/*
    * Copyright (C) 2015, Google Inc.
    * and other copyright owners as documented in the project's IP log.
    *
    * This program and the accompanying materials are made available
    * under the terms of the Eclipse Distribution License v1.0 which
    * accompanies this distribution, is reproduced below, and is
    * available at http://www.eclipse.org/org/documents/edl-v10.php
    *
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or
   * without modification, are permitted provided that the following
   * conditions are met:
   *
   * - Redistributions of source code must retain the above copyright
   *   notice, this list of conditions and the following disclaimer.
   *
   * - Redistributions in binary form must reproduce the above
   *   copyright notice, this list of conditions and the following
   *   disclaimer in the documentation and/or other materials provided
   *   with the distribution.
   *
   * - Neither the name of the Eclipse Foundation, Inc. nor the
   *   names of its contributors may be used to endorse or promote
   *   products derived from this software without specific prior
   *   written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
   * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  package org.eclipse.jgit.transport;
  
  import static java.nio.charset.StandardCharsets.UTF_8;
  
  import static org.eclipse.jgit.util.RawParseUtils.lastIndexOfTrim;
  
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.Locale;
  import java.util.TimeZone;
  
  import org.eclipse.jgit.lib.PersonIdent;
  import org.eclipse.jgit.util.MutableInteger;
  import org.eclipse.jgit.util.RawParseUtils;
  
  /**
   * Identity in a push certificate.
   * <p>
   * This is similar to a {@link PersonIdent} in that it contains a name,
   * timestamp, and timezone offset, but differs in the following ways:
   * <ul>
   * <li>It is always parsed from a UTF-8 string, rather than a raw commit
   *   buffer.</li>
   * <li>It is not guaranteed to contain a name and email portion, since any UTF-8
   *   string is a valid OpenPGP User ID (RFC4880 5.1.1). The raw User ID is
   *   always available as {@link #getUserId()}, but {@link #getEmailAddress()}
   *   may return null.</li>
   * <li>The raw text from which the identity was parsed is available with {@link
   *   #getRaw()}. This is necessary for losslessly reconstructing the signed push
   *   certificate payload.</li>
   * <li>
   * </ul>
   *
   * @since 4.1
   */
  public class PushCertificateIdent {
  	/**
  	 * Parse an identity from a string.
  	 * <p>
  	 * Spaces are trimmed when parsing the timestamp and timezone offset, with one
  	 * exception. The timestamp must be preceded by a single space, and the rest
  	 * of the string prior to that space (including any additional whitespace) is
  	 * treated as the OpenPGP User ID.
  	 * <p>
  	 * If either the timestamp or timezone offsets are missing, mimics {@link
  	 * RawParseUtils#parsePersonIdent(String)} behavior and sets them both to
  	 * zero.
  	 *
  	 * @param str
  	 *            string to parse.
  	 * @return identity, never null.
  	 */
  	public static PushCertificateIdent parse(String str) {
  		MutableInteger p = new MutableInteger();
  		byte[] raw = str.getBytes(UTF_8);
  		int tzBegin = raw.length - 1;
 		tzBegin = lastIndexOfTrim(raw, ' ', tzBegin);
 		if (tzBegin < 0 || raw[tzBegin] != ' ') {
 			return new PushCertificateIdent(str, str, 0, 0);
 		}
 		int whenBegin = tzBegin++;
 		int tz = RawParseUtils.parseTimeZoneOffset(raw, tzBegin, p);
 		boolean hasTz = p.value != tzBegin;
 
 		whenBegin = lastIndexOfTrim(raw, ' ', whenBegin);
 		if (whenBegin < 0 || raw[whenBegin] != ' ') {
 			return new PushCertificateIdent(str, str, 0, 0);
 		}
 		int idEnd = whenBegin++;
 		long when = RawParseUtils.parseLongBase10(raw, whenBegin, p);
 		boolean hasWhen = p.value != whenBegin;
 
 		if (hasTz && hasWhen) {
 			idEnd = whenBegin - 1;
 		} else {
 			// If either tz or when are non-numeric, mimic parsePersonIdent behavior and
 			// set them both to zero.
 			tz = 0;
 			when = 0;
 			if (hasTz && !hasWhen) {
 				// Only one trailing numeric field; assume User ID ends before this
 				// field, but discard its value.
 				idEnd = tzBegin - 1;
 			} else {
 				// No trailing numeric fields; User ID is whole raw value.
 				idEnd = raw.length;
 			}
 		}
 		String id = new String(raw, 0, idEnd, UTF_8);
 
 		return new PushCertificateIdent(str, id, when * 1000L, tz);
 	}
 
 	private final String raw;
 	private final String userId;
 	private final long when;
 	private final int tzOffset;
 
 	/**
 	 * Construct a new identity from an OpenPGP User ID.
 	 *
 	 * @param userId
 	 *            OpenPGP User ID; any UTF-8 string.
 	 * @param when
 	 *            local time.
 	 * @param tzOffset
 	 *            timezone offset; see {@link #getTimeZoneOffset()}.
 	 */
 	public PushCertificateIdent(String userId, long when, int tzOffset) {
 		this.userId = userId;
 		this.when = when;
 		this.tzOffset = tzOffset;
 		StringBuilder sb = new StringBuilder(userId).append(' ').append(when / 1000)
 				.append(' ');
 		PersonIdent.appendTimezone(sb, tzOffset);
 		raw = sb.toString();
 	}
 
 	private PushCertificateIdent(String raw, String userId, long when,
 			int tzOffset) {
 		this.raw = raw;
 		this.userId = userId;
 		this.when = when;
 		this.tzOffset = tzOffset;
 	}
 
 	/**
 	 * Get the raw string from which this identity was parsed.
 	 * <p>
 	 * If the string was constructed manually, a suitable canonical string is
 	 * returned.
 	 * <p>
 	 * For the purposes of bytewise comparisons with other OpenPGP IDs, the string
 	 * must be encoded as UTF-8.
 	 *
 	 * @return the raw string.
 	 */
 	public String getRaw() {
 		return raw;
 	}
 
 	/** @return the OpenPGP User ID, which may be any string. */
 	public String getUserId() {
 		return userId;
 	}
 
 	/**
 	 * @return the name portion of the User ID. If no email address would be
 	 *         parsed by {@link #getEmailAddress()}, returns the full User ID with
 	 *         spaces trimmed.
 	 */
 	public String getName() {
 		int nameEnd = userId.indexOf('<');
 		if (nameEnd < 0 || userId.indexOf('>', nameEnd) < 0) {
 			nameEnd = userId.length();
 		}
 		nameEnd--;
 		while (nameEnd >= 0 && userId.charAt(nameEnd) == ' ') {
 			nameEnd--;
 		}
 		int nameBegin = 0;
 		while (nameBegin < nameEnd && userId.charAt(nameBegin) == ' ') {
 			nameBegin++;
 		}
 		return userId.substring(nameBegin, nameEnd + 1);
 	}
 
 	/**
 	 * @return the email portion of the User ID, if one was successfully parsed
 	 *         from {@link #getUserId()}, or null.
 	 */
 	public String getEmailAddress() {
 		int emailBegin = userId.indexOf('<');
 		if (emailBegin < 0) {
 			return null;
 		}
 		int emailEnd = userId.indexOf('>', emailBegin);
 		if (emailEnd < 0) {
 			return null;
 		}
 		return userId.substring(emailBegin + 1, emailEnd);
 	}
 
 	/** @return the timestamp of the identity. */
 	public Date getWhen() {
 		return new Date(when);
 	}
 
 	/**
 	 * @return this person's declared time zone; null if the timezone is unknown.
 	 */
 	public TimeZone getTimeZone() {
 		return PersonIdent.getTimeZone(tzOffset);
 	}
 
 	/**
 	 * @return this person's declared time zone as minutes east of UTC. If the
 	 *         timezone is to the west of UTC it is negative.
 	 */
 	public int getTimeZoneOffset() {
 		return tzOffset;
 	}
 
 	@Override
 	public boolean equals(Object o) {
 		return (o instanceof PushCertificateIdent)
 			&& raw.equals(((PushCertificateIdent) o).raw);
 	}
 
 	@Override
 	public int hashCode() {
 		return raw.hashCode();
 	}
 
 	@SuppressWarnings("nls")
 	@Override
 	public String toString() {
 		SimpleDateFormat fmt;
 		fmt = new SimpleDateFormat("EEE MMM d HH:mm:ss yyyy Z", Locale.US);
 		fmt.setTimeZone(getTimeZone());
 		return getClass().getSimpleName()
 			+ "[raw=\"" + raw + "\","
 			+ " userId=\"" + userId + "\","
 			+ " " + fmt.format(Long.valueOf(when)) + "]";
 	}
 }