package org.gcube.informationsystem.resourceregistry.instances.base.entities;

import java.util.HashMap;
import java.util.Map;

import org.gcube.com.fasterxml.jackson.databind.JsonNode;
import org.gcube.com.fasterxml.jackson.databind.ObjectMapper;
import org.gcube.com.fasterxml.jackson.databind.node.ArrayNode;
import org.gcube.com.fasterxml.jackson.databind.node.ObjectNode;
import org.gcube.informationsystem.base.reference.AccessType;
import org.gcube.informationsystem.base.reference.entities.EntityElement;
import org.gcube.informationsystem.base.reference.relations.RelationElement;
import org.gcube.informationsystem.resourceregistry.api.exceptions.AvailableInAnotherContextException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.NotFoundException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.entities.EntityAlreadyPresentException;
import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext;
import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagement;
import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagementUtility;
import org.gcube.informationsystem.resourceregistry.instances.base.relations.RelationElementManagement;
import org.gcube.informationsystem.resourceregistry.utils.DBUtility;
import org.gcube.informationsystem.types.reference.entities.EntityType;

import com.arcadedb.database.Document;
import com.arcadedb.graph.Edge;
import com.arcadedb.graph.MutableVertex;
import com.arcadedb.graph.Vertex;
import com.arcadedb.remote.RemoteDatabase;

/**
 * @author Luca Frosini (ISTI - CNR)
 */
public abstract class EntityElementManagement<E extends EntityElement, ET extends EntityType> extends ElementManagement<Vertex, ET> {
	
	public final static String IN_PREFIX = "in_";
	public final static String OUT_PREFIX = "out_";
	
	/**
	 * Provide a cache edge-internal-id -> RelationManagement 
	 * this avoid to recreate the relationManagement of already visited edges
	 */
	protected Map<String,RelationElementManagement<?,?,?,?>> relationManagements;
	
	protected EntityElementManagement(AccessType accessType) {
		super(accessType);
		
		this.ignoreStartWithKeys.add(IN_PREFIX.toLowerCase());
		this.ignoreStartWithKeys.add(OUT_PREFIX.toLowerCase());
		this.ignoreStartWithKeys.add(IN_PREFIX.toUpperCase());
		this.ignoreStartWithKeys.add(OUT_PREFIX.toUpperCase());
		
		this.relationManagements = new HashMap<>();
		
	}
	
	protected EntityElementManagement(AccessType accessType, SecurityContext workingContext, RemoteDatabase database) {
		this(accessType);
		this.database = database;
		setWorkingContext(workingContext);
	}
	
	/*
	 * It works perfectly in case of any kind of update. In case of use from create
	 * the cache does not work by using the ID because until commit the edge has a
	 * fake id starting with - (minus) sign. This not imply any collateral effect
	 * but a better solution is a desiderata.
	 */
	protected RelationElementManagement<?,?,?,?> getBaseRelationManagement(Edge edge) throws ResourceRegistryException {
		String id = edge.getIdentity().toString();
		RelationElementManagement<?,?,?,?> relationManagement = relationManagements.get(id);
		if(relationManagement == null) {
			relationManagement = ElementManagementUtility.getRelationManagement(getWorkingContext(), database, edge);
			relationManagements.put(id, relationManagement);
		}
		return relationManagement;
	}
	
	protected void addToRelationManagement(RelationElementManagement<?,?,?,?> baseRelationManagement)
			throws ResourceRegistryException {
		Document elem = baseRelationManagement.getElement();
		String id = elem.getIdentity().toString();
		if(relationManagements.get(id) != null && relationManagements.get(id) != baseRelationManagement) {
			StringBuilder errorMessage = new StringBuilder();
			errorMessage.append("Two different instance of ");
			errorMessage.append(baseRelationManagement.getClass().getSimpleName());
			errorMessage.append(" point to the same ");
			errorMessage.append(elem.getClass().getSimpleName());
			errorMessage.append(". ");
			errorMessage.append(DBUtility.SHOULD_NOT_OCCUR_ERROR_MESSAGE);
			throw new ResourceRegistryException(errorMessage.toString());
		}
		relationManagements.put(id, baseRelationManagement);
	}
	
	protected static JsonNode addRelation(JsonNode sourceResource, JsonNode relation, String arrayKey)
			throws ResourceRegistryException {
		ObjectMapper objectMapper = new ObjectMapper();
		ArrayNode relationArray = objectMapper.createArrayNode();
		try {
			if(sourceResource.has(arrayKey)) {
				relationArray = (ArrayNode) sourceResource.get(arrayKey);
			}
			relationArray.add(relation);
			
			((ObjectNode) sourceResource).replace(arrayKey, relationArray);
		} catch(Exception e) {
			throw new ResourceRegistryException(e);
		}
		return sourceResource;
	}
	
	protected Vertex createVertex() throws EntityAlreadyPresentException, ResourceRegistryException {
		
		logger.trace("Going to create {} for {} ({}) using {}", Vertex.class.getSimpleName(), accessType.getName(),
				typeName, jsonNode);
		
		try {

			// TODO
//			if(documentType.isAbstract()) {
//				String error = String.format(
//						"Trying to create an instance of %s of type %s which is abstract. The operation will be aborted.",
//						accessType.getName(), typeName);
//				throw new ResourceRegistryException(error);
//			}
			
			try {
				if(uuid != null) {
					Vertex v = getElement();
					if(v != null) {
						String error = String.format("A %s with UUID %s already exist", typeName, uuid.toString());
						throw getSpecificAlreadyPresentException(error);
					}
				}
				
			} catch(NotFoundException e) {
				try {
					Document el = ElementManagementUtility.getAnyElementByUUID(uuid);
					String error = String.format("UUID %s is already used by another Element. This is not allowed.",
							uuid.toString(), 
							(el instanceof Vertex) ? EntityElement.NAME : RelationElement.NAME);
					throw new ResourceRegistryException(error);
					
				} catch(NotFoundException e1) {
					// OK the UUID is not already used.
				}
			} catch(AvailableInAnotherContextException e) {
				throw e;
			}
			
			MutableVertex vertexEntity = database.newVertex(typeName);
			this.element = vertexEntity;
			
			if(accessType == AccessType.RESOURCE) {
				// Facet and relation are created in calling method
			} else {
				updateProperties(documentType, element, jsonNode, ignoreKeys, ignoreStartWithKeys);
			}
			
			logger.info("Created {} is {}", Vertex.class.getSimpleName(),
					DBUtility.getAsStringForLogging(element));
			
			return element;
		} catch(ResourceRegistryException e) {
			throw e;
		} catch(Exception e) {
			logger.trace("Error while creating {} for {} ({}) using {}", Vertex.class.getSimpleName(),
					accessType.getName(), typeName, jsonNode, e);
			throw new ResourceRegistryException("Error Creating " + typeName + " with " + jsonNode, e.getCause());
		}
	}
		
}