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

import static org.gcube.smartgears.Constants.token_header;
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 javax.xml.bind.annotation.XmlRootElement;
import javax.xml.crypto.dsig.keyinfo.RetrievalMethod;

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.common.security.providers.SecretManagerProvider;
import org.gcube.common.security.secrets.GCubeSecret;
import org.gcube.common.security.secrets.JWTSecret;
import org.gcube.common.security.secrets.Secret;
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.handlers.application.ResponseEvent;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

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

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

	private static final String BEARER_AUTH_PREFIX ="Bearer"; 

	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();
		
		SecretManagerProvider.instance.set(getSecret(call));
		
		validateAgainstLifecycle(call);

		rejectUnauthorizedCalls(call);

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

	}

	@Override
	public void handleResponse(ResponseEvent e) {
		log.debug("resetting all the Thread local for this call.");
		SecretManagerProvider.instance.reset();
	}


	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 context = SecretManagerProvider.instance.get().getContext();

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

		ScopeBean bean = new ScopeBean(context);

		ContainerConfiguration conf = appContext.container().configuration();
		if (!conf.allowedContexts().contains(context) && 
				!(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(),context,appContext.container().configuration().allowedContexts());
			invalid_request_error.fire(appContext.name()+" cannot be called in scope "+context);
		}
	}

	private void rejectUnauthorizedCalls(RequestEvent call){

		Secret secret = SecretManagerProvider.instance.get();

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

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

	private void validatePolicy(String scope, RequestEvent call){
		//TODO: must be re-think	
	}

	private Secret getSecret(RequestEvent call){
		String token = call.request().getParameter(token_header)==null?	call.request().getHeader(token_header):call.request().getParameter(token_header);
		String authHeader  = call.request().getHeader(Constants.authorization_header);

		log.trace("authorization header is {}",authHeader);
		log.trace("token header is {}", token);

		String accessToken = null;
		if (authHeader!=null && !authHeader.isEmpty()) 
			if (authHeader.startsWith(BEARER_AUTH_PREFIX))
				accessToken = authHeader.substring(BEARER_AUTH_PREFIX.length()).trim();

		Secret secret = null;
		if (accessToken!=null) 
			secret = new JWTSecret(accessToken);
		else if (token!=null) 
				secret = new GCubeSecret(token);
		return secret;
	}


}