package com.satgate.IpgConf2.validation;

import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import java.lang.reflect.Method;

import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

@Target({TYPE,ANNOTATION_TYPE})
@Retention(RUNTIME)
@Constraint(validatedBy = UniqueValidator.class)
@Documented
public @interface Unique {
    String message() default "{com.satgate.IpgConf2.validation.unique}";

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default { };

    String property();
}


package com.satgate.IpgConf2.validation;

import com.satgate.IpgConf2.dao.CommonRepository;
import com.satgate.IpgConf2.dao.UserRepository;
import com.satgate.IpgConf2.entity.AbstractSecureObject;
import com.satgate.IpgConf2.security.User;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import java.io.Serializable;
import java.util.Collection;

public class UniqueValidator implements ConstraintValidator<Unique,Object>{
    private Logger logger = LoggerFactory.getLogger(UniqueValidator.class);

    @Autowired
    private CommonRepository commonRepository;

    private String uniqueField;

    @Override
    public void initialize(Unique unique) {
        uniqueField = unique.property();
    }

    @Override
    public boolean isValid(Object value, ConstraintValidatorContext constraintValidatorContext) {
        try {
            Collection<?> possibilities = commonRepository.getAllByField(value.getClass(),uniqueField,value.getClass().getField(uniqueField).get(value));
            if (possibilities.isEmpty()) {
                //No entries - entry is unique
                return true;
            }
            if (possibilities.size()>1) {
                //Too much entries
                return false;
            }

            //We have exactly one entry in the collection, and this entry could be our value
            if (value instanceof AbstractSecureObject && possibilities.toArray()[0] instanceof AbstractSecureObject ) {
                if (((AbstractSecureObject)value).getId().equals(((AbstractSecureObject) possibilities.toArray()[0]).getId())) {
                    return true; //It's the same object
                }
            }
            return false;
        } catch (Exception e) {
            logger.warn("No such field or other error in UniqueValidator, field: "+uniqueField+" class: "+value.getClass().getName());
            return false;
        }
    }
}