import express from 'express';
import db from '../database.js';
import { authenticateToken, optionalAuth } from '../middleware/auth.js';

const router = express.Router();

// Get all collections (hierarchical)
router.get('/', authenticateToken, (req, res) => {
  const query = `
    SELECT c.*,
           p.name as parent_name,
           COUNT(DISTINCT m.id) as model_count
    FROM collections c
    LEFT JOIN collections p ON c.parent_id = p.id
    LEFT JOIN models m ON c.id = m.collection_id
    WHERE c.user_id = ?
    GROUP BY c.id
    ORDER BY c.parent_id ASC, c.created_at DESC
  `;

  db.all(query, [req.user.id], (err, collections) => {
    if (err) {
      return res.status(500).json({ error: err.message });
    }

    // Build hierarchical structure
    const collectionMap = new Map();
    const rootCollections = [];

    collections.forEach(c => {
      c.children = [];
      collectionMap.set(c.id, c);
    });

    collections.forEach(c => {
      if (c.parent_id) {
        const parent = collectionMap.get(c.parent_id);
        if (parent) {
          parent.children.push(c);
        }
      } else {
        rootCollections.push(c);
      }
    });

    res.json({ collections: rootCollections, all: collections });
  });
});

// Get single collection with models
router.get('/:id', authenticateToken, (req, res) => {
  const collectionQuery = `
    SELECT c.*, COUNT(m.id) as model_count
    FROM collections c
    LEFT JOIN models m ON c.id = m.collection_id
    WHERE c.id = ? AND c.user_id = ?
    GROUP BY c.id
  `;

  db.get(collectionQuery, [req.params.id, req.user.id], (err, collection) => {
    if (err) {
      return res.status(500).json({ error: err.message });
    }
    if (!collection) {
      return res.status(404).json({ error: 'Collection not found' });
    }

    const modelsQuery = `
      SELECT m.*, GROUP_CONCAT(t.name) as tags
      FROM models m
      LEFT JOIN model_tags mt ON m.id = mt.model_id
      LEFT JOIN tags t ON mt.tag_id = t.id
      WHERE m.collection_id = ?
      GROUP BY m.id
      ORDER BY m.created_at DESC
    `;

    db.all(modelsQuery, [req.params.id], (err, models) => {
      if (err) {
        return res.status(500).json({ error: err.message });
      }

      collection.models = models.map(model => ({
        ...model,
        tags: model.tags ? model.tags.split(',') : []
      }));

      res.json(collection);
    });
  });
});

// Create collection
router.post('/', authenticateToken, (req, res) => {
  const { name, description, parentId } = req.body;

  if (!name) {
    return res.status(400).json({ error: 'Collection name is required' });
  }

  const query = 'INSERT INTO collections (name, description, parent_id, user_id) VALUES (?, ?, ?, ?)';

  db.run(query, [name, description || null, parentId || null, req.user.id], function (err) {
    if (err) {
      return res.status(500).json({ error: err.message });
    }

    res.status(201).json({
      message: 'Collection created successfully',
      collectionId: this.lastID,
      collection: {
        id: this.lastID,
        name,
        description,
        parent_id: parentId
      }
    });
  });
});

// Update collection
router.put('/:id', authenticateToken, (req, res) => {
  const { name, description } = req.body;
  const updates = [];
  const params = [];

  if (name !== undefined) {
    updates.push('name = ?');
    params.push(name);
  }
  if (description !== undefined) {
    updates.push('description = ?');
    params.push(description);
  }

  if (updates.length === 0) {
    return res.status(400).json({ error: 'No fields to update' });
  }

  params.push(req.params.id);
  const query = `UPDATE collections SET ${updates.join(', ')} WHERE id = ?`;

  db.run(query, params, function (err) {
    if (err) {
      return res.status(500).json({ error: err.message });
    }

    if (this.changes === 0) {
      return res.status(404).json({ error: 'Collection not found' });
    }

    res.json({ message: 'Collection updated successfully' });
  });
});

// Delete collection
router.delete('/:id', authenticateToken, (req, res) => {
  db.run('DELETE FROM collections WHERE id = ?', [req.params.id], function (err) {
    if (err) {
      return res.status(500).json({ error: err.message });
    }

    if (this.changes === 0) {
      return res.status(404).json({ error: 'Collection not found' });
    }

    res.json({ message: 'Collection deleted successfully' });
  });
});

export default router;