package org.gcube.informationsystem.resourceregistry.queries.templates;

import org.gcube.com.fasterxml.jackson.core.JsonProcessingException;
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.queries.templates.reference.entities.QueryTemplate;
import org.gcube.informationsystem.resourceregistry.api.exceptions.AlreadyPresentException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.NotFoundException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.queries.InvalidQueryException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.types.SchemaViolationException;
import org.gcube.informationsystem.resourceregistry.contexts.security.QueryTemplatesSecurityContext;
import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext;
import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagementUtility;
import org.gcube.informationsystem.resourceregistry.instances.base.entities.EntityElementManagement;
import org.gcube.informationsystem.resourceregistry.queries.json.JsonQuery;
import org.gcube.informationsystem.resourceregistry.utils.DBUtility;
import org.gcube.informationsystem.serialization.ElementMapper;
import org.gcube.informationsystem.types.reference.entities.EntityType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.arcadedb.database.Document;
import com.arcadedb.graph.Vertex;
import com.arcadedb.query.sql.executor.Result;
import com.arcadedb.query.sql.executor.ResultSet;
import com.arcadedb.remote.RemoteDatabase;

/**
 * @author Luca Frosini (ISTI - CNR)
 */
public class QueryTemplateManagement extends EntityElementManagement<QueryTemplate, EntityType> {

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

	protected String name;
	protected JsonNode params;

	public QueryTemplateManagement() {
		super(AccessType.QUERY_TEMPLATE);
		this.typeName = QueryTemplate.NAME;
	}

	public QueryTemplateManagement(RemoteDatabase database) throws ResourceRegistryException {
		this();
		this.database = database;
		getWorkingContext();
	}

	protected void checkERMatch() throws ResourceRegistryException {
		getDocumentType();
	}
	
	protected void checkNameMatch() throws ResourceRegistryException {
		if(jsonNode!=null && name!=null) {
			String jsonName = jsonNode.get(QueryTemplate.NAME_PROPERTY).asText();
			if(name.compareTo(jsonName)!=0) {
				String error = String.format(
						"Name provided in json (%s) differs from the one (%s) used to identify the %s instance",
						jsonName, name, typeName);
				throw new ResourceRegistryException(error);
			}
		}
	}
	
	public void setName(String name) throws ResourceRegistryException {
		this.name = name;
		checkNameMatch();
	}
	
	protected void checkJsonNode() throws ResourceRegistryException {
		super.checkJsonNode();
		checkNameMatch();
	}
	
	public String getName() {
		if (name == null) {
			if (element == null) {
				if (jsonNode != null) {
					name = jsonNode.get(QueryTemplate.NAME_PROPERTY).asText();
				}
			} else {
				name = element.getString(QueryTemplate.NAME_PROPERTY);
			}
		}
		return name;
	}
	
	@Override
	protected SecurityContext getWorkingContext() throws ResourceRegistryException {
		if (workingContext == null) {
			workingContext = QueryTemplatesSecurityContext.getInstance();
		}
		return workingContext;
	}
	
	@Override
	protected JsonNode createCompleteJsonNode() throws ResourceRegistryException {
		try {
			JsonNode queryTemplate = serializeSelfAsJsonNode();
			ObjectMapper objectMapper = new ObjectMapper();
			String templateString = element.getString(QueryTemplate.TEMPLATE_PROPERTY);
			JsonNode templateJsonNode = objectMapper.readTree(templateString);
			((ObjectNode) queryTemplate).replace(QueryTemplate.TEMPLATE_PROPERTY, templateJsonNode);
			return queryTemplate;
		}catch (ResourceRegistryException e) {
			throw e;
		}catch (Exception e) {
			throw new ResourceRegistryException(e);
		}
		
	}
	
	protected StringBuffer getSelectQuery() {
		StringBuffer select = new StringBuffer();
		select.append("SELECT FROM ");
		select.append(QueryTemplate.NAME);
		select.append(" WHERE ");
		select.append(QueryTemplate.NAME_PROPERTY);
		select.append(" = ");
		select.append("\"");
		select.append(getName());
		select.append("\"");
		return select;
	}
	
	protected void checkIfNameAlreadyExists() throws AlreadyPresentException {
		StringBuffer select = getSelectQuery();
		
		StringBuffer errorMessage = new StringBuffer();
		errorMessage.append("A ");
		errorMessage.append(QueryTemplate.NAME);
		errorMessage.append(" with ");
		errorMessage.append(this.getName());
		errorMessage.append(" already exists");
		
		logger.trace("Checking if {} -> {}", errorMessage, select);
		
		ResultSet resultSet = database.command("sql", select.toString());

		if (resultSet != null) {
			try {
				if(resultSet.hasNext()) {
					throw new AlreadyPresentException(errorMessage.toString());
				}
			}finally {
				resultSet.close();
			}
		}
		
	}

	protected void tryTemplate() throws Exception {
		QueryTemplate queryTemplate = ElementMapper.unmarshal(QueryTemplate.class, jsonNode.toString());
		JsonNode jsonQueryNode = queryTemplate.getJsonQuery();
		JsonQuery jsonQuery = new JsonQuery();
		jsonQuery.setJsonQuery(jsonQueryNode);
		try {
			jsonQuery.query();
		}catch (ResourceRegistryException e) {
			throw e;
		}catch (Exception e) {
			throw new ResourceRegistryException(e);
		}
	}
	
	@Override
	public Vertex retrieveElement() throws NotFoundException, ResourceRegistryException {
		try {
			StringBuffer select = getSelectQuery();
			ResultSet resultSet = database.query("sql", select.toString());
			
			if(resultSet == null || !resultSet.hasNext()) {
				if(resultSet!=null) {
					resultSet.close();
				}
				throw new NotFoundException("Error retrieving " + QueryTemplate.NAME + " with name " + getName());
			}
			
			Result result = resultSet.next();
			Vertex queryTemplate = ElementManagementUtility.getElementFromOptional(result.getVertex());
			
			logger.trace("{} representing vertex is {}", QueryTemplate.NAME, DBUtility.getAsStringForLogging(queryTemplate));
			
			if(resultSet.hasNext()) {
				resultSet.close();
				throw new NotFoundException("Found more than one " + QueryTemplate.NAME + " with name " + name + ". This should not occur, please contact the administrator");
			}
			
			resultSet.close();
			return queryTemplate;
		} catch(NotFoundException e) {
			throw getSpecificNotFoundException(e);
		} catch(ResourceRegistryException e) {
			throw e;
		} catch(Exception e) {
			throw new ResourceRegistryException(e);
		}
	}
	
	@Override
	protected Vertex reallyCreate() throws AlreadyPresentException, InvalidQueryException, ResourceRegistryException {
		try {
			checkIfNameAlreadyExists();
			tryTemplate();
			createVertex();
			return getElement();
		} 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());
		}
	}

	@Override
	protected Vertex reallyUpdate() throws NotFoundException, ResourceRegistryException {
		try {
			tryTemplate();
			Vertex queryTemplate = getElement();
			queryTemplate = (Vertex) updateProperties(documentType, queryTemplate, jsonNode, ignoreKeys, ignoreStartWithKeys);
			return getElement();
		} 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());
		}
	}

	@Override
	protected void reallyDelete() throws NotFoundException, ResourceRegistryException {
		logger.debug("Going to delete {} with name {}", accessType.getName(), name);
		getElement().delete();
	}

	@Override
	protected NotFoundException getSpecificNotFoundException(NotFoundException e) {
		return new NotFoundException(e);
	}

	@Override
	protected AlreadyPresentException getSpecificAlreadyPresentException(String message) {
		return new AlreadyPresentException(message);
	}

	@Override
	public String reallyGetAll(boolean polymorphic) throws ResourceRegistryException {
		ObjectMapper objectMapper = new ObjectMapper();
		ArrayNode arrayNode = objectMapper.createArrayNode();
		Iterable<Document> iterable = database.browseClass(typeName, polymorphic);
		for (Document vertex : iterable) {
			QueryTemplateManagement queryTemplateManagement = new QueryTemplateManagement();
			queryTemplateManagement.setElement((Vertex) vertex);
			try {
				JsonNode jsonObject = queryTemplateManagement.serializeAsJsonNode();
				arrayNode.add(jsonObject);
			} catch (ResourceRegistryException e) {
				logger.error("Unable to correctly serialize {}. It will be excluded from results. {}",
						vertex.toString(), DBUtility.SHOULD_NOT_OCCUR_ERROR_MESSAGE);
			}
		}
		try {
			return objectMapper.writeValueAsString(arrayNode);
		} catch (JsonProcessingException e) {
			throw new ResourceRegistryException(e);
		}
	}

	public void setParams(String params) throws ResourceRegistryException {
		try {
			if(params!=null && params.compareTo("")!=0) {
				ObjectMapper objectMapper = new ObjectMapper();
				JsonNode jsonNode = objectMapper.readTree(params);
				setParams(jsonNode);
			}
		} catch (ResourceRegistryException e) {
			throw e;
		} catch (Exception e) {
			throw new ResourceRegistryException(e);
		}
		
	}
	
	public void setParams(JsonNode params) throws ResourceRegistryException {
		this.params = params;
	}

	/**
	 * Run the query after having replaced query parameter with the provided values
	 * @return the result as JSON string
	 * @throws Exception 
	 */
	public String run() throws ResourceRegistryException {
		try {
			String read = read();
			QueryTemplate queryTemplate = ElementMapper.unmarshal(QueryTemplate.class, read);
			JsonNode query = null; 
			if(params!=null) {
				query = queryTemplate.getJsonQuery(params);
			}else {
				query = queryTemplate.getJsonQuery();
			}
			JsonQuery jsonQuery = new JsonQuery();
			jsonQuery.setJsonQuery(query);
			return jsonQuery.query();
		} catch (ResourceRegistryException e) {
			throw e;
		} catch (Exception e) {
			throw new ResourceRegistryException(e);
		}
	}
	
	public void sanityCheck() throws SchemaViolationException, ResourceRegistryException {
		// No sanity check required
	}
	
}