package org.gcube.informationsystem.resourceregistry.contexts;

import java.util.HashMap;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.UUID;

import org.gcube.common.authorization.utils.manager.SecretManagerProvider;
import org.gcube.common.scope.impl.ScopeBean;
import org.gcube.informationsystem.contexts.reference.entities.Context;
import org.gcube.informationsystem.contexts.reference.relations.IsParentOf;
import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.contexts.ContextException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.contexts.ContextNotFoundException;
import org.gcube.informationsystem.resourceregistry.contexts.security.AdminSecurityContext;
import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext;
import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext.PermissionMode;
import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagementUtility;
import org.gcube.informationsystem.resourceregistry.utils.DBUtility;
import org.gcube.informationsystem.resourceregistry.utils.UUIDUtility;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.arcadedb.graph.MutableVertex;
import com.arcadedb.graph.Vertex;
import com.arcadedb.graph.Vertex.DIRECTION;
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 ContextUtility {
	
	private static final Logger logger = LoggerFactory.getLogger(ContextUtility.class);
	
	private Map<UUID,SecurityContext> contexts;
	
	private static ContextUtility contextUtility;
	
	public static ContextUtility getInstance() {
		if(contextUtility == null) {
			contextUtility = new ContextUtility();
		}
		return contextUtility;
	}
	
	private ContextUtility() {
		contexts = new HashMap<>();
	}
	
	public static String getCurrentContextFullName() {
		return SecretManagerProvider.instance.get().getContext();
	}
	
	public static SecurityContext getCurrentSecurityContext() throws ResourceRegistryException {
		String fullName = getCurrentContextFullName();
		if(fullName == null) {
			throw new ContextException("Null Token and Scope. Please set your token first.");
		}
		return ContextUtility.getInstance().getSecurityContextByFullName(fullName);
	}
	
	public static AdminSecurityContext getAdminSecurityContext() throws ResourceRegistryException {
		AdminSecurityContext adminSecurityContext = AdminSecurityContext.getInstance();
		return adminSecurityContext;
	}
	
	public synchronized void addSecurityContext(SecurityContext securityContext) {
		contexts.put(securityContext.getUUID(), securityContext);
	}
	
	public synchronized void addSecurityContext(String fullname, SecurityContext securityContext) {
		contexts.put(securityContext.getUUID(), securityContext);
	}
	
	public synchronized SecurityContext getSecurityContextByFullName(String fullName) throws ContextException {
//		ODatabaseDocument current = ContextUtility.getCurrentODatabaseDocumentFromThreadLocal();
		RemoteDatabase database = null;
		try {
			SecurityContext securityContext = null;
			
			logger.trace("Trying to get {} for {}", SecurityContext.class.getSimpleName(), fullName);
			UUID uuid = ServerContextCache.getInstance().getUUIDByFullName(fullName);
			
			if(uuid != null) {
				securityContext = contexts.get(uuid);
			}
			
			if(securityContext==null) {
				logger.trace("{} for {} is not in cache. Going to get it", SecurityContext.class.getSimpleName(),
						fullName);
				database = getAdminSecurityContext().getRemoteDatabase(PermissionMode.READER);
				
				MutableVertex contextVertex = getContextVertexByFullName(database, fullName);
				
				uuid = UUIDUtility.getUUID(contextVertex);
				
				securityContext = getSecurityContextByUUID(uuid, contextVertex);
				
				addSecurityContext(fullName, securityContext);
				
			} 
			
			return securityContext;
			
		} catch(ContextException e) {
			throw e;
		} catch(Exception e) {
			throw new ContextException("Unable to retrieve Context UUID from current Context", e);
		} finally {
			if(database!=null) {
				database.close();
			}
			
//			if(current!=null) {
//				current.activateOnCurrentThread();
//			}
		}
	}
	
	public SecurityContext getSecurityContextByUUID(UUID uuid) throws ResourceRegistryException {
		return getSecurityContextByUUID(uuid, null);
	}
	
	public static RemoteDatabase getCurrentODatabaseDocumentFromThreadLocal() {
		RemoteDatabase current = null;
		try {
			// current =  (RemoteDatabase) ODatabaseRecordThreadLocal.instance().get();
		}catch (Exception e) {
			// It is possible that there is no current ODatabaseDocument
		}
		return current;
	}
	
	private Vertex getContextVertexByUUID(UUID uuid) throws ResourceRegistryException {
		RemoteDatabase current = ContextUtility.getCurrentODatabaseDocumentFromThreadLocal();
		RemoteDatabase database = null;
		try {
			database = getAdminSecurityContext().getRemoteDatabase(PermissionMode.READER);
			Vertex vertex = DBUtility.getElementByUUID(database, Context.NAME, uuid,
					Vertex.class);
			return vertex;
		} finally {
			if(database!=null) {
				database.close();
			}
			
//			if(current!=null) {
//				current.activateOnCurrentThread();
//			}
		}
	}
	
	private SecurityContext getSecurityContextByUUID(UUID uuid, Vertex contextVertex) throws ResourceRegistryException {
		SecurityContext securityContext = contexts.get(uuid);
		if(securityContext == null) {
			
			securityContext = new SecurityContext(uuid);
			
			try {
				if(contextVertex == null) {
					contextVertex = getContextVertexByUUID(uuid);
				}
				Vertex parentVertex = contextVertex.getVertices(DIRECTION.IN, IsParentOf.NAME).iterator().next();
				
				if(parentVertex != null) {
					UUID parentUUID = UUIDUtility.getUUID(parentVertex);
					securityContext.setParentSecurityContext(getSecurityContextByUUID(parentUUID, parentVertex));
				}
				
			} catch(NoSuchElementException e) {
				// No parent
			}
			
			contexts.put(uuid, securityContext);
		}
		
		return securityContext;
	}
	
	/*
	protected UUID getContextUUIDFromFullName(String fullName) throws ResourceRegistryException {
		OVertex contextVertex = getContextVertexByFullName(fullName);
		return Utility.getUUID(contextVertex);
	}
	*/
	
	private MutableVertex getContextVertexByFullName(RemoteDatabase database , String fullName) throws ResourceRegistryException {
		logger.trace("Going to get {} {} with full name '{}'", Context.NAME, Vertex.class.getSimpleName(), fullName);
			
		ScopeBean scopeBean = new ScopeBean(fullName);
		String name = scopeBean.name();
		
		// TODO Rewrite better query. This query works because all the scope parts has a different name
		String select = "SELECT FROM " + Context.class.getSimpleName() + " WHERE " + Context.NAME_PROPERTY + " = :name";
		Map<String, String> map = new HashMap<>();
		map.put("name", name);
		
		ResultSet resultSet = database.command("sql", select, map);
		
		if(resultSet == null || !resultSet.hasNext()) {
			throw new ContextNotFoundException("Error retrieving context with name " + fullName);
		}
		
		Result result = resultSet.next();
		MutableVertex context = (MutableVertex) ElementManagementUtility.getElementFromOptional(result.getVertex());
		
		logger.trace("Context Representing Vertex : {}", DBUtility.getAsStringForLogging(context));
		
		if(resultSet.hasNext()) {
			throw new ContextNotFoundException("Found more than one context with name " + name
					+ "but required the one with path" + fullName + ". Please Reimplement the query");
		}
		
		return context;
	}
	
}