/*
    * SPDX-FileCopyrightText: Copyright (c) 2011-2026 Yegor Bugayenko
    * SPDX-License-Identifier: MIT
    */
   package com.qulice.checkstyle;
   
   import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
   import com.puppycrawl.tools.checkstyle.api.FileText;
   import java.io.File;
  
  /**
   * Check if import lines are all together without any empty lines or comments.
   *
   * <p>All {@code import} instructions shall stay together, without any empty
   * lines between them. If you need to separate them because the list is too
   * big - it's time to refactor the class and make is smaller.
   *
   * @since 0.3
   */
  public final class ImportCohesionCheck extends AbstractFileSetCheck {
  
      /**
       * The "import" keyword.
       */
      private static final String IMPORT = "import ";
  
      @Override
      public void processFiltered(final File file, final FileText lines) {
          int first = -1;
          int last = -1;
          for (int pos = 0; pos < lines.size(); pos += 1) {
              final String line = lines.get(pos);
              if (line.startsWith(ImportCohesionCheck.IMPORT)) {
                  if (first == -1) {
                      first = pos;
                  }
                  last = pos;
              }
          }
          if (first == -1) {
              return;
          }
          if (this.check(first, last, lines)) {
              this.fireErrors(file.getPath());
          }
      }
  
      /**
       * Perform check for empty lines and comments inside imports.
       * @param first Line number where import occurred first
       * @param last Line number where import occurred first
       * @param lines All file line by line
       * @return True if check is failed
       */
      private boolean check(final int first, final int last,
          final FileText lines
      ) {
          boolean failure = false;
          if (first == 0 || !lines.get(first - 1).isEmpty()) {
              this.log(first, "Line before imports should be empty");
              failure = true;
          }
          if (lines.size() > last + 1 && !lines.get(last + 1).isEmpty()) {
              this.log(last + 2, "Line after imports should be empty");
              failure = true;
          }
          for (int pos = first; pos < last; pos += 1) {
              final String line = lines.get(pos);
              if (!line.startsWith(ImportCohesionCheck.IMPORT)) {
                  this.log(
                      pos + 1,
                      "Empty line or comment between imports is not allowed"
                  );
                  failure = true;
              }
          }
          return failure;
      }
  }