const express = require('express');
const router = express.Router();
const { getDatabase } = require('../db/init');

// Golden Retriever panel markers tracked by Breedr
const GR_MARKERS = [
  'PRA1', 'PRA2', 'prcd-PRA', 'GR-PRA1', 'GR-PRA2',
  'ICH1', 'ICH2', 'NCL', 'DM', 'MD'
];

// GET all genetic tests for a dog
router.get('/dog/:dogId', (req, res) => {
  try {
    const db = getDatabase();
    const tests = db.prepare(`
      SELECT * FROM genetic_tests
      WHERE dog_id = ?
      ORDER BY marker ASC
    `).all(req.params.dogId);

    // Return a full panel including not_tested placeholders
    const byMarker = {};
    for (const t of tests) byMarker[t.marker] = t;

    const panel = GR_MARKERS.map(marker => ({
      marker,
      ...(byMarker[marker] || { result: 'not_tested', dog_id: Number(req.params.dogId) })
    }));

    res.json({ tests, panel });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// GET pairing risk — compare sire + dam carrier status
// Usage: GET /api/genetics/pairing-risk?sireId=1&damId=2
router.get('/pairing-risk', (req, res) => {
  try {
    const { sireId, damId } = req.query;
    if (!sireId || !damId) {
      return res.status(400).json({ error: 'sireId and damId are required' });
    }

    const db = getDatabase();

    const getResults = (dogId) => {
      const rows = db.prepare('SELECT marker, result FROM genetic_tests WHERE dog_id = ?').all(dogId);
      const map = {};
      for (const r of rows) map[r.marker] = r.result;
      return map;
    };

    const sireResults = getResults(sireId);
    const damResults  = getResults(damId);

    const risks = [];
    for (const marker of GR_MARKERS) {
      const s = sireResults[marker] || 'not_tested';
      const d = damResults[marker]  || 'not_tested';

      // Both affected or carrier x carrier = risk
      if (
        (s === 'affected' || d === 'affected') ||
        (s === 'carrier'  && d === 'carrier')
      ) {
        risks.push({
          marker,
          sire_result: s,
          dam_result: d,
          risk_level: (s === 'affected' || d === 'affected') ? 'high' : 'moderate',
          note: s === 'affected' || d === 'affected'
            ? 'One or both parents are affected — do not breed'
            : 'Both parents are carriers — 25% chance of affected offspring',
        });
      }
    }

    res.json({
      sire_id: Number(sireId),
      dam_id: Number(damId),
      risks,
      safe_to_pair: risks.length === 0,
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// GET single genetic test
router.get('/:id', (req, res) => {
  try {
    const db = getDatabase();
    const test = db.prepare('SELECT * FROM genetic_tests WHERE id = ?').get(req.params.id);
    if (!test) return res.status(404).json({ error: 'Genetic test not found' });
    res.json(test);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// POST create genetic test
router.post('/', (req, res) => {
  try {
    const { dog_id, test_provider, marker, result, test_date, document_url, notes } = req.body;

    if (!dog_id || !marker || !result) {
      return res.status(400).json({ error: 'dog_id, marker, and result are required' });
    }
    if (!['clear', 'carrier', 'affected', 'not_tested'].includes(result)) {
      return res.status(400).json({ error: 'result must be: clear | carrier | affected | not_tested' });
    }

    const db = getDatabase();
    const dbResult = db.prepare(`
      INSERT INTO genetic_tests (dog_id, test_provider, marker, result, test_date, document_url, notes)
      VALUES (?, ?, ?, ?, ?, ?, ?)
    `).run(dog_id, test_provider || null, marker, result, test_date || null, document_url || null, notes || null);

    const test = db.prepare('SELECT * FROM genetic_tests WHERE id = ?').get(dbResult.lastInsertRowid);
    res.status(201).json(test);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// PUT update genetic test
router.put('/:id', (req, res) => {
  try {
    const { test_provider, marker, result, test_date, document_url, notes } = req.body;

    const db = getDatabase();
    db.prepare(`
      UPDATE genetic_tests
      SET test_provider = ?, marker = ?, result = ?, test_date = ?,
          document_url = ?, notes = ?, updated_at = datetime('now')
      WHERE id = ?
    `).run(test_provider || null, marker, result, test_date || null, document_url || null, notes || null, req.params.id);

    const test = db.prepare('SELECT * FROM genetic_tests WHERE id = ?').get(req.params.id);
    res.json(test);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// DELETE genetic test
router.delete('/:id', (req, res) => {
  try {
    const db = getDatabase();
    db.prepare('DELETE FROM genetic_tests WHERE id = ?').run(req.params.id);
    res.json({ message: 'Genetic test deleted successfully' });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

module.exports = router;