package eu.dnetlib.uoaadmintools.recaptcha;

import eu.dnetlib.uoaadmintools.configuration.properties.GoogleConfig;
import eu.dnetlib.uoaadmintools.entities.GoogleResponse;
import eu.dnetlib.uoaadmintools.handlers.InvalidReCaptchaException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Configurable;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;
import org.springframework.web.client.RestOperations;

import java.net.URI;
import java.util.regex.Pattern;

@Service
@Configurable
public class VerifyRecaptcha {

    @Autowired
    private RestOperations restTemplate;

    @Autowired
    private  GoogleConfig googleConfig;

    private static Pattern RESPONSE_PATTERN = Pattern.compile("[A-Za-z0-9_-]+");

    @Bean
    public RestOperations restTemplate(RestTemplateBuilder builder) {
        return builder.build();
    }

    public void processResponse(String response) throws InvalidReCaptchaException{
        if(!responseSanityCheck(response)) {
            throw new InvalidReCaptchaException("Response contains invalid characters");
        }

        URI verifyUri = URI.create(String.format(
                "https://www.google.com/recaptcha/api/siteverify?secret=%s&response=%s",
                googleConfig.getSecret(), response));

        GoogleResponse googleResponse = restTemplate.getForObject(verifyUri, GoogleResponse.class);

        if(!googleResponse.isSuccess()) {
            throw new InvalidReCaptchaException("reCaptcha was not successfully validated");
        }
    }

    private boolean responseSanityCheck(String response) {
        return StringUtils.hasLength(response) && RESPONSE_PATTERN.matcher(response).matches();
    }
}