content: /*
   * Copyright 2015 Google Inc.
   *
   * 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.
   */
  
  package com.google.googlejavaformat.java;
  
  import com.google.common.base.CharMatcher;
  import com.google.common.base.Strings;
  import com.google.googlejavaformat.CommentsHelper;
  import com.google.googlejavaformat.Input.Tok;
  import com.google.googlejavaformat.Newlines;
  import com.google.googlejavaformat.java.javadoc.JavadocFormatter;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /** {@code JavaCommentsHelper} extends {@link CommentsHelper} to rewrite Java comments. */
  public final class JavaCommentsHelper implements CommentsHelper {
  
    private final String lineSeparator;
    private final JavaFormatterOptions options;
  
    public JavaCommentsHelper(String lineSeparator, JavaFormatterOptions options) {
      this.lineSeparator = lineSeparator;
      this.options = options;
    }
  
    @Override
    public String rewrite(Tok tok, int maxWidth, int column0) {
      if (!tok.isComment()) {
        return tok.getOriginalText();
      }
      String text = tok.getOriginalText();
      if (tok.isJavadocComment() && options.formatJavadoc()) {
        text = JavadocFormatter.formatJavadoc(text, column0);
      }
      List<String> lines = new ArrayList<>();
      Iterator<String> it = Newlines.lineIterator(text);
      while (it.hasNext()) {
        lines.add(CharMatcher.whitespace().trimTrailingFrom(it.next()));
      }
      if (tok.isSlashSlashComment()) {
        return indentLineComments(lines, column0);
      }
      return CommentsHelper.reformatParameterComment(tok)
          .orElseGet(
              () ->
                  javadocShaped(lines)
                      ? indentJavadoc(lines, column0)
                      : preserveIndentation(lines, column0));
    }
  
    // For non-javadoc-shaped block comments, shift the entire block to the correct
    // column, but do not adjust relative indentation.
    private String preserveIndentation(List<String> lines, int column0) {
      StringBuilder builder = new StringBuilder();
  
      // find the leftmost non-whitespace character in all trailing lines
      int startCol = -1;
      for (int i = 1; i < lines.size(); i++) {
        int lineIdx = CharMatcher.whitespace().negate().indexIn(lines.get(i));
        if (lineIdx >= 0 && (startCol == -1 || lineIdx < startCol)) {
          startCol = lineIdx;
        }
      }
  
      // output the first line at the current column
      builder.append(lines.get(0));
  
      // output all trailing lines with plausible indentation
      for (int i = 1; i < lines.size(); ++i) {
        builder.append(lineSeparator).append(Strings.repeat(" ", column0));
        // check that startCol is valid index, e.g. for blank lines
        if (lines.get(i).length() >= startCol) {
          builder.append(lines.get(i).substring(startCol));
        } else {
          builder.append(lines.get(i));
        }
      }
      return builder.toString();
    }
  
    // Wraps and re-indents line comments.
    private String indentLineComments(List<String> lines, int column0) {
      lines = wrapLineComments(lines, column0);
      StringBuilder builder = new StringBuilder();
      builder.append(lines.get(0).trim());
      String indentString = Strings.repeat(" ", column0);
      for (int i = 1; i < lines.size(); ++i) {
        builder.append(lineSeparator).append(indentString).append(lines.get(i).trim());
      }
      return builder.toString();
    }
  
    // Preserve special `//noinspection` and `//$NON-NLS-x$` comments used by IDEs, which cannot
    // contain leading spaces.
    private static final Pattern LINE_COMMENT_MISSING_SPACE_PREFIX =
        Pattern.compile("^(//+)(?!noinspection|\\$NON-NLS-\\d+\\$)[^\\s/]");
  
    private List<String> wrapLineComments(List<String> lines, int column0) {
      List<String> result = new ArrayList<>();
      for (String line : lines) {
        // Add missing leading spaces to line comments: `//foo` -> `// foo`.
        Matcher matcher = LINE_COMMENT_MISSING_SPACE_PREFIX.matcher(line);
        if (matcher.find()) {
          int length = matcher.group(1).length();
          line = Strings.repeat("/", length) + " " + line.substring(length);
        }
        if (line.startsWith("// MOE:")) {
          // don't wrap comments for https://github.com/google/MOE
          result.add(line);
          continue;
        }
        while (line.length() + column0 > Formatter.MAX_LINE_LENGTH) {
          int idx = Formatter.MAX_LINE_LENGTH - column0;
          // only break on whitespace characters, and ignore the leading `// `
          while (idx >= 2 && !CharMatcher.whitespace().matches(line.charAt(idx))) {
            idx--;
          }
          if (idx <= 2) {
            break;
          }
          result.add(line.substring(0, idx));
          line = "//" + line.substring(idx);
        }
        result.add(line);
      }
      return result;
    }
  
    // Remove leading whitespace (trailing was already removed), and re-indent.
    // Add a +1 indent before '*', and add the '*' if necessary.
    private String indentJavadoc(List<String> lines, int column0) {
      StringBuilder builder = new StringBuilder();
      builder.append(lines.get(0).trim());
      int indent = column0 + 1;
      String indentString = Strings.repeat(" ", indent);
      for (int i = 1; i < lines.size(); ++i) {
        builder.append(lineSeparator).append(indentString);
        String line = lines.get(i).trim();
        if (!line.startsWith("*")) {
          builder.append("* ");
        }
        builder.append(line);
      }
      return builder.toString();
    }
  
    // Returns true if the comment looks like javadoc
    private static boolean javadocShaped(List<String> lines) {
      Iterator<String> it = lines.iterator();
      if (!it.hasNext()) {
        return false;
      }
      String first = it.next().trim();
      // if it's actually javadoc, we're done
      if (first.startsWith("/**")) {
        return true;
      }
      // if it's a block comment, check all trailing lines for '*'
      if (!first.startsWith("/*")) {
        return false;
      }
      while (it.hasNext()) {
        if (!it.next().trim().startsWith("*")) {
          return false;
        }
      }
      return true;
    }
  }
  
  