/*
    * 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.apache.maven.scm.provider.svn;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.maven.scm.ScmBranch;
  import org.apache.maven.scm.ScmTag;
  import org.apache.maven.scm.ScmVersion;
  import org.apache.maven.scm.provider.svn.repository.SvnScmProviderRepository;
  
  public final class SvnTagBranchUtils {
  
      private SvnTagBranchUtils() {}
  
      public static final String[] REVISION_SPECIFIERS = new String[] {"HEAD", "BASE", "COMMITTED", "PREV"};
  
      public static final String SVN_TRUNK = "trunk";
  
      public static final String SVN_BRANCHES = "branches";
  
      public static final String SVN_TAGS = "tags";
  
      public static final String[] SVN_BASE_DIRS = new String[] {SVN_TRUNK, SVN_BRANCHES, SVN_TAGS};
  
      /**
       * Simple helper function to concatenate two paths together with a "/".
       * Handles trailing / on basePath.
       * Returns no trailing "/" if the addlPath is null.
       */
      static String appendPath(String basePath, String addlPath) {
          basePath = StringUtils.stripEnd(basePath, "/");
  
          if (addlPath == null || addlPath.isEmpty()) {
              return basePath;
          } else {
              return basePath + "/" + StringUtils.stripStart(addlPath, "/");
          }
      }
  
      /**
       * Returns the project root for the given repository url,
       * where "project root" is the root of the /trunk, /branches, /tags
       * directories.
       *
       * @param repoPath repository path/url to be searched
       * @return TODO
       */
      public static String getProjectRoot(String repoPath) {
          for (int i = 0; i < SVN_BASE_DIRS.length; i++) {
              String base = "/" + SVN_BASE_DIRS[i];
              int pos = repoPath.lastIndexOf(base + "/");
              if (repoPath.endsWith(base)) {
                  return repoPath.substring(0, repoPath.length() - base.length());
              } else if (pos >= 0) {
                  return repoPath.substring(0, pos);
              }
          }
  
          // At this point we were unable to locate the project root of this url
          // so assume that the repository url specified is the project root
          return appendPath(repoPath, null);
      }
  
      public static String resolveTagBase(SvnScmProviderRepository repository) {
          return resolveTagBase(repository.getUrl());
      }
  
      public static String resolveTagBase(String repositoryUrl) {
          return appendPath(getProjectRoot(repositoryUrl), SVN_TAGS);
      }
  
      public static String resolveBranchBase(SvnScmProviderRepository repository) {
          return resolveBranchBase(repository.getUrl());
      }
  
      public static String resolveBranchBase(String repositoryUrl) {
          return appendPath(getProjectRoot(repositoryUrl), SVN_BRANCHES);
      }
  
      /**
       * Resolves a tag to a repository url.
       * By supplying the repository to this function (rather than calling {@link #resolveTagUrl(String,ScmTag)}
       * the resolution can use the repository's tagBase to override the default tag location.
      *
      * @param repository the repository to use as a base for tag resolution
      * @param tag        tag name
      * @return TODO
      * @see #resolveUrl(String,String,String,ScmBranch)
      */
     public static String resolveTagUrl(SvnScmProviderRepository repository, ScmTag tag) {
         return resolveUrl(repository.getUrl(), repository.getTagBase(), SVN_TAGS, tag);
     }
 
     /**
      * Resolves a tag to a repository url.
      * Will not use the {@link SvnScmProviderRepository#getTagBase()} during resolution.
      *
      * @param repositoryUrl string url for the repository
      * @param tag           tag name
      * @return TODO
      * @see #resolveUrl(String,String,String,ScmBranch)
      */
     public static String resolveTagUrl(String repositoryUrl, ScmTag tag) {
         return resolveUrl(repositoryUrl, null, SVN_TAGS, tag);
     }
 
     /**
      * Resolves a branch name to a repository url.
      * By supplying the repository to this function (rather than calling {@link #resolveBranchUrl(String,ScmBranch)}
      * the resolution can use the repository's tagBase to override the default tag location.
      *
      * @param repository the repository to use as a base for tag resolution
      * @param branch     tag name
      * @return TODO
      * @see #resolveUrl(String,String,String,ScmBranch)
      */
     public static String resolveBranchUrl(SvnScmProviderRepository repository, ScmBranch branch) {
         return resolveUrl(repository.getUrl(), repository.getBranchBase(), SVN_BRANCHES, branch);
     }
 
     /**
      * Resolves a branch name to a repository url.
      * Will not use the {@link SvnScmProviderRepository#getTagBase()} during resolution.
      *
      * @param repositoryUrl string url for the repository
      * @param branch        branch name
      * @return TODO
      * @see #resolveUrl(String,String,String,ScmBranch)
      */
     public static String resolveBranchUrl(String repositoryUrl, ScmBranch branch) {
         return resolveUrl(repositoryUrl, resolveBranchBase(repositoryUrl), SVN_BRANCHES, branch);
     }
 
     private static String addSuffix(String baseString, String suffix) {
         return (suffix != null) ? baseString + suffix : baseString;
     }
 
     /**
      * Resolves a tag or branch name to a repository url.<br>
      * If the <code>branchTagName</code> is an absolute URL, that value is returned.
      * (i.e. http://foo.com/svn/myproject/tags/my-tag)<br>
      * <p>
      * If the repository has a {@link SvnScmProviderRepository#getTagBase()} specified,
      * the tag is simply appended to the tagBase value. Note that at this time, we are using
      * the tagBase as a base for both branches and tags.<br>
      * <p>
      * If the <code>branchTagName</code> contains a branch/tag specifier (i.e. "/branches", "/tags", "/trunk"),
      * the <code>branchTagName</code> is appended to the <code>projectRoot</code> without adding the subdir.<br>
      * Else, the result is in the format of <code>projectRoot/subdir/branchTagName</code> directory.<br>
      *
      * @param repositoryUrl string url for the repository
      * @param tagBase       tagBase to use
      * @param subdir        subdirectory to append to the project root
      *                      (for branching use "branches", tags use "tags")
      * @param branchTag     name of the actual branch or tag. Can be an absolute url, simple tag/branch name,
      *                      or even contain a relative path to the root like "branches/my-branch"
      * @return TODO
      */
     public static String resolveUrl(String repositoryUrl, String tagBase, String subdir, ScmBranch branchTag) {
         String branchTagName = branchTag.getName();
         String projectRoot = getProjectRoot(repositoryUrl);
         branchTagName = StringUtils.strip(branchTagName, "/");
 
         if (branchTagName == null || branchTagName.isEmpty()) {
             return null;
         }
 
         // Look for a query string as in ViewSVN urls
         String queryString = null;
         if (repositoryUrl.indexOf('?') >= 0) {
             queryString = repositoryUrl.substring(repositoryUrl.indexOf('?'));
             // if repositoryUrl contains a query string, remove it from repositoryUrlRoot; will be re-appended later
             projectRoot = StringUtils.replace(projectRoot, queryString, "");
         }
 
         if (branchTagName.indexOf("://") >= 0) {
             // branch/tag is already an absolute url so just return it.
             return branchTagName;
         }
 
         // User has a tagBase specified so just return the name appended to the tagBase
         if ((tagBase != null && !tagBase.isEmpty())
                 && !tagBase.equals(resolveTagBase(repositoryUrl))
                 && !tagBase.equals(resolveBranchBase(repositoryUrl))) {
             return appendPath(tagBase, branchTagName);
         }
 
         // Look for any "branches/" or "tags/" specifiers in the branchTagName. If one occurs,
         // don't append the subdir to the projectRoot when appending the name
         for (int i = 0; i < SVN_BASE_DIRS.length; i++) {
             if (branchTagName.startsWith(SVN_BASE_DIRS[i] + "/")) {
                 return addSuffix(appendPath(projectRoot, branchTagName), queryString);
             }
         }
 
         return addSuffix(appendPath(appendPath(projectRoot, subdir), branchTagName), queryString);
     }
 
     /* Helper function that does the checking for {@link #isRevisionSpecifier}
      */
     private static boolean checkRevisionArg(String arg) {
         if (StringUtils.isNumeric(arg) || (arg.startsWith("{") && arg.endsWith("}"))) {
             return true;
         }
 
         for (int i = 0; i < REVISION_SPECIFIERS.length; i++) {
             if (REVISION_SPECIFIERS[i].equalsIgnoreCase(arg)) {
                 return true;
             }
         }
 
         return false;
     }
 
     /**
      * Returns whether the supplied tag refers to an actual revision or
      * is specifying a tag/branch url in the repository.
      * According to the subversion documentation, the following are valid revision specifiers:
      * NUMBER       revision number
      * "{" DATE "}" revision at start of the date
      * "HEAD"       latest in repository
      * "BASE"       base rev of item's working copy
      * "COMMITTED"  last commit at or before BASE
      * "PREV"
      * <p>
      * For command such as diff, the revision argument can be in the format of:
      * IDENTIFIER:IDENTIFIER   where IDENTIFIER is one of the args listed above.
      */
     public static boolean isRevisionSpecifier(ScmVersion version) {
         if (version == null) {
             return false;
         }
 
         String versionName = version.getName();
 
         if (versionName == null || versionName.isEmpty()) {
             return false;
         }
 
         if (checkRevisionArg(versionName)) {
             return true;
         }
 
         String[] parts = StringUtils.split(versionName, ":");
         if (parts.length == 2 && StringUtils.isNotEmpty(parts[0]) && StringUtils.isNotEmpty(parts[1])) {
             return checkRevisionArg(parts[0]) && checkRevisionArg(parts[1]);
         }
 
         return false;
     }
 }