/**
 * Parse an NDJSON (newline-delimited JSON) stream into an async generator.
 *
 * Works with both Node.js `ReadableStream` and browser `ReadableStream<Uint8Array>`.
 * Handles partial lines across chunk boundaries gracefully.
 */
export async function* parseNdjsonStream<T = unknown>(
  body: ReadableStream<Uint8Array>
): AsyncGenerator<T> {
  const reader = body.getReader();
  const decoder = new TextDecoder();
  let buffer = '';

  try {
    while (true) {
      const { done, value } = await reader.read();
      if (done) break;

      buffer += decoder.decode(value, { stream: true });
      const lines = buffer.split('\n');
      buffer = lines.pop() ?? '';

      for (const line of lines) {
        const trimmed = line.trim();
        if (!trimmed) continue;
        try {
          yield JSON.parse(trimmed) as T;
        } catch {
          // skip malformed lines
        }
      }
    }

    // Process remaining buffer after stream ends
    if (buffer.trim()) {
      try {
        yield JSON.parse(buffer.trim()) as T;
      } catch {
        // skip
      }
    }
  } finally {
    reader.releaseLock();
  }
}