/****************************************************************************
 * Copyright (c) 2008 Composent, Inc. and others.
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * Contributors:
 *    Composent, Inc. - initial API and implementation
 *
 * SPDX-License-Identifier: EPL-2.0
 *****************************************************************************/

package org.eclipse.ecf.provider.filetransfer.browse;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.Authenticator;
import java.net.HttpURLConnection;
import java.net.PasswordAuthentication;
import java.net.URL;
import java.net.URLConnection;
import org.eclipse.ecf.core.security.Callback;
import org.eclipse.ecf.core.security.CallbackHandler;
import org.eclipse.ecf.core.security.IConnectContext;
import org.eclipse.ecf.core.security.NameCallback;
import org.eclipse.ecf.core.security.ObjectCallback;
import org.eclipse.ecf.core.security.UnsupportedCallbackException;
import org.eclipse.ecf.core.util.Proxy;
import org.eclipse.ecf.filetransfer.BrowseFileTransferException;
import org.eclipse.ecf.filetransfer.IRemoteFile;
import org.eclipse.ecf.filetransfer.IRemoteFileSystemListener;
import org.eclipse.ecf.filetransfer.IncomingFileTransferException;
import org.eclipse.ecf.filetransfer.identity.IFileID;
import org.eclipse.ecf.internal.provider.filetransfer.Activator;
import org.eclipse.ecf.internal.provider.filetransfer.IURLConnectionModifier;
import org.eclipse.ecf.internal.provider.filetransfer.Messages;
import org.eclipse.ecf.provider.filetransfer.util.JREProxyHelper;
import org.eclipse.osgi.util.NLS;

/**
 *
 */
public class URLFileSystemBrowser extends AbstractFileSystemBrowser {

	private static final String USERNAME_PREFIX = Messages.UrlConnectionRetrieveFileTransfer_USERNAME_PROMPT;

	private static final String JRE_CONNECT_TIMEOUT_PROPERTY = "sun.net.client.defaultConnectTimeout"; //$NON-NLS-1$

	// 10/26/2009:  Added being able to set with system property with name org.eclipse.ecf.provider.filetransfer.browse.connectTimeout
	// for https://bugs.eclipse.org/bugs/show_bug.cgi?id=292995
	private static final String DEFAULT_CONNECT_TIMEOUT = System.getProperty("org.eclipse.ecf.provider.filetransfer.browse.connectTimeout", "30000"); //$NON-NLS-1$ //$NON-NLS-2$

	private static final String JRE_READ_TIMEOUT_PROPERTY = "sun.net.client.defaultReadTimeout"; //$NON-NLS-1$

	// 10/26/2009:  Added being able to set with system property with name org.eclipse.ecf.provider.filetransfer.browse.readTimeout
	// for https://bugs.eclipse.org/bugs/show_bug.cgi?id=292995
	private static final String DEFAULT_READ_TIMEOUT = System.getProperty("org.eclipse.ecf.provider.filetransfer.browse.readTimeout", "30000"); //$NON-NLS-1$ //$NON-NLS-2$

	private JREProxyHelper proxyHelper = null;

	protected String username = null;

	protected String password = null;

	/**
	 * @param directoryOrFileID directory or file id
	 * @param listener listener
	 * @param directoryOrFileURL directory or file url
	 * @param connectContext connect context
	 * @param proxy proxy
	 */
	public URLFileSystemBrowser(IFileID directoryOrFileID, IRemoteFileSystemListener listener, URL directoryOrFileURL, IConnectContext connectContext, Proxy proxy) {
		super(directoryOrFileID, listener, directoryOrFileURL, connectContext, proxy);
		proxyHelper = new JREProxyHelper();
	}

	private void setupTimeouts() {
		String existingTimeout = System.getProperty(JRE_CONNECT_TIMEOUT_PROPERTY);
		if (existingTimeout == null) {
			System.setProperty(JRE_CONNECT_TIMEOUT_PROPERTY, DEFAULT_CONNECT_TIMEOUT);
		}
		existingTimeout = System.getProperty(JRE_READ_TIMEOUT_PROPERTY);
		if (existingTimeout == null) {
			System.setProperty(JRE_READ_TIMEOUT_PROPERTY, DEFAULT_READ_TIMEOUT);
		}
	}

	/* (non-Javadoc)
	 * @see org.eclipse.ecf.provider.filetransfer.browse.AbstractFileSystemBrowser#runRequest()
	 */
	protected void runRequest() throws Exception {
		int code = -1;
		try {
			setupProxies();
			setupAuthentication();
			setupTimeouts();
			URLConnection urlConnection = directoryOrFile.openConnection();
			// set cache to off if using jar protocol
			// this is for addressing bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=235933
			if (directoryOrFile.getProtocol().equalsIgnoreCase("jar")) { //$NON-NLS-1$
				urlConnection.setUseCaches(false);
			}
			// Add http 1.1 'Connection: close' header in order to potentially avoid
			// server issue described here https://bugs.eclipse.org/bugs/show_bug.cgi?id=234916#c13
			// See bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=247197
			// also see http 1.1 rfc section 14-10 in http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
			urlConnection.setRequestProperty("Connection", "close"); //$NON-NLS-1$ //$NON-NLS-2$

			IURLConnectionModifier connectionModifier = Activator.getDefault().getURLConnectionModifier();
			if (connectionModifier != null) {
				connectionModifier.setSocketFactoryForConnection(urlConnection);
			}
			if (urlConnection instanceof HttpURLConnection) {
				HttpURLConnection httpConnection = (HttpURLConnection) urlConnection;
				httpConnection.setRequestMethod("HEAD"); //$NON-NLS-1$
				httpConnection.connect();
			} else {
				InputStream ins = urlConnection.getInputStream();
				ins.close();
			}
			code = getResponseCode(urlConnection);
			if (isHTTP()) {
				if (code == HttpURLConnection.HTTP_OK) {
					// do nothing
				} else if (code == HttpURLConnection.HTTP_NOT_FOUND) {
					throw new BrowseFileTransferException(NLS.bind("File not found: {0}", directoryOrFile.toString()), code); //$NON-NLS-1$
				} else if (code == HttpURLConnection.HTTP_UNAUTHORIZED) {
					throw new BrowseFileTransferException("Unauthorized", code); //$NON-NLS-1$
				} else if (code == HttpURLConnection.HTTP_FORBIDDEN) {
					throw new BrowseFileTransferException("Forbidden", code); //$NON-NLS-1$
				} else if (code == HttpURLConnection.HTTP_PROXY_AUTH) {
					throw new BrowseFileTransferException("Proxy auth required", code); //$NON-NLS-1$
				} else {
					throw new BrowseFileTransferException(NLS.bind("General connection error with response code={0} and header(0)={1}", Integer.valueOf(code), urlConnection.getHeaderField(0)), code); //$NON-NLS-1$
				}
			}
			remoteFiles = new IRemoteFile[1];
			remoteFiles[0] = new URLRemoteFile(urlConnection.getLastModified(), urlConnection.getContentLength(), fileID);
		} catch (final FileNotFoundException e) {
			throw new IncomingFileTransferException(NLS.bind("File not found: {0}", directoryOrFile.toString()), 404); //$NON-NLS-1$
		} catch (Exception e) {
			Exception except = (e instanceof BrowseFileTransferException) ? e : new BrowseFileTransferException(NLS.bind("Could not connect to {0}", directoryOrFile), e, code); //$NON-NLS-1$
			throw except;
		}
	}

	private boolean isHTTP() {
		final String protocol = directoryOrFile.getProtocol();
		if (protocol.equalsIgnoreCase("http") || protocol.equalsIgnoreCase("https")) //$NON-NLS-1$ //$NON-NLS-2$
			return true;
		return false;
	}

	private int getResponseCode(URLConnection urlConnection) {
		int responseCode = -1;
		String response = urlConnection.getHeaderField(0);
		if (response == null) {
			responseCode = -1;
			return responseCode;
		}
		if (!response.startsWith("HTTP/")) //$NON-NLS-1$
			return -1;
		response = response.trim();
		final int mark = response.indexOf(" ") + 1; //$NON-NLS-1$
		if (mark == 0)
			return -1;
		int last = mark + 3;
		if (last > response.length())
			last = response.length();
		responseCode = Integer.parseInt(response.substring(mark, last));
		return responseCode;

	}

	protected void setupAuthentication() throws IOException, UnsupportedCallbackException {
		if (connectContext == null)
			return;
		final CallbackHandler callbackHandler = connectContext.getCallbackHandler();
		if (callbackHandler == null)
			return;
		final NameCallback usernameCallback = new NameCallback(USERNAME_PREFIX);
		final ObjectCallback passwordCallback = new ObjectCallback();
		// Call callback with username and password callbacks
		callbackHandler.handle(new Callback[] {usernameCallback, passwordCallback});
		username = usernameCallback.getName();
		Object o = passwordCallback.getObject();
		if (!(o instanceof String))
			throw new UnsupportedCallbackException(passwordCallback, Messages.UrlConnectionRetrieveFileTransfer_UnsupportedCallbackException);
		password = (String) passwordCallback.getObject();
		// Now set authenticator to our authenticator with user and password
		Authenticator.setDefault(new UrlConnectionAuthenticator());
	}

	class UrlConnectionAuthenticator extends Authenticator {
		/* (non-Javadoc)
		 * @see java.net.Authenticator#getPasswordAuthentication()
		 */
		protected PasswordAuthentication getPasswordAuthentication() {
			return new PasswordAuthentication(username, password.toCharArray());
		}
	}

	protected void setupProxy(final Proxy proxy2) {
		proxyHelper.setupProxy(proxy2);
	}

}