package org.springframework.security.web.authentication.preauth.j2ee;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.security.authentication.AuthenticationDetailsSource;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.mapping.Attributes2GrantedAuthoritiesMapper;
import org.springframework.security.core.authority.mapping.MappableAttributesRetriever;
import org.springframework.security.core.authority.mapping.SimpleAttributes2GrantedAuthoritiesMapper;
import org.springframework.security.web.authentication.preauth.PreAuthenticatedGrantedAuthoritiesWebAuthenticationDetails;
import org.springframework.util.Assert;

import javax.servlet.http.HttpServletRequest;
import java.util.*;

/**
 * Implementation of AuthenticationDetailsSource which converts the user's J2EE roles (as obtained by calling
 * {@link HttpServletRequest#isUserInRole(String)}) into {@code GrantedAuthority}s and stores these in the authentication
 * details object.
 *
 * @author Ruud Senden
 * @since 2.0
 */
public class J2eeBasedPreAuthenticatedWebAuthenticationDetailsSource
        implements AuthenticationDetailsSource<HttpServletRequest, PreAuthenticatedGrantedAuthoritiesWebAuthenticationDetails>,
        InitializingBean {

    protected final Log logger = LogFactory.getLog(getClass());
    /** The role attributes returned by the configured {@code MappableAttributesRetriever} */
    protected Set<String> j2eeMappableRoles;
    protected Attributes2GrantedAuthoritiesMapper j2eeUserRoles2GrantedAuthoritiesMapper =
        new SimpleAttributes2GrantedAuthoritiesMapper();

    /**
     * Check that all required properties have been set.
     */
    public void afterPropertiesSet() throws Exception {
        Assert.notNull(j2eeMappableRoles, "No mappable roles available");
        Assert.notNull(j2eeUserRoles2GrantedAuthoritiesMapper, "Roles to granted authorities mapper not set");
    }

    /**
     * Obtains the list of user roles based on the current user's JEE roles. The
     * {@link javax.servlet.http.HttpServletRequest#isUserInRole(String)} method is called for each of the values
     * in the {@code j2eeMappableRoles} set to determine if that role should be assigned to the user.
     *
     * @param request the request which should be used to extract the user's roles.
     * @return The subset of {@code j2eeMappableRoles} which applies to the current user making the request.
     */
    protected Collection<String> getUserRoles(HttpServletRequest request) {
        ArrayList<String> j2eeUserRolesList = new ArrayList<String>();

        for (String role : j2eeMappableRoles) {
            if (request.isUserInRole(role)) {
                j2eeUserRolesList.add(role);
            }
        }

        return j2eeUserRolesList;
    }

    /**
     * Builds the authentication details object.
     *
     * @see org.springframework.security.authentication.AuthenticationDetailsSource#buildDetails(Object)
     */
    public PreAuthenticatedGrantedAuthoritiesWebAuthenticationDetails buildDetails(HttpServletRequest context) {

        Collection<String> j2eeUserRoles = getUserRoles(context);
        Collection<? extends GrantedAuthority> userGas = j2eeUserRoles2GrantedAuthoritiesMapper.getGrantedAuthorities(j2eeUserRoles);

        if (logger.isDebugEnabled()) {
            logger.debug("J2EE roles [" + j2eeUserRoles + "] mapped to Granted Authorities: [" + userGas + "]");
        }

        PreAuthenticatedGrantedAuthoritiesWebAuthenticationDetails result =
                new PreAuthenticatedGrantedAuthoritiesWebAuthenticationDetails(context, userGas);

        return result;
    }

    /**
     * @param aJ2eeMappableRolesRetriever
     *            The MappableAttributesRetriever to use
     */
    public void setMappableRolesRetriever(MappableAttributesRetriever aJ2eeMappableRolesRetriever) {
        this.j2eeMappableRoles = Collections.unmodifiableSet(aJ2eeMappableRolesRetriever.getMappableAttributes());
    }

    /**
     * @param mapper
     *            The Attributes2GrantedAuthoritiesMapper to use
     */
    public void setUserRoles2GrantedAuthoritiesMapper(Attributes2GrantedAuthoritiesMapper mapper) {
        j2eeUserRoles2GrantedAuthoritiesMapper = mapper;
    }
}
