const express = require('express');

const normalizeQuery = (exerciseName, body) => {
  if (body && typeof body.query === 'string' && body.query.trim()) {
    return body.query.trim();
  }

  if (body && typeof body.name === 'string' && body.name.trim()) {
    return body.name.trim();
  }

  return `${exerciseName} exercise`;
};

const createExerciseResearchRouter = ({ pool, exaSearch }) => {
  if (!pool || typeof pool.query !== 'function') {
    throw new Error('Pool with query function is required');
  }
  if (!exaSearch || typeof exaSearch !== 'function') {
    throw new Error('exaSearch function is required');
  }

  const router = express.Router();

  router.post('/:id/research', async (req, res) => {
    try {
      const exerciseId = Number.parseInt(req.params.id, 10);
      if (!Number.isInteger(exerciseId)) {
        return res.status(400).json({ error: 'Exercise id must be an integer' });
      }

      const exerciseResult = await pool.query(
        'SELECT id, name, description, muscle_groups, difficulty, equipment_needed FROM exercises WHERE id = $1',
        [exerciseId]
      );

      if (!exerciseResult.rows.length) {
        return res.status(404).json({ error: 'Exercise not found' });
      }

      const exercise = exerciseResult.rows[0];
      const query = normalizeQuery(exercise.name, req.body);
      const requestedResults = req.body?.num_results;
      const numResults = Number.isInteger(requestedResults) && requestedResults > 0
        ? Math.min(requestedResults, 10)
        : 5;

      const { summary, results } = await exaSearch({ query, numResults });

      let researchRecord = null;
      try {
        const insertResult = await pool.query(
          `INSERT INTO research_results (exercise_id, query, summary, results, provider)
           VALUES ($1, $2, $3, $4, $5)
           RETURNING id, created_at`,
          [exerciseId, query, summary, JSON.stringify(results), 'exa']
        );
        researchRecord = insertResult.rows[0] || null;
      } catch (err) {
        console.warn('Failed to store research results:', err.message);
      }

      res.json({
        exercise,
        query,
        summary,
        results,
        stored: researchRecord
      });
    } catch (err) {
      console.error('Error running exercise research:', err);
      res.status(500).json({ error: 'Failed to fetch research' });
    }
  });

  return router;
};

module.exports = {
  createExerciseResearchRouter
};