Copyright (c) 2007, 2016 IBM Corporation 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: IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2007, 2016 IBM Corporation 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: IBM Corporation - initial API and implementation
 ******************************************************************************/
package org.eclipse.osgi.internal.signedcontent;

import java.io.IOException;
import java.io.InputStream;
import java.security.NoSuchAlgorithmException;
import java.security.cert.Certificate;
import java.security.cert.CertificateExpiredException;
import java.security.cert.CertificateNotYetValidException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.eclipse.osgi.signedcontent.InvalidContentException;
import org.eclipse.osgi.signedcontent.SignedContent;
import org.eclipse.osgi.signedcontent.SignedContentEntry;
import org.eclipse.osgi.signedcontent.SignerInfo;
import org.eclipse.osgi.storage.bundlefile.BundleEntry;
import org.eclipse.osgi.storage.bundlefile.BundleFile;
import org.eclipse.osgi.util.NLS;

public class SignedContentImpl implements SignedContent {
	final static SignerInfo[] EMPTY_SIGNERINFO = new SignerInfo[0];
	// the content which is signed
	volatile SignedBundleFile content; // TODO can this be more general?
	// the content entry md results used for entry content verification
	// keyed by entry path -> {SignerInfo[] infos, byte[][] results)}
	private final Map<String, Object> contentMDResults;
	private final SignerInfo[] signerInfos;
	// map of tsa singers keyed by SignerInfo -> {tsa_SignerInfo, signingTime}
	private Map<SignerInfo, Object[]> tsaSignerInfos;
	volatile private boolean checkedValid = false;

	public SignedContentImpl(SignerInfo[] signerInfos, Map<String, Object> contentMDResults) {
		this.signerInfos = signerInfos == null ? EMPTY_SIGNERINFO : signerInfos;
		this.contentMDResults = contentMDResults;
	}

	@Override
	public SignedContentEntry[] getSignedEntries() {
		if (contentMDResults == null)
			return new SignedContentEntry[0];
		List<SignedContentEntry> results = new ArrayList<>(contentMDResults.size());
		for (Map.Entry<String, Object> entry : contentMDResults.entrySet()) {
			String entryName = entry.getKey();
			Object[] mdResult = (Object[]) entry.getValue();
			results.add(new SignedContentEntryImpl(entryName, (SignerInfo[]) mdResult[0]));
		}
		return results.toArray(new SignedContentEntry[results.size()]);
	}

	@Override
	public SignedContentEntry getSignedEntry(String name) {
		if (contentMDResults == null)
			return null;
		Object[] mdResult = (Object[]) contentMDResults.get(name);
		return mdResult == null ? null : new SignedContentEntryImpl(name, (SignerInfo[]) mdResult[0]);
	}

	@Override
	public SignerInfo[] getSignerInfos() {
		return signerInfos;
	}

	@Override
	public Date getSigningTime(SignerInfo signerInfo) {
		if (tsaSignerInfos == null)
			return null;
		Object[] tsaInfo = tsaSignerInfos.get(signerInfo);
		return tsaInfo == null ? null : (Date) tsaInfo[1];
	}

	@Override
	public SignerInfo getTSASignerInfo(SignerInfo signerInfo) {
		if (tsaSignerInfos == null)
			return null;
		Object[] tsaInfo = tsaSignerInfos.get(signerInfo);
		return tsaInfo == null ? null : (SignerInfo) tsaInfo[0];
	}

	@Override
	public boolean isSigned() {
		return signerInfos.length > 0;
	}

	@Override
	public void checkValidity(SignerInfo signer) throws CertificateExpiredException, CertificateNotYetValidException {
		Date signingTime = getSigningTime(signer);
		if (checkedValid)
			return;
		Certificate[] certs = signer.getCertificateChain();
		for (Certificate cert : certs) {
			if (!(cert instanceof X509Certificate)) {
				continue;
			}
			if (signingTime == null) {
				((X509Certificate) cert).checkValidity();
			} else {
				((X509Certificate) cert).checkValidity(signingTime);
			}
		}
		checkedValid = true;
	}

	void setContent(SignedBundleFile content) {
		this.content = content;
	}

	void setTSASignerInfos(Map<SignerInfo, Object[]> tsaSignerInfos) {
		this.tsaSignerInfos = tsaSignerInfos;
	}

	void addTSASignerInfo(SignerInfo baseInfo, SignerInfo tsaSignerInfo, Date signingTime) {
		// sanity check to make sure the baseInfo is here
		if (!containsInfo(baseInfo))
			throw new IllegalArgumentException("The baseInfo is not found"); //$NON-NLS-1$
		if (tsaSignerInfos == null)
			tsaSignerInfos = new HashMap<>(signerInfos.length);
		tsaSignerInfos.put(baseInfo, new Object[] {tsaSignerInfo, signingTime});
	}

	Map<String, Object> getContentMDResults() {
		return contentMDResults;
	}

	private boolean containsInfo(SignerInfo signerInfo) {
		for (SignerInfo si : signerInfos) {
			if (signerInfo == si) {
				return true;
			}
		}
		return false;
	}

	InputStream getDigestInputStream(BundleEntry nestedEntry) throws IOException {
		if (contentMDResults == null)
			return nestedEntry.getInputStream();
		Object[] mdResult = (Object[]) contentMDResults.get(nestedEntry.getName());
		if (mdResult == null)
			return null;
		try {
			return new DigestedInputStream(nestedEntry, content, (SignerInfo[]) mdResult[0], (byte[][]) mdResult[1], nestedEntry.getSize());
		} catch (NoSuchAlgorithmException e) {
			throw new IOException(e);
		}
	}

	public class SignedContentEntryImpl implements SignedContentEntry {
		private final String entryName;
		private final SignerInfo[] entrySigners;

		public SignedContentEntryImpl(String entryName, SignerInfo[] entrySigners) {
			this.entryName = entryName;
			this.entrySigners = entrySigners == null ? EMPTY_SIGNERINFO : entrySigners;
		}

		@Override
		public String getName() {
			return entryName;
		}

		@Override
		public SignerInfo[] getSignerInfos() {
			return entrySigners;
		}

		@Override
		public boolean isSigned() {
			return entrySigners.length > 0;
		}

		@Override
		public void verify() throws IOException, InvalidContentException {
			BundleFile currentContent = content;
			if (currentContent == null)
				throw new InvalidContentException("The content was not set", null); //$NON-NLS-1$
			BundleEntry entry = null;
			SecurityException exception = null;
			try {
				entry = currentContent.getEntry(entryName);
			} catch (SecurityException e) {
				exception = e;
			}
			if (entry == null)
				throw new InvalidContentException(NLS.bind(SignedContentMessages.file_is_removed_from_jar, entryName, currentContent.getBaseFile().toString()), exception);
			entry.getBytes();
		}
	}
}