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

// OFA tests that count toward GRCA eligibility
const GRCA_REQUIRED = ['hip_ofa', 'hip_pennhip', 'elbow_ofa', 'heart_ofa', 'heart_echo', 'eye_caer'];
const GRCA_CORE = {
  hip:    ['hip_ofa', 'hip_pennhip'],
  elbow:  ['elbow_ofa'],
  heart:  ['heart_ofa', 'heart_echo'],
  eye:    ['eye_caer'],
};
const VALID_TEST_TYPES = ['hip_ofa', 'hip_pennhip', 'elbow_ofa', 'heart_ofa', 'heart_echo', 'eye_caer', 'thyroid_ofa', 'dna_panel'];

// Helper: compute clearance summary for a dog
function getClearanceSummary(db, dogId) {
  const records = db.prepare(`
    SELECT test_type, ofa_result, ofa_number, expires_at, test_date
    FROM health_records
    WHERE dog_id = ? AND test_type IS NOT NULL
    ORDER BY test_date DESC
  `).all(dogId);

  const today = new Date();
  const in90 = new Date(); in90.setDate(today.getDate() + 90);

  const summary = {};
  for (const [group, types] of Object.entries(GRCA_CORE)) {
    const match = records.find(r => types.includes(r.test_type));
    if (!match) {
      summary[group] = { status: 'missing', record: null };
    } else {
      let status = 'pass';
      if (match.expires_at) {
        const exp = new Date(match.expires_at);
        if (exp < today)          status = 'expired';
        else if (exp <= in90)     status = 'expiring_soon';
      }
      summary[group] = { status, record: match };
    }
  }
  return summary;
}

// GET all health records for a dog
router.get('/dog/:dogId', (req, res) => {
  try {
    const db = getDatabase();
    const records = db.prepare(`
      SELECT * FROM health_records
      WHERE dog_id = ?
      ORDER BY test_date DESC
    `).all(req.params.dogId);
    res.json(records);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// GET clearance summary (Hip / Elbow / Heart / Eyes) for a dog
router.get('/dog/:dogId/clearance-summary', (req, res) => {
  try {
    const db = getDatabase();
    const dog = db.prepare('SELECT id, birth_date, chic_number FROM dogs WHERE id = ?').get(req.params.dogId);
    if (!dog) return res.status(404).json({ error: 'Dog not found' });

    const summary = getClearanceSummary(db, dog.id);

    // Age check: must be >= 24 months for hip/elbow
    let ageEligible = false;
    if (dog.birth_date) {
      const months = (new Date() - new Date(dog.birth_date)) / (1000 * 60 * 60 * 24 * 30.44);
      ageEligible = months >= 24;
    }

    const allPass = Object.values(summary).every(s => ['pass', 'expiring_soon'].includes(s.status));
    const grca_eligible = allPass && ageEligible;

    res.json({ summary, grca_eligible, age_eligible: ageEligible, chic_number: dog.chic_number });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// GET CHIC eligibility check
router.get('/dog/:dogId/chic-eligible', (req, res) => {
  try {
    const db = getDatabase();
    const dog = db.prepare('SELECT id, chic_number FROM dogs WHERE id = ?').get(req.params.dogId);
    if (!dog) return res.status(404).json({ error: 'Dog not found' });

    const summary = getClearanceSummary(db, dog.id);
    const missing = Object.entries(summary)
      .filter(([, v]) => v.status === 'missing')
      .map(([k]) => k);

    res.json({
      chic_eligible: missing.length === 0,
      chic_number: dog.chic_number || null,
      missing_tests: missing,
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});


// POST create health record
router.post('/', (req, res) => {
  try {
    const {
      dog_id, record_type, test_type, test_name, test_date,
      ofa_result, ofa_number, performed_by, expires_at,
      document_url, result, vet_name, next_due, notes
    } = req.body;

    if (!dog_id || !record_type || !test_date) {
      return res.status(400).json({ error: 'dog_id, record_type, and test_date are required' });
    }

    if (test_type && !VALID_TEST_TYPES.includes(test_type)) {
      return res.status(400).json({ error: 'Invalid test_type' });
    }

    const db = getDatabase();
    const dbResult = db.prepare(`
      INSERT INTO health_records
        (dog_id, record_type, test_type, test_name, test_date,
         ofa_result, ofa_number, performed_by, expires_at,
         document_url, result, vet_name, next_due, notes)
      VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
    `).run(
      dog_id, record_type, test_type || null, test_name || null, test_date,
      ofa_result || null, ofa_number || null, performed_by || null, expires_at || null,
      document_url || null, result || null, vet_name || null, next_due || null, notes || null
    );

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

// PUT update health record
router.put('/:id', (req, res) => {
  try {
    const {
      record_type, test_type, test_name, test_date,
      ofa_result, ofa_number, performed_by, expires_at,
      document_url, result, vet_name, next_due, notes
    } = req.body;

    if (test_type && !VALID_TEST_TYPES.includes(test_type)) {
      return res.status(400).json({ error: 'Invalid test_type' });
    }

    const db = getDatabase();
    db.prepare(`
      UPDATE health_records
      SET record_type = ?, test_type = ?, test_name = ?, test_date = ?,
          ofa_result = ?, ofa_number = ?, performed_by = ?, expires_at = ?,
          document_url = ?, result = ?, vet_name = ?, next_due = ?, notes = ?,
          updated_at = datetime('now')
      WHERE id = ?
    `).run(
      record_type, test_type || null, test_name || null, test_date,
      ofa_result || null, ofa_number || null, performed_by || null, expires_at || null,
      document_url || null, result || null, vet_name || null, next_due || null, notes || null,
      req.params.id
    );

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

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

// GET cancer history for a dog
router.get('/dog/:dogId/cancer-history', (req, res) => {
  try {
    const db = getDatabase();
    const records = db.prepare(`
      SELECT * FROM cancer_history
      WHERE dog_id = ?
      ORDER BY age_at_diagnosis ASC, created_at DESC
    `).all(req.params.dogId);
    res.json(records);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// POST create cancer history record
router.post('/cancer-history', (req, res) => {
  try {
    const {
      dog_id, cancer_type, age_at_diagnosis, age_at_death, cause_of_death, notes
    } = req.body;

    if (!dog_id || !cancer_type) {
      return res.status(400).json({ error: 'dog_id and cancer_type are required' });
    }

    const db = getDatabase();
    
    // Update dog's age_at_death and cause_of_death if provided
    if (age_at_death || cause_of_death) {
      db.prepare(`
        UPDATE dogs SET 
          age_at_death = COALESCE(?, age_at_death),
          cause_of_death = COALESCE(?, cause_of_death)
        WHERE id = ?
      `).run(age_at_death || null, cause_of_death || null, dog_id);
    }

    const dbResult = db.prepare(`
      INSERT INTO cancer_history
        (dog_id, cancer_type, age_at_diagnosis, age_at_death, cause_of_death, notes)
      VALUES (?, ?, ?, ?, ?, ?)
    `).run(
      dog_id, cancer_type, age_at_diagnosis || null, 
      age_at_death || null, cause_of_death || null, notes || null
    );

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

// GET single health record (wildcard should go last to prevent overlap)
router.get('/:id', (req, res) => {
  try {
    const db = getDatabase();
    const record = db.prepare('SELECT * FROM health_records WHERE id = ?').get(req.params.id);
    if (!record) return res.status(404).json({ error: 'Health record not found' });
    res.json(record);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

module.exports = router;