Function embedChunksResilient

src/context/retrieval.ts:131–165

(
  chunks: Chunk[],
  embed: (texts: string[]) => Promise<number[][]>,
  opts: { batchSize?: number; maxChars?: number; onProgress?: (msg: string) => void } = {},
)

 * unit-testable without a model. Pure aside from the in-place embedding assignment.
 */
export async function embedChunksResilient(
  chunks: Chunk[],
  embed: (texts: string[]) => Promise<number[][]>,
  opts: { batchSize?: number; maxChars?: number; onProgress?: (msg: string) => void } = {},
): Promise<{ embedded: number; skipped: number }> {
  const batchSize = opts.batchSize ?? 32;
  const maxChars = opts.maxChars ?? EMBED_MAX_CHARS;
  let embedded = 0;
  let skipped = 0;
  for (let i = 0; i < chunks.length; i += batchSize) {
    const batch = chunks.slice(i, i + batchSize);
    const texts = batch.map(c => capTextForEmbedding(c.text, maxChars));
    try {
      const embs = await embed(texts);
      for (let j = 0; j < batch.length; j++) {
        if (embs[j] && embs[j]!.length > 0) { batch[j]!.embedding = embs[j]; embedded++; }
        else skipped++;
      }
    } catch {
      // Batch failed (e.g. one chunk still 400s) — degrade to per-chunk so a single
      // bad chunk costs only itself, not every chunk in the batch.
      for (let j = 0; j < batch.length; j++) {
        try {
          const [e] = await embed([capTextForEmbedding(batch[j]!.text, maxChars)]);
          if (e && e.length > 0) { batch[j]!.embedding = e; embedded++; }
          else skipped++;
        } catch { skipped++; }
      }
    }
    if (opts.onProgress && i % 256 === 0) {
      opts.onProgress(`  ${Math.min(i + batchSize, chunks.length)}/${chunks.length}`);
    }
  }
  return { embedded, skipped };
}

export function cosineSim(a: number[], b: number[]): number {
  let dot = 0, na = 0, nb = 0;