frontend/src/lib/numberTrace.ts

export function numberTrace(content: string, maxLineLength = 120): string[] {
  // The backend processor (TraceLineNumberProcessor) numbers lines **after**
  // splitting any line longer than `maxLineLength` into chunks and indenting
  // continuation chunks with two leading spaces.  To keep `raw_*_ref` mappings
  // consistent, we reproduce that exact behaviour here.

  const originalLines = content.split("\n");
  const processed: string[] = [];

  for (const line of originalLines) {
    if (maxLineLength && line.length > maxLineLength) {
      const chunks = [] as string[];
      for (let i = 0; i < line.length; i += maxLineLength) {
        chunks.push(line.slice(i, i + maxLineLength));
      }

      if (chunks.length) {
        // First chunk as-is
        processed.push(chunks[0]!);
        // Subsequent chunks get two-space indent so downstream logic can treat
        // them as "continuation" lines (see isContinuation in the visualizer).
        for (const chunk of chunks.slice(1)) {
          processed.push("  " + chunk);
        }
      }
    } else {
      processed.push(line);
    }
  }

  return processed.map((ln, idx) => `<L${idx + 1}> ${ln}`);
}