content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache 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.apache.org/licenses/LICENSE-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 com.datastax.dse.driver.internal.core.graph;
  
  import com.datastax.oss.driver.shaded.guava.common.collect.Sets;
  import java.util.List;
  import java.util.Set;
  import java.util.regex.Pattern;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  /**
   * List of predicates for geolocation usage with DseGraph and Search indexes. Should not be accessed
   * directly but through the {@link com.datastax.dse.driver.api.core.graph.predicates.Search} static
   * methods.
   */
  public enum SearchPredicate implements DsePredicate {
    /** Whether the text contains a given term as a token in the text (case insensitive). */
    token {
      @Override
      public boolean test(Object value, Object condition) {
        preEvaluate(condition);
        return value != null && evaluate(value.toString(), (String) condition);
      }
  
      boolean evaluate(String value, String terms) {
        Set<String> tokens = Sets.newHashSet(tokenize(value.toLowerCase()));
        terms = terms.trim();
        List<String> tokenTerms = tokenize(terms.toLowerCase());
        if (!terms.isEmpty() && tokenTerms.isEmpty()) {
          return false;
        }
        for (String term : tokenTerms) {
          if (!tokens.contains(term)) {
            return false;
          }
        }
        return true;
      }
  
      @Override
      public boolean isValidCondition(Object condition) {
        return condition != null && isNotBlank((String) condition);
      }
  
      @Override
      public String toString() {
        return "token";
      }
    },
  
    /** Whether the text contains a token that starts with a given term (case insensitive). */
    tokenPrefix {
      @Override
      public boolean test(Object value, Object condition) {
        preEvaluate(condition);
        return value != null && evaluate(value.toString(), (String) condition);
      }
  
      boolean evaluate(String value, String prefix) {
        for (String token : tokenize(value.toLowerCase())) {
          if (token.startsWith(prefix.toLowerCase().trim())) {
            return true;
          }
        }
        return false;
      }
  
      @Override
      public boolean isValidCondition(Object condition) {
        return condition != null;
      }
  
      @Override
      public String toString() {
        return "tokenPrefix";
      }
    },
  
    /** Whether the text contains a token that matches a regular expression (case insensitive). */
    tokenRegex {
      @Override
      public boolean test(Object value, Object condition) {
        preEvaluate(condition);
        return value != null && evaluate(value.toString(), (String) condition);
      }
  
      boolean evaluate(String value, String regex) {
        Pattern compiled = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
        for (String token : tokenize(value.toLowerCase())) {
          if (compiled.matcher(token).matches()) {
            return true;
          }
        }
        return false;
      }
  
      @Override
      public boolean isValidCondition(Object condition) {
        return condition != null && isNotBlank((String) condition);
      }
  
      @Override
      public String toString() {
        return "tokenRegex";
      }
    },
  
    /**
     * Whether some token in the text is within a given edit distance from the given term (case
     * insensitive).
     */
    tokenFuzzy {
      @Override
      public boolean test(Object value, Object condition) {
        preEvaluate(condition);
        if (value == null) {
          return false;
        }
  
        EditDistance fuzzyCondition = (EditDistance) condition;
  
        for (String token : tokenize(value.toString().toLowerCase())) {
          if (SearchUtils.getOptimalStringAlignmentDistance(token, fuzzyCondition.query.toLowerCase())
              <= fuzzyCondition.distance) {
            return true;
          }
        }
  
        return false;
      }
  
      @Override
      public boolean isValidCondition(Object condition) {
        return condition != null;
      }
  
      @Override
      public String toString() {
        return "tokenFuzzy";
      }
    },
  
    /** Whether the text starts with a given prefix (case sensitive). */
    prefix {
      @Override
      public boolean test(Object value, Object condition) {
        preEvaluate(condition);
        return value != null && value.toString().startsWith(((String) condition).trim());
      }
  
      @Override
      public boolean isValidCondition(Object condition) {
        return condition != null;
      }
  
      @Override
      public String toString() {
        return "prefix";
      }
    },
  
    /** Whether the text matches a regular expression (case sensitive). */
    regex {
      @Override
      public boolean test(Object value, Object condition) {
        preEvaluate(condition);
        return value != null
            && Pattern.compile((String) condition, Pattern.DOTALL)
                .matcher(value.toString())
                .matches();
      }
  
      @Override
      public boolean isValidCondition(Object condition) {
        return condition != null && isNotBlank((String) condition);
      }
  
      @Override
      public String toString() {
        return "regex";
      }
    },
  
    /** Whether the text is within a given edit distance from the given term (case sensitive). */
    fuzzy {
      @Override
      public boolean test(Object value, Object condition) {
        preEvaluate(condition);
        if (value == null) {
          return false;
        }
        EditDistance fuzzyCondition = (EditDistance) condition;
        return SearchUtils.getOptimalStringAlignmentDistance(value.toString(), fuzzyCondition.query)
            <= fuzzyCondition.distance;
      }
  
      @Override
      public boolean isValidCondition(Object condition) {
        return condition != null;
      }
  
      @Override
      public String toString() {
        return "fuzzy";
      }
    },
  
    /**
     * Whether tokenized text contains a given phrase, optionally within a given proximity (case
     * insensitive).
     */
    phrase {
      @Override
      public boolean test(Object value, Object condition) {
        preEvaluate(condition);
        if (value == null) {
          return false;
        }
  
        EditDistance phraseCondition = (EditDistance) condition;
  
        List<String> valueTokens = tokenize(value.toString().toLowerCase());
        List<String> phraseTokens = tokenize(phraseCondition.query.toLowerCase());
  
        int valuePosition = 0;
        int phrasePosition = 0;
        int distance = 0;
  
        // Look for matches while phrase/value tokens and distance budget remain
        while (phrasePosition < phraseTokens.size()
            && valuePosition < valueTokens.size()
            && distance <= phraseCondition.distance) {
  
          if (phraseTokens.get(phrasePosition).equals(valueTokens.get(valuePosition))) {
            // Early return-true when we've matched the whole phrase (within the specified distance)
            if (phrasePosition == phraseTokens.size() - 1) {
              return true;
            }
            phrasePosition++;
          } else if (0 < phrasePosition) {
            // We've previously found at least one matching token in the input string,
            // but the current token does not match the phrase.  Increment distance.
            distance++;
          }
  
          valuePosition++;
        }
  
        return false;
      }
  
      @Override
      public boolean isValidCondition(Object condition) {
        return condition != null;
      }
  
      @Override
      public String toString() {
        return "phrase";
      }
    };
  
    private static boolean isNotBlank(String str) {
      if (str == null || str.isEmpty()) {
        return false;
      }
      int strLen = str.length();
      for (int i = 0; i < strLen; i++) {
        if (!Character.isWhitespace(str.charAt(i))) {
          return true;
        }
      }
      return false;
    }
  
    // Match anything that is not either:
    // 1) a unicode letter, regardless of subcategory (same as Character.isLetter), or
    // 2) a unicode decimal digit number (same as Character.isDigit)
    private static final Pattern TOKEN_SPLIT_PATTERN = Pattern.compile("[^\\p{L}\\p{Nd}]");
  
    static List<String> tokenize(String str) {
      String[] rawTokens = TOKEN_SPLIT_PATTERN.split(str); // could contain empty strings
      return Stream.of(rawTokens).filter(t -> 0 < t.length()).collect(Collectors.toList());
    }
  }
  