getStatus();
		} catch (FileCreateException e) {
			return e.getStatus();
		}
		synchronized (result) {
			while (result[0] == null) {
				boolean logged = false;
				try {
					result.wait();
				} catch (InterruptedException e) {
					if (!logged)
						LogHelper.log(new Status(IStatus.WARNING, Activator.ID, "Unexpected interrupt while waiting on ECF transfer", e)); //$NON-NLS-1$
				}
			}
		}

		return result[0];
	}

	protected IStatus convertToStatus(Exception e) {
		if (e == null)
			return Status.OK_STATUS;
		if (e instanceof UserCancelledException)
			return new Status(IStatus.CANCEL, Activator.ID, e.getMessage(), e);
		return new Status(IStatus.ERROR, Activator.ID, e.getMessage(), e);
	}
}