How to Build a How Long Calculator

// Multi-source "how long" query harvester
  async function harvestHowLongQueries(seed: string): Promise<QueryResult[]> {
  const prefix = 'how long';
  const results: QueryResult[] = [];

  // Source 1: Google Autocomplete with alphabet expansion
  const autocomplete = await expandWithAlphabet(prefix, seed);
  results.push(...autocomplete.map(q => ({ query: q, source: 'autocomplete' })));

  // Source 2: People Also Ask (via SerpAPI or scraping)
  const paaQueries = await fetchPeopleAlsoAsk(`${prefix} ${seed}`);
  results.push(...paaQueries.map(q => ({ query: q, source: 'paa' })));

  // Source 3: Related searches
  const related = await fetchRelatedSearches(`${prefix} ${seed}`);
  results.push(...related.map(q => ({ query: q, source: 'related' })));

  return deduplicateAndRank(results);
  }

  interface QueryResult {
  query: string;
  source: string;
  estimatedVolume?: number;
  difficulty?: number;
  }

  // Cluster by vertical (cooking, travel, health, DIY, etc.)
  function clusterByVertical(queries: QueryResult[]): Record<string, QueryResult[]> {
  const verticals: Record<string, string[]> = {
    cooking: ['bake', 'cook', 'boil', 'grill', 'fry', 'roast', 'smoke', 'marinate'],
    travel: ['flight', 'drive', 'fly', 'travel', 'visa', 'passport'],
    health: ['cold', 'flu', 'heal', 'recover', 'pregnant', 'contagious', 'symptom'],
    diy: ['dry', 'cure', 'set', 'paint', 'stain', 'epoxy', 'concrete'],
    finance: ['refund', 'transfer', 'process', 'approve', 'credit'],
  };

  const clustered: Record<string, QueryResult[]> = {};
  for (const q of queries) {
    let matched = 'other';
    for (const [vertical, keywords] of Object.entries(verticals)) {
      if (keywords.some(kw => q.query.toLowerCase().includes(kw))) {
        matched = vertical;
        break;
      }
    }
    if (!clustered[matched]) clustered[matched] = [];
    clustered[matched].push(q);
  }
  return clustered;
  }