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 injectionBlind;
      
      private final InjectionModel injectionModel;
      private final String metadataInjectionProcess;
      
      /**
       * Constructor for preparation and blind confirmation.
       */
      public CallableBlindBit(String sqlQuery, InjectionModel injectionModel, InjectionBlindBit injectionBlind, BlindOperator blindOperator, String metadataInjectionProcess) {
          this.injectionModel = injectionModel;
          this.injectionBlind = injectionBlind;
          this.metadataInjectionProcess = metadataInjectionProcess;
          this.booleanUrl = this.injectionModel.getMediatorVendor().getVendor().instance().sqlTestBlindWithOperator(sqlQuery, blindOperator);
      }
      
      /**
       * Constructor for bits test.
       */
      public CallableBlindBit(
          String sqlQuery,
          int indexChar,
          int bit,
          InjectionModel injectionModel,
          InjectionBlindBit injectionBlind,
          BlindOperator blindOperator,
          String metadataInjectionProcess
      ) {
          this(sqlQuery, injectionModel, injectionBlind, blindOperator, metadataInjectionProcess);
          this.booleanUrl = this.injectionModel.getMediatorVendor().getVendor().instance().sqlBlindBit(sqlQuery, indexChar, bit, blindOperator);
          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.injectionBlind.getFalseDiffs());
          for (Diff falseDiff: falseDiffs) {  // ignored when false OR false => falsy empty
              // Fix #4386: NullPointerException on contains(), diffsWithReference initialized to new LinkedList<>()
              if (this.diffsWithReference.contains(falseDiff)) {
                  return false;
              }
          }
          List<Diff> trueDiffs = new CopyOnWriteArrayList<>(this.injectionBlind.getTrueDiffs());
          for (Diff trueDiff: trueDiffs) {
              if (!this.diffsWithReference.contains(trueDiff)) {  // required, set to false when empty falseDiffs
                  return false;
              }
          }
          return true;  // not in falseDiffs and in trueDiffs
      }
  
      /**
       * 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.injectionBlind.callUrl(this.booleanUrl, this.metadataInjectionProcess, this);
          this.diffsWithReference = CallableBlindBit.DIFF_MATCH_PATCH.diff_main(this.injectionBlind.getSourceReferencePage(), result, true);
          CallableBlindBit.DIFF_MATCH_PATCH.diff_cleanupEfficiency(this.diffsWithReference);
          return this;
      }
      
      public List<Diff> getDiffsWithReference() {
          return this.diffsWithReference;
      }
  }