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

const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    const uploadPath = process.env.UPLOAD_PATH || path.join(__dirname, '../../uploads');
    cb(null, uploadPath);
  },
  filename: (req, file, cb) => {
    const uniqueName = `${Date.now()}-${Math.random().toString(36).substring(7)}${path.extname(file.originalname)}`;
    cb(null, uniqueName);
  }
});

const upload = multer({
  storage,
  limits: { fileSize: 10 * 1024 * 1024 },
  fileFilter: (req, file, cb) => {
    const allowed = /jpeg|jpg|png|gif|webp/;
    if (allowed.test(path.extname(file.originalname).toLowerCase()) && allowed.test(file.mimetype)) {
      cb(null, true);
    } else {
      cb(new Error('Only image files are allowed'));
    }
  }
});

const emptyToNull = (v) => (v === '' || v === undefined) ? null : v;

// ── Shared SELECT columns ────────────────────────────────────────────────
const DOG_COLS = `
  id, name, registration_number, breed, sex, birth_date,
  color, microchip, photo_urls, notes, litter_id, is_active,
  is_champion, is_external, created_at, updated_at
`;

// ── Helper: attach parents to a list of dogs ─────────────────────────────
function attachParents(db, dogs) {
  const parentStmt = db.prepare(`
    SELECT p.parent_type, d.id, d.name, d.is_champion, d.is_external
    FROM parents p
    JOIN dogs d ON p.parent_id = d.id
    WHERE p.dog_id = ?
  `);
  dogs.forEach(dog => {
    dog.photo_urls = dog.photo_urls ? JSON.parse(dog.photo_urls) : [];
    const parents = parentStmt.all(dog.id);
    dog.sire = parents.find(p => p.parent_type === 'sire') || null;
    dog.dam  = parents.find(p => p.parent_type === 'dam')  || null;
  });
  return dogs;
}

// ── GET dogs
//    Default: kennel dogs only (is_external = 0)
//    ?include_external=1 : all active dogs (kennel + external)
//    ?external_only=1    : external dogs only
// ─────────────────────────────────────────────────────────────────────────
router.get('/', (req, res) => {
  try {
    const db = getDatabase();
    const includeExternal = req.query.include_external === '1' || req.query.include_external === 'true';
    const externalOnly    = req.query.external_only    === '1' || req.query.external_only    === 'true';

    let whereClause;
    if (externalOnly) {
      whereClause = 'WHERE is_active = 1 AND is_external = 1';
    } else if (includeExternal) {
      whereClause = 'WHERE is_active = 1';
    } else {
      whereClause = 'WHERE is_active = 1 AND is_external = 0';
    }

    const dogs = db.prepare(`
      SELECT ${DOG_COLS}
      FROM dogs
      ${whereClause}
      ORDER BY name
    `).all();

    res.json(attachParents(db, dogs));
  } catch (error) {
    console.error('Error fetching dogs:', error);
    res.status(500).json({ error: error.message });
  }
});

// ── GET all dogs (kennel + external) for dropdowns/pairing/pedigree ──────────
// Kept for backwards-compat; equivalent to GET /?include_external=1
router.get('/all', (req, res) => {
  try {
    const db = getDatabase();
    const dogs = db.prepare(`
      SELECT ${DOG_COLS}
      FROM dogs
      WHERE is_active = 1
      ORDER BY name
    `).all();
    res.json(attachParents(db, dogs));
  } catch (error) {
    console.error('Error fetching all dogs:', error);
    res.status(500).json({ error: error.message });
  }
});

// ── GET external dogs only (is_external = 1) ──────────────────────────────
// Kept for backwards-compat; equivalent to GET /?external_only=1
router.get('/external', (req, res) => {
  try {
    const db = getDatabase();
    const dogs = db.prepare(`
      SELECT ${DOG_COLS}
      FROM dogs
      WHERE is_active = 1 AND is_external = 1
      ORDER BY name
    `).all();
    res.json(attachParents(db, dogs));
  } catch (error) {
    console.error('Error fetching external dogs:', error);
    res.status(500).json({ error: error.message });
  }
});

// ── GET single dog (with parents + offspring) ──────────────────────────
router.get('/:id', (req, res) => {
  try {
    const db = getDatabase();
    const dog = db.prepare(`SELECT ${DOG_COLS} FROM dogs WHERE id = ?`).get(req.params.id);

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

    dog.photo_urls = dog.photo_urls ? JSON.parse(dog.photo_urls) : [];

    const parents = db.prepare(`
      SELECT p.parent_type, d.id, d.name, d.is_champion, d.is_external
      FROM parents p
      JOIN dogs d ON p.parent_id = d.id
      WHERE p.dog_id = ?
    `).all(req.params.id);

    dog.sire = parents.find(p => p.parent_type === 'sire') || null;
    dog.dam  = parents.find(p => p.parent_type === 'dam')  || null;

    dog.offspring = db.prepare(`
      SELECT d.id, d.name, d.sex, d.is_champion, d.is_external
      FROM dogs d
      JOIN parents p ON d.id = p.dog_id
      WHERE p.parent_id = ? AND d.is_active = 1
    `).all(req.params.id);

    res.json(dog);
  } catch (error) {
    console.error('Error fetching dog:', error);
    res.status(500).json({ error: error.message });
  }
});

// ── POST create dog ─────────────────────────────────────────────────────
router.post('/', (req, res) => {
  try {
    const { name, registration_number, breed, sex, birth_date, color,
            microchip, notes, sire_id, dam_id, litter_id, is_champion, is_external } = req.body;

    if (!name || !breed || !sex) {
      return res.status(400).json({ error: 'Name, breed, and sex are required' });
    }

    const db = getDatabase();
    const result = db.prepare(`
      INSERT INTO dogs (name, registration_number, breed, sex, birth_date, color,
                        microchip, notes, litter_id, photo_urls, is_champion, is_external)
      VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
    `).run(
      name,
      emptyToNull(registration_number),
      breed, sex,
      emptyToNull(birth_date),
      emptyToNull(color),
      emptyToNull(microchip),
      emptyToNull(notes),
      emptyToNull(litter_id),
      '[]',
      is_champion ? 1 : 0,
      is_external ? 1 : 0
    );

    const dogId = result.lastInsertRowid;

    if (sire_id && sire_id !== '' && sire_id !== null) {
      db.prepare('INSERT INTO parents (dog_id, parent_id, parent_type) VALUES (?, ?, ?)').run(dogId, sire_id, 'sire');
    }
    if (dam_id && dam_id !== '' && dam_id !== null) {
      db.prepare('INSERT INTO parents (dog_id, parent_id, parent_type) VALUES (?, ?, ?)').run(dogId, dam_id, 'dam');
    }

    const dog = db.prepare(`SELECT ${DOG_COLS} FROM dogs WHERE id = ?`).get(dogId);
    dog.photo_urls = [];

    console.log(`✔ Dog created: ${dog.name} (ID: ${dogId}, external: ${dog.is_external})`);
    res.status(201).json(dog);
  } catch (error) {
    console.error('Error creating dog:', error);
    res.status(500).json({ error: error.message });
  }
});

// ── PUT update dog ───────────────────────────────────────────────────────
router.put('/:id', (req, res) => {
  try {
    const { name, registration_number, breed, sex, birth_date, color,
            microchip, notes, sire_id, dam_id, litter_id, is_champion, is_external } = req.body;

    const db = getDatabase();
    db.prepare(`
      UPDATE dogs
      SET name = ?, registration_number = ?, breed = ?, sex = ?,
          birth_date = ?, color = ?, microchip = ?, notes = ?,
          litter_id = ?, is_champion = ?, is_external = ?, updated_at = datetime('now')
      WHERE id = ?
    `).run(
      name,
      emptyToNull(registration_number),
      breed, sex,
      emptyToNull(birth_date),
      emptyToNull(color),
      emptyToNull(microchip),
      emptyToNull(notes),
      emptyToNull(litter_id),
      is_champion ? 1 : 0,
      is_external ? 1 : 0,
      req.params.id
    );

    db.prepare('DELETE FROM parents WHERE dog_id = ?').run(req.params.id);
    if (sire_id && sire_id !== '' && sire_id !== null) {
      db.prepare('INSERT INTO parents (dog_id, parent_id, parent_type) VALUES (?, ?, ?)').run(req.params.id, sire_id, 'sire');
    }
    if (dam_id && dam_id !== '' && dam_id !== null) {
      db.prepare('INSERT INTO parents (dog_id, parent_id, parent_type) VALUES (?, ?, ?)').run(req.params.id, dam_id, 'dam');
    }

    const dog = db.prepare(`SELECT ${DOG_COLS} FROM dogs WHERE id = ?`).get(req.params.id);
    dog.photo_urls = dog.photo_urls ? JSON.parse(dog.photo_urls) : [];

    console.log(`✔ Dog updated: ${dog.name} (ID: ${req.params.id})`);
    res.json(dog);
  } catch (error) {
    console.error('Error updating dog:', error);
    res.status(500).json({ error: error.message });
  }
});

// ── DELETE dog (hard delete with cascade) ───────────────────────────────
router.delete('/:id', (req, res) => {
  try {
    const db = getDatabase();
    const existing = db.prepare('SELECT id, name FROM dogs WHERE id = ?').get(req.params.id);
    if (!existing) return res.status(404).json({ error: 'Dog not found' });

    const id = req.params.id;
    db.prepare('DELETE FROM parents        WHERE parent_id = ?').run(id);
    db.prepare('DELETE FROM parents        WHERE dog_id    = ?').run(id);
    db.prepare('DELETE FROM health_records WHERE dog_id    = ?').run(id);
    db.prepare('DELETE FROM heat_cycles    WHERE dog_id    = ?').run(id);
    db.prepare('DELETE FROM dogs           WHERE id        = ?').run(id);

    console.log(`✔ Dog #${id} (${existing.name}) permanently deleted`);
    res.json({ success: true, message: `${existing.name} has been deleted` });
  } catch (error) {
    console.error('Error deleting dog:', error);
    res.status(500).json({ error: error.message });
  }
});

// ── POST upload photo ────────────────────────────────────────────────────
router.post('/:id/photos', upload.single('photo'), (req, res) => {
  try {
    if (!req.file) return res.status(400).json({ error: 'No file uploaded' });

    const db = getDatabase();
    const dog = db.prepare('SELECT photo_urls FROM dogs WHERE id = ?').get(req.params.id);
    if (!dog) return res.status(404).json({ error: 'Dog not found' });

    const photoUrls = dog.photo_urls ? JSON.parse(dog.photo_urls) : [];
    photoUrls.push(`/uploads/${req.file.filename}`);
    db.prepare('UPDATE dogs SET photo_urls = ? WHERE id = ?').run(JSON.stringify(photoUrls), req.params.id);

    res.json({ url: `/uploads/${req.file.filename}`, photos: photoUrls });
  } catch (error) {
    console.error('Error uploading photo:', error);
    res.status(500).json({ error: error.message });
  }
});

// ── DELETE photo ──────────────────────────────────────────────────────
router.delete('/:id/photos/:photoIndex', (req, res) => {
  try {
    const db = getDatabase();
    const dog = db.prepare('SELECT photo_urls FROM dogs WHERE id = ?').get(req.params.id);
    if (!dog) return res.status(404).json({ error: 'Dog not found' });

    const photoUrls  = dog.photo_urls ? JSON.parse(dog.photo_urls) : [];
    const photoIndex = parseInt(req.params.photoIndex);

    if (photoIndex >= 0 && photoIndex < photoUrls.length) {
      const photoPath = path.join(
        process.env.UPLOAD_PATH || path.join(__dirname, '../../uploads'),
        path.basename(photoUrls[photoIndex])
      );
      if (fs.existsSync(photoPath)) fs.unlinkSync(photoPath);
      photoUrls.splice(photoIndex, 1);
      db.prepare('UPDATE dogs SET photo_urls = ? WHERE id = ?').run(JSON.stringify(photoUrls), req.params.id);
    }

    res.json({ photos: photoUrls });
  } catch (error) {
    console.error('Error deleting photo:', error);
    res.status(500).json({ error: error.message });
  }
});

module.exports = router;