/**
 * Copyright 2005-2016 The Kuali Foundation
 *
 * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
 *
 * 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.kuali.rice.krad.datadictionary.validation.processor;

import org.kuali.rice.core.api.uif.DataType;
import org.kuali.rice.core.api.util.RiceKeyConstants;
import org.kuali.rice.krad.datadictionary.exception.AttributeValidationException;
import org.kuali.rice.krad.datadictionary.validation.AttributeValueReader;
import org.kuali.rice.krad.datadictionary.validation.ValidationUtils;
import org.kuali.rice.krad.datadictionary.validation.ValidationUtils.Result;
import org.kuali.rice.krad.datadictionary.validation.constraint.Constraint;
import org.kuali.rice.krad.datadictionary.validation.constraint.LengthConstraint;
import org.kuali.rice.krad.datadictionary.validation.result.ConstraintValidationResult;
import org.kuali.rice.krad.datadictionary.validation.result.DictionaryValidationResult;
import org.kuali.rice.krad.datadictionary.validation.result.ProcessorResult;

/**
 * 
 * @author Kuali Rice Team (rice.collab@kuali.org) 
 */
public class LengthConstraintProcessor extends MandatoryElementConstraintProcessor<LengthConstraint> {

    private static final String MIN_LENGTH_KEY = "validation.minLengthConditional";
    private static final String MAX_LENGTH_KEY = "validation.maxLengthConditional";
    private static final String RANGE_KEY = "validation.lengthRange";

        private static final String CONSTRAINT_NAME = "length constraint";
        
        /**
         * @see org.kuali.rice.krad.datadictionary.validation.processor.ConstraintProcessor#process(DictionaryValidationResult, Object, org.kuali.rice.krad.datadictionary.validation.capability.Validatable, org.kuali.rice.krad.datadictionary.validation.AttributeValueReader)
         */
        @Override
        public ProcessorResult process(DictionaryValidationResult result, Object value, LengthConstraint constraint, AttributeValueReader attributeValueReader) throws AttributeValidationException {

                // To accommodate the needs of other processors, the ConstraintProcessor.process() method returns a list of ConstraintValidationResult objects
                // but since a definition that is length constrained only constrains a single field, there is effectively always a single constraint
                // being imposed
                return new ProcessorResult(processSingleLengthConstraint(result, value, constraint, attributeValueReader));
        }

        @Override 
        public String getName() {
                return CONSTRAINT_NAME;
        }
        
        /**
         * @see org.kuali.rice.krad.datadictionary.validation.processor.ConstraintProcessor#getConstraintType()
         */
        @Override
        public Class<? extends Constraint> getConstraintType() {
                return LengthConstraint.class;
        }
        
        protected ConstraintValidationResult processSingleLengthConstraint(DictionaryValidationResult result, Object value, LengthConstraint constraint, AttributeValueReader attributeValueReader) throws AttributeValidationException {
                // Can't process any range constraints on null values
                if (ValidationUtils.isNullOrEmpty(value))
                        return result.addSkipped(attributeValueReader, CONSTRAINT_NAME);

                DataType dataType = constraint.getDataType();
                Object typedValue = value;

                if (dataType != null) {
                        typedValue = ValidationUtils.convertToDataType(value, dataType, dateTimeService);
                }       

                // The only thing that can have a length constraint currently is a string. 
                if (typedValue instanceof String) {
                        return validateLength(result, (String)typedValue, constraint, attributeValueReader);
                } 
                
                return result.addSkipped(attributeValueReader, CONSTRAINT_NAME);
        }
        
        
        protected ConstraintValidationResult validateLength(DictionaryValidationResult result, String value, LengthConstraint constraint, AttributeValueReader attributeValueReader) throws IllegalArgumentException {
                Integer valueLength = Integer.valueOf(value.length());
                
                Integer maxLength = constraint.getMaxLength();
                Integer minLength = constraint.getMinLength();
                
                Result lessThanMax = ValidationUtils.isLessThanOrEqual(valueLength, maxLength);
                Result greaterThanMin = ValidationUtils.isGreaterThanOrEqual(valueLength, minLength);
                
        // It's okay for one end of the range to be undefined - that's not an error. It's only an error if one of them is invalid 
        if (lessThanMax != Result.INVALID && greaterThanMin != Result.INVALID) { 
                // Of course, if they're both undefined then we didn't actually have a real constraint
                if (lessThanMax == Result.UNDEFINED && greaterThanMin == Result.UNDEFINED)
                        return result.addNoConstraint(attributeValueReader, CONSTRAINT_NAME);
                
                // In this case, we've succeeded
                return result.addSuccess(attributeValueReader, CONSTRAINT_NAME);
        }
        
                String maxErrorParameter = maxLength != null ? maxLength.toString() : null;
                String minErrorParameter = minLength != null ? minLength.toString() : null;
        
        // If both comparisons happened then if either comparison failed we can show the end user the expected range on both sides.
        if (lessThanMax != Result.UNDEFINED && greaterThanMin != Result.UNDEFINED) 
                return result.addError(RANGE_KEY, attributeValueReader, CONSTRAINT_NAME, RiceKeyConstants.ERROR_OUT_OF_RANGE, minErrorParameter, maxErrorParameter);
        // If it's the max comparison that fails, then just tell the end user what the max can be
        else if (lessThanMax == Result.INVALID)
                return result.addError(MAX_LENGTH_KEY, attributeValueReader, CONSTRAINT_NAME, RiceKeyConstants.ERROR_INCLUSIVE_MAX, maxErrorParameter);
        // Otherwise, just tell them what the min can be
        else 
                return result.addError(MIN_LENGTH_KEY, attributeValueReader, CONSTRAINT_NAME, RiceKeyConstants.ERROR_EXCLUSIVE_MIN, minErrorParameter);
        
        }

}