/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-18 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * Licensed 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.
 * ============LICENSE_END=========================================================
 */

package org.onap.aai.edges;

import static com.jayway.jsonpath.Criteria.where;
import static com.jayway.jsonpath.Filter.filter;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;
import com.jayway.jsonpath.Criteria;
import com.jayway.jsonpath.DocumentContext;
import com.jayway.jsonpath.Filter;

import java.io.IOException;
import java.util.*;
import java.util.Map.Entry;
import java.util.concurrent.ExecutionException;
import java.util.stream.Collectors;

import javax.annotation.PostConstruct;

import org.apache.tinkerpop.gremlin.structure.Direction;
import org.onap.aai.edges.enums.DirectionNotation;
import org.onap.aai.edges.enums.EdgeField;
import org.onap.aai.edges.enums.EdgeType;
import org.onap.aai.edges.exceptions.AmbiguousRuleChoiceException;
import org.onap.aai.edges.exceptions.EdgeRuleNotFoundException;
import org.onap.aai.setup.SchemaVersion;
import org.onap.aai.setup.SchemaVersions;
import org.onap.aai.setup.Translator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

/**
 * EdgeIngestor - ingests A&AI edge rule schema files per given config, serves that edge rule
 * information, including allowing various filters to extract particular rules.
 */
@Component
public class EdgeIngestor {
    private static final Logger LOGGER = LoggerFactory.getLogger(EdgeIngestor.class);
    private Map<SchemaVersion, List<DocumentContext>> versionJsonFilesMap = new TreeMap<>();
    private static final String READ_START = "$.rules.[?]";
    private static final String READ_ALL_START = "$.rules.*";
    private SchemaVersions schemaVersions;

    Map<SchemaVersion, List<String>> filesToIngest;

    private Set<String> multipleLabelKeys;

    private LoadingCache<SchemaFilter, Multimap<String, EdgeRule>> cacheFilterStore;

    private LoadingCache<String, String[]> cousinLabelStore;

    private Set<Translator> translators;

    @Autowired
    public EdgeIngestor(Set<Translator> translatorSet) {
        this.translators = translatorSet;
    }

    @PostConstruct
    public void initialize() {

        for (Translator translator : translators) {
            try {
                LOGGER.debug("Processing the translator");
                translateAll(translator);

            } catch (Exception e) {
                LOGGER.error("Error while Processing the translator" + e.getMessage());
                throw new ExceptionInInitializerError("EdgeIngestor could not ingest schema");
            }
        }
        if (versionJsonFilesMap.isEmpty() || schemaVersions == null) {
            throw new ExceptionInInitializerError("EdgeIngestor could not ingest edgerules");
        }
    }

    public void translateAll(Translator translator) throws ExceptionInInitializerError {
        /*
         * Use SchemaVersions from the Translator
         */
        this.schemaVersions = translator.getSchemaVersions();
        List<SchemaVersion> schemaVersionList = this.schemaVersions.getVersions();
        List<String> jsonPayloads = null;
        JsonIngestor ji = new JsonIngestor();
        Map<SchemaVersion, List<String>> edgeRulesToIngest = new HashMap<>(); // Obtain a map of schema versions to a
                                                                              // list of strings. One List per key

        // Add to the map the JSON file per version.
        for (SchemaVersion version : schemaVersionList) {
            LOGGER.debug("Version being processed" + version);
            // If the flag is set to not use the local files, obtain the Json from the service.
            try {
                jsonPayloads = translator.getJsonPayload(version); // need to change this - need to receive the json
                                                                   // files.
            } catch (IOException e) {
                LOGGER.error("Error in retrieving the JSON Payload" + e.getMessage());
                throw new ExceptionInInitializerError("EdgeIngestor could not ingest schema");
            }
            if (jsonPayloads == null || jsonPayloads.isEmpty()) {
                continue;
            }
            LOGGER.debug("Retrieved json from SchemaService");
            edgeRulesToIngest.put(version, jsonPayloads);
        }
        versionJsonFilesMap = ji.ingestContent(edgeRulesToIngest);

        this.cacheFilterStore = CacheBuilder.newBuilder().maximumSize(2000)
                .build(new CacheLoader<SchemaFilter, Multimap<String, EdgeRule>>() {
                    @Override
                    public Multimap<String, EdgeRule> load(SchemaFilter key) {
                        return extractRules(key);
                    }
                });

        this.cousinLabelStore = CacheBuilder.newBuilder().maximumSize(50).build(new CacheLoader<String, String[]>() {
            @Override
            public String[] load(String key) throws Exception {
                return retrieveCousinLabels(key);
            }
        });
    }

    // //-----methods for getting rule info-----//
    //
    /**
     * Gets list of all edge rules defined in the latest version's schema
     *
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules associated with those types
     *         where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Map will be empty if
     *         no rules are found.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     * @throws EdgeRuleNotFoundException if none found
     */
    public Multimap<String, EdgeRule> getAllCurrentRules() throws EdgeRuleNotFoundException {
        return getAllRules(schemaVersions.getDefaultVersion());
    }

    /**
     * Retrieves all the nodes that contain multiple edge labels
     *
     * A lazy instantiation to retrieve all this info on first call
     *
     * @return a set containing a list of strings where each string is
     *         concatenated by a pipe (|) character such as aNodeType|bNodeType
     */
    public Set<String> getMultipleLabelKeys() {

        if (multipleLabelKeys == null) {
            multipleLabelKeys = new HashSet<>();
            try {
                final Multimap<String, EdgeRule> edges = this.getAllCurrentRules();
                if (edges == null || edges.isEmpty()) {
                    LOGGER.warn("Unable to find any edge rules for the latest version");
                    return multipleLabelKeys;
                }
                edges.keySet().forEach(key -> {
                    Collection<EdgeRule> rules = edges.get(key);
                    if (rules.size() > 1) {
                        multipleLabelKeys.add(key);
                    }
                });
            } catch (EdgeRuleNotFoundException e) {
                LOGGER.info("For the latest schema version, unable to find any edges with multiple keys");
            }
        }

        return multipleLabelKeys;
    }

    /**
     * Gets list of all edge rules defined in the given version's schema
     *
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules associated with those types
     *         where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Map will be empty if
     *         no rules are found.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     * @throws EdgeRuleNotFoundException if none found
     */
    public Multimap<String, EdgeRule> getAllRules(SchemaVersion v) throws EdgeRuleNotFoundException {
        Multimap<String, EdgeRule> found = extractRules(null, v);
        if (found.isEmpty()) {
            throw new EdgeRuleNotFoundException("No rules found for version " + v.toString() + ".");
        } else {
            return found;
        }
    }

    /**
     * Finds the rules (if any) matching the given query criteria. If none, the returned Multimap
     * will be empty.
     *
     * @param q - EdgeRuleQuery with filter criteria set
     *
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Map will be empty if
     *         no rules are found.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     * @throws EdgeRuleNotFoundException if none found
     */

    public Multimap<String, EdgeRule> getRules(EdgeRuleQuery q) throws EdgeRuleNotFoundException {
        Multimap<String, EdgeRule> found = null;
        Optional<SchemaVersion> versionOpt = q.getVersion();
        if (versionOpt.isPresent()) {
            found = extractRules(q.getFilter(), versionOpt.get());
        } else {
            found = extractRules(q.getFilter(), schemaVersions.getDefaultVersion());
        }
        if (found.isEmpty()) {
            throw new EdgeRuleNotFoundException("No rules found for " + q.toString());
        } else {
            Multimap<String, EdgeRule> copy = ArrayListMultimap.create();
            found.entries().stream().forEach((entry) -> {
                EdgeRule rule = new EdgeRule(entry.getValue());
                if (!q.getFromType().equals(rule.getFrom())) {
                    /*
                     * To maintain backwards compatibility with old EdgeRules API,
                     * where the direction of the returned EdgeRule would be
                     * flipped (if necessary) to match the directionality of
                     * the input params.
                     * ie, If the rule is from=A,to=B,direction=OUT,
                     * if the user asked (A,B) the direction would be OUT,
                     * if they asked (B,A), it would be IN to match.
                     */
                    rule.flipDirection();
                }
                copy.put(entry.getKey(), rule);
            });

            return copy;
        }
    }

    /**
     * Gets the rule satisfying the given filter criteria. If there are more than one
     * that match, return the default rule. If there is no clear default to return, or
     * no rules match at all, error.
     *
     * @param q - EdgeRuleQuery with filter criteria set
     * @return EdgeRule satisfying given criteria
     * @throws EdgeRuleNotFoundException if none found that match
     * @throws AmbiguousRuleChoiceException if multiple match but no way to choice one from them
     *         Specifically, if multiple node type pairs come back (ie bar|foo and asdf|foo,
     *         no way to know which is appropriate over the others),
     *         or if there is a mix of Tree and Cousin edges because again there is no way to
     *         know which is "defaulter" than the other.
     *         The default property only clarifies among multiple cousin edges of the same node pair,
     *         ex: which l-interface|logical-link rule to default to.
     */
    public EdgeRule getRule(EdgeRuleQuery q) throws EdgeRuleNotFoundException, AmbiguousRuleChoiceException {
        Multimap<String, EdgeRule> found = null;
        Optional<SchemaVersion> versionOpt = q.getVersion();
        if (versionOpt.isPresent()) {
            found = extractRules(q.getFilter(), versionOpt.get());
        } else {
            found = extractRules(q.getFilter(), schemaVersions.getDefaultVersion());
        }

        if (found.isEmpty()) {
            throw new EdgeRuleNotFoundException("No rule found for " + q.toString() + ".");
        }

        EdgeRule rule = null;
        if (found.keys().size() == 1) { // only one found, cool we're done
            for (Entry<String, EdgeRule> e : found.entries()) {
                rule = e.getValue();
            }
        } else {
            rule = getDefaultRule(found);
        }

        if (rule == null) { // should never get here though
            throw new EdgeRuleNotFoundException("No rule found for " + q.toString() + ".");
        } else {
            rule = new EdgeRule(rule);
            if (!q.getFromType().equals(rule.getFrom())) {
                /*
                 * To maintain backwards compatibility with old EdgeRules API,
                 * where the direction of the returned EdgeRule would be
                 * flipped (if necessary) to match the directionality of
                 * the input params.
                 * ie, If the rule is from=A,to=B,direction=OUT,
                 * if the user asked (A,B) the direction would be OUT,
                 * if they asked (B,A), it would be IN to match.
                 */
                rule.flipDirection();
            }
            return rule;
        }
    }

    private EdgeRule getDefaultRule(Multimap<String, EdgeRule> found) throws AmbiguousRuleChoiceException {
        if (found.keySet().size() > 1) { // ie multiple node pairs (a|c and b|c not just all a|c) case
            StringBuilder sb = new StringBuilder();
            for (String k : found.keySet()) {
                sb.append(k).append(" ");
            }
            throw new AmbiguousRuleChoiceException(
                    "No way to select single rule from these pairs: " + sb.toString() + ".");
        }

        int defaultCount = 0;
        EdgeRule defRule = null;
        for (Entry<String, EdgeRule> e : found.entries()) {
            EdgeRule rule = e.getValue();
            if (rule.isDefault()) {
                defaultCount++;
                defRule = rule;
            }
        }
        if (defaultCount > 1) {
            throw new AmbiguousRuleChoiceException("Multiple defaults found.");
        } else if (defaultCount == 0) {
            throw new AmbiguousRuleChoiceException("No default found.");
        }

        return defRule;
    }

    /**
     * Checks if there exists any rule that satisfies the given filter criteria.
     *
     * @param q - EdgeRuleQuery with filter criteria set
     * @return boolean
     */
    public boolean hasRule(EdgeRuleQuery q) {
        Optional<SchemaVersion> versionOpt = q.getVersion();
        if (versionOpt.isPresent()) {
            return !extractRules(q.getFilter(), versionOpt.get()).isEmpty();
        } else {
            return !extractRules(q.getFilter(), schemaVersions.getDefaultVersion()).isEmpty();
        }
    }

    /**
     * Gets all cousin rules for the given node type in the latest schema version.
     *
     * @param nodeType
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Map will be empty if
     *         no rules are found.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     */
    public Multimap<String, EdgeRule> getCousinRules(String nodeType) {
        return getCousinRules(nodeType, schemaVersions.getDefaultVersion()); // default to latest
    }

    public String[] retrieveCousinLabels(String nodeType) {

        Multimap<String, EdgeRule> cousinRules = getCousinRules(nodeType);
        String[] cousinLabels = new String[cousinRules.size()];

        return cousinRules.entries().stream().map(entry -> entry.getValue().getLabel()).collect(Collectors.toList())
                .toArray(cousinLabels);
    }

    public String[] retrieveCachedCousinLabels(String nodeType) throws ExecutionException {
        return cousinLabelStore.get(nodeType);
    }

    /**
     * Gets all cousin rules for the given node type in the given schema version.
     *
     * @param nodeType
     * @param v - the version of the edge rules to query
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Map will be empty if
     *         no rules are found.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     */
    public Multimap<String, EdgeRule> getCousinRules(String nodeType, SchemaVersion v) {
        return extractRules(new EdgeRuleQuery.Builder(nodeType).edgeType(EdgeType.COUSIN).build().getFilter(), v);
    }

    /**
     * Returns if the given node type has any cousin relationships in the current version.
     *
     * @param nodeType
     * @return boolean
     */
    public boolean hasCousinRule(String nodeType) {
        return hasCousinRule(nodeType, schemaVersions.getDefaultVersion());
    }

    /**
     * Returns if the given node type has any cousin relationships in the given version.
     *
     * @param nodeType
     * @return boolean
     */
    public boolean hasCousinRule(String nodeType, SchemaVersion v) {
        return !getCousinRules(nodeType, v).isEmpty();
    }

    /**
     * Gets all rules where "{given nodeType} contains {otherType}" in the latest schema version.
     *
     * @param nodeType - node type that is the container in the returned relationships
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Map will be empty if
     *         no rules are found.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     */
    public Multimap<String, EdgeRule> getChildRules(String nodeType) {
        return getChildRules(nodeType, schemaVersions.getDefaultVersion());
    }

    /**
     * Gets all rules where "{given nodeType} contains {otherType}" in the given schema version.
     *
     * @param nodeType - node type that is the container in the returned relationships
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Map will be empty if
     *         no rules are found.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     */
    public Multimap<String, EdgeRule> getChildRules(String nodeType, SchemaVersion v) {
        Filter from = assembleFilterSegments(where(EdgeField.FROM.toString()).is(nodeType),
                getSameDirectionContainmentCriteria());
        Filter to = assembleFilterSegments(where(EdgeField.TO.toString()).is(nodeType),
                getOppositeDirectionContainmentCriteria());
        Filter total = from.or(to);

        return extractRules(total, v);
    }

    /**
     * Returns if the given node type has any child relationships (ie it contains another node type) in the current
     * version.
     *
     * @param nodeType
     * @return boolean
     */
    public boolean hasChildRule(String nodeType) {
        return hasChildRule(nodeType, schemaVersions.getDefaultVersion());
    }

    /**
     * Returns if the given node type has any child relationships (ie it contains another node type) in the given
     * version.
     *
     * @param nodeType
     * @return boolean
     */
    public boolean hasChildRule(String nodeType, SchemaVersion v) {
        return !getChildRules(nodeType, v).isEmpty();
    }

    /**
     * Gets all rules where "{given nodeType} is contained by {otherType}" in the latest schema version.
     *
     * @param nodeType - node type that is the containee in the returned relationships
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Map will be empty if
     *         no rules are found.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     */
    public Multimap<String, EdgeRule> getParentRules(String nodeType) {
        return getParentRules(nodeType, schemaVersions.getDefaultVersion());
    }

    /**
     * Gets all rules where "{given nodeType} is contained by {otherType}" in the given schema version.
     *
     * @param nodeType - node type that is the containee in the returned relationships
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Map will be empty if
     *         no rules are found.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     */
    public Multimap<String, EdgeRule> getParentRules(String nodeType, SchemaVersion v) {
        Filter from = assembleFilterSegments(where(EdgeField.FROM.toString()).is(nodeType),
                getOppositeDirectionContainmentCriteria());
        Filter to = assembleFilterSegments(where(EdgeField.TO.toString()).is(nodeType),
                getSameDirectionContainmentCriteria());
        Filter total = from.or(to);

        return extractRules(total, v);
    }

    /**
     * Returns if the given node type has any parent relationships (ie it is contained by another node type) in the
     * current version.
     *
     * @param nodeType
     * @return boolean
     */
    public boolean hasParentRule(String nodeType) {
        return hasParentRule(nodeType, schemaVersions.getDefaultVersion());
    }

    /**
     * Returns if the given node type has any parent relationships (ie it is contained by another node type) in the
     * given version.
     *
     * @param nodeType
     * @return boolean
     */
    public boolean hasParentRule(String nodeType, SchemaVersion v) {
        return !getParentRules(nodeType, v).isEmpty();
    }

    /**
     * Applies the given filter to the DocumentContext(s) for the given version to extract
     * edge rules, and converts this extracted information into the Multimap form
     *
     * @param filter - JsonPath filter to read the DocumentContexts with. May be null
     *        to denote no filter, ie get all.
     * @param v - The schema version to extract from
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Map will be empty if
     *         no rules are found.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     */
    private Multimap<String, EdgeRule> extractRules(Filter filter, SchemaVersion v) {
        SchemaFilter schemaFilter = new SchemaFilter(filter, v);
        try {
            return cacheFilterStore.get(schemaFilter);
        } catch (ExecutionException e) {
            LOGGER.info("Encountered exception during the retrieval of the rules");
            return ArrayListMultimap.create();
        }
    }

    public Multimap<String, EdgeRule> extractRules(SchemaFilter schemaFilter) {
        List<Map<String, String>> foundRules = new ArrayList<>();
        List<DocumentContext> docs = versionJsonFilesMap.get(schemaFilter.getSchemaVersion());
        if (docs != null) {
            for (DocumentContext doc : docs) {
                if (schemaFilter.getFilter() == null) {
                    foundRules.addAll(doc.read(READ_ALL_START));
                } else {
                    foundRules.addAll(doc.read(READ_START, Filter.parse(schemaFilter.getFilter())));
                }
            }
        }

        return convertToEdgeRules(foundRules);
    }

    // -----filter building helpers-----//
    /**
     * ANDs together the given start criteria with each criteria in the pieces list, and
     * then ORs together these segments into one filter.
     *
     * JsonPath doesn't have an OR method on Criteria, only on Filters, so assembling
     * a complete filter requires this sort of roundabout construction.
     *
     * @param start - Criteria of the form where(from/to).is(nodeType)
     *        (ie the start of any A&AI edge rule query)
     * @param pieces - Other Criteria to be applied
     * @return Filter constructed from the given Criteria
     */
    private Filter assembleFilterSegments(Criteria start, List<Criteria> pieces) {
        List<Filter> segments = new ArrayList<>();
        for (Criteria c : pieces) {
            segments.add(filter(start).and(c));
        }
        Filter assembled = segments.remove(0);
        for (Filter f : segments) {
            assembled = assembled.or(f);
        }
        return assembled;
    }

    /**
     * Builds the sub-Criteria for a containment edge rule query where the direction
     * and containment fields must match.
     *
     * Used for getChildRules() where the container node type is in the "from" position and
     * for getParentRules() where the containee type is in the "to" position.
     *
     * @return List<Criteria> covering property permutations defined with either notation or explicit direction
     */
    private List<Criteria> getSameDirectionContainmentCriteria() {
        List<Criteria> crits = new ArrayList<>();

        crits.add(where(EdgeField.CONTAINS.toString()).is(DirectionNotation.DIRECTION.toString()));

        crits.add(where(EdgeField.DIRECTION.toString()).is(Direction.OUT.toString()).and(EdgeField.CONTAINS.toString())
                .is(Direction.OUT.toString()));

        crits.add(where(EdgeField.DIRECTION.toString()).is(Direction.IN.toString()).and(EdgeField.CONTAINS.toString())
                .is(Direction.IN.toString()));

        return crits;
    }

    /**
     * Builds the sub-Criteria for a containment edge rule query where the direction
     * and containment fields must not match.
     *
     * Used for getChildRules() where the container node type is in the "to" position and
     * for getParentRules() where the containee type is in the "from" position.
     *
     * @return List<Criteria> covering property permutations defined with either notation or explicit direction
     */
    private List<Criteria> getOppositeDirectionContainmentCriteria() {
        List<Criteria> crits = new ArrayList<>();

        crits.add(where(EdgeField.CONTAINS.toString()).is(DirectionNotation.OPPOSITE.toString()));

        crits.add(where(EdgeField.DIRECTION.toString()).is(Direction.OUT.toString()).and(EdgeField.CONTAINS.toString())
                .is(Direction.IN.toString()));

        crits.add(where(EdgeField.DIRECTION.toString()).is(Direction.IN.toString()).and(EdgeField.CONTAINS.toString())
                .is(Direction.OUT.toString()));

        return crits;
    }

    // -----rule packaging helpers-----//
    /**
     * Converts the raw output from reading the json file to the Multimap<String key, EdgeRule> format
     *
     * @param allFound - raw edge rule output read from json file(s)
     *        (could be empty if none found)
     * @return Multimap<String, EdgeRule> of node names keys to the EdgeRules where the key takes the form of
     *         {alphabetically first nodetype}|{alphabetically second nodetype}. Will be empty if input
     *         was empty.
     *         ex: buildAlphabetizedKey("l-interface", "logical-link") -> "l-interface|logical-link"
     *         buildAlphabetizedKey("logical-link", "l-interface") -> "l-interface|logical-link"
     *
     *         This is alphabetical order to normalize the keys, as sometimes there will be multiple
     *         rules for a pair of node types but the from/to value in the json is flipped for some of them.
     */
    private Multimap<String, EdgeRule> convertToEdgeRules(List<Map<String, String>> allFound) {
        Multimap<String, EdgeRule> rules = ArrayListMultimap.create();

        TypeAlphabetizer alpher = new TypeAlphabetizer();

        for (Map<String, String> raw : allFound) {
            EdgeRule converted = new EdgeRule(raw);
            if (converted.getFrom().equals(converted.getTo())) {
                /*
                 * the way the code worked in the past was with outs and
                 * when we switched it to in the same-node-type to
                 * same-node-type parent child edges were failing because all
                 * of the calling code would pass the parent as the left argument,
                 * so it was either in that method swap the parent/child,
                 * flip the edge rule or make all callers swap. the last seemed
                 * like a bad idea. and felt like the edge flip was the better
                 * of the remaining 2
                 */
                converted.flipDirection();
            }
            String alphabetizedKey =
                    alpher.buildAlphabetizedKey(raw.get(EdgeField.FROM.toString()), raw.get(EdgeField.TO.toString()));
            rules.put(alphabetizedKey, converted);
        }

        return rules;
    }

}