/*
    * This file is part of dependency-check-core.
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   * Copyright (c) 2013 Jeremy Long. All Rights Reserved.
   */
  package org.owasp.dependencycheck.utils;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  import javax.annotation.concurrent.NotThreadSafe;
  import org.apache.commons.lang3.StringUtils;
  import org.apache.commons.lang3.builder.HashCodeBuilder;
  import org.jetbrains.annotations.NotNull;
  
  /**
   * <p>
   * Simple object to track the parts of a version number. The parts are contained
   * in a List such that version 1.2.3 will be stored as:  <code>versionParts[0] = 1;
   * versionParts[1] = 2;
   * versionParts[2] = 3;
   * </code></p>
   * <p>
   * Note, the parser contained in this class expects the version numbers to be
   * separated by periods. If a different separator is used the parser will likely
   * fail.</p>
   *
   * @author Jeremy Long
   */
  @NotThreadSafe
  public class DependencyVersion implements Iterable<String>, Comparable<DependencyVersion> {
  
      /**
       * A list of the version parts.
       */
      private List<String> versionParts;
  
      /**
       * Constructor for a empty DependencyVersion.
       */
      public DependencyVersion() {
      }
  
      /**
       * Constructor for a DependencyVersion that will parse a version string.
       * <b>Note</b>, this should only be used when the version passed in is
       * already known to be a well formatted version number. Otherwise,
       * DependencyVersionUtil.parseVersion() should be used instead.
       *
       * @param version the well formatted version number to parse
       */
      public DependencyVersion(String version) {
          parseVersion(version);
      }
  
      /**
       * Parses a version string into its sub parts: major, minor, revision,
       * build, etc. <b>Note</b>, this should only be used to parse something that
       * is already known to be a version number.
       *
       * @param version the version string to parse
       */
      public final void parseVersion(String version) {
          versionParts = new ArrayList<>();
          if (version != null) {
              final Pattern rx = Pattern
                      .compile("(\\d+[a-z]{1,3}$|[a-z]{1,3}[_-]?\\d+|\\d+|(rc|release|snapshot|beta|alpha)$)",
                              Pattern.CASE_INSENSITIVE);
              final Matcher matcher = rx.matcher(version.toLowerCase());
              while (matcher.find()) {
                  versionParts.add(matcher.group());
              }
              if (versionParts.isEmpty()) {
                  versionParts.add(version);
              }
          }
      }
  
      /**
       * Get the value of versionParts.
       *
       * @return the value of versionParts
       */
      public List<String> getVersionParts() {
          return versionParts;
     }
 
     /**
      * Set the value of versionParts.
      *
      * @param versionParts new value of versionParts
      */
     public void setVersionParts(List<String> versionParts) {
         this.versionParts = versionParts;
     }
 
     /**
      * Retrieves an iterator for the version parts.
      *
      * @return an iterator for the version parts
      */
     @NotNull
     @Override
     public Iterator<String> iterator() {
         return versionParts.iterator();
     }
 
     /**
      * Reconstructs the version string from the split version parts.
      *
      * @return a string representing the version.
      */
     @Override
     public String toString() {
         return StringUtils.join(versionParts, '.');
     }
 
     /**
      * Compares the equality of this object to the one passed in as a parameter.
      *
      * @param obj the object to compare equality
      * @return returns true only if the two objects are equal, otherwise false
      */
     @Override
     public boolean equals(Object obj) {
         if (obj == null || !(obj instanceof DependencyVersion)) {
             return false;
         }
         if (this == obj) {
             return true;
         }
         final DependencyVersion other = (DependencyVersion) obj;
         final int minVersionMatchLength = Math.min(this.versionParts.size(), other.versionParts.size());
         final int maxVersionMatchLength = Math.max(this.versionParts.size(), other.versionParts.size());
 
         if (minVersionMatchLength == 1 && maxVersionMatchLength >= 3) {
             return false;
         }
 
         //TODO steal better version of code from compareTo
         for (int i = 0; i < minVersionMatchLength; i++) {
             final String thisPart = this.versionParts.get(i);
             final String otherPart = other.versionParts.get(i);
             if (!thisPart.equals(otherPart)) {
                 return false;
             }
         }
         if (this.versionParts.size() > minVersionMatchLength) {
             for (int i = minVersionMatchLength; i < this.versionParts.size(); i++) {
                 if (!"0".equals(this.versionParts.get(i))) {
                     return false;
                 }
             }
         }
 
         if (other.versionParts.size() > minVersionMatchLength) {
             for (int i = minVersionMatchLength; i < other.versionParts.size(); i++) {
                 if (!"0".equals(other.versionParts.get(i))) {
                     return false;
                 }
             }
         }
 
         /*
          *  if (this.versionParts != other.versionParts && (this.versionParts == null || !this.versionParts.equals(other.versionParts))) {
          *      return false;
          *  }
          */
         return true;
     }
 
     /**
      * Calculates the hashCode for this object.
      *
      * @return the hashCode
      */
     @Override
     public int hashCode() {
         return new HashCodeBuilder(5, 71)
                 .append(versionParts)
                 .toHashCode();
     }
 
     /**
      * Determines if the three most major major version parts are identical. For
      * instances, if version 1.2.3.4 was compared to 1.2.3 this function would
      * return true.
      *
      * @param version the version number to compare
      * @return true if the first three major parts of the version are identical
      */
     public boolean matchesAtLeastThreeLevels(DependencyVersion version) {
         if (version == null) {
             return false;
         }
         if (Math.abs(this.versionParts.size() - version.versionParts.size()) >= 3) {
             return false;
         }
 
         final int max = Math.min(this.versionParts.size(), version.versionParts.size());
 
         boolean ret = true;
         for (int i = 0; i < max; i++) {
             final String thisVersion = this.versionParts.get(i);
             final String otherVersion = version.getVersionParts().get(i);
             if (i >= 3) {
                 if (thisVersion.compareToIgnoreCase(otherVersion) >= 0) {
                     ret = false;
                     break;
                 }
             } else if (!thisVersion.equals(otherVersion)) {
                 ret = false;
                 break;
             }
         }
 
         return ret;
     }
 
     @Override
     public int compareTo(@NotNull DependencyVersion version) {
         if (version == null) {
             return 1;
         }
         final List<String> left = this.getVersionParts();
         final List<String> right = version.getVersionParts();
         final int max = Math.min(left.size(), right.size());
 
         for (int i = 0; i < max; i++) {
             final String lStr = left.get(i);
             final String rStr = right.get(i);
             if (lStr.equals(rStr)) {
                 continue;
             }
             try {
                 final int l = Integer.parseInt(lStr);
                 final int r = Integer.parseInt(rStr);
                 if (l < r) {
                     return -1;
                 } else if (l > r) {
                     return 1;
                 }
             } catch (NumberFormatException ex) {
                 final int comp = left.get(i).compareTo(right.get(i));
                 if (comp < 0) {
                     return -1;
                 } else if (comp > 0) {
                     return 1;
                 }
             }
         }
         return Integer.compare(left.size(), right.size());
     }
 }