/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-2018 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.serialization.queryformats;

import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;

import javax.ws.rs.core.MultivaluedMap;

import org.apache.tinkerpop.gremlin.process.traversal.step.util.Tree;
import org.apache.tinkerpop.gremlin.structure.Vertex;
import org.onap.aai.db.props.AAIProperties;
import org.onap.aai.exceptions.AAIException;
import org.onap.aai.introspection.Introspector;
import org.onap.aai.introspection.Loader;
import org.onap.aai.introspection.exceptions.AAIUnknownObjectException;
import org.onap.aai.serialization.db.DBSerializer;
import org.onap.aai.serialization.queryformats.exceptions.AAIFormatVertexException;
import org.onap.aai.serialization.queryformats.params.AsTree;
import org.onap.aai.serialization.queryformats.params.Depth;
import org.onap.aai.serialization.queryformats.params.NodesOnly;
import org.onap.aai.serialization.queryformats.utils.UrlBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Resource extends MultiFormatMapper {

    private static final Logger logger = LoggerFactory.getLogger(Resource.class);

    private final Loader loader;
    private final DBSerializer serializer;
    private final UrlBuilder urlBuilder;
    private final boolean includeUrl;
    private final boolean nodesOnly;
    private final int depth;
    private final boolean isSkipRelatedTo;

    public Resource(Builder builder) {
        this.loader = builder.getLoader();
        this.serializer = builder.getSerializer();
        this.urlBuilder = builder.getUrlBuilder();
        this.includeUrl = builder.isIncludeUrl();
        this.nodesOnly = builder.isNodesOnly();
        this.depth = builder.getDepth();
        this.isSkipRelatedTo = builder.isSkipRelatedTo();
        this.isTree = builder.isTree();
    }

    @Override
    protected Optional<JsonObject> getRelatedNodesFromTree(Tree<?> tree, Map<String, List<String>> properties)
            throws AAIFormatVertexException {
        if (tree.isEmpty()) {
            return Optional.of(new JsonObject());
        }

        Map<String, Set<String>> filterPropertiesMap = createFilteredPropertyMap(properties);

        JsonObject t = new JsonObject();
        JsonArray ja = this.getRelatedNodesArray(tree, filterPropertiesMap, "related-nodes");
        if (ja.size() > 0) {
            t.add("results", ja);
            return Optional.of(t);
        }

        return Optional.empty();
    }

    protected JsonArray getRelatedNodesArray(Tree<?> tree, Map<String, Set<String>> filterPropertiesMap,
            String nodeIdentifier) throws AAIFormatVertexException {
        JsonArray nodes = new JsonArray();
        if (tree.isEmpty()) {
            return nodes;
        }
        for (Map.Entry<?, ? extends Tree<?>> entry : tree.entrySet()) {
            JsonObject me = new JsonObject();
            if (entry.getKey() instanceof Vertex) {
                Optional<JsonObject> obj = this.getJsonFromVertex((Vertex) entry.getKey());
                if (obj.isPresent()) {
                    me = getPropertyFilteredObject(obj, filterPropertiesMap);
                } else {
                    continue;
                }
            }
            JsonArray ja = this.getRelatedNodesArray(entry.getValue(), filterPropertiesMap, nodeIdentifier);
            if (ja.size() > 0) {
                try {
                    for (Map.Entry<String, JsonElement> mapEntry : me.entrySet()) {
                        JsonElement value = mapEntry.getValue();
                        if (value != null && value.isJsonObject()) {
                            value.getAsJsonObject().add(nodeIdentifier, ja);
                        }
                    }
                } catch (Exception e) {
                    logger.debug("Failed to add related-nodes array: {}", e.getMessage());
                    throw new AAIFormatVertexException("Failed to add related-nodes array: " + e.getMessage(), e);
                }
            }
            nodes.add(me);
        }
        return nodes;
    }

    @Override
    protected Optional<JsonObject> getJsonFromVertex(Vertex v) throws AAIFormatVertexException {

        JsonObject json = new JsonObject();

        if (this.includeUrl) {
            json.addProperty("url", this.urlBuilder.pathed(v));
        }
        Optional<JsonObject> jsonObject = this.vertexToJsonObject(v);
        if (jsonObject.isPresent()) {
            json.add(v.<String>property(AAIProperties.NODE_TYPE).orElse(null), jsonObject.get());
        } else {
            return Optional.empty();
        }
        return Optional.of(json);
    }

    @Override
    protected Optional<JsonObject> getJsonFromVertex(Vertex v, Map<String, List<String>> properties)
            throws AAIFormatVertexException {
        JsonObject json = new JsonObject();

        if (this.includeUrl) {
            json.addProperty("url", this.urlBuilder.pathed(v));
        }
        Optional<JsonObject> jsonObject = this.vertexToJsonObject(v);
        if (jsonObject.isPresent()) {
            String nodeType = v.<String>value(AAIProperties.NODE_TYPE);
            Map<String, Set<String>> filterPropertiesMap = createFilteredPropertyMap(properties); // this change is for
                                                                                                  // resource_and_url
                                                                                                  // with/out as-tree.
                                                                                                  // and no as-tree req
            JsonObject jo = filterProperties(jsonObject, nodeType, filterPropertiesMap);
            json.add(v.<String>property(AAIProperties.NODE_TYPE).orElse(null), jo);
        } else {
            return Optional.empty();
        }
        return Optional.of(json);
    }

    protected Optional<JsonObject> vertexToJsonObject(Vertex v) throws AAIFormatVertexException {
        if (v == null) {
            return Optional.empty();
        }
        try {
            final Introspector obj =
                    getLoader().introspectorFromName(v.<String>property(AAIProperties.NODE_TYPE).orElse(null));

            final List<Vertex> wrapper = new ArrayList<>();

            wrapper.add(v);

            try {
                getSerializer().dbToObject(wrapper, obj, this.depth, this.nodesOnly, "false", isSkipRelatedTo);
            } catch (AAIException | UnsupportedEncodingException e) {
                throw new AAIFormatVertexException(
                        "Failed to format vertex - error while serializing: " + e.getMessage(), e);
            }

            final String json = obj.marshal(false);

            return Optional.of(JsonParser.parseString(json).getAsJsonObject());
        } catch (AAIUnknownObjectException e) {
            return Optional.empty();
        }
    }

    @Override
    public int parallelThreshold() {
        return 20;
    }

    private Loader getLoader() {
        return loader;
    }

    private DBSerializer getSerializer() {
        return serializer;
    }

    public static class Builder implements NodesOnly<Builder>, Depth<Builder>, AsTree<Builder> {

        private final Loader loader;
        private final DBSerializer serializer;
        private final UrlBuilder urlBuilder;
        private boolean includeUrl = false;
        private boolean nodesOnly = false;
        private int depth = 1;
        private MultivaluedMap<String, String> params;
        private boolean tree = false;

        public Builder(Loader loader, DBSerializer serializer, UrlBuilder urlBuilder) {
            this.loader = loader;
            this.serializer = serializer;
            this.urlBuilder = urlBuilder;
        }

        public Builder(Loader loader, DBSerializer serializer, UrlBuilder urlBuilder,
                MultivaluedMap<String, String> params) {
            this.loader = loader;
            this.serializer = serializer;
            this.urlBuilder = urlBuilder;
            this.params = params;
        }

        protected Loader getLoader() {
            return this.loader;
        }

        protected DBSerializer getSerializer() {
            return this.serializer;
        }

        protected UrlBuilder getUrlBuilder() {
            return this.urlBuilder;
        }

        protected MultivaluedMap<String, String> getParams() {
            return this.params;
        }

        public boolean isSkipRelatedTo() {
            if (params != null) {
                boolean isSkipRelatedTo = true;
                if (params.containsKey("skip-related-to")) {
                    String skipRelatedTo = params.getFirst("skip-related-to");
                    isSkipRelatedTo = !(skipRelatedTo != null && skipRelatedTo.equals("false"));
                } else {
                    // if skip-related-to param is missing, then default it to false;
                    isSkipRelatedTo = false;
                }
                return isSkipRelatedTo;
            }
            return true;
        }

        protected boolean isTree() {
            return this.tree;
        }

        public Builder isTree(Boolean tree) {
            this.tree = tree;
            return this;
        }

        public Builder includeUrl() {
            this.includeUrl = true;
            return this;
        }

        public Builder nodesOnly(Boolean nodesOnly) {
            this.nodesOnly = nodesOnly;
            return this;
        }

        public boolean isNodesOnly() {
            return this.nodesOnly;
        }

        public Builder depth(Integer depth) {
            this.depth = depth;
            return this;
        }

        public int getDepth() {
            return this.depth;
        }

        public boolean isIncludeUrl() {
            return this.includeUrl;
        }

        public Resource build() {
            return new Resource(this);
        }
    }
}