/**
 * 
 */
package org.gcube.informationsystem.resourceregistry.er.entity;

import java.io.IOException;
import java.util.HashSet;
import java.util.Set;
import java.util.UUID;

import org.codehaus.jettison.json.JSONObject;
import org.gcube.informationsystem.model.embedded.Header;
import org.gcube.informationsystem.model.entity.Entity;
import org.gcube.informationsystem.model.entity.Facet;
import org.gcube.informationsystem.model.entity.Resource;
import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.context.ContextException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.entity.EntityAlreadyPresentException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.entity.EntityNotFoundException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.entity.facet.FacetNotFoundException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.entity.resource.ResourceNotFoundException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.SchemaNotFoundException;
import org.gcube.informationsystem.resourceregistry.context.ContextUtility;
import org.gcube.informationsystem.resourceregistry.context.SecurityContextMapper;
import org.gcube.informationsystem.resourceregistry.context.SecurityContextMapper.PermissionMode;
import org.gcube.informationsystem.resourceregistry.er.ERManagement;
import org.gcube.informationsystem.resourceregistry.er.relation.RelationManagement;
import org.gcube.informationsystem.resourceregistry.schema.SchemaManagementImpl;
import org.gcube.informationsystem.resourceregistry.utils.HeaderUtility;
import org.gcube.informationsystem.resourceregistry.utils.Utility;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.tinkerpop.blueprints.Direction;
import com.tinkerpop.blueprints.Edge;
import com.tinkerpop.blueprints.Vertex;
import com.tinkerpop.blueprints.impls.orient.OrientGraph;
import com.tinkerpop.blueprints.impls.orient.OrientVertex;
import com.tinkerpop.blueprints.impls.orient.OrientVertexType;

/**
 * @author Luca Frosini (ISTI - CNR)
 */
public abstract class EntityManagement<E extends Entity> {

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

	public final String AT = "@";
	public final String UNDERSCORE = "_";

	protected final Set<String> ignoreKeys;
	protected final Set<String> ignoreStartWithKeys;

	protected final Class<E> entityClass;
	protected final String baseType;

	protected OrientGraph orientGraph;

	protected UUID uuid;
	protected JsonNode jsonNode;
	protected String entityType;
	protected Vertex vertex;

	protected EntityManagement(Class<E> entityClass) {
		this.ignoreKeys = new HashSet<String>();
		this.ignoreKeys.add(Entity.HEADER_PROPERTY);

		this.ignoreStartWithKeys = new HashSet<String>();
		this.ignoreStartWithKeys.add(OrientVertex.CONNECTION_IN_PREFIX
				.toLowerCase());
		this.ignoreStartWithKeys.add(OrientVertex.CONNECTION_OUT_PREFIX
				.toLowerCase());
		this.ignoreStartWithKeys.add(OrientVertex.CONNECTION_IN_PREFIX
				.toUpperCase());
		this.ignoreStartWithKeys.add(OrientVertex.CONNECTION_OUT_PREFIX
				.toUpperCase());
		this.ignoreStartWithKeys.add(AT);
		this.ignoreStartWithKeys.add(UNDERSCORE);

		this.entityClass = entityClass;
		if (Facet.class.isAssignableFrom(entityClass)) {
			this.baseType = Facet.NAME;
		} else if (Resource.class.isAssignableFrom(entityClass)) {
			this.baseType = Resource.NAME;
		} else {
			this.baseType = Entity.NAME;
		}
	}

	protected EntityManagement(Class<E> entityClass, OrientGraph orientGraph) {
		this(entityClass);
		this.orientGraph = orientGraph;
	}

	public void setVertex(Vertex vertex) throws ResourceRegistryException {
		if (vertex == null) {
			throw new ResourceRegistryException("Trying to set null Vertex in "
					+ this);
		}
		this.vertex = vertex;
		this.uuid = HeaderUtility.getHeader(vertex).getUUID();
	}

	public void setUUID(UUID uuid) throws ResourceRegistryException {
		this.uuid = uuid;
		if (jsonNode != null) {
			checkUUIDMatch();
		}
	}

	public void setJSON(JsonNode jsonNode) throws ResourceRegistryException {
		this.jsonNode = jsonNode;

		checkJSON();
	}

	public void setJSON(String jsonRepresentation)
			throws ResourceRegistryException {
		ObjectMapper mapper = new ObjectMapper();
		try {
			this.jsonNode = mapper.readTree(jsonRepresentation);
		} catch (IOException e) {
			throw new ResourceRegistryException(e);
		}

		checkJSON();
	}

	protected void checkJSON() throws ResourceRegistryException {
		if (uuid == null) {
			try {
				uuid = org.gcube.informationsystem.impl.utils.Utility
						.getUUIDFromJsonNode(jsonNode);
			} catch (Exception e) {

			}
		} else {
			checkUUIDMatch();
		}

		if (this.entityType == null) {
			this.entityType = ERManagement.getClassProperty(jsonNode);
		} else {
			checkEntityMatch();
		}
	}

	public void setEntityType(String entityType)
			throws ResourceRegistryException {
		this.entityType = entityType;
		if (entityType == null || entityType.compareTo("") == 0) {
			if (Facet.class.isAssignableFrom(entityClass)) {
				entityType = Facet.NAME;
			}
			if (Resource.class.isAssignableFrom(entityClass)) {
				entityType = Resource.NAME;
			}
		}
		if (jsonNode != null) {
			checkEntityMatch();
		}
	}

	protected void checkEntityMatch() throws ResourceRegistryException {
		String type = ERManagement.getClassProperty(jsonNode);
		if (type != null && type.compareTo(entityType) != 0) {
			String error = String
					.format("Declared resourceType does not match with json representation %s!=%s",
							entityType, type);
			logger.trace(error);
			throw new ResourceRegistryException(error);
		}

		try {
			SchemaManagementImpl.getTypeSchema(entityType, baseType);
		} catch (SchemaNotFoundException e) {
			throw e;
		}
	}

	protected void checkUUIDMatch() throws ResourceRegistryException {
		Header header = null;
		try {
			header = HeaderUtility.getHeader(jsonNode, false);
		} catch (Exception e) {
			throw new ResourceRegistryException(e);
		}

		if (header != null) {
			UUID resourceUUID = header.getUUID();
			if (resourceUUID.compareTo(uuid) != 0) {
				String error = String
						.format("UUID provided in header (%s) differs from the one (%s) used to identify the %s instance",
								resourceUUID.toString(), uuid.toString(),
								entityType);
				throw new ResourceRegistryException(error);

			}
		}
	}

	public Vertex getVertex() throws EntityNotFoundException,
			ResourceRegistryException {
		try {
			if (vertex == null) {
				vertex = Utility.getElementByUUID(orientGraph,
						entityType == null ? baseType : entityType, uuid,
						Vertex.class);
			}
			return vertex;
		} catch (ResourceRegistryException e) {
			if (Resource.class.isAssignableFrom(entityClass)) {
				throw new ResourceNotFoundException(e);
			} else if (Facet.class.isAssignableFrom(entityClass)) {
				throw new FacetNotFoundException(e);
			} else {
				throw e;
			}
		}

	}

	protected Vertex createVertex() throws EntityAlreadyPresentException,
			ResourceRegistryException {

		logger.trace("Going to create {} for {} ({}) using {}",
				Vertex.class.getSimpleName(), baseType, entityType, jsonNode);

		try {

			Vertex vertexEntity = orientGraph.addVertex("class:" + entityType);

			try {

				Vertex v = getVertex();
				if (v != null) {
					String error = String.format(
							"A %s with UUID %s already exist", entityType,
							uuid.toString());
					throw new EntityAlreadyPresentException(error);
				}

			} catch (EntityAlreadyPresentException e) {
				throw e;
			} catch (Exception e) {
				// no header or no header with uuid is provided and it is fine
			}

			this.vertex = vertexEntity;

			Header entityHeader = HeaderUtility.getHeader(jsonNode, true);
			if (entityHeader != null) {
				vertex.setProperty(Entity.HEADER_PROPERTY, entityHeader);
			} else {
				entityHeader = HeaderUtility.addHeader(vertex, null);
			}

			if (Resource.class.isAssignableFrom(entityClass)) {
				// Facet and relation are created in calling method
			} else {
				ERManagement.updateProperties(vertex, jsonNode, ignoreKeys,
						ignoreStartWithKeys);
			}

			ContextUtility.addToActualContext(orientGraph, vertex);

			((OrientVertex) vertex).save();

			logger.info("Created {} is {}", Vertex.class.getSimpleName(),
					Utility.toJsonString((OrientVertex) vertex, true));

			return vertex;
		} catch (ResourceRegistryException e) {
			throw e;
		} catch (Exception e) {
			logger.trace("Error while creating {} for {} ({}) using {}",
					Vertex.class.getSimpleName(), baseType, entityType,
					jsonNode, e);
			throw new ResourceRegistryException("Error Creating " + entityType
					+ " with " + jsonNode, e.getCause());
		}
	}

	public abstract String serialize() throws ResourceRegistryException;

	public abstract JSONObject serializeAsJson()
			throws ResourceRegistryException;

	public abstract Vertex reallyCreate() throws EntityAlreadyPresentException,
			ResourceRegistryException;

	public abstract Vertex reallyUpdate() throws EntityNotFoundException,
			ResourceRegistryException;

	public abstract boolean reallyDelete() throws EntityNotFoundException,
			ResourceRegistryException;

	public boolean reallyAddToContext() throws ContextException,
			ResourceRegistryException {

		ContextUtility.addToActualContext(orientGraph, getVertex());

		Iterable<Edge> edges = vertex.getEdges(Direction.OUT);

		for (Edge edge : edges) {
			@SuppressWarnings("rawtypes")
			RelationManagement relationManagement = RelationManagement
					.getRelationManagement(orientGraph, edge);
			relationManagement.reallyAddToContext();
		}

		return true;
	}

	public boolean reallyRemoveFromContext() throws ContextException,
			ResourceRegistryException {
		
		ContextUtility.removeFromActualContext(orientGraph, getVertex());

		Iterable<Edge> edges = vertex.getEdges(Direction.OUT);

		for (Edge edge : edges) {
			@SuppressWarnings("rawtypes")
			RelationManagement relationManagement = RelationManagement
					.getRelationManagement(orientGraph, edge);
			relationManagement.reallyRemoveFromContext();
		}

		return true;
	}

	@SuppressWarnings("rawtypes")
	public static EntityManagement getEntityManagement(OrientGraph orientGraph,
			Vertex vertex) throws ResourceRegistryException {
		OrientVertexType orientVertexType = ((OrientVertex) vertex).getType();
		EntityManagement entityManagement = null;
		if (orientVertexType.isSubClassOf(Resource.NAME)) {
			entityManagement = new ResourceManagement(orientGraph);
		} else if (orientVertexType.isSubClassOf(Facet.NAME)) {
			entityManagement = new FacetManagement(orientGraph);
		} else {
			String error = String.format("{%s is not a %s nor a %s. "
					+ "This is really strange and should not occur. "
					+ "Please Investigate it.", vertex, Resource.NAME,
					Facet.NAME);
			throw new ResourceRegistryException(error);
		}
		entityManagement.setVertex(vertex);
		return entityManagement;
	}

	public String create() throws EntityAlreadyPresentException,
			ResourceRegistryException {

		try {
			orientGraph = ContextUtility
					.getActualSecurityContextGraph(PermissionMode.WRITER);

			reallyCreate();

			orientGraph.commit();

			return serialize();

		} catch (ResourceRegistryException e) {
			if (orientGraph != null) {
				orientGraph.rollback();
			}
			throw e;
		} catch (Exception e) {
			if (orientGraph != null) {
				orientGraph.rollback();
			}
			throw new ResourceRegistryException(e);
		} finally {
			if (orientGraph != null) {
				orientGraph.shutdown();
			}
		}
	}

	public String read() throws EntityNotFoundException,
			ResourceRegistryException {
		try {
			orientGraph = ContextUtility
					.getActualSecurityContextGraph(PermissionMode.READER);

			getVertex();

			return serialize();
		} catch (ResourceRegistryException e) {
			throw e;
		} catch (Exception e) {
			throw new ResourceRegistryException(e);
		} finally {
			if (orientGraph != null) {
				orientGraph.shutdown();
			}
		}
	}

	public String update() throws EntityNotFoundException,
			ResourceRegistryException {
		try {
			orientGraph = ContextUtility
					.getActualSecurityContextGraph(PermissionMode.WRITER);

			reallyUpdate();

			orientGraph.commit();

			return serialize();

		} catch (ResourceRegistryException e) {
			if (orientGraph != null) {
				orientGraph.rollback();
			}
			throw e;
		} catch (Exception e) {
			logger.debug("Unable to update {} with UUID {} usign {}", baseType,
					uuid, jsonNode, e);
			if (orientGraph != null) {
				orientGraph.rollback();
			}
			throw new ResourceRegistryException(e);
		} finally {
			if (orientGraph != null) {
				orientGraph.shutdown();
			}
		}

	}

	public boolean delete() throws FacetNotFoundException,
			ResourceRegistryException {
		logger.debug("Going to delete {} with UUID {}", baseType, uuid);

		try {
			orientGraph = ContextUtility
					.getActualSecurityContextGraph(PermissionMode.WRITER);

			boolean deleted = reallyDelete();

			orientGraph.commit();

			logger.info("{} with UUID {} was successfully deleted.", baseType,
					uuid);

			return deleted;

		} catch (ResourceRegistryException e) {
			logger.error("Unable to delete {} with UUID {}", baseType, uuid, e);
			if (orientGraph != null) {
				orientGraph.rollback();
			}
			throw e;
		} catch (Exception e) {
			logger.error("Unable to delete {} with UUID {}", baseType, uuid, e);
			if (orientGraph != null) {
				orientGraph.rollback();
			}
			throw new ResourceRegistryException(e);
		} finally {
			if (orientGraph != null) {
				orientGraph.shutdown();
			}
		}
	}

	public boolean addToContext() throws ContextException {
		logger.debug("Going to add {} with UUID {} to actual Context",
				baseType, uuid);

		try {
			orientGraph = SecurityContextMapper.getSecurityContextFactory(
					SecurityContextMapper.ADMIN_SECURITY_CONTEXT_UUID,
					PermissionMode.WRITER).getTx();

			boolean added = reallyAddToContext();

			orientGraph.commit();
			logger.info("{} with UUID {} successfully added to actual Context",
					baseType, uuid);

			return added;
		} catch (Exception e) {
			logger.error("Unable to add {} with UUID {} to actual Context",
					baseType, uuid, e);
			if (orientGraph != null) {
				orientGraph.rollback();
			}
			throw new ContextException(e);
		} finally {
			if (orientGraph != null) {
				orientGraph.shutdown();
			}
		}
	}

	public boolean removeFromContext() throws ContextException {
		logger.debug("Going to remove {} with UUID {} from actual Context",
				baseType, uuid);

		try {
			orientGraph = SecurityContextMapper.getSecurityContextFactory(
					SecurityContextMapper.ADMIN_SECURITY_CONTEXT_UUID,
					PermissionMode.WRITER).getTx();

			boolean removed = reallyRemoveFromContext();

			orientGraph.commit();
			logger.info(
					"{} with UUID {} successfully removed from actual Context",
					baseType, uuid);

			return removed;
		} catch (Exception e) {
			logger.error(
					"Unable to remove {} with UUID {} from actual Context",
					baseType, uuid, e);
			if (orientGraph != null) {
				orientGraph.rollback();
			}
			throw new ContextException(e);
		} finally {
			if (orientGraph != null) {
				orientGraph.shutdown();
			}
		}
	}

}