package org.gcube.smartgears.handlers.application.request;

import static org.gcube.common.authorization.client.Constants.authorizationService;
import static org.gcube.smartgears.handlers.application.request.RequestError.application_failed_error;
import static org.gcube.smartgears.handlers.application.request.RequestError.application_unavailable_error;
import static org.gcube.smartgears.handlers.application.request.RequestError.invalid_request_error;

import java.util.List;

import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;

import org.gcube.common.authorization.library.PolicyUtils;
import org.gcube.common.authorization.library.policies.Policy;
import org.gcube.common.authorization.library.policies.User2ServicePolicy;
import org.gcube.common.authorization.library.policies.UserEntity;
import org.gcube.common.authorization.library.provider.SecurityTokenProvider;
import org.gcube.common.authorization.library.provider.ServiceIdentifier;
import org.gcube.common.authorization.utils.manager.SecretManagerProvider;
import org.gcube.common.scope.api.ScopeProvider;
import org.gcube.common.scope.impl.ScopeBean;
import org.gcube.common.scope.impl.ScopeBean.Type;
import org.gcube.smartgears.Constants;
import org.gcube.smartgears.configuration.Mode;
import org.gcube.smartgears.configuration.container.ContainerConfiguration;
import org.gcube.smartgears.context.application.ApplicationContext;
import org.gcube.smartgears.handlers.application.RequestEvent;
import org.gcube.smartgears.handlers.application.RequestHandler;
import org.gcube.smartgears.utils.Utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@XmlRootElement(name = Constants.request_validation)
public class RequestValidator extends RequestHandler {

	@XmlAttribute(required=false, name="oauth")
	@Deprecated
	boolean oauthCompatibility = false; 

	private static Logger log = LoggerFactory.getLogger(RequestValidator.class);

	private ApplicationContext appContext;

	@Override
	public String getName() {
		return Constants.request_validation;
	}

	@Override
	public void handleRequest(RequestEvent call) {

		log.trace("executing request validator ON REQUEST");

		appContext = call.context();

		validateAgainstLifecycle(call);

		rejectUnauthorizedCalls(call);

		if (appContext.container().configuration().mode()!=Mode.offline) {
			validateScopeCall();
			validatePolicy(ScopeProvider.instance.get(), call);
		}

	}

	private void validateAgainstLifecycle(RequestEvent call) {

		switch(appContext.lifecycle().state()) {

		case stopped :
			application_unavailable_error.fire(); break;

		case failed: 
			application_failed_error.fire(); break;

		default: 
			//nothing to do, but avoids warnings
		}


	}

	private void validateScopeCall() {

		String scope = ScopeProvider.instance.get();

		if (scope == null) {
			log.warn("rejecting unscoped call to {}",appContext.name());
			invalid_request_error.fire("call is unscoped"); 
		}

		ScopeBean bean = new ScopeBean(scope);

		ContainerConfiguration conf = appContext.container().configuration();
		if (!conf.allowedContexts().contains(scope) && 
				!(conf.authorizeChildrenContext() && bean.is(Type.VRE) && conf.allowedContexts().contains(bean.enclosingScope().toString()) ) ) {
			log.warn("rejecting call to {} in invalid context {}, allowed context are {}",appContext.name(),scope,appContext.container().configuration().allowedContexts());
			invalid_request_error.fire(appContext.name()+" cannot be called in scope "+scope);
		}
	}

	private void rejectUnauthorizedCalls(RequestEvent call){

		String token = SecurityTokenProvider.instance.get();
		String context = SecretManagerProvider.instance.get().getContext();

		if (token == null && context==null){
			log.warn("rejecting call to {}, authorization required",appContext.name(),token);
			RequestError.request_not_authorized_error.fire(appContext.name()+": authorization required");
		} 
	}

	@Override
	public String toString() {
		return getName();
	}

	private void validatePolicy(String scope, RequestEvent call){
		log.info("accessing policy validator in scope {} ", scope);

		ServiceIdentifier serviceIdentifier = Utils.getServiceInfo(call.context()).getServiceIdentifier();

		String callerId = SecretManagerProvider.instance.get().getUser().getUsername();

		List<Policy> policies = null;
		try {
			policies = authorizationService().getPolicies(scope);
		}catch (Exception e) {
			invalid_request_error.fire("error contating authorization for polices"); 
		}
		
		for (Policy policy: policies) {
			log.debug("policy: {}", policy.getPolicyAsString() );

			if (PolicyUtils.isPolicyValidForClient(policy.getServiceAccess(), serviceIdentifier )) {
				boolean toReject = false;
				UserEntity entity = (((User2ServicePolicy) policy).getEntity());
				if (entity.getIdentifier()!=null)
					toReject = entity.getIdentifier().equals(callerId);
				else if (entity.getExcludes().isEmpty()) 
					toReject = true;
				else toReject = !entity.getExcludes().contains(callerId);
				if (toReject) {
					log.error("rejecting call to {} : {} is not allowed to contact the service ",appContext.name(), callerId); 
					RequestError.request_not_authorized_error.fire("rejecting call to "+appContext.name()+" for polices: "+callerId+" is not allowed to contact the service: "+serviceIdentifier.getServiceName() );
				}
			}	

		}

	}
	


}