/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  package org.eclipse.aether.util.version;
  
  import java.util.ArrayList;
  import java.util.Collection;
  
  import org.eclipse.aether.version.InvalidVersionSpecificationException;
  import org.eclipse.aether.version.VersionScheme;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A version scheme using a generic version syntax and common sense sorting.
   * <p>
   * This scheme accepts versions of any form, interpreting a version as a sequence of numeric and alphabetic segments.
   * The characters '-', '_', and '.' as well as the mere transitions from digit to letter and vice versa delimit the
   * version segments. Delimiters are treated as equivalent.
   * </p>
   * <p>
   * Numeric segments are compared mathematically, alphabetic segments are compared lexicographically and
   * case-insensitively. However, the following qualifier strings are recognized and treated specially: "alpha" = "a" &lt;
   * "beta" = "b" &lt; "milestone" = "m" &lt; "cr" = "rc" &lt; "snapshot" &lt; "final" = "ga" &lt; "sp". All of those
   * well-known qualifiers are considered smaller/older than other strings. An empty segment/string is equivalent to 0.
   * </p>
   * <p>
   * In addition to the above mentioned qualifiers, the tokens "min" and "max" may be used as final version segment to
   * denote the smallest/greatest version having a given prefix. For example, "1.2.min" denotes the smallest version in
   * the 1.2 line, "1.2.max" denotes the greatest version in the 1.2 line. A version range of the form "[M.N.*]" is short
   * for "[M.N.min, M.N.max]".
   * </p>
   * <p>
   * Numbers and strings are considered incomparable against each other. Where version segments of different kind would
   * collide, comparison will instead assume that the previous segments are padded with trailing 0 or "ga" segments,
   * respectively, until the kind mismatch is resolved, e.g. "1-alpha" = "1.0.0-alpha" &lt; "1.0.1-ga" = "1.0.1".
   * </p>
   */
  public final class GenericVersionScheme implements VersionScheme {
  
      /**
       * Creates a new instance of the version scheme for parsing versions.
       */
      public GenericVersionScheme() {}
  
      @Override
      public GenericVersion parseVersion(final String version) throws InvalidVersionSpecificationException {
          return new GenericVersion(version);
      }
  
      @Override
      public GenericVersionRange parseVersionRange(final String range) throws InvalidVersionSpecificationException {
          return new GenericVersionRange(range);
      }
  
      @Override
      public GenericVersionConstraint parseVersionConstraint(final String constraint)
              throws InvalidVersionSpecificationException {
          String process = requireNonNull(constraint, "constraint cannot be null");
  
          Collection<GenericVersionRange> ranges = new ArrayList<>();
  
          while (process.startsWith("[") || process.startsWith("(")) {
              int index1 = process.indexOf(')');
              int index2 = process.indexOf(']');
  
              int index = index2;
              if (index2 < 0 || (index1 >= 0 && index1 < index2)) {
                  index = index1;
              }
  
              if (index < 0) {
                  throw new InvalidVersionSpecificationException(constraint, "Unbounded version range " + constraint);
              }
  
              GenericVersionRange range = parseVersionRange(process.substring(0, index + 1));
              ranges.add(range);
  
              process = process.substring(index + 1).trim();
  
              if (process.startsWith(",")) {
                  process = process.substring(1).trim();
              }
          }
 
         if (process.length() > 0 && !ranges.isEmpty()) {
             throw new InvalidVersionSpecificationException(
                     constraint, "Invalid version range " + constraint + ", expected [ or ( but got " + process);
         }
 
         GenericVersionConstraint result;
         if (ranges.isEmpty()) {
             result = new GenericVersionConstraint(parseVersion(constraint));
         } else {
             result = new GenericVersionConstraint(UnionVersionRange.from(ranges));
         }
 
         return result;
     }
 
     @Override
     public boolean equals(final Object obj) {
         if (this == obj) {
             return true;
         }
 
         return obj != null && getClass().equals(obj.getClass());
     }
 
     @Override
     public int hashCode() {
         return getClass().hashCode();
     }
 
     // CHECKSTYLE_OFF: LineLength
     /**
      * A handy main method that behaves similarly like maven-artifact ComparableVersion is, to make possible test
      * and possibly compare differences between the two.
      * <p>
      * To check how "1.2.7" compares to "1.2-SNAPSHOT", for example, you can issue
      * <pre>java -cp ${maven.repo.local}/org/apache/maven/resolver/maven-resolver-api/${resolver.version}/maven-resolver-api-${resolver.version}.jar:${maven.repo.local}/org/apache/maven/resolver/maven-resolver-util/${resolver.version}/maven-resolver-util-${resolver.version}.jar org.eclipse.aether.util.version.GenericVersionScheme "1.2.7" "1.2-SNAPSHOT"</pre>
      * command to command line, output is very similar to that of ComparableVersion on purpose.
      */
     // CHECKSTYLE_ON: LineLength
     public static void main(String... args) {
         System.out.println("Display parameters as parsed by Maven Resolver (in canonical form and as a list of tokens)"
                 + " and comparison result:");
         if (args.length == 0) {
             return;
         }
 
         GenericVersion prev = null;
         int i = 1;
         for (String version : args) {
             GenericVersion c = new GenericVersion(version);
 
             if (prev != null) {
                 int compare = prev.compareTo(c);
                 System.out.println(
                         "   " + prev + ' ' + ((compare == 0) ? "==" : ((compare < 0) ? "<" : ">")) + ' ' + version);
             }
 
             System.out.println((i++) + ". " + version + " -> " + c.asString() + "; tokens: " + c.asItems());
 
             prev = c;
         }
     }
 }