cw_regexp_replace_generic.sqlx

config { hasOutput: true }
/*
 * Copyright 2022 Google LLC
 *
 * Licensed 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.
 */

 /* Generic regexp_replace, which is the 6-args version with regexp_mode already decoded */
CREATE OR REPLACE FUNCTION ${self()}(haystack STRING, regexp STRING, replacement STRING, offset INT64, occurrence INT64, mode STRING) RETURNS STRING
LANGUAGE js AS """
  if (haystack == null || regexp == null || replacement == null || offset == null || occurrence == null || mode == null) return null;
  replacement = replacement.replace('\\\\', '$');
  let regExp = new RegExp(regexp, mode);
  if (occurrence == 0)
      return haystack.replace(regExp, replacement);
  const start = offset - 1;
  const index = occurrence - 1;
  let relevantString = haystack.substring(start);
  let a, count = 0;
  while ((a = regExp.exec(relevantString)) !== null && count++ < index) {
      relevantString = relevantString.substr(regExp.lastIndex);
      regExp.lastIndex = 0;
  }
  if (a == null) return haystack;
  const prefix = haystack.substr(0, haystack.length - relevantString.length);
  if (mode.indexOf('g') >= 0) {
      mode = mode.replace('g', '');
      regExp = new RegExp(regexp, mode);
  }
  return prefix + relevantString.replace(regExp, replacement);
""";