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.Collections;
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.AccessTokenProvider;
import org.gcube.common.authorization.library.provider.AuthorizationProvider;
import org.gcube.common.authorization.library.provider.SecurityTokenProvider;
import org.gcube.common.authorization.library.provider.ServiceIdentifier;
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 context;

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

	@Override
	public void handleRequest(RequestEvent call) {

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

		log.trace("accessToken is null? {} \nGcubeToken is null ? {} \nscope rpvideris null? {}", 
				AccessTokenProvider.instance.get()==null, 
				SecurityTokenProvider.instance.get()==null, 
				ScopeProvider.instance.get()==null);
		
		context = call.context();

		validateAgainstLifecycle(call);

		rejectUnauthorizedCalls(call);

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

	}

	private void validateAgainstLifecycle(RequestEvent call) {

		switch(context.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 {}",context.name());
			invalid_request_error.fire("call is unscoped"); 
		}

		ScopeBean bean = new ScopeBean(scope);

		ContainerConfiguration conf = context.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 {}",context.name(),scope,context.container().configuration().allowedContexts());
			invalid_request_error.fire(context.name()+" cannot be called in scope "+scope);
		}
	}

	private void rejectUnauthorizedCalls(RequestEvent call){

		String token = SecurityTokenProvider.instance.get();
		String accessToken = AccessTokenProvider.instance.get();
				
		if (token == null && accessToken==null){
			log.warn("rejecting call to {}, authorization required",context.name(),token);
			RequestError.request_not_authorized_error.fire(context.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 previousToken = SecurityTokenProvider.instance.get();
		try {
			String serviceToken = context.configuration().startTokens().stream().findFirst().get();
			SecurityTokenProvider.instance.set(serviceToken);
			String callerId = AuthorizationProvider.instance.get().getClient().getId();

			List<Policy> policies = Collections.emptyList();
			try {
				policies = authorizationService().getPolicies(scope);
			}catch (Exception e) {
				log.error("error contacting authorization services for policies"); 
			}

			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 ",context.name(), callerId); 
						RequestError.request_not_authorized_error.fire("rejecting call to "+context.name()+" for polices: "+callerId+" is not allowed to contact the service: "+serviceIdentifier.getServiceName() );
					}
				}	

			}
		}finally {
			SecurityTokenProvider.instance.set(previousToken);
		}
	}



}