/*
 * 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 legal-notices/CDDLv1_0.txt
 * or http://forgerock.org/license/CDDLv1.0.html.
 * 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 legal-notices/CDDLv1_0.txt.
 * 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.forgerock.opendj.ldap.schema;

import static org.forgerock.opendj.ldap.CoreMessages.*;
import static org.forgerock.opendj.ldap.schema.SchemaConstants.EXTENSIBLE_OBJECT_OBJECTCLASS_NAME;
import static org.forgerock.opendj.ldap.schema.SchemaConstants.EXTENSIBLE_OBJECT_OBJECTCLASS_OID;
import static org.forgerock.opendj.ldap.schema.SchemaConstants.TOP_OBJECTCLASS_NAME;

import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.forgerock.i18n.LocalizableMessage;

import com.forgerock.opendj.util.Validator;

/**
 * This class defines a data structure for storing and interacting with an
 * objectclass, which contains a collection of attributes that must and/or may
 * be present in an entry with that objectclass.
 * <p>
 * Where ordered sets of names, attribute types, 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 ObjectClass extends SchemaElement {
    // The OID that may be used to reference this definition.
    private final String oid;

    // The set of user defined names for this definition.
    private final List<String> names;

    // Indicates whether this definition is declared "obsolete".
    private final boolean isObsolete;

    // The reference to the superior objectclasses.
    private final Set<String> superiorClassOIDs;

    // The objectclass type for this objectclass.
    private final ObjectClassType objectClassType;

    // The set of required attribute types for this objectclass.
    private final Set<String> requiredAttributeOIDs;

    // The set of optional attribute types for this objectclass.
    private final Set<String> optionalAttributeOIDs;

    // The definition string used to create this objectclass.
    private final String definition;

    private Set<ObjectClass> superiorClasses = Collections.emptySet();
    private Set<AttributeType> declaredRequiredAttributes = Collections.emptySet();
    private Set<AttributeType> requiredAttributes = Collections.emptySet();
    private Set<AttributeType> declaredOptionalAttributes = Collections.emptySet();
    private Set<AttributeType> optionalAttributes = Collections.emptySet();

    // Indicates whether or not validation has been performed.
    private boolean needsValidating = true;

    // The indicates whether or not validation failed.
    private boolean isValid = false;

    ObjectClass(final String oid, final List<String> names, final String description,
            final boolean obsolete, final Set<String> superiorClassOIDs,
            final Set<String> requiredAttributeOIDs, final Set<String> optionalAttributeOIDs,
            final ObjectClassType objectClassType, final Map<String, List<String>> extraProperties,
            final String definition) {
        super(description, extraProperties);

        Validator.ensureNotNull(oid, names);
        Validator.ensureNotNull(superiorClassOIDs, requiredAttributeOIDs, optionalAttributeOIDs,
                objectClassType);
        this.oid = oid;
        this.names = names;
        this.isObsolete = obsolete;
        this.superiorClassOIDs = superiorClassOIDs;
        this.objectClassType = objectClassType;
        this.requiredAttributeOIDs = requiredAttributeOIDs;
        this.optionalAttributeOIDs = optionalAttributeOIDs;

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

    /**
     * Construct a extensibleObject object class where the set of allowed
     * attribute types of this object class is implicitly the set of all
     * attribute types of userApplications usage.
     *
     * @param description
     *            The description for this schema definition
     * @param extraProperties
     *            The map of "extra" properties for this schema definition
     */
    ObjectClass(final String description, final Map<String, List<String>> extraProperties) {
        super(description, extraProperties);
        this.oid = EXTENSIBLE_OBJECT_OBJECTCLASS_OID;
        this.names = Collections.singletonList(EXTENSIBLE_OBJECT_OBJECTCLASS_NAME);
        this.isObsolete = false;
        this.superiorClassOIDs = Collections.singleton(TOP_OBJECTCLASS_NAME);
        this.objectClassType = ObjectClassType.AUXILIARY;
        this.requiredAttributeOIDs = Collections.emptySet();
        this.optionalAttributeOIDs = Collections.emptySet();

        this.definition = buildDefinition();
    }

    /**
     * Returns {@code true} if the provided object is an object class having the
     * same numeric OID as this object class.
     *
     * @param o
     *            The object to be compared.
     * @return {@code true} if the provided object is a object class having the
     *         same numeric OID as this object class.
     */
    @Override
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        } else if (o instanceof ObjectClass) {
            final ObjectClass other = (ObjectClass) o;
            return oid.equals(other.oid);
        } else {
            return false;
        }
    }

    /**
     * Returns an unmodifiable set containing the optional attributes for this
     * object class. Note that this set will not automatically include any
     * optional attributes for superior object classes.
     *
     * @return An unmodifiable set containing the optional attributes for this
     *         object class.
     */
    public Set<AttributeType> getDeclaredOptionalAttributes() {
        return declaredOptionalAttributes;
    }

    /**
     * Returns an unmodifiable set containing the required attributes for this
     * object class. Note that this set will not automatically include any
     * required attributes for superior object classes.
     *
     * @return An unmodifiable set containing the required attributes for this
     *         object class.
     */
    public Set<AttributeType> getDeclaredRequiredAttributes() {
        return declaredRequiredAttributes;
    }

    /**
     * Returns the name or OID for this schema definition. If it has one or more
     * names, then the primary name will be returned. If it does not have any
     * names, then the OID will be returned.
     *
     * @return The name or OID for this schema definition.
     */
    public String getNameOrOID() {
        if (names.isEmpty()) {
            return oid;
        }
        return names.get(0);
    }

    /**
     * Returns an unmodifiable list containing the user-defined names that may
     * be used to reference this schema definition.
     *
     * @return Returns an unmodifiable list containing the user-defined names
     *         that may be used to reference this schema definition.
     */
    public List<String> getNames() {
        return names;
    }

    /**
     * Returns the objectclass type for this objectclass.
     *
     * @return The objectclass type for this objectclass.
     */
    public ObjectClassType getObjectClassType() {

        return objectClassType;
    }

    /**
     * Returns the OID for this schema definition.
     *
     * @return The OID for this schema definition.
     */
    public String getOID() {

        return oid;
    }

    /**
     * Returns an unmodifiable set containing the optional attributes for this
     * object class and any superior object classes that it might have.
     *
     * @return An unmodifiable set containing the optional attributes for this
     *         object class and any superior object classes that it might have.
     */
    public Set<AttributeType> getOptionalAttributes() {
        return optionalAttributes;
    }

    /**
     * Returns an unmodifiable set containing the required attributes for this
     * object class and any superior object classes that it might have.
     *
     * @return An unmodifiable set containing the required attributes for this
     *         object class and any superior object classes that it might have.
     */
    public Set<AttributeType> getRequiredAttributes() {
        return requiredAttributes;
    }

    /**
     * Returns an unmodifiable set containing the superior classes for this
     * object class.
     *
     * @return An unmodifiable set containing the superior classes for this
     *         object class.
     */
    public Set<ObjectClass> getSuperiorClasses() {
        return superiorClasses;
    }

    /**
     * Returns the hash code for this object class. It will be calculated as the
     * hash code of the numeric OID.
     *
     * @return The hash code for this object class.
     */
    @Override
    public int hashCode() {
        return oid.hashCode();
    }

    /**
     * Indicates whether this schema definition has the specified name.
     *
     * @param name
     *            The name for which to make the determination.
     * @return <code>true</code> if the specified name is assigned to this
     *         schema definition, or <code>false</code> if not.
     */
    public boolean hasName(final String name) {
        for (final String n : names) {
            if (n.equalsIgnoreCase(name)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Indicates whether this schema definition has the specified name or OID.
     *
     * @param value
     *            The value for which to make the determination.
     * @return <code>true</code> if the provided value matches the OID or one of
     *         the names assigned to this schema definition, or
     *         <code>false</code> if not.
     */
    public boolean hasNameOrOID(final String value) {
        return hasName(value) || getOID().equals(value);
    }

    /**
     * Indicates whether this objectclass is a descendant of the provided class.
     *
     * @param objectClass
     *            The objectClass for which to make the determination.
     * @return <code>true</code> if this objectclass is a descendant of the
     *         provided class, or <code>false</code> if not.
     */
    public boolean isDescendantOf(final ObjectClass objectClass) {
        for (final ObjectClass sup : superiorClasses) {
            if (sup.equals(objectClass) || sup.isDescendantOf(objectClass)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Indicates whether this schema definition is declared "obsolete".
     *
     * @return <code>true</code> if this schema definition is declared
     *         "obsolete", or <code>false</code> if not.
     */
    public boolean isObsolete() {
        return isObsolete;
    }

    /**
     * Indicates whether the provided attribute type is included in the optional
     * attribute list for this or any of its superior objectclasses.
     *
     * @param attributeType
     *            The attribute type for which to make the determination.
     * @return <code>true</code> if the provided attribute type is optional for
     *         this objectclass or any of its superior classes, or
     *         <code>false</code> if not.
     */
    public boolean isOptional(final AttributeType attributeType) {
        return optionalAttributes.contains(attributeType);
    }

    /**
     * Indicates whether the provided attribute type is included in the required
     * attribute list for this or any of its superior objectclasses.
     *
     * @param attributeType
     *            The attribute type for which to make the determination.
     * @return <code>true</code> if the provided attribute type is required by
     *         this objectclass or any of its superior classes, or
     *         <code>false</code> if not.
     */
    public boolean isRequired(final AttributeType attributeType) {
        return requiredAttributes.contains(attributeType);
    }

    /**
     * Indicates whether the provided attribute type is in the list of required
     * or optional attributes for this objectclass or any of its superior
     * classes.
     *
     * @param attributeType
     *            The attribute type for which to make the determination.
     * @return <code>true</code> if the provided attribute type is required or
     *         allowed for this objectclass or any of its superior classes, or
     *         <code>false</code> if it is not.
     */
    public boolean isRequiredOrOptional(final AttributeType attributeType) {
        return isRequired(attributeType) || isOptional(attributeType);
    }

    /**
     * Returns the string representation of this schema definition in the form
     * specified in RFC 2252.
     *
     * @return The string representation of this schema definition in the form
     *         specified in RFC 2252.
     */
    @Override
    public String toString() {
        return definition;
    }

    ObjectClass duplicate() {
        return new ObjectClass(oid, names, description, isObsolete, superiorClassOIDs,
                requiredAttributeOIDs, optionalAttributeOIDs, objectClassType, extraProperties,
                definition);
    }

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

        if (!names.isEmpty()) {
            final Iterator<String> iterator = names.iterator();

            final String firstName = iterator.next();
            if (iterator.hasNext()) {
                buffer.append(" NAME ( '");
                buffer.append(firstName);

                while (iterator.hasNext()) {
                    buffer.append("' '");
                    buffer.append(iterator.next());
                }

                buffer.append("' )");
            } else {
                buffer.append(" NAME '");
                buffer.append(firstName);
                buffer.append("'");
            }
        }

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

        if (isObsolete) {
            buffer.append(" OBSOLETE");
        }

        if (!superiorClassOIDs.isEmpty()) {
            final Iterator<String> iterator = superiorClassOIDs.iterator();

            final String firstName = iterator.next();
            if (iterator.hasNext()) {
                buffer.append(" SUP ( ");
                buffer.append(firstName);

                while (iterator.hasNext()) {
                    buffer.append(" $ ");
                    buffer.append(iterator.next());
                }

                buffer.append(" )");
            } else {
                buffer.append(" SUP ");
                buffer.append(firstName);
            }
        }

        if (objectClassType != null) {
            buffer.append(" ");
            buffer.append(objectClassType.toString());
        }

        if (!requiredAttributeOIDs.isEmpty()) {
            final Iterator<String> iterator = requiredAttributeOIDs.iterator();

            final String firstName = iterator.next();
            if (iterator.hasNext()) {
                buffer.append(" MUST ( ");
                buffer.append(firstName);

                while (iterator.hasNext()) {
                    buffer.append(" $ ");
                    buffer.append(iterator.next());
                }

                buffer.append(" )");
            } else {
                buffer.append(" MUST ");
                buffer.append(firstName);
            }
        }

        if (!optionalAttributeOIDs.isEmpty()) {
            final Iterator<String> iterator = optionalAttributeOIDs.iterator();

            final String firstName = iterator.next();
            if (iterator.hasNext()) {
                buffer.append(" MAY ( ");
                buffer.append(firstName);

                while (iterator.hasNext()) {
                    buffer.append(" $ ");
                    buffer.append(iterator.next());
                }

                buffer.append(" )");
            } else {
                buffer.append(" MAY ");
                buffer.append(firstName);
            }
        }
    }

    boolean validate(final Schema schema, final List<ObjectClass> invalidSchemaElements,
            final List<LocalizableMessage> warnings) {
        // Avoid validating this schema element more than once. This may occur
        // if
        // multiple object classes specify the same superior.
        if (!needsValidating) {
            return isValid;
        }

        // Prevent re-validation.
        needsValidating = false;

        // Init a flag to check to inheritance from top (only needed for
        // structural object classes) per RFC 4512
        boolean derivesTop = objectClassType != ObjectClassType.STRUCTURAL;

        if (!superiorClassOIDs.isEmpty()) {
            superiorClasses = new HashSet<ObjectClass>(superiorClassOIDs.size());
            ObjectClass superiorClass;
            for (final String superClassOid : superiorClassOIDs) {
                try {
                    superiorClass = schema.getObjectClass(superClassOid);
                } catch (final UnknownSchemaElementException e) {
                    final LocalizableMessage message =
                            WARN_ATTR_SYNTAX_OBJECTCLASS_UNKNOWN_SUPERIOR_CLASS1.get(
                                    getNameOrOID(), superClassOid);
                    failValidation(invalidSchemaElements, warnings, message);
                    return false;
                }

                // Make sure that the inheritance configuration is acceptable.
                final ObjectClassType superiorType = superiorClass.getObjectClassType();
                switch (objectClassType) {
                case ABSTRACT:
                    // Abstract classes may only inherit from other abstract
                    // classes.
                    if (superiorType != ObjectClassType.ABSTRACT) {
                        final LocalizableMessage message =
                                WARN_ATTR_SYNTAX_OBJECTCLASS_INVALID_SUPERIOR_TYPE1.get(
                                        getNameOrOID(), objectClassType.toString(), superiorType
                                                .toString(), superiorClass.getNameOrOID());
                        failValidation(invalidSchemaElements, warnings, message);
                        return false;
                    }
                    break;

                case AUXILIARY:
                    // Auxiliary classes may only inherit from abstract classes
                    // or
                    // other auxiliary classes.
                    if (superiorType != ObjectClassType.ABSTRACT
                            && superiorType != ObjectClassType.AUXILIARY) {
                        final LocalizableMessage message =
                                WARN_ATTR_SYNTAX_OBJECTCLASS_INVALID_SUPERIOR_TYPE1.get(
                                        getNameOrOID(), objectClassType.toString(), superiorType
                                                .toString(), superiorClass.getNameOrOID());
                        failValidation(invalidSchemaElements, warnings, message);
                        return false;
                    }
                    break;

                case STRUCTURAL:
                    // Structural classes may only inherit from abstract classes
                    // or other structural classes.
                    if (superiorType != ObjectClassType.ABSTRACT
                            && superiorType != ObjectClassType.STRUCTURAL) {
                        final LocalizableMessage message =
                                WARN_ATTR_SYNTAX_OBJECTCLASS_INVALID_SUPERIOR_TYPE1.get(
                                        getNameOrOID(), objectClassType.toString(), superiorType
                                                .toString(), superiorClass.getNameOrOID());
                        failValidation(invalidSchemaElements, warnings, message);
                        return false;
                    }
                    break;
                }

                // All existing structural object classes defined in this schema
                // are implicitly guaranteed to inherit from top
                if (!derivesTop && superiorType == ObjectClassType.STRUCTURAL) {
                    derivesTop = true;
                }

                // First ensure that the superior has been validated and fail if
                // it is
                // invalid.
                if (!superiorClass.validate(schema, invalidSchemaElements, warnings)) {
                    final LocalizableMessage message =
                            WARN_ATTR_SYNTAX_OBJECTCLASS_INVALID_SUPERIOR_CLASS.get(getNameOrOID(),
                                    superClassOid);
                    failValidation(invalidSchemaElements, warnings, message);
                    return false;
                }

                // Inherit all required attributes from superior class.
                Iterator<AttributeType> i = superiorClass.getRequiredAttributes().iterator();
                if (i.hasNext() && requiredAttributes == Collections.EMPTY_SET) {
                    requiredAttributes = new HashSet<AttributeType>();
                }
                while (i.hasNext()) {
                    requiredAttributes.add(i.next());
                }

                // Inherit all optional attributes from superior class.
                i = superiorClass.getRequiredAttributes().iterator();
                if (i.hasNext() && requiredAttributes == Collections.EMPTY_SET) {
                    requiredAttributes = new HashSet<AttributeType>();
                }
                while (i.hasNext()) {
                    requiredAttributes.add(i.next());
                }

                superiorClasses.add(superiorClass);
            }
        }

        if (!derivesTop) {
            derivesTop = isDescendantOf(schema.getObjectClass("2.5.6.0"));
        }

        // Structural classes must have the "top" objectclass somewhere
        // in the superior chain.
        if (!derivesTop) {
            final LocalizableMessage message =
                    WARN_ATTR_SYNTAX_OBJECTCLASS_STRUCTURAL_SUPERIOR_NOT_TOP1.get(getNameOrOID());
            failValidation(invalidSchemaElements, warnings, message);
            return false;
        }

        if (oid.equals(EXTENSIBLE_OBJECT_OBJECTCLASS_OID)) {
            declaredOptionalAttributes = new HashSet<AttributeType>(requiredAttributeOIDs.size());
            for (final AttributeType attributeType : schema.getAttributeTypes()) {
                if (attributeType.getUsage() == AttributeUsage.USER_APPLICATIONS) {
                    declaredOptionalAttributes.add(attributeType);
                }
            }
            optionalAttributes = declaredRequiredAttributes;
        } else {
            if (!requiredAttributeOIDs.isEmpty()) {
                declaredRequiredAttributes =
                        new HashSet<AttributeType>(requiredAttributeOIDs.size());
                AttributeType attributeType;
                for (final String requiredAttribute : requiredAttributeOIDs) {
                    try {
                        attributeType = schema.getAttributeType(requiredAttribute);
                    } catch (final UnknownSchemaElementException e) {
                        // This isn't good because it means that the objectclass
                        // requires an attribute type that we don't know
                        // anything
                        // about.
                        final LocalizableMessage message =
                                WARN_ATTR_SYNTAX_OBJECTCLASS_UNKNOWN_REQUIRED_ATTR1.get(
                                        getNameOrOID(), requiredAttribute);
                        failValidation(invalidSchemaElements, warnings, message);
                        return false;
                    }
                    declaredRequiredAttributes.add(attributeType);
                }
                if (requiredAttributes == Collections.EMPTY_SET) {
                    requiredAttributes = declaredRequiredAttributes;
                } else {
                    requiredAttributes.addAll(declaredRequiredAttributes);
                }
            }

            if (!optionalAttributeOIDs.isEmpty()) {
                declaredOptionalAttributes =
                        new HashSet<AttributeType>(optionalAttributeOIDs.size());
                AttributeType attributeType;
                for (final String optionalAttribute : optionalAttributeOIDs) {
                    try {
                        attributeType = schema.getAttributeType(optionalAttribute);
                    } catch (final UnknownSchemaElementException e) {
                        // This isn't good because it means that the objectclass
                        // requires an attribute type that we don't know
                        // anything
                        // about.
                        final LocalizableMessage message =
                                WARN_ATTR_SYNTAX_OBJECTCLASS_UNKNOWN_OPTIONAL_ATTR1.get(
                                        getNameOrOID(), optionalAttribute);
                        failValidation(invalidSchemaElements, warnings, message);
                        return false;
                    }
                    declaredOptionalAttributes.add(attributeType);
                }
                if (optionalAttributes == Collections.EMPTY_SET) {
                    optionalAttributes = declaredOptionalAttributes;
                } else {
                    optionalAttributes.addAll(declaredOptionalAttributes);
                }
            }
        }

        declaredOptionalAttributes = Collections.unmodifiableSet(declaredOptionalAttributes);
        declaredRequiredAttributes = Collections.unmodifiableSet(declaredRequiredAttributes);
        optionalAttributes = Collections.unmodifiableSet(optionalAttributes);
        requiredAttributes = Collections.unmodifiableSet(requiredAttributes);
        superiorClasses = Collections.unmodifiableSet(superiorClasses);

        return (isValid = true);
    }

    private void failValidation(final List<ObjectClass> invalidSchemaElements,
            final List<LocalizableMessage> warnings, final LocalizableMessage message) {
        invalidSchemaElements.add(this);
        warnings.add(ERR_OC_VALIDATION_FAIL.get(toString(), message));
    }
}