package net.curisit.securis.ioc;

import java.io.IOException;
import java.lang.reflect.Method;
import java.util.List;
import java.util.Set;

import javax.annotation.Priority;
import javax.inject.Inject;
import javax.persistence.EntityManager;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.ws.rs.Priorities;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;
import javax.ws.rs.ext.Provider;
import javax.ws.rs.ext.WriterInterceptor;
import javax.ws.rs.ext.WriterInterceptorContext;

import net.curisit.securis.db.User;
import net.curisit.securis.security.BasicSecurityContext;
import net.curisit.securis.security.Securable;
import net.curisit.securis.utils.CacheTTL;
import net.curisit.securis.utils.TokenHelper;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.jboss.resteasy.core.Dispatcher;
import org.jboss.resteasy.core.ResourceMethodInvoker;
import org.jboss.resteasy.core.ServerResponse;
import org.jboss.resteasy.spi.Failure;
import org.jboss.resteasy.spi.HttpRequest;
import org.jboss.resteasy.spi.ResteasyProviderFactory;

@Provider
@Priority(Priorities.AUTHENTICATION)
public class RequestsInterceptor implements ContainerRequestFilter, WriterInterceptor {
    private static final Logger LOG = LogManager.getLogger(RequestsInterceptor.class);

    @Context
    private HttpServletResponse servletResponse;

    @Context
    private HttpServletRequest servletRequest;

    @Inject
    private CacheTTL cache;

    @Inject
    private TokenHelper tokenHelper;

    @Context
    private Dispatcher dispatcher;

    @Inject
    private EntityManagerProvider emProvider;

    @Override
    public void filter(ContainerRequestContext containerRequestContext) throws IOException {
        EntityManager em = emProvider.getEntityManager();
        LOG.info("GETTING EM: {}", em);

        ResteasyProviderFactory.pushContext(EntityManager.class, em);

        ResourceMethodInvoker methodInvoker = (ResourceMethodInvoker) containerRequestContext
                .getProperty("org.jboss.resteasy.core.ResourceMethodInvoker");
        Method method = methodInvoker.getMethod();

        LOG.debug("Stored in context, em: {}, {}", em, method.toGenericString());

        boolean next = checkSecurableMethods(containerRequestContext, method);
        if (next) {
            prepareTransaction(containerRequestContext, method, em);
        }
    }

    private void prepareTransaction(ContainerRequestContext containerRequestContext, Method method, EntityManager em) {

        if (method.isAnnotationPresent(EnsureTransaction.class)) {
            LOG.debug("Beginning a new transaction");
            em.getTransaction().begin();
        }
    }

    private boolean checkSecurableMethods(ContainerRequestContext containerRequestContext, Method method) {
        if (!method.isAnnotationPresent(Securable.class)) {
            return true;
        }
        String token = servletRequest.getHeader(TokenHelper.TOKEN_HEADER_PÀRAM);
        if (token == null || !tokenHelper.isTokenValid(token)) {
            LOG.info("Access denied to '{}', Token not valid.", servletRequest.getPathInfo());
            containerRequestContext.abortWith(Response.status(Status.UNAUTHORIZED).build());
            return false;
        } else {

            // If roles == 0 we only need to validate the token
            String username = tokenHelper.extractUserFromToken(token);
            int userRoles = getUserRoles(username);
            Set<Integer> orgs = getUserOrganizations(username);

            BasicSecurityContext scw = new BasicSecurityContext(username, userRoles, servletRequest.isSecure());
            scw.setOrganizationsIds(orgs);
            containerRequestContext.setSecurityContext(scw);
            // Next line provide injection in resource methods
            ResteasyProviderFactory.pushContext(BasicSecurityContext.class, scw);
            LOG.debug("Added custom SecurityContext for user {}, orgs: {}", username, orgs);
        }
        return true;

    }

    private Set<Integer> getUserOrganizations(String username) {
        @SuppressWarnings("unchecked")
        Set<Integer> userOrgs = cache.get("orgs_" + username, Set.class);
        if (userOrgs == null) {
            EntityManager em = ResteasyProviderFactory.getContextData(EntityManager.class);

            // Theorically this shouldn't be never null, but just in case...
            User user = em.find(User.class, username);
            if (user != null) {
                userOrgs = user.getAllOrgsIds();
                // We store user orgs in cache only for one hour
                cache.set("orgs_" + username, userOrgs, 3600);
            }
        }

        return userOrgs;
    }

    private int getUserRoles(String username) {
        if (username == null) {
            return 0;
        }
        Integer userRoles = cache.get("roles_" + username, Integer.class);
        if (userRoles == null) {
            EntityManager em = ResteasyProviderFactory.getContextData(EntityManager.class);

            User user = em.find(User.class, username);
            if (user != null) {
                userRoles = 0;
                List<Integer> roles = user.getRoles();
                for (Integer rol : roles) {
                    userRoles += rol;
                }
                // We store user roles in cache only for one hour
                cache.set("roles_" + username, userRoles, 3600);
                cache.set("orgs_" + username, user.getOrgsIds(), 3600);
            }
        }
        return userRoles == null ? 0 : userRoles.intValue();
    }

    // @Override
    public ServerResponse preProcess(HttpRequest request, ResourceMethodInvoker method) throws Failure, WebApplicationException {
        return null;
    }

    @Override
    public void aroundWriteTo(WriterInterceptorContext context) throws IOException, WebApplicationException {
        context.proceed();
        EntityManager em = ResteasyProviderFactory.getContextData(EntityManager.class);
        try {
            if (em != null && em.getTransaction().isActive()) {
                if (servletResponse.getStatus() == Status.OK.getStatusCode()) {
                    em.getTransaction().commit();
                    LOG.debug("COMMIT");
                } else {
                    // This code is never executed if there is an error the
                    // filter chain is broken
                    em.getTransaction().rollback();
                    LOG.debug("ROLLBACK");
                }
            }
        } finally {
            if (em.isOpen()) {
                LOG.info("CLOSING EM: {}, trans: {}", em, em.isJoinedToTransaction());
                try {
                    em.close();
                } catch (Exception ex) {
                    ex.printStackTrace();
                    LOG.error("Error closing EM: {}, {}", em, ex);
                }
            }
        }
    }

}