Function clampToValidLine

src/codeScan/util/diffLineRanges.ts:181–224

(
  filepath: string,
  line: number,
  ranges: FileLineRanges,
)

 * @returns The clamped line number, or null if file not in diff
 */
export function clampToValidLine(
  filepath: string,
  line: number,
  ranges: FileLineRanges,
): number | null {
  const fileRanges = ranges.get(filepath);
  if (!fileRanges || fileRanges.length === 0) {
    return null;
  }

  // If already valid, return as-is
  if (isLineInDiff(filepath, line, ranges)) {
    return line;
  }

  // Sort ranges by start line
  const sortedRanges = [...fileRanges].sort((a, b) => a.start - b.start);

  // If line is before all ranges, return start of first range
  if (line < sortedRanges[0].start) {
    return sortedRanges[0].start;
  }

  // If line is after all ranges, return end of last range
  const lastRange = sortedRanges[sortedRanges.length - 1];
  if (line > lastRange.end) {
    return lastRange.end;
  }

  // Line is in a gap - find the closest range
  for (let i = 0; i < sortedRanges.length - 1; i++) {
    const currentRange = sortedRanges[i];
    const nextRange = sortedRanges[i + 1];

    // Check if line is in the gap between current and next range
    if (line > currentRange.end && line < nextRange.start) {
      // Return end of current range (comment on last visible line before gap)
      return currentRange.end;
    }
  }

  // Shouldn't reach here, but return end of last range as fallback
  return lastRange.end;
}

/**
 * Clamp a comment's line range to valid diff lines.