Function buildFallbackTopics

lib/ai-processing.ts:451–516

(
  transcript: TranscriptSegment[],
  maxTopics: number,
  fullText: string,
  theme?: string
)

}

function buildFallbackTopics(
  transcript: TranscriptSegment[],
  maxTopics: number,
  fullText: string,
  theme?: string
): ParsedTopic[] {
  // Don't generate generic fallbacks for theme-based generation
  // If AI can't find theme-relevant content, return empty array
  if (theme) {
    console.log(`[buildFallbackTopics] Skipping fallback generation for theme: "${theme}"`);
    return [];
  }

  if (transcript.length === 0) {
    if (!fullText) return [];
    return [
      {
        title: theme ? `${theme} overview` : 'Full Video',
        quote: {
          timestamp: '[00:00-00:30]',
          text: fullText.substring(0, 200)
        }
      }
    ];
  }

  const fallbackCount = Math.min(6, Math.max(1, maxTopics));
  const chunkSize = Math.ceil(transcript.length / fallbackCount);
  const fallbackTopics: ParsedTopic[] = [];

  for (let i = 0; i < fallbackCount && i * chunkSize < transcript.length; i++) {
    const startIdx = i * chunkSize;
    const endIdx = Math.min((i + 1) * chunkSize, transcript.length);
    const chunkSegments = transcript.slice(startIdx, endIdx);

    if (chunkSegments.length === 0) continue;

    const startTime = chunkSegments[0].start;
    const endSegment = chunkSegments[chunkSegments.length - 1];
    const endTime = endSegment.start + endSegment.duration;

    fallbackTopics.push({
      title: buildFallbackTopicTitle(startTime, endTime),
      quote: {
        timestamp: `[${formatTime(startTime)}-${formatTime(endTime)}]`,
        text:
          chunkSegments
            .map((s) => s.text)
            .join(' ')
            .substring(0, 200) + '...'
      }
    });
  }

  if (fallbackTopics.length === 0 && fullText) {
    fallbackTopics.push({
      title: theme ? `${theme} spotlight` : 'Full Video',
      quote: {