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');

// Configure multer for photo uploads
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 }, // 10MB limit
  fileFilter: (req, file, cb) => {
    const allowedTypes = /jpeg|jpg|png|gif|webp/;
    const extname = allowedTypes.test(path.extname(file.originalname).toLowerCase());
    const mimetype = allowedTypes.test(file.mimetype);
    if (extname && mimetype) {
      cb(null, true);
    } else {
      cb(new Error('Only image files are allowed'));
    }
  }
});

// Helper function to convert empty strings to null
const emptyToNull = (value) => {
  return (value === '' || value === undefined) ? null : value;
};

// GET all dogs
router.get('/', (req, res) => {
  try {
    const db = getDatabase();
    const dogs = db.prepare(`
      SELECT id, name, registration_number, breed, sex, birth_date,
             color, microchip, photo_urls, notes, litter_id, is_active,
             created_at, updated_at
      FROM dogs 
      WHERE is_active = 1 
      ORDER BY name
    `).all();
    
    // Parse photo_urls JSON
    dogs.forEach(dog => {
      dog.photo_urls = dog.photo_urls ? JSON.parse(dog.photo_urls) : [];
    });
    
    res.json(dogs);
  } catch (error) {
    console.error('Error fetching dogs:', error);
    res.status(500).json({ error: error.message });
  }
});

// GET single dog by ID with parents and offspring
router.get('/:id', (req, res) => {
  try {
    const db = getDatabase();
    const dog = db.prepare(`
      SELECT id, name, registration_number, breed, sex, birth_date,
             color, microchip, photo_urls, notes, litter_id, is_active,
             created_at, updated_at
      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) : [];
    
    // Get parents from parents table
    const parents = db.prepare(`
      SELECT p.parent_type, d.* 
      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;
    
    // Get offspring
    dog.offspring = db.prepare(`
      SELECT d.* 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 new dog
router.post('/', (req, res) => {
  try {
    const { name, registration_number, breed, sex, birth_date, color, microchip, notes, sire_id, dam_id, litter_id } = req.body;
    
    console.log('Creating dog with data:', { name, breed, sex, sire_id, dam_id, litter_id });
    
    if (!name || !breed || !sex) {
      return res.status(400).json({ error: 'Name, breed, and sex are required' });
    }
    
    const db = getDatabase();
    
    // Insert dog (dogs table has NO sire/dam columns)
    const result = db.prepare(`
      INSERT INTO dogs (name, registration_number, breed, sex, birth_date, color, microchip, notes, litter_id, photo_urls)
      VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
    `).run(
      name, 
      emptyToNull(registration_number), 
      breed, 
      sex, 
      emptyToNull(birth_date), 
      emptyToNull(color), 
      emptyToNull(microchip),
      emptyToNull(notes),
      emptyToNull(litter_id),
      '[]'
    );
    
    const dogId = result.lastInsertRowid;
    console.log(`✓ Dog inserted with ID: ${dogId}`);
    
    // Add sire relationship if provided
    if (sire_id && sire_id !== '' && sire_id !== null) {
      console.log(`  Adding sire relationship: dog ${dogId} -> sire ${sire_id}`);
      db.prepare('INSERT INTO parents (dog_id, parent_id, parent_type) VALUES (?, ?, ?)').
        run(dogId, sire_id, 'sire');
      console.log(`  ✓ Sire relationship added`);
    }
    
    // Add dam relationship if provided
    if (dam_id && dam_id !== '' && dam_id !== null) {
      console.log(`  Adding dam relationship: dog ${dogId} -> dam ${dam_id}`);
      db.prepare('INSERT INTO parents (dog_id, parent_id, parent_type) VALUES (?, ?, ?)').
        run(dogId, dam_id, 'dam');
      console.log(`  ✓ Dam relationship added`);
    }
    
    // Fetch the created dog
    const dog = db.prepare(`
      SELECT id, name, registration_number, breed, sex, birth_date,
             color, microchip, photo_urls, notes, litter_id, is_active,
             created_at, updated_at
      FROM dogs
      WHERE id = ?
    `).get(dogId);
    dog.photo_urls = [];
    
    console.log(`✓ Dog created successfully: ${dog.name} (ID: ${dogId})`);
    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 } = req.body;
    
    console.log(`Updating dog ${req.params.id} with data:`, { name, breed, sex, sire_id, dam_id, litter_id });
    
    const db = getDatabase();
    
    // Update dog record (dogs table has NO sire/dam columns)
    db.prepare(`
      UPDATE dogs 
      SET name = ?, registration_number = ?, breed = ?, sex = ?, 
          birth_date = ?, color = ?, microchip = ?, notes = ?, litter_id = ?
      WHERE id = ?
    `).run(
      name, 
      emptyToNull(registration_number), 
      breed, 
      sex, 
      emptyToNull(birth_date), 
      emptyToNull(color), 
      emptyToNull(microchip),
      emptyToNull(notes),
      emptyToNull(litter_id),
      req.params.id
    );
    console.log(`  ✓ Dog record updated`);
    
    // Remove existing parent relationships
    db.prepare('DELETE FROM parents WHERE dog_id = ?').run(req.params.id);
    console.log(`  ✓ Old parent relationships removed`);
    
    // Add new sire relationship if provided
    if (sire_id && sire_id !== '' && sire_id !== null) {
      console.log(`  Adding sire relationship: dog ${req.params.id} -> sire ${sire_id}`);
      db.prepare('INSERT INTO parents (dog_id, parent_id, parent_type) VALUES (?, ?, ?)').
        run(req.params.id, sire_id, 'sire');
      console.log(`  ✓ Sire relationship added`);
    }
    
    // Add new dam relationship if provided
    if (dam_id && dam_id !== '' && dam_id !== null) {
      console.log(`  Adding dam relationship: dog ${req.params.id} -> dam ${dam_id}`);
      db.prepare('INSERT INTO parents (dog_id, parent_id, parent_type) VALUES (?, ?, ?)').
        run(req.params.id, dam_id, 'dam');
      console.log(`  ✓ Dam relationship added`);
    }
    
    // Fetch updated dog
    const dog = db.prepare(`
      SELECT id, name, registration_number, breed, sex, birth_date,
             color, microchip, photo_urls, notes, litter_id, is_active,
             created_at, updated_at
      FROM dogs
      WHERE id = ?
    `).get(req.params.id);
    dog.photo_urls = dog.photo_urls ? JSON.parse(dog.photo_urls) : [];
    
    console.log(`✓ Dog updated successfully: ${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 (soft delete)
router.delete('/:id', (req, res) => {
  try {
    const db = getDatabase();
    db.prepare('UPDATE dogs SET is_active = 0 WHERE id = ?').run(req.params.id);
    console.log(`✓ Dog soft-deleted: ID ${req.params.id}`);
    res.json({ message: 'Dog deleted successfully' });
  } catch (error) {
    console.error('Error deleting dog:', error);
    res.status(500).json({ error: error.message });
  }
});

// POST upload photo for dog
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 from dog
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]));
      
      // Delete file from disk
      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;