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

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

// GET all active heat cycles (with dog info)
router.get('/heat-cycles/active', (req, res) => {
  try {
    const db = getDatabase();
    const cycles = db.prepare(`
      SELECT hc.*, d.name as dog_name, d.registration_number, d.breed, d.birth_date
      FROM heat_cycles hc
      JOIN dogs d ON hc.dog_id = d.id
      WHERE hc.end_date IS NULL OR hc.end_date >= date('now', '-30 days')
      ORDER BY hc.start_date DESC
    `).all();
    res.json(cycles);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// GET all heat cycles (all dogs, for calendar population)
router.get('/heat-cycles', (req, res) => {
  try {
    const db = getDatabase();
    const { year, month } = req.query;
    let query = `
      SELECT hc.*, d.name as dog_name, d.registration_number, d.breed
      FROM heat_cycles hc
      JOIN dogs d ON hc.dog_id = d.id
    `;
    const params = [];
    if (year && month) {
      query += ` WHERE strftime('%Y', hc.start_date) = ? AND strftime('%m', hc.start_date) = ?`;
      params.push(year, month.toString().padStart(2, '0'));
    }
    query += ' ORDER BY hc.start_date DESC';
    const cycles = db.prepare(query).all(...params);
    res.json(cycles);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// GET breeding date suggestions for a heat cycle
// Returns optimal breeding window based on start_date (days 9-15 of cycle)
router.get('/heat-cycles/:id/suggestions', (req, res) => {
  try {
    const db = getDatabase();
    const cycle = db.prepare(`
      SELECT hc.*, d.name as dog_name
      FROM heat_cycles hc
      JOIN dogs d ON hc.dog_id = d.id
      WHERE hc.id = ?
    `).get(req.params.id);

    if (!cycle) return res.status(404).json({ error: 'Heat cycle not found' });

    const start = new Date(cycle.start_date);

    const addDays = (d, n) => {
      const r = new Date(d);
      r.setDate(r.getDate() + n);
      return r.toISOString().split('T')[0];
    };

    // Standard canine heat cycle windows
    res.json({
      cycle_id: cycle.id,
      dog_name: cycle.dog_name,
      start_date: cycle.start_date,
      windows: [
        {
          label: 'Proestrus',
          description: 'Bleeding begins, not yet receptive',
          start: addDays(start, 0),
          end: addDays(start, 8),
          color: 'pink',
          type: 'proestrus'
        },
        {
          label: 'Optimal Breeding Window',
          description: 'Estrus — highest fertility, best time to breed',
          start: addDays(start, 9),
          end: addDays(start, 15),
          color: 'green',
          type: 'optimal'
        },
        {
          label: 'Late Estrus',
          description: 'Fertility declining but breeding still possible',
          start: addDays(start, 16),
          end: addDays(start, 21),
          color: 'yellow',
          type: 'late'
        },
        {
          label: 'Diestrus',
          description: 'Cycle ending, not receptive',
          start: addDays(start, 22),
          end: addDays(start, 28),
          color: 'gray',
          type: 'diestrus'
        }
      ],
      // If a breeding_date was logged, compute whelping estimate
      whelping: cycle.breeding_date ? {
        breeding_date: cycle.breeding_date,
        earliest: addDays(new Date(cycle.breeding_date), 58),
        expected: addDays(new Date(cycle.breeding_date), 63),
        latest: addDays(new Date(cycle.breeding_date), 68)
      } : null
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// POST create heat cycle
router.post('/heat-cycles', (req, res) => {
  try {
    const { dog_id, start_date, end_date, breeding_date, breeding_successful, notes } = req.body;

    if (!dog_id || !start_date) {
      return res.status(400).json({ error: 'Dog ID and start date are required' });
    }

    const db = getDatabase();

    // Verify dog is female
    const dog = db.prepare('SELECT sex FROM dogs WHERE id = ?').get(dog_id);
    if (!dog || dog.sex !== 'female') {
      return res.status(400).json({ error: 'Dog must be female' });
    }

    const result = db.prepare(`
      INSERT INTO heat_cycles (dog_id, start_date, end_date, breeding_date, breeding_successful, notes)
      VALUES (?, ?, ?, ?, ?, ?)
    `).run(dog_id, start_date, end_date || null, breeding_date || null, breeding_successful || 0, notes || null);

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

// PUT update heat cycle
router.put('/heat-cycles/:id', (req, res) => {
  try {
    const { start_date, end_date, breeding_date, breeding_successful, notes } = req.body;
    const db = getDatabase();
    db.prepare(`
      UPDATE heat_cycles 
      SET start_date = ?, end_date = ?, breeding_date = ?, breeding_successful = ?, notes = ?
      WHERE id = ?
    `).run(start_date, end_date || null, breeding_date || null, breeding_successful || 0, notes || null, req.params.id);
    const cycle = db.prepare('SELECT * FROM heat_cycles WHERE id = ?').get(req.params.id);
    res.json(cycle);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// DELETE heat cycle
router.delete('/heat-cycles/:id', (req, res) => {
  try {
    const db = getDatabase();
    db.prepare('DELETE FROM heat_cycles WHERE id = ?').run(req.params.id);
    res.json({ message: 'Heat cycle deleted successfully' });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// GET whelping calculator (standalone)
router.get('/whelping-calculator', (req, res) => {
  try {
    const { breeding_date } = req.query;
    if (!breeding_date) {
      return res.status(400).json({ error: 'Breeding date is required' });
    }
    const breedDate = new Date(breeding_date);
    const addDays = (d, n) => { const r = new Date(d); r.setDate(r.getDate() + n); return r.toISOString().split('T')[0]; };
    res.json({
      breeding_date,
      expected_whelping_date: addDays(breedDate, 63),
      earliest_date: addDays(breedDate, 58),
      latest_date: addDays(breedDate, 68),
      gestation_days: 63
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

module.exports = router;