const express = require('express');
const db = require('../db');
const router = express.Router();

// GET /api/search?q=term
router.get('/', (req, res) => {
  const q = req.query.q || '';
  const term = q.trim();
  if (!term) {
    return res.json({ messages: [], pdfs: [] });
  }

  try {
    const messageResults = [];
    const pdfResults = [];
    const fts5 = db._fts5Available;

    // Sanitize term for FTS5: quote each whitespace-separated term
    const safeTerm = term.split(/\s+/).filter(Boolean).map(t => `"${t.replace(/"/g, '""')}"`).join(' ');
    const fts5Term = fts5 ? safeTerm : null;

    if (fts5 && fts5Term) {
      // FTS5 path: use MATCH with snippet highlighting and BM25 ranking
      const messageRows = db.prepare(`
        SELECT m.id, m.conversation_id, m.content,
          snippet(messages_fts, 1, '<b>', '</b>', '…', 16) as snippet,
          rank
        FROM messages_fts
        JOIN messages m ON m.id = messages_fts.rowid
        WHERE messages_fts MATCH ?
        ORDER BY rank
        LIMIT 25
      `).all(fts5Term);

      const pdfRows = db.prepare(`
        SELECT p.id, p.original_name, p.content_markdown,
          snippet(pdfs_fts, 1, '<b>', '</b>', '…', 16) as snippet,
          rank
        FROM pdfs_fts
        JOIN pdfs p ON p.id = pdfs_fts.rowid
        WHERE pdfs_fts MATCH ?
        ORDER BY rank
        LIMIT 25
      `).all(fts5Term);

      for (const row of messageRows) {
        messageResults.push({
          type: 'message',
          id: row.id,
          title: row.content?.slice(0, 60) || 'Mensaje',
          snippet: row.snippet || '',
          rank: row.rank || 0,
          conversation_id: row.conversation_id,
        });
      }

      for (const row of pdfRows) {
        pdfResults.push({
          type: 'pdf',
          id: row.id,
          title: row.original_name || 'PDF',
          snippet: row.snippet || '',
          rank: row.rank || 0,
        });
      }
    } else {
      // LIKE fallback (no ranking, no snippets)
      const likeTerm = `%${term}%`;
      const messageRows = db.prepare(
        `SELECT id, conversation_id, content FROM messages WHERE content LIKE ? LIMIT 25`
      ).all(likeTerm);
      const pdfRows = db.prepare(
        `SELECT id, original_name, content_markdown FROM pdfs WHERE content_markdown LIKE ? LIMIT 25`
      ).all(likeTerm);

      for (const row of messageRows) {
        messageResults.push({
          type: 'message',
          id: row.id,
          title: row.content?.slice(0, 60) || 'Mensaje',
          snippet: row.content?.slice(0, 120) || '',
          rank: 0,
          conversation_id: row.conversation_id,
        });
      }

      for (const row of pdfRows) {
        pdfResults.push({
          type: 'pdf',
          id: row.id,
          title: row.original_name || 'PDF',
          snippet: row.content_markdown?.slice(0, 120) || '',
          rank: 0,
        });
      }
    }

    // Return grouped results — keep message BM25 and PDF BM25 ranks separate (different indexes)
    messageResults.sort((a, b) => (a.rank || 0) - (b.rank || 0));
    pdfResults.sort((a, b) => (a.rank || 0) - (b.rank || 0));
    res.json({ messages: messageResults.slice(0, 25), pdfs: pdfResults.slice(0, 25) });
  } catch (err) {
    console.error('[search] error:', err.message);
    res.status(500).json({ error: err.message });
  }
});

module.exports = router;