/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE
 * or https://OpenDS.dev.java.net/OpenDS.LICENSE.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE.  If applicable,
 * add the following below this CDDL HEADER, with the fields enclosed
 * by brackets "[]" replaced with your own identifying information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *
 *      Copyright 2009 Sun Microsystems, Inc.
 */

package org.opends.sdk.schema;



import static com.sun.opends.sdk.messages.Messages.*;

import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;

import org.opends.sdk.ByteSequence;
import org.opends.sdk.LocalizableMessage;
import org.opends.sdk.LocalizableMessageBuilder;

import com.sun.opends.sdk.util.Validator;



/**
 * This class defines a data structure for storing and interacting with
 * an LDAP syntaxes, which constrain the structure of attribute values
 * stored in an LDAP directory, and determine the representation of
 * attribute and assertion values transferred in the LDAP protocol.
 * <p>
 * Syntax implementations must extend the
 * <code>SyntaxImplementation</code> class so they can be used by OpenDS
 * to validate attribute values.
 * <p>
 * Where ordered sets of names, or extra properties are provided, the
 * ordering will be preserved when the associated fields are accessed
 * via their getters or via the {@link #toString()} methods.
 */
public final class Syntax extends SchemaElement
{
  private final String oid;
  private final String definition;
  private MatchingRule equalityMatchingRule;
  private MatchingRule orderingMatchingRule;
  private MatchingRule substringMatchingRule;
  private MatchingRule approximateMatchingRule;
  private Schema schema;
  private SyntaxImpl impl;



  Syntax(String oid, String description,
      Map<String, List<String>> extraProperties, String definition,
      SyntaxImpl implementation)
  {
    super(description, extraProperties);

    Validator.ensureNotNull(oid);
    this.oid = oid;

    if (definition != null)
    {
      this.definition = definition;
    }
    else
    {
      this.definition = buildDefinition();
    }
    this.impl = implementation;
  }

  Syntax(String oid)
  {
    super("", Collections.singletonMap("X-SUBST",
        Collections.singletonList(Schema.getDefaultSyntax().getOID())));

    Validator.ensureNotNull(oid);
    this.oid = oid;
    this.definition = buildDefinition();
    this.impl = Schema.getDefaultSyntax().impl;
  }



  /**
   * Retrieves the default approximate matching rule that will be used
   * for attributes with this syntax.
   *
   * @return The default approximate matching rule that will be used for
   *         attributes with this syntax, or {@code null} if approximate
   *         matches will not be allowed for this type by default.
   */
  public MatchingRule getApproximateMatchingRule()
  {
    return approximateMatchingRule;
  }



  /**
   * Retrieves the default equality matching rule that will be used for
   * attributes with this syntax.
   *
   * @return The default equality matching rule that will be used for
   *         attributes with this syntax, or {@code null} if equality
   *         matches will not be allowed for this type by default.
   */
  public MatchingRule getEqualityMatchingRule()
  {
    return equalityMatchingRule;
  }



  /**
   * Retrieves the OID for this attribute syntax.
   *
   * @return The OID for this attribute syntax.
   */
  public String getOID()
  {
    return oid;
  }



  /**
   * Retrieves the default ordering matching rule that will be used for
   * attributes with this syntax.
   *
   * @return The default ordering matching rule that will be used for
   *         attributes with this syntax, or {@code null} if ordering
   *         matches will not be allowed for this type by default.
   */
  public MatchingRule getOrderingMatchingRule()
  {
    return orderingMatchingRule;
  }



  /**
   * Retrieves the default substring matching rule that will be used for
   * attributes with this syntax.
   *
   * @return The default substring matching rule that will be used for
   *         attributes with this syntax, or {@code null} if substring
   *         matches will not be allowed for this type by default.
   */
  public MatchingRule getSubstringMatchingRule()
  {
    return substringMatchingRule;
  }



  /**
   * Retrieves the hash code for this schema element. It will be
   * calculated as the sum of the characters in the OID.
   *
   * @return The hash code for this attribute syntax.
   */
  @Override
  public int hashCode()
  {
    return getOID().hashCode();
  }



  /**
   * Indicates whether this attribute syntax requires that values must
   * be encoded using the Basic Encoding Rules (BER) used by X.500
   * directories and always include the {@code binary} attribute
   * description option.
   *
   * @return {@code true} this attribute syntax requires that values
   *         must be BER encoded and always include the {@code binary}
   *         attribute description option, or {@code false} if not.
   * @see <a href="http://tools.ietf.org/html/rfc4522">RFC 4522 -
   *      Lightweight Directory Access Protocol (LDAP): The Binary
   *      Encoding Option </a>
   */
  public boolean isBEREncodingRequired()
  {
    return impl.isBEREncodingRequired();
  }



  /**
   * Indicates whether this attribute syntax would likely be a human
   * readable string.
   *
   * @return {@code true} if this attribute syntax would likely be a
   *         human readable string or {@code false} if not.
   */
  public boolean isHumanReadable()
  {
    return impl.isHumanReadable();
  }



  /**
   * Retrieves a string representation of this attribute syntax in the
   * format defined in RFC 2252.
   *
   * @return A string representation of this attribute syntax in the
   *         format defined in RFC 2252.
   */
  @Override
  public String toString()
  {
    return definition;
  }



  /**
   * Indicates whether the provided value is acceptable for use in an
   * attribute with this syntax. If it is not, then the reason may be
   * appended to the provided buffer.
   *
   * @param value
   *          The value for which to make the determination.
   * @param invalidReason
   *          The buffer to which the invalid reason should be appended.
   * @return {@code true} if the provided value is acceptable for use
   *         with this syntax, or {@code false} if not.
   */
  public boolean valueIsAcceptable(ByteSequence value,
      LocalizableMessageBuilder invalidReason)
  {
    return impl.valueIsAcceptable(schema, value, invalidReason);
  }



  Syntax duplicate()
  {
    return new Syntax(oid, description, extraProperties, definition,
        impl);
  }



  @Override
  void toStringContent(StringBuilder buffer)
  {
    buffer.append(oid);

    if (description != null && description.length() > 0)
    {
      buffer.append(" DESC '");
      buffer.append(description);
      buffer.append("'");
    }
  }



  @Override
  void validate(List<LocalizableMessage> warnings, Schema schema)
      throws SchemaException
  {
    this.schema = schema;
    if (impl == null)
    {
      // See if we need to override the implementation of the syntax
      for (final Map.Entry<String, List<String>> property : extraProperties
          .entrySet())
      {
        // Enums are handled in the schema builder.
        if (property.getKey().equalsIgnoreCase("x-subst"))
        {
          /**
           * One unimplemented syntax can be substituted by another
           * defined syntax. A substitution syntax is an
           * LDAPSyntaxDescriptionSyntax with X-SUBST extension.
           */
          final Iterator<String> values =
              property.getValue().iterator();
          if (values.hasNext())
          {
            final String value = values.next();
            if (value.equals(oid))
            {
              final LocalizableMessage message =
                  ERR_ATTR_SYNTAX_CYCLIC_SUB_SYNTAX.get(oid);
              throw new SchemaException(message);
            }
            if (!schema.hasSyntax(value))
            {
              final LocalizableMessage message =
                  ERR_ATTR_SYNTAX_UNKNOWN_SUB_SYNTAX.get(oid, value);
              throw new SchemaException(message);
            }
            final Syntax subSyntax = schema.getSyntax(value);
            if (subSyntax.impl == null)
            {
              // The substitution syntax was never validated.
              subSyntax.validate(warnings, schema);
            }
            impl = subSyntax.impl;
          }
        }
        else if (property.getKey().equalsIgnoreCase("x-pattern"))
        {
          final Iterator<String> values =
              property.getValue().iterator();
          if (values.hasNext())
          {
            final String value = values.next();
            try
            {
              final Pattern pattern = Pattern.compile(value);
              impl = new RegexSyntaxImpl(pattern);
            }
            catch (final Exception e)
            {
              final LocalizableMessage message =
                  WARN_ATTR_SYNTAX_LDAPSYNTAX_REGEX_INVALID_PATTERN
                      .get(oid, value);
              throw new SchemaException(message);
            }
          }
        }
      }

      // Try to find an implementation in the core schema
      if (impl == null && Schema.getDefaultSchema().hasSyntax(oid))
      {
        impl = Schema.getDefaultSchema().getSyntax(oid).impl;
      }
      if (impl == null && Schema.getCoreSchema().hasSyntax(oid))
      {
        impl = Schema.getCoreSchema().getSyntax(oid).impl;
      }

      if (impl == null)
      {
        impl = Schema.getDefaultSyntax().impl;
        final LocalizableMessage message =
            WARN_ATTR_SYNTAX_NOT_IMPLEMENTED.get(oid, Schema
                .getDefaultSyntax().getOID());
        warnings.add(message);
      }
    }

    // Get references to the default matching rules. It will be ok
    // if we can't find some. Just warn.
    if (impl.getEqualityMatchingRule() != null)
    {
      if (schema.hasMatchingRule(impl.getEqualityMatchingRule()))
      {
        equalityMatchingRule =
            schema.getMatchingRule(impl.getEqualityMatchingRule());
      }
      else
      {
        final LocalizableMessage message =
            ERR_ATTR_SYNTAX_UNKNOWN_EQUALITY_MATCHING_RULE.get(impl
                .getEqualityMatchingRule(), impl.getName());
        warnings.add(message);
      }
    }

    if (impl.getOrderingMatchingRule() != null)
    {
      if (schema.hasMatchingRule(impl.getOrderingMatchingRule()))
      {
        orderingMatchingRule =
            schema.getMatchingRule(impl.getOrderingMatchingRule());
      }
      else
      {
        final LocalizableMessage message =
            ERR_ATTR_SYNTAX_UNKNOWN_ORDERING_MATCHING_RULE.get(impl
                .getOrderingMatchingRule(), impl.getName());
        warnings.add(message);
      }
    }

    if (impl.getSubstringMatchingRule() != null)
    {
      if (schema.hasMatchingRule(impl.getSubstringMatchingRule()))
      {
        substringMatchingRule =
            schema.getMatchingRule(impl.getSubstringMatchingRule());
      }
      else
      {
        final LocalizableMessage message =
            ERR_ATTR_SYNTAX_UNKNOWN_SUBSTRING_MATCHING_RULE.get(impl
                .getSubstringMatchingRule(), impl.getName());
        warnings.add(message);
      }
    }

    if (impl.getApproximateMatchingRule() != null)
    {
      if (schema.hasMatchingRule(impl.getApproximateMatchingRule()))
      {
        approximateMatchingRule =
            schema.getMatchingRule(impl.getApproximateMatchingRule());
      }
      else
      {
        final LocalizableMessage message =
            ERR_ATTR_SYNTAX_UNKNOWN_APPROXIMATE_MATCHING_RULE.get(impl
                .getApproximateMatchingRule(), impl.getName());
        warnings.add(message);
      }
    }
  }
}