studio/services/bot/lib/transcript.ts

export type CaptionChunk = {
  text: string;
  timestamp: string;
  speaker?: string;
};

const MS_PER_MINUTE = 60_000;

export function getLastNMinutes(
  transcript: CaptionChunk[],
  minutes: number
): CaptionChunk[] {
  if (transcript.length === 0) return [];
  const cutoff = Date.now() - minutes * MS_PER_MINUTE;
  return transcript.filter((c) => {
    const t = Date.parse(c.timestamp);
    return !Number.isNaN(t) && t >= cutoff;
  });
}

export function formatTranscript(chunks: CaptionChunk[]): string {
  if (chunks.length === 0) return '(no transcript in window)';
  return chunks
    .map((c) => {
      const who = c.speaker ? `${c.speaker}: ` : '';
      return `[${c.timestamp}] ${who}${c.text}`;
    })
    .join('\n');
}