package com.philemonworks.selfdiagnose;
   
   import java.util.ArrayList;
   import java.util.List;
   
   import org.xml.sax.Attributes;
   
   public class CollectionIteratorTask extends DiagnosticTask {
       private static final long serialVersionUID = -6424385910785821011L;
  
      private ArrayList tasks = new ArrayList();
      
      private String expression = "";
      
      /**
       * This method is sent from the SelfDiagnoseHandler when a configuration is being processed. Use the passed
       * attributes to initialize the receiver.
       * If a variable parameter is passed then store it.
       * 
       * @param attributes
       *        org.xml.sax.Attributes
       */
      public void initializeFromAttributes(Attributes attributes){
          super.initializeFromAttributes(attributes);  
          this.setExpression(attributes.getValue("value"));
      }
  
      public String getDescription() {
          return "Iterates over elements from the collection value";
      }
      public DiagnosticTaskResult createResult(){
          return new CompositeDiagnosticTaskResult(this);
      }
      public void run(ExecutionContext ctx, DiagnosticTaskResult result) throws DiagnoseException {
          Object collection = ctx.resolveValue(expression);
          if (collection == null) {
              result.setErrorMessage("Expression ["+expression+"] does not evaluate to a collection;  found null instead");
              return;            
          }
          if (!canBeIterated(collection)) {
              result.setErrorMessage("Expression does not evaluate to a collection;  found ["+collection+"] instead");
              return;
          }
          int count = 0;
          if (!(result instanceof CompositeDiagnosticTaskResult)) throw new RuntimeException("bug"); 
          CompositeDiagnosticTaskResult composedResult = (CompositeDiagnosticTaskResult)result;
          // either a List or an Array
          if (collection.getClass().isArray()) {
              Object[] array = (Object[])collection;
              for (int i=0;i<array.length;i++) {                
                  this.iterateUsingEach(ctx, composedResult, array[i]);
                  count = count + tasks.size();
              }
          } else if (collection instanceof List) {
              List list = (List)collection;
              for (int i=0;i<list.size();i++) {                
                  this.iterateUsingEach(ctx, composedResult, list.get(i));
                  count = count + tasks.size();
              }
          }
          int failed = composedResult.howManyErrors();
          if (failed > 0) {
              result.setFailedMessage(failed + " out of " + count + " checks failed.");
          } else {
              result.setPassedMessage("All " + count + " checks passed");
          }        
      }
      private void iterateUsingEach(ExecutionContext ctx,CompositeDiagnosticTaskResult composedResult, Object each) throws DiagnoseException {
          for (int t=0;t<tasks.size();t++) {
              DiagnosticTask eachTask = (DiagnosticTask)tasks.get(t);
              ctx.setValue(this.getVariableName(), each);
              DiagnosticTaskResult eachResult = eachTask.createResult();
              eachTask.run(ctx, eachResult);
              composedResult.addResult(eachResult);
          }
      }
      
      private boolean canBeIterated(Object value) {
          return value.getClass().isArray() || value instanceof java.util.List;
      }
      
      public void register(DiagnosticTask task) {
          tasks.add(task);        
      }
      
      public List getTasks() { return tasks; }
  
      public String getExpression() {
          return expression;
      }
  
      public void setExpression(String expression) {
          this.expression = expression;
      }
  }