import com.mongodb.DBObject;
import org.springframework.core.convert.converter.Converter;
import org.springframework.data.convert.ReadingConverter;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.oauth2.provider.OAuth2Authentication;
import org.springframework.security.oauth2.provider.OAuth2Request;
import us.sdata.enroll.security.CustomUserDetails;

import java.util.*;

/**
 * Converter to deserialize back into an OAuth2Authentication Object made necessary because
 * Spring Mongo can't map clientAuthentication to authorizationRequest.
 */
@ReadingConverter
public class OAuth2AuthenticationReadConverter implements Converter<DBObject, OAuth2Authentication> {

    @Override
    public OAuth2Authentication convert(DBObject source) {
        DBObject storedRequest = (DBObject) source.get("storedRequest");
        OAuth2Request oAuth2Request = new OAuth2Request((Map<String, String>) storedRequest.get("requestParameters"),
            (String) storedRequest.get("clientId"), null, true, new HashSet((List) storedRequest.get("scope")),
            null, null, null, null);

        DBObject userAuthorization = (DBObject) source.get("userAuthentication");
        Object principal = getPrincipalObject(userAuthorization.get("principal"));
        Authentication userAuthentication = new UsernamePasswordAuthenticationToken(principal,
            userAuthorization.get("credentials"), getAuthorities((List) userAuthorization.get("authorities")));

        return new OAuth2Authentication(oAuth2Request, userAuthentication);
    }

    private Object getPrincipalObject(Object principal) {
        if (principal instanceof DBObject) {
            DBObject principalDBObject = (DBObject) principal;

            String userName = (String) principalDBObject.get("username");
            String password = "";
            boolean enabled = (boolean) principalDBObject.get("enabled");
            boolean accountNonExpired = (boolean) principalDBObject.get("accountNonExpired");
            boolean credentialsNonExpired = (boolean) principalDBObject.get("credentialsNonExpired");
            boolean accountNonLocked = (boolean) principalDBObject.get("accountNonLocked");

            /*
             * retrieve the custom fields from principal object and map to CustomUserDetails so that we can use them later on  SpEL queries via OAuth2Authentication object
             */
            String customerId = (String) principalDBObject.get("customerId");

            return new CustomUserDetails(userName, password, enabled,
                accountNonExpired, credentialsNonExpired, accountNonLocked, Collections.EMPTY_LIST, customerId);


        } else {
            return principal;
        }
    }

    private Collection<GrantedAuthority> getAuthorities(List<Map<String, String>> authorities) {
        Set<GrantedAuthority> grantedAuthorities = new HashSet<>(authorities.size());
        for (Map<String, String> authority : authorities) {
            grantedAuthorities.add(new SimpleGrantedAuthority(authority.get("role")));
        }
        return grantedAuthorities;
    }
}