Function buildReducePrompt

lib/ai-processing.ts:280–338

(
  candidates: CandidateTopic[],
  maxTopics: number,
  videoInfo?: Partial<VideoInfo>,
  minTopics: number = 0,
  segmentLabel?: string,
  language?: string
)

}

function buildReducePrompt(
  candidates: CandidateTopic[],
  maxTopics: number,
  videoInfo?: Partial<VideoInfo>,
  minTopics: number = 0,
  segmentLabel?: string,
  language?: string
): string {
  const videoInfoBlock = formatVideoInfoForPrompt(videoInfo);
  const segmentContext = segmentLabel
    ? `Focus: ${segmentLabel} of the video.`
    : '';
  const safeMin = Math.max(0, Math.min(minTopics, maxTopics));
  const selectionGuidance =
    safeMin > 0
      ? `Return between ${safeMin} and ${maxTopics} standout highlights. If fewer than ${safeMin} candidates truly meet the quality bar, respond with only the clips that do—even if that's less. Never exceed ${maxTopics}.`
      : `Return up to ${maxTopics} standout highlights that maximize diversity, insight, and narrative punch while reusing the provided quotes. It's acceptable to send back a single clip if only one deserves the spotlight.`;
  const languageInstruction = language
    ? (() => {
        const langName = getLanguageName(language);
        return `\n<languageRequirement>IMPORTANT: You MUST generate all titles in ${langName} to match the transcript language. Keep quote text and timestamps unchanged.</languageRequirement>\n`;
      })()
    : '';

  const candidateBlock = candidates
    .map((candidate, idx) => {
      const timestamp = candidate.quote?.timestamp ?? '[??:??-??:??]';
      const quoteText = candidate.quote?.text ?? '';
      const chunkWindow = `[${formatTime(candidate.chunkStart)}-${formatTime(
        candidate.chunkEnd
      )}]`;
      return `Candidate ${idx + 1}
Chunk window: ${chunkWindow}
Original title: ${candidate.title}
Quote timestamp: ${timestamp}
Quote text: ${quoteText}`;
    })
    .join('\n\n');

  return `<task>
<role>You are a senior editorial strategist assembling the final highlight reel lineup.</role>${languageInstruction}
<context>
${videoInfoBlock}
You have ${candidates.length} candidate quotes extracted from the transcript.
${segmentContext}
</context>
<goal>Choose the strongest highlights for this segment of the video.</goal>
<instructions>
  <item>${selectionGuidance}</item>
  <item>Review the candidates and choose the strongest, most distinct ideas within this segment.</item>
  <item>If two candidates overlap, keep the better one.</item>
  <item>You may rewrite titles for clarity, but you must keep the quote text and timestamp as provided.</item>
  <item>Respond with strict JSON: [{"candidateIndex":number,"title":"string"}]. Indices are 1-based and reference the numbered candidates below.</item>
</instructions>
<candidates><![CDATA[
${candidateBlock}
]]></candidates>
</task>`;