/*
    * Copyright 2011 The Kuali Foundation
    *
    * Licensed under the Educational Community License, Version 1.0 (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/ecl1.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.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.DataType;
  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 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(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(attributeValueReader, CONSTRAINT_NAME, RiceKeyConstants.ERROR_INCLUSIVE_MAX, maxErrorParameter);
         // Otherwise, just tell them what the min can be
         else 
         	return result.addError(attributeValueReader, CONSTRAINT_NAME, RiceKeyConstants.ERROR_EXCLUSIVE_MIN, minErrorParameter);
         
 	}
 
 }