/*
    *  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
    *
   *    https://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.directory.api.ldap.model.ldif;
  
  
  import java.io.IOException;
  import java.nio.charset.StandardCharsets;
  import java.util.Base64;
  
  import javax.naming.directory.Attributes;
  
  import org.apache.directory.api.i18n.I18n;
  import org.apache.directory.api.ldap.model.entry.Attribute;
  import org.apache.directory.api.ldap.model.entry.AttributeUtils;
  import org.apache.directory.api.ldap.model.entry.DefaultAttribute;
  import org.apache.directory.api.ldap.model.entry.Entry;
  import org.apache.directory.api.ldap.model.entry.Modification;
  import org.apache.directory.api.ldap.model.entry.Value;
  import org.apache.directory.api.ldap.model.exception.LdapException;
  import org.apache.directory.api.ldap.model.exception.LdapInvalidAttributeValueException;
  import org.apache.directory.api.ldap.model.message.ResultCodeEnum;
  import org.apache.directory.api.ldap.model.name.Dn;
  import org.apache.directory.api.util.Strings;
  
  
  /**
   * Some LDIF helper methods.
   *
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public final class LdifUtils
  {
      /** The array that will be used to match the first char.*/
      private static final boolean[] LDIF_SAFE_STARTING_CHAR_ALPHABET = new boolean[128];
  
      /** The array that will be used to match the other chars.*/
      private static final boolean[] LDIF_SAFE_OTHER_CHARS_ALPHABET = new boolean[128];
  
      /** The default length for a line in a ldif file */
      private static final int DEFAULT_LINE_LENGTH = 80;
  
      /** The file separator */
      private static final String LINE_SEPARATOR = System.getProperty( "line.separator" );
  
      static
      {
          // Initialization of the array that will be used to match the first char.
          for ( int i = 0; i < 128; i++ )
          {
              LDIF_SAFE_STARTING_CHAR_ALPHABET[i] = true;
          }
  
          // 0 (NUL)
          LDIF_SAFE_STARTING_CHAR_ALPHABET[0] = false;
          // 10 (LF)
          LDIF_SAFE_STARTING_CHAR_ALPHABET[10] = false;
          // 13 (CR)
          LDIF_SAFE_STARTING_CHAR_ALPHABET[13] = false;
          // 32 (SPACE)
          LDIF_SAFE_STARTING_CHAR_ALPHABET[32] = false;
          // 58 (:)
          LDIF_SAFE_STARTING_CHAR_ALPHABET[58] = false;
          // 60 (>)
          LDIF_SAFE_STARTING_CHAR_ALPHABET[60] = false;
  
          // Initialization of the array that will be used to match the other chars.
          for ( int i = 0; i < 128; i++ )
          {
              LDIF_SAFE_OTHER_CHARS_ALPHABET[i] = true;
          }
  
          // 0 (NUL)
          LDIF_SAFE_OTHER_CHARS_ALPHABET[0] = false;
          // 10 (LF)
          LDIF_SAFE_OTHER_CHARS_ALPHABET[10] = false;
          // 13 (CR)
          LDIF_SAFE_OTHER_CHARS_ALPHABET[13] = false;
      }
  
  
      /**
       * Private constructor.
      */
     private LdifUtils()
     {
     }
 
 
     /**
      * Checks if the input String contains only safe values, that is, the data
      * does not need to be encoded for use with LDIF. The rules for checking safety
      * are based on the rules for LDIF (LDAP Data Interchange Format) per RFC 2849.
      * The data does not need to be encoded if all the following are true:
      *
      * The data cannot start with the following char values:
      * <ul>
      * <li>00 (NUL)</li>
      * <li>10 (LF)</li>
      * <li>13 (CR)</li>
      * <li>32 (SPACE)</li>
      * <li>58 (:)</li>
      * <li>60 (&lt;)</li>
      * <li>Any character with value greater than 127</li>
      * </ul>
      *
      * The data cannot contain any of the following char values:
      * <ul>
      * <li>00 (NUL)</li>
      * <li>10 (LF)</li>
      * <li>13 (CR)</li>
      * <li>Any character with value greater than 127</li>
      * </ul>
      *
      * The data cannot end with a space.
      *
      * @param str the String to be checked
      * @return true if encoding not required for LDIF
      */
     public static boolean isLDIFSafe( String str )
     {
         if ( Strings.isEmpty( str ) )
         {
             // A null string is LDIF safe
             return true;
         }
 
         // Checking the first char
         char currentChar = str.charAt( 0 );
 
         if ( ( currentChar > 127 ) || !LDIF_SAFE_STARTING_CHAR_ALPHABET[currentChar] )
         {
             return false;
         }
 
         // Checking the other chars
         for ( int i = 1; i < str.length(); i++ )
         {
             currentChar = str.charAt( i );
 
             if ( ( currentChar > 127 ) || !LDIF_SAFE_OTHER_CHARS_ALPHABET[currentChar] )
             {
                 return false;
             }
         }
 
         // The String cannot end with a space
         return currentChar != ' ';
     }
 
 
     /**
      * Convert an Attributes as LDIF
      * 
      * @param attrs the Attributes to convert
      * @return the corresponding LDIF code as a String
      * @throws LdapException If a naming exception is encountered.
      */
     public static String convertToLdif( Attributes attrs ) throws LdapException
     {
         return convertAttributesToLdif( AttributeUtils.toEntry( attrs, null ), DEFAULT_LINE_LENGTH );
     }
 
 
     /**
      * Convert an Attributes as LDIF
      * 
      * @param attrs the Attributes to convert
      * @param length The ldif line length
      * @return the corresponding LDIF code as a String
      * @throws LdapException If a naming exception is encountered.
      */
     public static String convertToLdif( Attributes attrs, int length ) throws LdapException
     {
         return convertAttributesToLdif( AttributeUtils.toEntry( attrs, null ), length );
     }
 
 
     /**
      * Convert an Attributes as LDIF. The Dn is written.
      * 
      * @param attrs the Attributes to convert
      * @param dn The Dn for this entry
      * @param length The ldif line length
      * @return the corresponding LDIF code as a String
      * @throws LdapException If a naming exception is encountered.
      */
     public static String convertToLdif( Attributes attrs, Dn dn, int length ) throws LdapException
     {
         return convertToLdif( AttributeUtils.toEntry( attrs, dn ), length );
     }
 
 
     /**
      * Convert an Attributes as LDIF. The Dn is written.
      * 
      * @param attrs the Attributes to convert
      * @param dn The Dn for this entry
      * @return the corresponding LDIF code as a String
      * @throws LdapException If a naming exception is encountered.
      */
     public static String convertToLdif( Attributes attrs, Dn dn ) throws LdapException
     {
         return convertToLdif( AttributeUtils.toEntry( attrs, dn ), DEFAULT_LINE_LENGTH );
     }
 
 
     /**
      * Convert an Entry to LDIF
      * 
      * @param entry the Entry to convert
      * @return the corresponding LDIF code as a String
      */
     public static String convertToLdif( Entry entry )
     {
         return convertToLdif( entry, DEFAULT_LINE_LENGTH );
     }
 
 
     /**
      * Convert an Entry to LDIF including a version number at the top
      * 
      * @param entry the Entry to convert
      * @param includeVersionInfo flag to tell whether to include version number or not
      * @return the corresponding LDIF code as a String
      */
     public static String convertToLdif( Entry entry, boolean includeVersionInfo )
     {
         String ldif = convertToLdif( entry, DEFAULT_LINE_LENGTH );
 
         if ( includeVersionInfo )
         {
             ldif = "version: 1" + LINE_SEPARATOR + ldif;
         }
 
         return ldif;
     }
 
 
     /**
      * Convert all the Entry's attributes to LDIF. The Dn is not written
      * 
      * @param entry the Entry to convert
      * @return the corresponding LDIF code as a String
      */
     public static String convertAttributesToLdif( Entry entry )
     {
         return convertAttributesToLdif( entry, DEFAULT_LINE_LENGTH );
     }
 
 
     /**
      * Convert a LDIF String to a JNDI attributes.
      *
      * @param ldif The LDIF string containing an attribute value
      * @return An Attributes instance
      * @exception LdapLdifException If the LDIF String cannot be converted to an Attributes
      */
     public static Attributes getJndiAttributesFromLdif( String ldif ) throws LdapLdifException
     {
         try ( LdifAttributesReader reader = new LdifAttributesReader() )
         {
             return AttributeUtils.toAttributes( reader.parseEntry( ldif ) );
         }
         catch ( IOException ioe )
         {
             throw new LdapLdifException( ioe.getMessage(), ioe );
         }
     }
 
 
     /**
      * Convert an Entry as LDIF
      * 
      * @param entry the Entry to convert
      * @param length the expected line length
      * @return the corresponding LDIF code as a String
      */
     public static String convertToLdif( Entry entry, int length )
     {
         StringBuilder sb = new StringBuilder();
 
         if ( entry.getDn() != null )
         {
             // First, dump the Dn
             if ( isLDIFSafe( entry.getDn().getName() ) )
             {
                 sb.append( stripLineToNChars( "dn: " + entry.getDn().getName(), length ) );
             }
             else
             {
                 sb.append( stripLineToNChars( "dn:: " + encodeBase64( entry.getDn().getName() ), length ) );
             }
 
             sb.append( '\n' );
         }
 
         // Then all the attributes
         for ( Attribute attribute : entry )
         {
             sb.append( convertToLdif( attribute, length ) );
         }
 
         return sb.toString();
     }
 
 
     /**
      * Convert the Entry's attributes to LDIF. The Dn is not written.
      * 
      * @param entry the Entry to convert
      * @param length the expected line length
      * @return the corresponding LDIF code as a String
      */
     public static String convertAttributesToLdif( Entry entry, int length )
     {
         StringBuilder sb = new StringBuilder();
 
         // Then all the attributes
         for ( Attribute attribute : entry )
         {
             sb.append( convertToLdif( attribute, length ) );
         }
 
         return sb.toString();
     }
 
 
     /**
      * Convert an LdifEntry to LDIF
      * 
      * @param entry the LdifEntry to convert
      * @return the corresponding LDIF as a String
      * @throws LdapException If a naming exception is encountered.
      */
     public static String convertToLdif( LdifEntry entry ) throws LdapException
     {
         return convertToLdif( entry, DEFAULT_LINE_LENGTH );
     }
 
 
     /**
      * Convert an LdifEntry to LDIF
      * 
      * @param entry the LdifEntry to convert
      * @param length The maximum line's length
      * @return the corresponding LDIF as a String
      * @throws LdapException If a naming exception is encountered.
      */
     public static String convertToLdif( LdifEntry entry, int length ) throws LdapException
     {
         StringBuilder sb = new StringBuilder();
 
         // First, dump the Dn
         if ( isLDIFSafe( entry.getDn().getName() ) )
         {
             sb.append( stripLineToNChars( "dn: " + entry.getDn(), length ) );
         }
         else
         {
             sb.append( stripLineToNChars( "dn:: " + encodeBase64( entry.getDn().getName() ), length ) );
         }
 
         sb.append( '\n' );
 
         // Dump the ChangeType
         String changeType = Strings.toLowerCaseAscii( entry.getChangeType().toString() );
 
         if ( entry.getChangeType() != ChangeType.None )
         {
             // First dump the controls if any
             if ( entry.hasControls() )
             {
                 for ( LdifControl control : entry.getControls().values() )
                 {
                     StringBuilder controlStr = new StringBuilder();
 
                     controlStr.append( "control: " ).append( control.getOid() );
                     controlStr.append( " " ).append( control.isCritical() );
 
                     if ( control.hasValue() )
                     {
                         controlStr.append( "::" ).append( Base64.getEncoder().encode( control.getValue() ) );
                     }
 
                     sb.append( stripLineToNChars( controlStr.toString(), length ) );
                     sb.append( '\n' );
                 }
             }
 
             sb.append( stripLineToNChars( "changetype: " + changeType, length ) );
             sb.append( '\n' );
         }
 
         switch ( entry.getChangeType() )
         {
             case None:
                 if ( entry.hasControls() )
                 {
                     sb.append( stripLineToNChars( "changetype: " + ChangeType.Add, length ) );
                 }
 
                 // Fallthrough
 
             case Add:
                 if ( entry.getEntry() == null )
                 {
                     throw new LdapException( I18n.err( I18n.ERR_13472_ENTRY_WITH_NO_ATTRIBUTE ) );
                 }
 
                 // Now, iterate through all the attributes
                 for ( Attribute attribute : entry.getEntry() )
                 {
                     sb.append( convertToLdif( attribute, length ) );
                 }
 
                 break;
 
             case Delete:
                 if ( entry.getEntry() != null )
                 {
                     throw new LdapException( I18n.err( I18n.ERR_13471_DELETED_ENTRY_WITH_ATTRIBUTES ) );
                 }
 
                 break;
 
             case ModDn:
             case ModRdn:
                 if ( entry.getEntry() != null )
                 {
                     throw new LdapException( I18n.err( I18n.ERR_13473_MODDN_WITH_ATTRIBUTES ) );
                 }
 
                 // Stores the new Rdn
                 Attribute newRdn = new DefaultAttribute( "newrdn", entry.getNewRdn() );
                 sb.append( convertToLdif( newRdn, length ) );
 
                 // Stores the deleteoldrdn flag
                 sb.append( "deleteoldrdn: " );
 
                 if ( entry.isDeleteOldRdn() )
                 {
                     sb.append( "1" );
                 }
                 else
                 {
                     sb.append( "0" );
                 }
 
                 sb.append( '\n' );
 
                 // Stores the optional newSuperior
                 if ( !Strings.isEmpty( entry.getNewSuperior() ) )
                 {
                     Attribute newSuperior = new DefaultAttribute( "newsuperior", entry.getNewSuperior() );
                     sb.append( convertToLdif( newSuperior, length ) );
                 }
 
                 break;
 
             case Modify:
                 boolean isFirst = true;
                 
                 for ( Modification modification : entry.getModifications() )
                 {
                     
                     if ( isFirst )
                     {
                         isFirst = false;
                     }
                     else
                     {
                         sb.append( "-\n" );
                     }
 
                     switch ( modification.getOperation() )
                     {
                         case ADD_ATTRIBUTE:
                             sb.append( "add: " );
                             break;
 
                         case REMOVE_ATTRIBUTE:
                             sb.append( "delete: " );
                             break;
 
                         case REPLACE_ATTRIBUTE:
                             sb.append( "replace: " );
                             break;
 
                         case INCREMENT_ATTRIBUTE:
                             sb.append( "increment: " );
                             break;
 
                         default:
                             throw new IllegalArgumentException( I18n.err( I18n.ERR_13434_UNEXPECTED_MOD_OPERATION, modification.getOperation() ) );
                     }
 
                     sb.append( modification.getAttribute().getUpId() );
                     sb.append( '\n' );
 
                     sb.append( convertToLdif( modification.getAttribute(), length ) );
                 }
 
                 sb.append( '-' );
                 break;
 
             default:
                 throw new IllegalArgumentException( I18n.err( I18n.ERR_13431_UNEXPECTED_CHANGETYPE, entry.getChangeType() ) );
         }
 
         sb.append( '\n' );
 
         return sb.toString();
     }
 
 
     /**
      * Base64 encode a String
      * 
      * @param str The string to encode
      * @return the base 64 encoded string
      */
     private static String encodeBase64( String str )
     {
         // force encoding using UTF-8 charset, as required in RFC2849 note 7
         return new String( Base64.getEncoder().encode( Strings.getBytesUtf8( str ) ), StandardCharsets.UTF_8 );
     }
 
 
     /**
      * Converts an EntryAttribute to LDIF
      * 
      * @param attr the EntryAttribute to convert
      * @return the corresponding LDIF code as a String
      */
     public static String convertToLdif( Attribute attr )
     {
         return convertToLdif( attr, DEFAULT_LINE_LENGTH );
     }
 
 
     /**
      * Converts an EntryAttribute as LDIF
      * 
      * @param attr the EntryAttribute to convert
      * @param length the expected line length
      * @return the corresponding LDIF code as a String
      */
     public static String convertToLdif( Attribute attr, int length )
     {
         StringBuilder sb = new StringBuilder();
         
         if ( attr.size() == 0 )
         {
             // Special case : we don't have any value
             return "";
         }
 
         for ( Value value : attr )
         {
             StringBuilder lineBuffer = new StringBuilder();
 
             lineBuffer.append( attr.getUpId() );
 
             // First, deal with null value (which is valid)
             if ( value.isNull() )
             {
                 lineBuffer.append( ':' );
             }
             else if ( value.isHumanReadable() )
             {
                 // It's a String but, we have to check if encoding isn't required
                 String str = value.getString();
 
                 if ( !LdifUtils.isLDIFSafe( str ) )
                 {
                     lineBuffer.append( ":: " ).append( encodeBase64( str ) );
                 }
                 else
                 {
                     lineBuffer.append( ':' );
 
                     if ( str != null )
                     {
                         lineBuffer.append( ' ' ).append( str );
                     }
                 }
             }
             else
             {
                 // It is binary, so we have to encode it using Base64 before adding it
                 String encoded = new String( Base64.getEncoder().encode( value.getBytes() ), StandardCharsets.UTF_8 );
 
                 lineBuffer.append( ":: " + encoded );
             }
 
             lineBuffer.append( '\n' );
             sb.append( stripLineToNChars( lineBuffer.toString(), length ) );
         }
 
         return sb.toString();
     }
 
 
     /**
      * Strips the String every n specified characters
      * 
      * @param str the string to strip
      * @param nbChars the number of characters
      * @return the stripped String
      */
     public static String stripLineToNChars( String str, int nbChars )
     {
         int strLength = str.length();
 
         if ( strLength <= nbChars )
         {
             return str;
         }
 
         if ( nbChars < 2 )
         {
             throw new IllegalArgumentException( I18n.err( I18n.ERR_13474_LINE_LENGTH_TOO_SHORT ) );
         }
 
         // We will first compute the new size of the LDIF result
         // It's at least nbChars chars plus one for \n
         int charsPerLine = nbChars - 1;
 
         int remaining = ( strLength - nbChars ) % charsPerLine;
 
         int nbLines = 1 + ( ( strLength - nbChars ) / charsPerLine ) + ( remaining == 0 ? 0 : 1 );
 
         int nbCharsTotal = strLength + nbLines + nbLines - 2;
 
         char[] buffer = new char[nbCharsTotal];
         char[] orig = str.toCharArray();
 
         int posSrc = 0;
         int posDst = 0;
 
         System.arraycopy( orig, posSrc, buffer, posDst, nbChars );
         posSrc += nbChars;
         posDst += nbChars;
 
         for ( int i = 0; i < nbLines - 2; i++ )
         {
             buffer[posDst++] = '\n';
             buffer[posDst++] = ' ';
 
             System.arraycopy( orig, posSrc, buffer, posDst, charsPerLine );
             posSrc += charsPerLine;
             posDst += charsPerLine;
         }
 
         buffer[posDst++] = '\n';
         buffer[posDst++] = ' ';
         System.arraycopy( orig, posSrc, buffer, posDst, remaining == 0 ? charsPerLine : remaining );
 
         return new String( buffer );
     }
 
 
     /**
      * Build a new Attributes instance from a LDIF list of lines. The values can be
      * either a complete Ava, or a couple of AttributeType ID and a value (a String or
      * a byte[]). The following sample shows the three cases :
      *
      * <pre>
      * Attribute attr = AttributeUtils.createAttributes(
      *     "objectclass: top",
      *     "cn", "My name",
      *     "jpegPhoto", new byte[]{0x01, 0x02} );
      * </pre>
      *
      * @param avas The AttributeType and Values, using a ldif format, or a couple of
      * Attribute ID/Value
      * @return An Attributes instance
      * @throws LdapException If the data are invalid
      */
     public static Attributes createJndiAttributes( Object... avas ) throws LdapException
     {
         StringBuilder sb = new StringBuilder();
         int pos = 0;
         boolean valueExpected = false;
 
         for ( Object ava : avas )
         {
             if ( !valueExpected )
             {
                 if ( !( ava instanceof String ) )
                 {
                     throw new LdapInvalidAttributeValueException( ResultCodeEnum.INVALID_ATTRIBUTE_SYNTAX, I18n.err(
                         I18n.ERR_13233_ATTRIBUTE_ID_MUST_BE_A_STRING, pos + 1 ) );
                 }
 
                 String attribute = ( String ) ava;
                 sb.append( attribute );
 
                 if ( attribute.indexOf( ':' ) != -1 )
                 {
                     sb.append( '\n' );
                 }
                 else
                 {
                     valueExpected = true;
                 }
             }
             else
             {
                 if ( ava instanceof String )
                 {
                     sb.append( ": " ).append( ( String ) ava ).append( '\n' );
                 }
                 else if ( ava instanceof byte[] )
                 {
                     sb.append( ":: " );
                     sb.append( new String( Base64.getEncoder().encode( ( byte[] ) ava ), StandardCharsets.UTF_8 ) );
                     sb.append( '\n' );
                 }
                 else
                 {
                     throw new LdapInvalidAttributeValueException( ResultCodeEnum.INVALID_ATTRIBUTE_SYNTAX, I18n.err(
                         I18n.ERR_13234_ATTRIBUTE_VAL_STRING_OR_BYTE, pos + 1 ) );
                 }
 
                 valueExpected = false;
             }
         }
 
         if ( valueExpected )
         {
             throw new LdapInvalidAttributeValueException( ResultCodeEnum.INVALID_ATTRIBUTE_SYNTAX, I18n
                 .err( I18n.ERR_13234_ATTRIBUTE_VAL_STRING_OR_BYTE ) );
         }
 
         try ( LdifAttributesReader reader = new LdifAttributesReader() ) 
         {
             return AttributeUtils.toAttributes( reader.parseEntry( sb.toString() ) );
         }
         catch ( IOException ioe )
         {
             throw new LdapLdifException( ioe.getMessage(), ioe );
         }
     }
 }