/**
    * Copyright 2005-2014 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.validator;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.kuali.rice.krad.datadictionary.DataDictionary;
  import org.kuali.rice.krad.datadictionary.DataDictionaryEntry;
  import org.kuali.rice.krad.datadictionary.DataDictionaryException;
  import org.kuali.rice.krad.datadictionary.DefaultListableBeanFactory;
  import org.kuali.rice.krad.datadictionary.uif.UifBeanFactoryPostProcessor;
  import org.kuali.rice.krad.datadictionary.uif.UifDictionaryBean;
  import org.kuali.rice.krad.uif.UifConstants;
  import org.kuali.rice.krad.uif.component.Component;
  import org.kuali.rice.krad.uif.lifecycle.ViewLifecycleUtils;
  import org.kuali.rice.krad.uif.lifecycle.ViewLifecycle;
  import org.kuali.rice.krad.uif.lifecycle.ViewLifecycleUtils;
  import org.kuali.rice.krad.uif.util.LifecycleElement;
  import org.kuali.rice.krad.uif.view.View;
  import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
  import org.springframework.core.io.FileSystemResource;
  import org.springframework.core.io.Resource;
  import org.springframework.core.io.ResourceLoader;
  
  /**
   * A validator for Rice Dictionaries that stores the information found during its validation.
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class Validator {
      private static final Log LOG = LogFactory.getLog(Validator.class);
  
      private static ArrayList<ErrorReport> errorReports = new ArrayList<ErrorReport>();
  
      private ValidationTrace tracerTemp;
      private int numberOfErrors;
      private int numberOfWarnings;
  
      /**
       * Constructor creating an empty validation report
       */
      public Validator() {
          tracerTemp = new ValidationTrace();
          numberOfErrors = 0;
          numberOfWarnings = 0;
      }
  
      public static void addErrorReport(ErrorReport report) {
          errorReports.add(report);
      }
  
      public static void resetErrorReport() {
          errorReports = new ArrayList<ErrorReport>();
      }
  
      /**
       * Runs the validations on a collection of beans
       *
       * @param beans - Collection of beans being validated
       * @param failOnWarning - Whether detecting a warning should cause the validation to fail
       * @return Returns true if the beans past validation
       */
      private boolean runValidations(DefaultListableBeanFactory beans, boolean failOnWarning) {
          LOG.info("Starting Dictionary Validation");
          resetErrorReport();
          Map<String, View> uifBeans;
  
          try {
              uifBeans = beans.getBeansOfType(View.class);
              for (View views : uifBeans.values()) {
                  try {
                      ValidationTrace tracer = tracerTemp.getCopy();
                      if (doValidationOnUIFBean(views)) {
                          tracer.setValidationStage(ValidationTrace.START_UP);
                          runValidationsOnComponents(views, tracer);
                      }
                  } catch (Exception e) {
                      String value[] = {views.getId(), "Exception = " + e.getMessage()};
                      tracerTemp.createError("Error Validating Bean View", value);
                  }
             }
         } catch (Exception e) {
             String value[] = {"Validation set = views", "Exception = " + e.getMessage()};
             tracerTemp.createError("Error in Loading Spring Beans", value);
         }
 
         Map<String, DataDictionaryEntry> ddBeans;
 
         try {
             ddBeans = beans.getBeansOfType(DataDictionaryEntry.class);
             for (DataDictionaryEntry entry : ddBeans.values()) {
                 try {
 
                     ValidationTrace tracer = tracerTemp.getCopy();
                     tracer.setValidationStage(ValidationTrace.BUILD);
                     entry.completeValidation(tracer);
 
                 } catch (Exception e) {
                     String value[] = {"Validation set = Data Dictionary Entries", "Exception = " + e.getMessage()};
                     tracerTemp.createError("Error in Loading Spring Beans", value);
                 }
             }
         } catch (Exception e) {
             String value[] = {"Validation set = Data Dictionary Entries", "Exception = " + e.getMessage()};
             tracerTemp.createError("Error in Loading Spring Beans", value);
         }
 
         compileFinalReport();
 
         LOG.info("Completed Dictionary Validation");
 
         if (numberOfErrors > 0) {
             return false;
         }
         if (failOnWarning) {
             if (numberOfWarnings > 0) {
                 return false;
             }
         }
 
         return true;
     }
 
     /**
      * Validates a UIF Component
      *
      * @param object - The UIF Component to be validated
      * @param failOnWarning - Whether the validation should fail if warnings are found
      * @return Returns true if the validation passes
      */
     public boolean validate(Component object, boolean failOnWarning) {
         LOG.info("Starting Dictionary Validation");
 
         if (doValidationOnUIFBean(object)) {
             ValidationTrace tracer = tracerTemp.getCopy();
             resetErrorReport();
 
             tracer.setValidationStage(ValidationTrace.BUILD);
 
             LOG.debug("Validating Component: " + object.getId());
             object.completeValidation(tracer.getCopy());
 
             runValidationsOnLifecycle(object, tracer.getCopy());
         }
 
         compileFinalReport();
 
         LOG.info("Completed Dictionary Validation");
 
         if (numberOfErrors > 0) {
             return false;
         }
         if (failOnWarning) {
             if (numberOfWarnings > 0) {
                 return false;
             }
         }
 
         return true;
     }
 
     /**
      * Validates the beans in a collection of xml files
      * @param xmlFiles files to validate
      * @param failOnWarning - Whether detecting a warning should cause the validation to fail
      * 
      * @return Returns true if the beans past validation
      */
     public boolean validate(String[] xmlFiles, boolean failOnWarning) {
         DefaultListableBeanFactory beans = loadBeans(xmlFiles);
 
         return runValidations(beans, failOnWarning);
     }
 
     /**
      * Validates a collection of beans
      *
      * @param xmlFiles - The collection of xml files used to load the provided beans
      * @param loader - The source that was used to load the beans
      * @param beans - Collection of preloaded beans
      * @param failOnWarning - Whether detecting a warning should cause the validation to fail
      * @return Returns true if the beans past validation
      */
     public boolean validate(String xmlFiles[], ResourceLoader loader, DefaultListableBeanFactory beans,
             boolean failOnWarning) {
         tracerTemp = new ValidationTrace(xmlFiles, loader);
         return runValidations(beans, failOnWarning);
     }
 
     /**
      * Runs the validations on a component
      *
      * @param component - The component being checked
      * @param tracer - The current bean trace for the validation line
      */
     private void runValidationsOnComponents(Component component, ValidationTrace tracer) {
 
         try {
             ViewLifecycle.getExpressionEvaluator().populatePropertyExpressionsFromGraph(component, false);
         } catch (Exception e) {
             String value[] = {"view = " + component.getId()};
             tracerTemp.createError("Error Validating Bean View while loading expressions", value);
         }
 
         LOG.debug("Validating View: " + component.getId());
 
         try {
             component.completeValidation(tracer.getCopy());
         } catch (Exception e) {
             String value[] = {component.getId()};
             tracerTemp.createError("Error Validating Bean View", value);
         }
 
         try {
             runValidationsOnLifecycle(component, tracer.getCopy());
         } catch (Exception e) {
             String value[] = {component.getId(),
                     ViewLifecycleUtils.getElementsForLifecycle(component).size() + "",
                     "Exception " + e.getMessage()};
             tracerTemp.createError("Error Validating Bean Lifecycle", value);
         }
     }
 
     /**
      * Runs the validations on a components lifecycle items
      *
      * @param element - The component whose lifecycle items are being checked
      * @param tracer - The current bean trace for the validation line
      */
     private void runValidationsOnLifecycle(LifecycleElement element, ValidationTrace tracer) {
         Map<String, LifecycleElement> nestedComponents =
                 ViewLifecycleUtils.getElementsForLifecycle(element, UifConstants.ViewPhases.INITIALIZE);
         if (nestedComponents == null) {
             return;
         }
 
         Component component = null;
         if (element instanceof Component) {
             component = (Component) element;
             if (!doValidationOnUIFBean(component)) {
                 return;
             }
             tracer.addBean(component);
         }
         
         for (LifecycleElement temp : nestedComponents.values()) {
             if (!(temp instanceof Component)) {
                 continue;
             }
             if (tracer.getValidationStage() == ValidationTrace.START_UP) {
                 ViewLifecycle.getExpressionEvaluator().populatePropertyExpressionsFromGraph((UifDictionaryBean) temp, false);
             }
             if (((Component) temp).isRender()) {
                 ((DataDictionaryEntry) temp).completeValidation(tracer.getCopy());
                 runValidationsOnLifecycle(temp, tracer.getCopy());
             }
         }
         
         ViewLifecycleUtils.recycleElementMap(nestedComponents);
     }
 
     /**
      * Checks if the component being checked is a default or template component by seeing if its id starts with "uif"
      *
      * @param component - The component being checked
      * @return Returns true if the component is not a default or template
      */
     private boolean doValidationOnUIFBean(Component component) {
         if (component.getId() == null) {
             return true;
         }
         if (component.getId().length() < 3) {
             return true;
         }
         String temp = component.getId().substring(0, 3).toLowerCase();
         if (temp.contains("uif")) {
             return false;
         }
         return true;
     }
 
     /**
      * Validates an expression string for correct Spring Expression language syntax
      *
      * @param expression - The expression being validated
      * @return Returns true if the expression is of correct SpringEL syntax
      */
     public static boolean validateSpringEL(String expression) {
         if (expression == null) {
             return true;
         }
         if (expression.compareTo("") == 0) {
             return true;
         }
         if (expression.length() <= 3) {
             return false;
         }
 
         if (!expression.substring(0, 1).contains("@") || !expression.substring(1, 2).contains("{") ||
                 !expression.substring(expression.length() - 1, expression.length()).contains("}")) {
             return false;
         }
 
         expression = expression.substring(2, expression.length() - 2);
 
         ArrayList<String> values = getExpressionValues(expression);
 
         for (int i = 0; i < values.size(); i++) {
             checkPropertyName(values.get(i));
         }
 
         return true;
     }
 
     /**
      * Gets the list of properties from an expression
      *
      * @param expression - The expression being validated.
      * @return A list of properties from the expression.
      */
     private static ArrayList<String> getExpressionValues(String expression) {
         expression = StringUtils.replace(expression, "!=", " != ");
         expression = StringUtils.replace(expression, "==", " == ");
         expression = StringUtils.replace(expression, ">", " > ");
         expression = StringUtils.replace(expression, "<", " < ");
         expression = StringUtils.replace(expression, "<=", " <= ");
         expression = StringUtils.replace(expression, ">=", " >= ");
 
         ArrayList<String> controlNames = new ArrayList<String>();
         controlNames.addAll(ViewLifecycle.getExpressionEvaluator().findControlNamesInExpression(expression));
 
         return controlNames;
     }
 
     /**
      * Checks the property for a valid name.
      *
      * @param name - The property name.
      * @return True if the validation passes, false if not
      */
     private static boolean checkPropertyName(String name) {
         if (!Character.isLetter(name.charAt(0))) {
             return false;
         }
 
         return true;
     }
 
     /**
      * Checks if a property of a Component is being set by expressions
      *
      * @param object - The Component being checked
      * @param property - The property being set
      * @return Returns true if the property is contained in the Components property expressions
      */
     public static boolean checkExpressions(Component object, String property) {
         if (object.getPropertyExpressions().containsKey(property)) {
             return true;
         }
         return false;
     }
 
     /**
      * Compiles general information on the validation from the list of generated error reports
      */
     private void compileFinalReport() {
         ArrayList<ErrorReport> reports = Validator.errorReports;
         for (int i = 0; i < reports.size(); i++) {
             if (reports.get(i).getErrorStatus() == ErrorReport.ERROR) {
                 numberOfErrors++;
             } else if (reports.get(i).getErrorStatus() == ErrorReport.WARNING) {
                 numberOfWarnings++;
             }
         }
     }
 
     /**
      * Loads the Spring Beans from a list of xml files
      *
      * @param xmlFiles
      * @return The Spring Bean Factory for the provided list of xml files
      */
     public DefaultListableBeanFactory loadBeans(String[] xmlFiles) {
 
         LOG.info("Starting XML File Load");
         DefaultListableBeanFactory beans = new DefaultListableBeanFactory();
         XmlBeanDefinitionReader xmlReader = new XmlBeanDefinitionReader(beans);
 
         DataDictionary.setupProcessor(beans);
 
         ArrayList<String> coreFiles = new ArrayList<String>();
         ArrayList<String> testFiles = new ArrayList<String>();
 
         for (int i = 0; i < xmlFiles.length; i++) {
             if (xmlFiles[i].contains("classpath")) {
                 coreFiles.add(xmlFiles[i]);
             } else {
                 testFiles.add(xmlFiles[i]);
             }
         }
         String core[] = new String[coreFiles.size()];
         coreFiles.toArray(core);
 
         String test[] = new String[testFiles.size()];
         testFiles.toArray(test);
 
         try {
             xmlReader.loadBeanDefinitions(core);
         } catch (Exception e) {
             LOG.error("Error loading bean definitions", e);
             throw new DataDictionaryException("Error loading bean definitions: " + e.getLocalizedMessage(), e);
         }
 
         try {
             xmlReader.loadBeanDefinitions(getResources(test));
         } catch (Exception e) {
             LOG.error("Error loading bean definitions", e);
             throw new DataDictionaryException("Error loading bean definitions: " + e.getLocalizedMessage(), e);
         }
 
         UifBeanFactoryPostProcessor factoryPostProcessor = new UifBeanFactoryPostProcessor();
         factoryPostProcessor.postProcessBeanFactory(beans);
 
         tracerTemp = new ValidationTrace(xmlFiles, xmlReader.getResourceLoader());
 
         LOG.info("Completed XML File Load");
 
         return beans;
     }
 
     /**
      * Converts the list of file paths into a list of resources
      *
      * @param files The list of file paths for conversion
      * @return A list of resources created from the file paths
      */
     private Resource[] getResources(String files[]) {
         Resource resources[] = new Resource[files.length];
         for (int i = 0; i < files.length; i++) {
             resources[0] = new FileSystemResource(files[i]);
         }
 
         return resources;
     }
 
     /**
      * Retrieves the number of errors found in the validation
      *
      * @return The number of errors found in the validation
      */
     public int getNumberOfErrors() {
         return numberOfErrors;
     }
 
     /**
      * Retrieves the number of warnings found in the validation
      *
      * @return The number of warnings found in the validation
      */
     public int getNumberOfWarnings() {
         return numberOfWarnings;
     }
 
     /**
      * Retrieves an individual error report for errors found during the validation
      *
      * @param index
      * @return The error report at the provided index
      */
     public ErrorReport getErrorReport(int index) {
         return errorReports.get(index);
     }
 
     /**
      * Retrieves the number of error reports generated during the validation
      *
      * @return The number of ErrorReports
      */
     public int getErrorReportSize() {
         return errorReports.size();
     }
 
     public static List<ErrorReport> getErrorReports() {
         return Collections.unmodifiableList(errorReports);
     }
 }