/*
 * 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.syncope.core.provisioning.java;

import java.text.ParseException;
import java.time.temporal.TemporalAccessor;
import java.util.ArrayList;
import java.util.Base64;
import java.util.HashSet;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Collectors;
import org.apache.commons.jexl3.JexlContext;
import org.apache.commons.jexl3.MapContext;
import org.apache.commons.lang3.BooleanUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.reflect.FieldUtils;
import org.apache.commons.lang3.tuple.Pair;
import org.apache.syncope.common.lib.Attr;
import org.apache.syncope.common.lib.to.AnyObjectTO;
import org.apache.syncope.common.lib.to.AnyTO;
import org.apache.syncope.common.lib.to.GroupTO;
import org.apache.syncope.common.lib.to.GroupableRelatableTO;
import org.apache.syncope.common.lib.to.Item;
import org.apache.syncope.common.lib.to.Mapping;
import org.apache.syncope.common.lib.to.MembershipTO;
import org.apache.syncope.common.lib.to.OrgUnit;
import org.apache.syncope.common.lib.to.Provision;
import org.apache.syncope.common.lib.to.RealmTO;
import org.apache.syncope.common.lib.to.UserTO;
import org.apache.syncope.common.lib.types.AnyTypeKind;
import org.apache.syncope.common.lib.types.AttrSchemaType;
import org.apache.syncope.core.persistence.api.dao.AnyObjectDAO;
import org.apache.syncope.core.persistence.api.dao.AnyTypeDAO;
import org.apache.syncope.core.persistence.api.dao.ApplicationDAO;
import org.apache.syncope.core.persistence.api.dao.GroupDAO;
import org.apache.syncope.core.persistence.api.dao.ImplementationDAO;
import org.apache.syncope.core.persistence.api.dao.RealmDAO;
import org.apache.syncope.core.persistence.api.dao.RelationshipTypeDAO;
import org.apache.syncope.core.persistence.api.dao.UserDAO;
import org.apache.syncope.core.persistence.api.entity.Any;
import org.apache.syncope.core.persistence.api.entity.AnyType;
import org.apache.syncope.core.persistence.api.entity.AnyUtils;
import org.apache.syncope.core.persistence.api.entity.AnyUtilsFactory;
import org.apache.syncope.core.persistence.api.entity.Application;
import org.apache.syncope.core.persistence.api.entity.Attributable;
import org.apache.syncope.core.persistence.api.entity.DerSchema;
import org.apache.syncope.core.persistence.api.entity.ExternalResource;
import org.apache.syncope.core.persistence.api.entity.GroupableRelatable;
import org.apache.syncope.core.persistence.api.entity.Implementation;
import org.apache.syncope.core.persistence.api.entity.Membership;
import org.apache.syncope.core.persistence.api.entity.PlainAttr;
import org.apache.syncope.core.persistence.api.entity.PlainAttrValue;
import org.apache.syncope.core.persistence.api.entity.PlainSchema;
import org.apache.syncope.core.persistence.api.entity.Realm;
import org.apache.syncope.core.persistence.api.entity.Relationship;
import org.apache.syncope.core.persistence.api.entity.RelationshipType;
import org.apache.syncope.core.persistence.api.entity.VirSchema;
import org.apache.syncope.core.persistence.api.entity.anyobject.AnyObject;
import org.apache.syncope.core.persistence.api.entity.group.Group;
import org.apache.syncope.core.persistence.api.entity.user.Account;
import org.apache.syncope.core.persistence.api.entity.user.LAPlainAttr;
import org.apache.syncope.core.persistence.api.entity.user.LinkedAccount;
import org.apache.syncope.core.persistence.api.entity.user.User;
import org.apache.syncope.core.provisioning.api.AccountGetter;
import org.apache.syncope.core.provisioning.api.DerAttrHandler;
import org.apache.syncope.core.provisioning.api.IntAttrName;
import org.apache.syncope.core.provisioning.api.IntAttrNameParser;
import org.apache.syncope.core.provisioning.api.MappingManager;
import org.apache.syncope.core.provisioning.api.PlainAttrGetter;
import org.apache.syncope.core.provisioning.api.VirAttrHandler;
import org.apache.syncope.core.provisioning.api.cache.VirAttrCache;
import org.apache.syncope.core.provisioning.api.cache.VirAttrCacheKey;
import org.apache.syncope.core.provisioning.api.data.ItemTransformer;
import org.apache.syncope.core.provisioning.api.jexl.JexlUtils;
import org.apache.syncope.core.provisioning.api.utils.FormatUtils;
import org.apache.syncope.core.provisioning.java.utils.ConnObjectUtils;
import org.apache.syncope.core.provisioning.java.utils.MappingUtils;
import org.apache.syncope.core.spring.security.Encryptor;
import org.identityconnectors.framework.common.FrameworkUtil;
import org.identityconnectors.framework.common.objects.Attribute;
import org.identityconnectors.framework.common.objects.AttributeBuilder;
import org.identityconnectors.framework.common.objects.AttributeUtil;
import org.identityconnectors.framework.common.objects.Name;
import org.identityconnectors.framework.common.objects.OperationalAttributes;
import org.identityconnectors.framework.common.objects.Uid;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.transaction.annotation.Transactional;

public class DefaultMappingManager implements MappingManager {

    protected static final Logger LOG = LoggerFactory.getLogger(MappingManager.class);

    protected static final Encryptor ENCRYPTOR = Encryptor.getInstance();

    protected final AnyTypeDAO anyTypeDAO;

    protected final UserDAO userDAO;

    protected final AnyObjectDAO anyObjectDAO;

    protected final GroupDAO groupDAO;

    protected final RelationshipTypeDAO relationshipTypeDAO;

    protected final RealmDAO realmDAO;

    protected final ApplicationDAO applicationDAO;

    protected final ImplementationDAO implementationDAO;

    protected final DerAttrHandler derAttrHandler;

    protected final VirAttrHandler virAttrHandler;

    protected final VirAttrCache virAttrCache;

    protected final AnyUtilsFactory anyUtilsFactory;

    protected final IntAttrNameParser intAttrNameParser;

    public DefaultMappingManager(
            final AnyTypeDAO anyTypeDAO,
            final UserDAO userDAO,
            final AnyObjectDAO anyObjectDAO,
            final GroupDAO groupDAO,
            final RelationshipTypeDAO relationshipTypeDAO,
            final RealmDAO realmDAO,
            final ApplicationDAO applicationDAO,
            final ImplementationDAO implementationDAO,
            final DerAttrHandler derAttrHandler,
            final VirAttrHandler virAttrHandler,
            final VirAttrCache virAttrCache,
            final AnyUtilsFactory anyUtilsFactory,
            final IntAttrNameParser intAttrNameParser) {

        this.anyTypeDAO = anyTypeDAO;
        this.userDAO = userDAO;
        this.anyObjectDAO = anyObjectDAO;
        this.groupDAO = groupDAO;
        this.relationshipTypeDAO = relationshipTypeDAO;
        this.realmDAO = realmDAO;
        this.applicationDAO = applicationDAO;
        this.implementationDAO = implementationDAO;
        this.derAttrHandler = derAttrHandler;
        this.virAttrHandler = virAttrHandler;
        this.virAttrCache = virAttrCache;
        this.anyUtilsFactory = anyUtilsFactory;
        this.intAttrNameParser = intAttrNameParser;
    }

    protected List<Implementation> getTransformers(final Item item) {
        return item.getTransformers().stream().
                map(implementationDAO::find).
                filter(Objects::nonNull).
                collect(Collectors.toList());
    }

    protected String processPreparedAttr(final Pair<String, Attribute> preparedAttr, final Set<Attribute> attributes) {
        String connObjectKey = null;

        if (preparedAttr != null) {
            if (preparedAttr.getLeft() != null) {
                connObjectKey = preparedAttr.getLeft();
            }

            if (preparedAttr.getRight() != null) {
                Attribute alreadyAdded = AttributeUtil.find(preparedAttr.getRight().getName(), attributes);

                if (alreadyAdded == null) {
                    attributes.add(preparedAttr.getRight());
                } else {
                    attributes.remove(alreadyAdded);

                    Set<Object> values = new HashSet<>();
                    if (alreadyAdded.getValue() != null && !alreadyAdded.getValue().isEmpty()) {
                        values.addAll(alreadyAdded.getValue());
                    }

                    if (preparedAttr.getRight().getValue() != null) {
                        values.addAll(preparedAttr.getRight().getValue());
                    }

                    attributes.add(AttributeBuilder.build(preparedAttr.getRight().getName(), values));
                }
            }
        }

        return connObjectKey;
    }

    protected static Name getName(final String evalConnObjectLink, final String connObjectKey) {
        // If connObjectLink evaluates to an empty string, just use the provided connObjectKey as Name(),
        // otherwise evaluated connObjectLink expression is taken as Name().
        Name name;
        if (StringUtils.isBlank(evalConnObjectLink)) {
            // add connObjectKey as __NAME__ attribute ...
            LOG.debug("Add connObjectKey [{}] as {}", connObjectKey, Name.NAME);
            name = new Name(connObjectKey);
        } else {
            LOG.debug("Add connObjectLink [{}] as {}", evalConnObjectLink, Name.NAME);
            name = new Name(evalConnObjectLink);

            // connObjectKey not propagated: it will be used to set the value for __UID__ attribute
            LOG.debug("connObjectKey will be used just as {} attribute", Uid.NAME);
        }

        return name;
    }

    /**
     * Build __NAME__ for propagation.
     * First look if there is a defined connObjectLink for the given resource (and in
     * this case evaluate as JEXL); otherwise, take given connObjectKey.
     *
     * @param any given any object
     * @param provision external resource
     * @param connObjectKey connector object key
     * @return the value to be propagated as __NAME__
     */
    protected Name evaluateNAME(final Any<?> any, final Provision provision, final String connObjectKey) {
        if (StringUtils.isBlank(connObjectKey)) {
            // LOG error but avoid to throw exception: leave it to the external resource
            LOG.warn("Missing ConnObjectKey value for {}: ", any.getType().getKey());
        }

        // Evaluate connObjectKey expression
        String connObjectLink = provision.getMapping() == null
                ? null
                : provision.getMapping().getConnObjectLink();
        String evalConnObjectLink = null;
        if (StringUtils.isNotBlank(connObjectLink)) {
            JexlContext jexlContext = new MapContext();
            JexlUtils.addFieldsToContext(any, jexlContext);
            JexlUtils.addPlainAttrsToContext(any.getPlainAttrs(), jexlContext);
            JexlUtils.addDerAttrsToContext(any, derAttrHandler, jexlContext);
            evalConnObjectLink = JexlUtils.evaluate(connObjectLink, jexlContext).toString();
        }

        return getName(evalConnObjectLink, connObjectKey);
    }

    /**
     * Build __NAME__ for propagation.
     * First look if there is a defined connObjectLink for the given resource (and in
     * this case evaluate as JEXL); otherwise, take given connObjectKey.
     *
     * @param realm given any object
     * @param orgUnit external resource
     * @param connObjectKey connector object key
     * @return the value to be propagated as __NAME__
     */
    protected Name evaluateNAME(final Realm realm, final OrgUnit orgUnit, final String connObjectKey) {
        if (StringUtils.isBlank(connObjectKey)) {
            // LOG error but avoid to throw exception: leave it to the external resource
            LOG.warn("Missing ConnObjectKey value for Realms");
        }

        // Evaluate connObjectKey expression
        String connObjectLink = orgUnit.getConnObjectLink();
        String evalConnObjectLink = null;
        if (StringUtils.isNotBlank(connObjectLink)) {
            JexlContext jexlContext = new MapContext();
            JexlUtils.addFieldsToContext(realm, jexlContext);
            evalConnObjectLink = JexlUtils.evaluate(connObjectLink, jexlContext).toString();
        }

        return getName(evalConnObjectLink, connObjectKey);
    }

    @Transactional(readOnly = true)
    @Override
    public Pair<String, Set<Attribute>> prepareAttrsFromAny(
            final Any<?> any,
            final String password,
            final boolean changePwd,
            final Boolean enable,
            final ExternalResource resource,
            final Provision provision) {

        LOG.debug("Preparing resource attributes for {} with provision {} for attributes {}",
                any, provision, any.getPlainAttrs());

        Set<Attribute> attributes = new HashSet<>();
        String[] connObjectKeyValue = new String[1];

        MappingUtils.getPropagationItems(provision.getMapping().getItems().stream()).forEach(mapItem -> {
            LOG.debug("Processing expression '{}'", mapItem.getIntAttrName());

            try {
                String processedConnObjectKeyValue = processPreparedAttr(
                        prepareAttr(
                                resource,
                                provision,
                                mapItem,
                                any,
                                password,
                                AccountGetter.DEFAULT,
                                AccountGetter.DEFAULT,
                                PlainAttrGetter.DEFAULT),
                        attributes);
                if (processedConnObjectKeyValue != null) {
                    connObjectKeyValue[0] = processedConnObjectKeyValue;
                }
            } catch (Exception e) {
                LOG.error("Expression '{}' processing failed", mapItem.getIntAttrName(), e);
            }
        });

        MappingUtils.getConnObjectKeyItem(provision).ifPresent(connObjectKeyItem -> {
            Attribute connObjectKeyAttr = AttributeUtil.find(connObjectKeyItem.getExtAttrName(), attributes);
            if (connObjectKeyAttr != null) {
                attributes.remove(connObjectKeyAttr);
                attributes.add(AttributeBuilder.build(connObjectKeyItem.getExtAttrName(), connObjectKeyValue[0]));
            }
            Name name = evaluateNAME(any, provision, connObjectKeyValue[0]);
            attributes.add(name);
            if (connObjectKeyAttr == null
                    && connObjectKeyValue[0] != null && !connObjectKeyValue[0].equals(name.getNameValue())) {

                attributes.add(AttributeBuilder.build(connObjectKeyItem.getExtAttrName(), connObjectKeyValue[0]));
            }
        });

        if (enable != null) {
            attributes.add(AttributeBuilder.buildEnabled(enable));
        }
        if (!changePwd) {
            Attribute pwdAttr = AttributeUtil.find(OperationalAttributes.PASSWORD_NAME, attributes);
            if (pwdAttr != null) {
                attributes.remove(pwdAttr);
            }
        }

        return Pair.of(connObjectKeyValue[0], attributes);
    }

    @Transactional(readOnly = true)
    @Override
    public Set<Attribute> prepareAttrsFromLinkedAccount(
            final User user,
            final LinkedAccount account,
            final String password,
            final boolean changePwd,
            final Provision provision) {

        LOG.debug("Preparing resource attributes for linked account {} of user {} with provision {} "
                + "for user attributes {} with override {}",
                account, user, provision, user.getPlainAttrs(), account.getPlainAttrs());

        Set<Attribute> attributes = new HashSet<>();

        MappingUtils.getPropagationItems(provision.getMapping().getItems().stream()).forEach(mapItem -> {
            LOG.debug("Processing expression '{}'", mapItem.getIntAttrName());

            try {
                processPreparedAttr(
                        prepareAttr(
                                account.getResource(),
                                provision,
                                mapItem,
                                user,
                                password,
                                acct -> account.getUsername() == null ? AccountGetter.DEFAULT.apply(acct) : account,
                                acct -> account.getPassword() == null ? AccountGetter.DEFAULT.apply(acct) : account,
                                (attributable, schema) -> {
                                    PlainAttr<?> result = null;
                                    if (attributable instanceof User) {
                                        Optional<? extends LAPlainAttr> accountAttr = account.getPlainAttr(schema);
                                        if (accountAttr.isPresent()) {
                                            result = accountAttr.get();
                                        }
                                    }
                                    if (result == null) {
                                        result = PlainAttrGetter.DEFAULT.apply(attributable, schema);
                                    }
                                    return result;
                                }),
                        attributes);
            } catch (Exception e) {
                LOG.error("Expression '{}' processing failed", mapItem.getIntAttrName(), e);
            }
        });

        String connObjectKey = account.getConnObjectKeyValue();
        MappingUtils.getConnObjectKeyItem(provision).ifPresent(connObjectKeyItem -> {
            Attribute connObjectKeyExtAttr = AttributeUtil.find(connObjectKeyItem.getExtAttrName(), attributes);
            if (connObjectKeyExtAttr != null) {
                attributes.remove(connObjectKeyExtAttr);
                attributes.add(AttributeBuilder.build(connObjectKeyItem.getExtAttrName(), connObjectKey));
            }
            Name name = evaluateNAME(user, provision, connObjectKey);
            attributes.add(name);
            if (!connObjectKey.equals(name.getNameValue()) && connObjectKeyExtAttr == null) {
                attributes.add(AttributeBuilder.build(connObjectKeyItem.getExtAttrName(), connObjectKey));
            }
        });

        if (account.isSuspended() != null) {
            attributes.add(AttributeBuilder.buildEnabled(BooleanUtils.negate(account.isSuspended())));
        }
        if (!changePwd) {
            Attribute pwdAttr = AttributeUtil.find(OperationalAttributes.PASSWORD_NAME, attributes);
            if (pwdAttr != null) {
                attributes.remove(pwdAttr);
            }
        }

        return attributes;
    }

    protected String getIntValue(final Realm realm, final Item orgUnitItem) {
        String value = null;
        switch (orgUnitItem.getIntAttrName()) {
            case "key":
                value = realm.getKey();
                break;

            case "name":
                value = realm.getName();
                break;

            case "fullpath":
                value = realm.getFullPath();
                break;

            default:
        }

        return value;
    }

    @Override
    public Pair<String, Set<Attribute>> prepareAttrsFromRealm(final Realm realm, final OrgUnit orgUnit) {
        LOG.debug("Preparing resource attributes for {} with orgUnit {}", realm, orgUnit);

        Set<Attribute> attributes = new HashSet<>();
        String[] connObjectKeyValue = new String[1];

        MappingUtils.getPropagationItems(orgUnit.getItems().stream()).forEach(orgUnitItem -> {
            LOG.debug("Processing expression '{}'", orgUnitItem.getIntAttrName());

            String value = getIntValue(realm, orgUnitItem);

            if (orgUnitItem.isConnObjectKey()) {
                connObjectKeyValue[0] = value;
            }

            Attribute alreadyAdded = AttributeUtil.find(orgUnitItem.getExtAttrName(), attributes);
            if (alreadyAdded == null) {
                if (value == null) {
                    attributes.add(AttributeBuilder.build(orgUnitItem.getExtAttrName()));
                } else {
                    attributes.add(AttributeBuilder.build(orgUnitItem.getExtAttrName(), value));
                }
            } else if (value != null) {
                attributes.remove(alreadyAdded);

                Set<Object> values = new HashSet<>();
                if (alreadyAdded.getValue() != null && !alreadyAdded.getValue().isEmpty()) {
                    values.addAll(alreadyAdded.getValue());
                }
                values.add(value);

                attributes.add(AttributeBuilder.build(orgUnitItem.getExtAttrName(), values));
            }
        });

        Optional<Item> connObjectKeyItem = orgUnit.getConnObjectKeyItem();
        if (connObjectKeyItem.isPresent()) {
            Attribute connObjectKeyAttr = AttributeUtil.find(connObjectKeyItem.get().getExtAttrName(), attributes);
            if (connObjectKeyAttr != null) {
                attributes.remove(connObjectKeyAttr);
                attributes.add(AttributeBuilder.build(connObjectKeyItem.get().getExtAttrName(), connObjectKeyValue[0]));
            }
            attributes.add(evaluateNAME(realm, orgUnit, connObjectKeyValue[0]));
        }

        return Pair.of(connObjectKeyValue[0], attributes);
    }

    protected String decodePassword(final Account account) {
        try {
            return ENCRYPTOR.decode(account.getPassword(), account.getCipherAlgorithm());
        } catch (Exception e) {
            LOG.error("Could not decode password for {}", account, e);
            return null;
        }
    }

    protected String getPasswordAttrValue(final Account account, final String defaultValue) {
        String passwordAttrValue;
        if (account instanceof LinkedAccount) {
            if (account.getPassword() != null) {
                passwordAttrValue = decodePassword(account);
            } else {
                passwordAttrValue = defaultValue;
            }
        } else {
            if (StringUtils.isNotBlank(defaultValue)) {
                passwordAttrValue = defaultValue;
            } else if (account.canDecodeSecrets()) {
                passwordAttrValue = decodePassword(account);
            } else {
                passwordAttrValue = null;
            }
        }

        return passwordAttrValue;
    }

    @Override
    public Pair<String, Attribute> prepareAttr(
            final ExternalResource resource,
            final Provision provision,
            final Item item,
            final Any<?> any,
            final String password,
            final AccountGetter usernameAccountGetter,
            final AccountGetter passwordAccountGetter,
            final PlainAttrGetter plainAttrGetter) {

        IntAttrName intAttrName;
        try {
            intAttrName = intAttrNameParser.parse(item.getIntAttrName(), any.getType().getKind());
        } catch (ParseException e) {
            LOG.error("Invalid intAttrName '{}' specified, ignoring", item.getIntAttrName(), e);
            return null;
        }

        AttrSchemaType schemaType = intAttrName.getSchema() instanceof PlainSchema
                ? intAttrName.getSchema().getType()
                : AttrSchemaType.String;
        boolean readOnlyVirSchema = intAttrName.getSchema() instanceof VirSchema
                ? intAttrName.getSchema().isReadonly()
                : false;

        Pair<AttrSchemaType, List<PlainAttrValue>> intValues = getIntValues(
                resource, provision, item, intAttrName, schemaType, any, usernameAccountGetter, plainAttrGetter);
        schemaType = intValues.getLeft();
        List<PlainAttrValue> values = intValues.getRight();

        LOG.debug("Define mapping for: "
                + "\n* ExtAttrName " + item.getExtAttrName()
                + "\n* is connObjectKey " + item.isConnObjectKey()
                + "\n* is password " + item.isPassword()
                + "\n* mandatory condition " + item.getMandatoryCondition()
                + "\n* Schema " + intAttrName.getSchema()
                + "\n* ClassType " + schemaType.getType().getName()
                + "\n* AttrSchemaType " + schemaType
                + "\n* Values " + values);

        Pair<String, Attribute> result;
        if (readOnlyVirSchema) {
            result = null;
        } else {
            List<Object> objValues = new ArrayList<>();

            for (PlainAttrValue value : values) {
                if (FrameworkUtil.isSupportedAttributeType(schemaType.getType())) {
                    objValues.add(value.getValue());
                } else {
                    PlainSchema plainSchema = intAttrName.getSchema() instanceof PlainSchema
                            ? (PlainSchema) intAttrName.getSchema()
                            : null;
                    if (plainSchema == null || plainSchema.getType() != schemaType) {
                        objValues.add(value.getValueAsString(schemaType));
                    } else {
                        objValues.add(value.getValueAsString(plainSchema));
                    }
                }
            }

            if (item.isConnObjectKey()) {
                result = Pair.of(objValues.isEmpty() ? null : objValues.iterator().next().toString(), null);
            } else if (item.isPassword() && any instanceof User) {
                String passwordAttrValue = getPasswordAttrValue(passwordAccountGetter.apply((User) any), password);
                if (passwordAttrValue == null) {
                    result = null;
                } else {
                    result = Pair.of(null, AttributeBuilder.buildPassword(passwordAttrValue.toCharArray()));
                }
            } else {
                result = Pair.of(null, objValues.isEmpty()
                        ? AttributeBuilder.build(item.getExtAttrName())
                        : AttributeBuilder.build(item.getExtAttrName(), objValues));
            }
        }

        return result;
    }

    @Transactional(readOnly = true)
    @SuppressWarnings("unchecked")
    @Override
    public Pair<AttrSchemaType, List<PlainAttrValue>> getIntValues(
            final ExternalResource resource,
            final Provision provision,
            final Item mapItem,
            final IntAttrName intAttrName,
            final AttrSchemaType schemaType,
            final Any<?> any,
            final AccountGetter usernameAccountGetter,
            final PlainAttrGetter plainAttrGetter) {

        LOG.debug("Get internal values for {} as '{}' on {}", any, mapItem.getIntAttrName(), resource);

        List<Any<?>> references = new ArrayList<>();
        Membership<?> membership = null;
        if (intAttrName.getEnclosingGroup() == null
                && intAttrName.getRelatedAnyObject() == null
                && intAttrName.getRelationshipAnyType() == null
                && intAttrName.getRelationshipType() == null
                && intAttrName.getRelatedUser() == null) {
            references.add(any);
        }
        if (any instanceof GroupableRelatable) {
            GroupableRelatable<?, ?, ?, ?, ?> groupableRelatable = (GroupableRelatable<?, ?, ?, ?, ?>) any;

            if (intAttrName.getEnclosingGroup() != null) {
                Group group = groupDAO.findByName(intAttrName.getEnclosingGroup());
                if (group == null
                        || any instanceof User
                                ? !userDAO.findAllGroupKeys((User) any).contains(group.getKey())
                                : any instanceof AnyObject
                                        ? !anyObjectDAO.findAllGroupKeys((AnyObject) any).contains(group.getKey())
                                        : false) {

                    LOG.warn("No (dyn) membership for {} in {}, ignoring",
                            intAttrName.getEnclosingGroup(), groupableRelatable);
                } else {
                    references.add(group);
                }
            } else if (intAttrName.getRelatedUser() != null) {
                User user = userDAO.findByUsername(intAttrName.getRelatedUser());
                if (user == null || user.getRelationships(groupableRelatable.getKey()).isEmpty()) {
                    LOG.warn("No relationship for {} in {}, ignoring",
                            intAttrName.getRelatedUser(), groupableRelatable);
                } else if (groupableRelatable.getType().getKind() == AnyTypeKind.USER) {
                    LOG.warn("Users cannot have relationship with other users, ignoring");
                } else {
                    references.add(user);
                }
            } else if (intAttrName.getRelatedAnyObject() != null) {
                AnyObject anyObject = anyObjectDAO.find(intAttrName.getRelatedAnyObject());
                if (anyObject == null || groupableRelatable.getRelationships(anyObject.getKey()).isEmpty()) {
                    LOG.warn("No relationship for {} in {}, ignoring",
                            intAttrName.getRelatedAnyObject(), groupableRelatable);
                } else {
                    references.add(anyObject);
                }
            } else if (intAttrName.getRelationshipAnyType() != null && intAttrName.getRelationshipType() != null) {
                RelationshipType relationshipType = relationshipTypeDAO.find(intAttrName.getRelationshipType());
                AnyType anyType = anyTypeDAO.find(intAttrName.getRelationshipAnyType());
                if (relationshipType == null || groupableRelatable.getRelationships(relationshipType).isEmpty()) {
                    LOG.warn("No relationship for type {} in {}, ignoring",
                            intAttrName.getRelationshipType(), groupableRelatable);
                } else if (anyType == null) {
                    LOG.warn("No anyType {}, ignoring", intAttrName.getRelationshipAnyType());
                } else {
                    references.addAll(groupableRelatable.getRelationships(relationshipType).stream().
                            filter(relationship -> anyType.equals(relationship.getRightEnd().getType())).
                            map(Relationship::getRightEnd).
                            collect(Collectors.toList()));
                }
            } else if (intAttrName.getMembershipOfGroup() != null) {
                Group group = groupDAO.findByName(intAttrName.getMembershipOfGroup());
                membership = groupableRelatable.getMembership(group.getKey()).orElse(null);
            }
        }
        if (references.isEmpty()) {
            LOG.warn("Could not determine the reference instance for {}", mapItem.getIntAttrName());
            return Pair.of(schemaType, List.of());
        }

        List<PlainAttrValue> values = new ArrayList<>();
        boolean transform = true;

        for (Any<?> ref : references) {
            AnyUtils anyUtils = anyUtilsFactory.getInstance(ref);
            if (intAttrName.getField() != null) {
                PlainAttrValue attrValue = anyUtils.newPlainAttrValue();

                switch (intAttrName.getField()) {
                    case "key":
                        attrValue.setStringValue(ref.getKey());
                        values.add(attrValue);
                        break;

                    case "username":
                        if (ref instanceof Account) {
                            attrValue.setStringValue(usernameAccountGetter.apply((Account) ref).getUsername());
                            values.add(attrValue);
                        }
                        break;

                    case "realm":
                        attrValue.setStringValue(ref.getRealm().getFullPath());
                        values.add(attrValue);
                        break;

                    case "password":
                        // ignore
                        break;

                    case "userOwner":
                    case "groupOwner":
                        Mapping uMappingTO = provision.getAnyType().equals(AnyTypeKind.USER.name())
                                ? provision.getMapping()
                                : null;
                        Mapping gMappingTO = provision.getAnyType().equals(AnyTypeKind.GROUP.name())
                                ? provision.getMapping()
                                : null;

                        if (ref instanceof Group) {
                            Group group = (Group) ref;
                            String groupOwnerValue = null;
                            if (group.getUserOwner() != null && uMappingTO != null) {
                                groupOwnerValue = getGroupOwnerValue(resource, provision, group.getUserOwner());
                            }
                            if (group.getGroupOwner() != null && gMappingTO != null) {
                                groupOwnerValue = getGroupOwnerValue(resource, provision, group.getGroupOwner());
                            }

                            if (StringUtils.isNotBlank(groupOwnerValue)) {
                                attrValue.setStringValue(groupOwnerValue);
                                values.add(attrValue);
                            }
                        }
                        break;

                    case "suspended":
                        if (ref instanceof User) {
                            attrValue.setBooleanValue(((User) ref).isSuspended());
                            values.add(attrValue);
                        }
                        break;

                    case "mustChangePassword":
                        if (ref instanceof User) {
                            attrValue.setBooleanValue(((User) ref).isMustChangePassword());
                            values.add(attrValue);
                        }
                        break;

                    default:
                        try {
                        Object fieldValue = FieldUtils.readField(ref, intAttrName.getField(), true);
                        if (fieldValue instanceof TemporalAccessor) {
                            // needed because ConnId does not natively supports the Date type
                            attrValue.setStringValue(FormatUtils.format((TemporalAccessor) fieldValue));
                        } else if (Boolean.TYPE.isInstance(fieldValue)) {
                            attrValue.setBooleanValue((Boolean) fieldValue);
                        } else if (Double.TYPE.isInstance(fieldValue) || Float.TYPE.isInstance(fieldValue)) {
                            attrValue.setDoubleValue((Double) fieldValue);
                        } else if (Long.TYPE.isInstance(fieldValue) || Integer.TYPE.isInstance(fieldValue)) {
                            attrValue.setLongValue((Long) fieldValue);
                        } else {
                            attrValue.setStringValue(fieldValue.toString());
                        }
                        values.add(attrValue);
                    } catch (Exception e) {
                        LOG.error("Could not read value of '{}' from {}", intAttrName.getField(), ref, e);
                    }
                }
            } else if (intAttrName.getSchemaType() != null) {
                switch (intAttrName.getSchemaType()) {
                    case PLAIN:
                        PlainAttr<?> attr;
                        if (membership == null) {
                            attr = plainAttrGetter.apply((Attributable) ref, intAttrName.getSchema().getKey());
                        } else {
                            attr = ((GroupableRelatable<?, ?, ?, ?, ?>) ref).getPlainAttr(
                                    intAttrName.getSchema().getKey(), membership).orElse(null);
                        }
                        if (attr != null) {
                            if (attr.getUniqueValue() != null) {
                                values.add(anyUtils.clonePlainAttrValue(attr.getUniqueValue()));
                            } else if (attr.getValues() != null) {
                                attr.getValues().forEach(value -> values.add(anyUtils.clonePlainAttrValue(value)));
                            }
                        }
                        break;

                    case DERIVED:
                        DerSchema derSchema = (DerSchema) intAttrName.getSchema();
                        String derValue = membership == null
                                ? derAttrHandler.getValue(ref, derSchema)
                                : derAttrHandler.getValue(ref, membership, derSchema);
                        if (derValue != null) {
                            PlainAttrValue attrValue = anyUtils.newPlainAttrValue();
                            attrValue.setStringValue(derValue);
                            values.add(attrValue);
                        }
                        break;

                    case VIRTUAL:
                        // virtual attributes don't get transformed
                        transform = false;

                        VirAttrCacheKey cacheKey = new VirAttrCacheKey(
                                ref.getType().getKey(), ref.getKey(), intAttrName.getSchema().getKey());
                        virAttrCache.expire(cacheKey);
                        LOG.debug("Evicted from cache: {}", cacheKey);

                        VirSchema virSchema = (VirSchema) intAttrName.getSchema();
                        List<String> virValues = membership == null
                                ? virAttrHandler.getValues(ref, virSchema)
                                : virAttrHandler.getValues(ref, membership, virSchema);
                        virValues.forEach(virValue -> {
                            PlainAttrValue attrValue = anyUtils.newPlainAttrValue();
                            attrValue.setStringValue(virValue);
                            values.add(attrValue);
                        });
                        break;

                    default:
                }
            } else if (intAttrName.getPrivilegesOfApplication() != null && ref instanceof User) {
                Application application = applicationDAO.find(intAttrName.getPrivilegesOfApplication());
                if (application == null) {
                    LOG.warn("Invalid application: {}", intAttrName.getPrivilegesOfApplication());
                } else {
                    userDAO.findAllRoles((User) ref).stream().
                            flatMap(role -> role.getPrivileges(application).stream()).
                            forEach(privilege -> {
                                PlainAttrValue attrValue = anyUtils.newPlainAttrValue();
                                attrValue.setStringValue(privilege.getKey());
                                values.add(attrValue);
                            });
                }
            }
        }

        LOG.debug("Internal values: {}", values);

        Pair<AttrSchemaType, List<PlainAttrValue>> transformed = Pair.of(schemaType, values);
        if (transform) {
            for (ItemTransformer transformer : MappingUtils.getItemTransformers(mapItem, getTransformers(mapItem))) {
                transformed = transformer.beforePropagation(
                        mapItem, any, transformed.getLeft(), transformed.getRight());
            }
            LOG.debug("Transformed values: {}", values);
        } else {
            LOG.debug("No transformation occurred");
        }

        return transformed;
    }

    protected String getGroupOwnerValue(
            final ExternalResource resource,
            final Provision provision,
            final Any<?> any) {

        Optional<Item> connObjectKeyItem = MappingUtils.getConnObjectKeyItem(provision);

        Pair<String, Attribute> preparedAttr = null;
        if (connObjectKeyItem.isPresent()) {
            preparedAttr = prepareAttr(
                    resource,
                    provision,
                    connObjectKeyItem.get(),
                    any,
                    null,
                    AccountGetter.DEFAULT,
                    AccountGetter.DEFAULT,
                    PlainAttrGetter.DEFAULT);
        }

        return Optional.ofNullable(preparedAttr).
                map(attr -> evaluateNAME(any, provision, attr.getKey()).getNameValue()).orElse(null);
    }

    @Transactional(readOnly = true)
    @Override
    public Optional<String> getConnObjectKeyValue(
            final Any<?> any,
            final ExternalResource resource,
            final Provision provision) {

        Optional<Item> connObjectKeyItem = provision.getMapping().getConnObjectKeyItem();
        if (connObjectKeyItem.isEmpty()) {
            LOG.error("Unable to locate conn object key item for {}", any.getType().getKey());
            return Optional.empty();
        }
        Item mapItem = connObjectKeyItem.get();
        Pair<AttrSchemaType, List<PlainAttrValue>> intValues;
        try {
            intValues = getIntValues(
                    resource,
                    provision,
                    mapItem,
                    intAttrNameParser.parse(mapItem.getIntAttrName(), any.getType().getKind()),
                    AttrSchemaType.String,
                    any,
                    AccountGetter.DEFAULT,
                    PlainAttrGetter.DEFAULT);
        } catch (ParseException e) {
            LOG.error("Invalid intAttrName '{}' specified, ignoring", mapItem.getIntAttrName(), e);
            intValues = Pair.of(AttrSchemaType.String, List.of());
        }
        return Optional.ofNullable(intValues.getRight().isEmpty()
                ? null
                : intValues.getRight().get(0).getValueAsString());
    }

    @Transactional(readOnly = true)
    @Override
    public Optional<String> getConnObjectKeyValue(final Realm realm, final OrgUnit orgUnit) {
        Optional<Item> connObjectKeyItem = orgUnit.getConnObjectKeyItem();
        if (connObjectKeyItem.isEmpty()) {
            LOG.error("Unable to locate conn object key item for Realms");
            return Optional.empty();
        }
        return Optional.ofNullable(getIntValue(realm, connObjectKeyItem.get()));
    }

    @Transactional(readOnly = true)
    @Override
    public void setIntValues(final Item mapItem, final Attribute attr, final AnyTO anyTO) {
        List<Object> values = null;
        if (attr != null) {
            values = attr.getValue();
            for (ItemTransformer transformer : MappingUtils.getItemTransformers(mapItem, getTransformers(mapItem))) {
                values = transformer.beforePull(mapItem, anyTO, values);
            }
        }
        values = Optional.ofNullable(values).orElse(List.of());

        IntAttrName intAttrName;
        try {
            intAttrName = intAttrNameParser.parse(mapItem.getIntAttrName(), AnyTypeKind.fromTOClass(anyTO.getClass()));
        } catch (ParseException e) {
            LOG.error("Invalid intAttrName '{}' specified, ignoring", mapItem.getIntAttrName(), e);
            return;
        }

        if (intAttrName.getField() != null) {
            switch (intAttrName.getField()) {
                case "password":
                    if (anyTO instanceof UserTO && !values.isEmpty()) {
                        ((UserTO) anyTO).setPassword(ConnObjectUtils.getPassword(values.get(0)));
                    }
                    break;

                case "username":
                    if (anyTO instanceof UserTO) {
                        ((UserTO) anyTO).setUsername(values.isEmpty() || values.get(0) == null
                                ? null
                                : values.get(0).toString());
                    }
                    break;

                case "name":
                    if (anyTO instanceof GroupTO) {
                        ((GroupTO) anyTO).setName(values.isEmpty() || values.get(0) == null
                                ? null
                                : values.get(0).toString());
                    } else if (anyTO instanceof AnyObjectTO) {
                        ((AnyObjectTO) anyTO).setName(values.isEmpty() || values.get(0) == null
                                ? null
                                : values.get(0).toString());
                    }
                    break;

                case "mustChangePassword":
                    if (anyTO instanceof UserTO && !values.isEmpty() && values.get(0) != null) {
                        ((UserTO) anyTO).setMustChangePassword(BooleanUtils.toBoolean(values.get(0).toString()));
                    }
                    break;

                case "userOwner":
                case "groupOwner":
                    if (anyTO instanceof GroupTO && attr != null) {
                        // using a special attribute (with schema "", that will be ignored) for carrying the
                        // GroupOwnerSchema value
                        Attr attrTO = new Attr();
                        attrTO.setSchema(StringUtils.EMPTY);
                        if (values.isEmpty() || values.get(0) == null) {
                            attrTO.getValues().add(StringUtils.EMPTY);
                        } else {
                            attrTO.getValues().add(values.get(0).toString());
                        }

                        ((GroupTO) anyTO).getPlainAttrs().add(attrTO);
                    }
                    break;

                default:
            }
        } else if (intAttrName.getSchemaType() != null && attr != null) {
            GroupableRelatableTO groupableTO;
            Group group;
            if (anyTO instanceof GroupableRelatableTO && intAttrName.getMembershipOfGroup() != null) {
                groupableTO = (GroupableRelatableTO) anyTO;
                group = groupDAO.findByName(intAttrName.getMembershipOfGroup());
            } else {
                groupableTO = null;
                group = null;
            }

            switch (intAttrName.getSchemaType()) {
                case PLAIN:
                    Attr attrTO = new Attr();
                    attrTO.setSchema(intAttrName.getSchema().getKey());

                    PlainSchema schema = (PlainSchema) intAttrName.getSchema();

                    for (Object value : values) {
                        AttrSchemaType schemaType = schema == null ? AttrSchemaType.String : schema.getType();
                        if (value != null) {
                            if (schemaType == AttrSchemaType.Binary) {
                                attrTO.getValues().add(Base64.getEncoder().encodeToString((byte[]) value));
                            } else {
                                attrTO.getValues().add(value.toString());
                            }
                        }
                    }

                    if (groupableTO == null || group == null) {
                        anyTO.getPlainAttrs().add(attrTO);
                    } else {
                        MembershipTO membership = groupableTO.getMembership(group.getKey()).orElseGet(() -> {
                            MembershipTO newMemb = new MembershipTO.Builder(group.getKey()).build();
                            groupableTO.getMemberships().add(newMemb);
                            return newMemb;
                        });
                        membership.getPlainAttrs().add(attrTO);
                    }
                    break;

                case DERIVED:
                    attrTO = new Attr();
                    attrTO.setSchema(intAttrName.getSchema().getKey());

                    if (groupableTO == null || group == null) {
                        anyTO.getDerAttrs().add(attrTO);
                    } else {
                        MembershipTO membership = groupableTO.getMembership(group.getKey()).orElseGet(() -> {
                            MembershipTO newMemb = new MembershipTO.Builder(group.getKey()).build();
                            groupableTO.getMemberships().add(newMemb);
                            return newMemb;
                        });
                        membership.getDerAttrs().add(attrTO);
                    }
                    break;

                case VIRTUAL:
                    attrTO = new Attr();
                    attrTO.setSchema(intAttrName.getSchema().getKey());

                    // virtual attributes don't get transformed, iterate over original attr.getValue()
                    if (attr.getValue() != null && !attr.getValue().isEmpty()) {
                        attr.getValue().stream().
                                filter(Objects::nonNull).
                                forEachOrdered(value -> attrTO.getValues().add(value.toString()));
                    }

                    if (groupableTO == null || group == null) {
                        anyTO.getVirAttrs().add(attrTO);
                    } else {
                        MembershipTO membership = groupableTO.getMembership(group.getKey()).orElseGet(() -> {
                            MembershipTO newMemb = new MembershipTO.Builder(group.getKey()).build();
                            groupableTO.getMemberships().add(newMemb);
                            return newMemb;
                        });
                        membership.getVirAttrs().add(attrTO);
                    }
                    break;

                default:
            }
        }
    }

    @Override
    public void setIntValues(final Item item, final Attribute attr, final RealmTO realmTO) {
        List<Object> values = null;
        if (attr != null) {
            values = attr.getValue();
            for (ItemTransformer transformer : MappingUtils.getItemTransformers(item, getTransformers(item))) {
                values = transformer.beforePull(item, realmTO, values);
            }
        }

        if (values != null && !values.isEmpty() && values.get(0) != null) {
            switch (item.getIntAttrName()) {
                case "name":
                    realmTO.setName(values.get(0).toString());
                    break;

                case "fullpath":
                    String parentFullPath = StringUtils.substringBeforeLast(values.get(0).toString(), "/");
                    Realm parent = realmDAO.findByFullPath(parentFullPath);
                    if (parent == null) {
                        LOG.warn("Could not find Realm with path {}, ignoring", parentFullPath);
                    } else {
                        realmTO.setParent(parent.getFullPath());
                    }
                    break;

                default:
            }
        }
    }

    @Transactional(readOnly = true)
    @Override
    public boolean hasMustChangePassword(final Provision provision) {
        return provision != null && provision.getMapping() != null
                && provision.getMapping().getItems().stream().
                        anyMatch(mappingItem -> "mustChangePassword".equals(mappingItem.getIntAttrName()));
    }
}
