package com.jsql.model.injection.strategy.blind.callable;
   
   import com.jsql.model.InjectionModel;
   import com.jsql.model.injection.strategy.blind.AbstractInjectionBit.BlindOperator;
   import com.jsql.model.injection.strategy.blind.InjectionBlindBit;
   import name.fraser.neil.plaintext.diff_match_patch;
   import static name.fraser.neil.plaintext.diff_match_patch.Diff;
   
   import java.util.LinkedList;
  import java.util.List;
  import java.util.concurrent.CopyOnWriteArrayList;
  
  /**
   * Define a call HTTP to the server, require the associated url, character
   * position and bit. Diffs represent the differences between
   * the reference page, and the current page.
   */
  public class CallableBlindBit extends AbstractCallableBit<CallableBlindBit> {
      
      private LinkedList<Diff> diffsWithReference = new LinkedList<>();  // List of differences found between the reference page, and the current page
      
      private static final diff_match_patch DIFF_MATCH_PATCH = new diff_match_patch();
  
      private final InjectionBlindBit injectionBlindBit;
      
      private final InjectionModel injectionModel;
      private final String metadataInjectionProcess;
      
      /**
       * Constructor for preparation and blind confirmation.
       */
      public CallableBlindBit(String sqlQuery, InjectionModel injectionModel, InjectionBlindBit injectionBlindBit, BlindOperator blindMode, String metadataInjectionProcess) {
          this.injectionModel = injectionModel;
          this.injectionBlindBit = injectionBlindBit;
          this.metadataInjectionProcess = metadataInjectionProcess;
          this.booleanUrl = this.injectionModel.getMediatorVendor().getVendor().instance().sqlTestBlindWithOperator(sqlQuery, blindMode);
      }
      
      /**
       * Constructor for bits test.
       */
      public CallableBlindBit(
          String sqlQuery,
          int indexChar,
          int bit,
          InjectionModel injectionModel,
          InjectionBlindBit injectionBlindBit,
          BlindOperator blindMode,
          String metadataInjectionProcess
      ) {
          this(sqlQuery, injectionModel, injectionBlindBit, blindMode, metadataInjectionProcess);
          this.booleanUrl = this.injectionModel.getMediatorVendor().getVendor().instance().sqlBlindBit(sqlQuery, indexChar, bit, blindMode);
          this.currentIndex = indexChar;
          this.currentBit = bit;
      }
  
      /**
       * Check if a result page means the SQL query is true,
       * confirm that nothing in the resulting page is also defined
       * in the pages from every FALSE SQL queries.
       * @return true if the current SQL query is true
       */
      @Override
      public boolean isTrue() {
          // Fix #95426: ConcurrentModificationException on iterator.next()
          List<Diff> falseDiffs = new CopyOnWriteArrayList<>(this.injectionBlindBit.getFalseDiffs());
          for (Diff falseDiff: falseDiffs) {
              // Fix #4386: NullPointerException on contains()
              // diffsWithReference is initialized to an empty new LinkedList<>()
              if (this.diffsWithReference.contains(falseDiff)) {
                  return false;
              }
          }
          return true;
      }
  
      /**
       * Process the URL HTTP call, use function inject() from the model.
       * Build the list of differences found between TRUE and the current page.
       * @return Functional Blind Callable
       */
      @Override
      public CallableBlindBit call() {
          String result = this.injectionBlindBit.callUrl(this.booleanUrl, this.metadataInjectionProcess, this);
          this.diffsWithReference = CallableBlindBit.DIFF_MATCH_PATCH.diff_main(this.injectionBlindBit.getSourceReferencePage(), result, true);
          CallableBlindBit.DIFF_MATCH_PATCH.diff_cleanupEfficiency(this.diffsWithReference);
          return this;
      }
      
      public List<Diff> getDiffsWithReference() {
          return this.diffsWithReference;
      }
  }