/*
    * Copyright 2009 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.osedu.org/licenses/ECL-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.kuali.student.contract.model.validation;
  
  import org.kuali.student.contract.model.Constraint;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  /**
   * This validates a constraint.
   * @author nwright
   */
  public class ConstraintValidator implements ModelValidator {
  
      private Constraint cons;
  
      public ConstraintValidator(Constraint cons) {
          this.cons = cons;
      }
      private Collection errors;
  
      @Override
      public Collection<String> validate() {
          this.errors = new ArrayList();
          validateMinMaxLength();
          validateMinMaxOccurs();
          validateMinMaxValue();
          return this.errors;
      }
  
      private void validateMinMaxLength() {
          if (!cons.getMinLength().equals("")) {
              int min = parseIntError(cons.getMinLength(), "minLength");
              if (min < 0) {
                  this.addError("minLength is less than zero");
              }
              if (!cons.getMaxLength().equals("")) {
                  int max = parseIntError(cons.getMaxLength(), "maxLength");
                  if (min < 0) {
                      this.addError("maxLength is less than zero");
                  }
  
                  if (min > max) {
                      addError("minLength exceeds the maxLength");
                  }
              }
          }
      }
  
      private void validateMinMaxOccurs() {
          if (!cons.getMinOccurs().equals("")) {
              int min = parseIntError(cons.getMinOccurs(), "minOccurs");
              if (min < 0) {
                  this.addError("minOccurs is less than zero");
              }
              if (!cons.getMaxOccurs().equals("")) {
                  int max = parseIntError(cons.getMaxOccurs(), "maxOccurs");
                  if (max < 0) {
                      this.addError("maxOccurs is less than zero");
                  }
                  if (min > max) {
                      addError("minOccurs exceeds the maxOccurs");
                  }
              }
          }
      }
  
      private void validateMinMaxValue() {
          if (!cons.getMinValue().equals("")) {
              int min = parseIntError(cons.getMinValue(), "minValue");
              if (min < 0) {
                  this.addError("minValue is less than zero");
              }
              if (!cons.getMaxValue().equals("")) {
                  int max = parseIntError(cons.getMaxValue(), "maxValue");
                  if (max < 0) {
                      this.addError("maxOccurs is less than zero");
                  }
                  if (min > max) {
                      addError("minOccurs exceeds the maxOccurs");
                  }
              }
          }
      }
 
     private int parseIntError(String value, String field) {
         if (value.equals("")) {
             return 0;
         }
         try {
             int val = Integer.parseInt(value);
             return val;
         } catch (NumberFormatException ex) {
             addError(field + " is [" + value + "] not an integer");
             return 0;
         }
     }
 
     private void addError(String msg) {
         String id = cons.getId();
         if (id.equals("")) {
             id = cons.getKey();
         }
         String error = "Error in constraint " + id + ": " + msg;
         if (!errors.contains(error)) {
             errors.add(error);
         }
     }
 }