/**
 * Copyright 2005-2016 hdiv.org
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * 	http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.hdiv.filter;

import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.hdiv.context.RequestContextHolder;
import org.hdiv.exception.HDIVException;

/**
 * Interface to validate a client request.
 *
 * @author Roberto Velasco
 * @author Gorka Vicente
 */
public interface IValidationHelper extends StateRestorer {

	/**
	 * Initialization of the objects needed for the validation process.
	 *
	 * @throws HDIVException if there is an initialization error.
	 */
	void init();

	/**
	 * Checks if the values of the parameters received in the request <code>request</code> are valid. These values are valid if and only if
	 * the noneditable parameters haven't been modified.<br>
	 *
	 * @param context request context
	 * @return {@link ValidatorHelperResult} with true value If all the parameter values of the request <code>request</code> pass the the
	 * HDIV validation. False, otherwise.
	 * @throws HDIVException If the request doesn't pass the HDIV validation an exception is thrown explaining the cause of the error.
	 */
	ValidatorHelperResult validate(ValidationContext context);

	/**
	 * It is called in the pre-processing stage of each user request.
	 *
	 * @param request HTTP servlet request
	 */
	void startPage(RequestContextHolder request);

	/**
	 * It is called in the post-processing stage of each user request.
	 *
	 * @param request HTTP servlet request
	 */
	void endPage(RequestContextHolder request);

	/**
	 * Internal Hdiv request
	 * @param request HTTP servlet request
	 * @param response HTTP servlet response
	 * @return true if internal
	 */
	boolean isInternal(HttpServletRequest request, HttpServletResponse response);

	/**
	 * Find internal errors
	 * @param t
	 * @param target
	 * @return
	 */
	List<ValidatorError> findCustomErrors(final Throwable t, String target);

	/**
	 * Check whether all the errors are legal
	 * @param errors
	 * @return
	 */
	boolean areErrorsLegal(List<ValidatorError> errors);

	boolean processEditableValidationErrors(final RequestContextHolder request, final List<ValidatorError> errors);

}
