/*
    * 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.commons.vfs2.provider;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.commons.vfs2.FileName;
  import org.apache.commons.vfs2.FileSystemException;
  import org.apache.commons.vfs2.FileType;
  import org.apache.commons.vfs2.NameScope;
  import org.apache.commons.vfs2.VFS;
  
  /**
   * A default file name implementation.
   */
  public abstract class AbstractFileName implements FileName {
  
      // URI Characters that are possible in local file names, but must be escaped
      // for proper URI handling.
      //
      // How reserved URI chars were selected:
      //
      // URIs can contain :, /, ?, #, @
      // See https://docs.oracle.com/javase/8/docs/api/java/net/URI.html
      // http://tools.ietf.org/html/rfc3986#section-2.2
      //
      // Since : and / occur before the path, only chars after path are escaped (i.e., # and ?)
      // ? is a reserved filesystem character for Windows and Unix, so can't be part of a file name.
      // Therefore only # is a reserved char in a URI as part of the path that can be in the file name.
      private static final char[] RESERVED_URI_CHARS = { '#', ' ' };
  
      private final String scheme;
      private final String absPath;
      private FileType type;
  
      // Cached attributes
      private String uriString;
      private String baseName;
      private String rootUri;
      private String extension;
      private String decodedAbsPath;
  
      private String key;
  
      public AbstractFileName(final String scheme, final String absPath, final FileType type) {
          this.rootUri = null;
          this.scheme = scheme;
          this.type = type;
          if (StringUtils.isEmpty(absPath)) {
              this.absPath = ROOT_PATH;
          } else {
              if (absPath.length() > 1 && absPath.endsWith("/")) {
                  this.absPath = absPath.substring(0, absPath.length() - 1);
              } else {
                  this.absPath = absPath;
              }
          }
      }
  
      @Override
      public boolean equals(final Object o) {
          if (this == o) {
              return true;
          }
          if (o == null || getClass() != o.getClass()) {
              return false;
          }
  
          final AbstractFileName/../../org/apache/commons/vfs2/provider/AbstractFileName.html#AbstractFileName">AbstractFileName that = (AbstractFileName) o;
  
          return getKey().equals(that.getKey());
      }
  
      @Override
      public int hashCode() {
          return getKey().hashCode();
      }
  
      /**
       * Implement Comparable.
       *
       * @param obj another abstract file name
       * @return negative number if less than, 0 if equal, positive if greater than.
       */
      @Override
      public int compareTo(final FileName obj) {
         final AbstractFileName/../../org/apache/commons/vfs2/provider/AbstractFileName.html#AbstractFileName">AbstractFileName name = (AbstractFileName) obj;
         return getKey().compareTo(name.getKey());
     }
 
     /**
      * Returns the URI of the file.
      *
      * @return the FileName as a URI.
      */
     @Override
     public String toString() {
         return getURI();
     }
 
     /**
      * Factory method for creating name instances.
      *
      * @param absolutePath The absolute path.
      * @param fileType The FileType.
      * @return The FileName.
      */
     public abstract FileName createName(String absolutePath, FileType fileType);
 
     /**
      * Builds the root URI for this file name. Note that the root URI must not end with a separator character.
      *
      * @param buffer A StringBuilder to use to construct the URI.
      * @param addPassword true if the password should be added, false otherwise.
      */
     protected abstract void appendRootUri(StringBuilder buffer, boolean addPassword);
 
     /**
      * Returns the base name of the file.
      *
      * @return The base name of the file.
      */
     @Override
     public String getBaseName() {
         if (baseName == null) {
             final int idx = getPath().lastIndexOf(SEPARATOR_CHAR);
             if (idx == -1) {
                 baseName = getPath();
             } else {
                 baseName = getPath().substring(idx + 1);
             }
         }
 
         return baseName;
     }
 
     /**
      * Returns the absolute path of the file, relative to the root of the file system that the file belongs to.
      *
      * @return The path String.
      */
     @Override
     public String getPath() {
         if (VFS.isUriStyle()) {
             return absPath + getUriTrailer();
         }
         return absPath;
     }
 
     protected String getUriTrailer() {
         return getType().hasChildren() ? "/" : "";
     }
 
     /**
      * Returns the decoded path.
      *
      * @return The decoded path String.
      * @throws FileSystemException If an error occurs.
      */
     @Override
     public String getPathDecoded() throws FileSystemException {
         if (decodedAbsPath == null) {
             decodedAbsPath = UriParser.decode(getPath());
         }
 
         return decodedAbsPath;
     }
 
     /**
      * Returns the name of the parent of the file.
      *
      * @return the FileName of the parent.
      */
     @Override
     public FileName getParent() {
         final String parentPath;
         final int idx = getPath().lastIndexOf(SEPARATOR_CHAR);
         if (idx == -1 || idx == getPath().length() - 1) {
             // No parent
             return null;
         }
         if (idx == 0) {
             // Root is the parent
             parentPath = SEPARATOR;
         } else {
             parentPath = getPath().substring(0, idx);
         }
         return createName(parentPath, FileType.FOLDER);
     }
 
     /**
      * find the root of the file system.
      *
      * @return The root FileName.
      */
     @Override
     public FileName getRoot() {
         FileName root = this;
         while (root.getParent() != null) {
             root = root.getParent();
         }
 
         return root;
     }
 
     /**
      * Returns the URI scheme of this file.
      *
      * @return The protocol used to access the file.
      */
     @Override
     public String getScheme() {
         return scheme;
     }
 
     /**
      * Returns the absolute URI of the file.
      *
      * @return The absolute URI of the file.
      */
     @Override
     public String getURI() {
         if (uriString == null) {
             uriString = createURI();
         }
         return uriString;
     }
 
     protected String createURI() {
         return createURI(false, true);
     }
 
     /**
      * Create a path that does not use the FileType since that field is not immutable.
      *
      * @return The key.
      */
     private String getKey() {
         if (key == null) {
             key = getURI();
         }
         return key;
     }
 
     /**
      * Returns the URI without a password.
      *
      * @return Returns the URI without a password.
      */
     @Override
     public String getFriendlyURI() {
         return createURI(false, false);
     }
 
     private String createURI(final boolean useAbsolutePath, final boolean usePassword) {
         final StringBuilder buffer = new StringBuilder();
         appendRootUri(buffer, usePassword);
         buffer.append(handleURISpecialCharacters(useAbsolutePath ? absPath : getPath()));
         return buffer.toString();
     }
 
     private String handleURISpecialCharacters(String uri) {
         if (!StringUtils.isEmpty(uri)) {
             try {
                 // VFS-325: Handle URI special characters in file name
                 // Decode the base URI and re-encode with URI special characters
                 uri = UriParser.decode(uri);
 
                 return UriParser.encode(uri, RESERVED_URI_CHARS);
             } catch (final FileSystemException e) {
                 // Default to base URI value
             }
         }
 
         return uri;
     }
 
     /**
      * Converts a file name to a relative name, relative to this file name.
      *
      * @param name The FileName.
      * @return The relative path to the file.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public String getRelativeName(final FileName name) throws FileSystemException {
         final String path = name.getPath();
 
         // Calculate the common prefix
         final int basePathLen = getPath().length();
         final int pathLen = path.length();
 
         // Deal with root
         if (basePathLen == 1 && pathLen == 1) {
             return ".";
         }
         if (basePathLen == 1) {
             return path.substring(1);
         }
 
         final int maxlen = Math.min(basePathLen, pathLen);
         int pos = 0;
         for (; pos < maxlen && getPath().charAt(pos) == path.charAt(pos); pos++) {
             // empty
         }
 
         if (pos == basePathLen && pos == pathLen) {
             // Same names
             return ".";
         }
         if (pos == basePathLen && pos < pathLen && path.charAt(pos) == SEPARATOR_CHAR) {
             // A descendent of the base path
             return path.substring(pos + 1);
         }
 
         // Strip the common prefix off the path
         final StringBuilder buffer = new StringBuilder();
         if (pathLen > 1 && (pos < pathLen || getPath().charAt(pos) != SEPARATOR_CHAR)) {
             // Not a direct ancestor, need to back up
             pos = getPath().lastIndexOf(SEPARATOR_CHAR, pos);
             buffer.append(path.substring(pos));
         }
 
         // Prepend a '../' for each element in the base path past the common
         // prefix
         buffer.insert(0, "..");
         pos = getPath().indexOf(SEPARATOR_CHAR, pos + 1);
         while (pos != -1) {
             buffer.insert(0, "../");
             pos = getPath().indexOf(SEPARATOR_CHAR, pos + 1);
         }
 
         return buffer.toString();
     }
 
     /**
      * Returns the root URI of the file system this file belongs to.
      *
      * @return The URI of the root.
      */
     @Override
     public String getRootURI() {
         if (rootUri == null) {
             final StringBuilder buffer = new StringBuilder();
             appendRootUri(buffer, true);
             buffer.append(SEPARATOR_CHAR);
             rootUri = buffer.toString().intern();
         }
         return rootUri;
     }
 
     /**
      * Returns the depth of this file name, within its file system.
      *
      * @return The depth of the file name.
      */
     @Override
     public int getDepth() {
         final int len = getPath().length();
         if (len == 0 || len == 1 && getPath().charAt(0) == SEPARATOR_CHAR) {
             return 0;
         }
         int depth = 1;
         for (int pos = 0; pos > -1 && pos < len; depth++) {
             pos = getPath().indexOf(SEPARATOR_CHAR, pos + 1);
         }
         return depth;
     }
 
     /**
      * Returns the extension of this file name.
      *
      * @return The file extension.
      */
     @Override
     public String getExtension() {
         if (extension == null) {
             getBaseName();
             final int pos = baseName.lastIndexOf('.');
             // if ((pos == -1) || (pos == baseName.length() - 1))
             // imario@ops.co.at: Review of patch from adagoubard@chello.nl
             // do not treat file names like
             // .bashrc c:\windows\.java c:\windows\.javaws c:\windows\.jedit c:\windows\.appletviewer
             // as extension
             if (pos < 1 || pos == baseName.length() - 1) {
                 // No extension
                 extension = "";
             } else {
                 extension = baseName.substring(pos + 1).intern();
             }
         }
         return extension;
     }
 
     /**
      * Determines if another file name is an ancestor of this file name.
      *
      * @param ancestor The FileName to check.
      * @return true if the FileName is an ancestor, false otherwise.
      */
     @Override
     public boolean isAncestor(final FileName ancestor) {
         if (!ancestor.getRootURI().equals(getRootURI())) {
             return false;
         }
         return checkName(ancestor.getPath(), getPath(), NameScope.DESCENDENT);
     }
 
     /**
      * Determines if another file name is a descendent of this file name.
      *
      * @param descendent The FileName to check.
      * @return true if the FileName is a descendent, false otherwise.
      */
     @Override
     public boolean isDescendent(final FileName descendent) {
         return isDescendent(descendent, NameScope.DESCENDENT);
     }
 
     /**
      * Determines if another file name is a descendent of this file name.
      *
      * @param descendent The FileName to check.
      * @param scope The NameScope.
      * @return true if the FileName is a descendent, false otherwise.
      */
     @Override
     public boolean isDescendent(final FileName descendent, final NameScope scope) {
         if (!descendent.getRootURI().equals(getRootURI())) {
             return false;
         }
         return checkName(getPath(), descendent.getPath(), scope);
     }
 
     /**
      * Checks if this file name is a name for a regular file by using its type.
      *
      * @return true if this file is a regular file.
      * @throws FileSystemException may be thrown by subclasses.
      * @see #getType()
      * @see FileType#FILE
      */
     @Override
     public boolean isFile() throws FileSystemException {
         // Use equals instead of == to avoid any class loader worries.
         return FileType.FILE.equals(this.getType());
     }
 
     /**
      * Returns the requested or current type of this name.
      * <p>
      * The "requested" type is the one determined during resolving the name. n this case the name is a
      * {@link FileType#FOLDER} if it ends with an "/" else it will be a {@link FileType#FILE}.
      * </p>
      * <p>
      * Once attached it will be changed to reflect the real type of this resource.
      * </p>
      *
      * @return {@link FileType#FOLDER} or {@link FileType#FILE}
      */
     @Override
     public FileType getType() {
         return type;
     }
 
     /**
      * Sets the type of this file e.g. when it will be attached.
      *
      * @param type {@link FileType#FOLDER} or {@link FileType#FILE}
      * @throws FileSystemException if an error occurs.
      */
     void setType(final FileType type) throws FileSystemException {
         if (type != FileType.FOLDER && type != FileType.FILE && type != FileType.FILE_OR_FOLDER) {
             throw new FileSystemException("vfs.provider/filename-type.error");
         }
 
         this.type = type;
     }
 
     /**
      * Checks whether a path fits in a particular scope of another path.
      *
      * @param basePath An absolute, normalised path.
      * @param path An absolute, normalised path.
      * @param scope The NameScope.
      * @return true if the path fits in the scope, false otherwise.
      */
     public static boolean checkName(final String basePath, final String path, final NameScope scope) {
         if (scope == NameScope.FILE_SYSTEM) {
             // All good
             return true;
         }
 
         if (!path.startsWith(basePath)) {
             return false;
         }
 
         int baseLen = basePath.length();
         if (VFS.isUriStyle()) {
             // strip the trailing "/"
             baseLen--;
         }
 
         if (scope == NameScope.CHILD) {
             return path.length() != baseLen && (baseLen <= 1 || path.charAt(baseLen) == SEPARATOR_CHAR)
                     && path.indexOf(SEPARATOR_CHAR, baseLen + 1) == -1;
         }
         if (scope == NameScope.DESCENDENT) {
             return path.length() != baseLen && (baseLen <= 1 || path.charAt(baseLen) == SEPARATOR_CHAR);
         }
         if (scope == NameScope.DESCENDENT_OR_SELF) {
             return baseLen <= 1 || path.length() <= baseLen || path.charAt(baseLen) == SEPARATOR_CHAR;
         }
         throw new IllegalArgumentException();
 
     }
 }