import express from 'express';
import pool from '../db/pool.js';
import { validateUuid } from '../middleware/errors.js';
import { v4 as uuidv4 } from 'uuid';

const router = express.Router();
router.param('id', (req, res, next) => validateUuid('id')(req, res, next));

// GET / - List bins. Filter by project_id when supplied; otherwise return
// every bin across every project so the Library / asset-context-menu can
// present a global "move to bin" picker.
router.get('/', async (req, res, next) => {
  try {
    const { project_id } = req.query;

    const params = [];
    let where = '';
    if (project_id) {
      where = 'WHERE b.project_id = $1';
      params.push(project_id);
    }

    const result = await pool.query(
      `SELECT b.*, p.name AS project_name,
              (SELECT COUNT(*)::int FROM assets a WHERE a.bin_id = b.id) AS asset_count
       FROM bins b
       LEFT JOIN projects p ON p.id = b.project_id
       ${where}
       ORDER BY b.created_at DESC`,
      params
    );

    res.json(result.rows);
  } catch (err) {
    next(err);
  }
});

// POST / - Create bin
router.post('/', async (req, res, next) => {
  try {
    const { project_id, name, parent_id } = req.body;

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

    const id = uuidv4();

    const result = await pool.query(
      `INSERT INTO bins (id, project_id, name, parent_id, created_at, updated_at)
       VALUES ($1, $2, $3, $4, NOW(), NOW())
       RETURNING *`,
      [id, project_id, name, parent_id || null]
    );

    res.status(201).json(result.rows[0]);
  } catch (err) {
    next(err);
  }
});

// PATCH /:id - Update bin
router.patch('/:id', async (req, res, next) => {
  try {
    const { id } = req.params;
    const { name, parent_id } = req.body;

    const updates = [];
    const params = [];
    let paramCount = 1;

    if (name !== undefined) {
      updates.push(`name = $${paramCount++}`);
      params.push(name);
    }

    if (parent_id !== undefined) {
      updates.push(`parent_id = $${paramCount++}`);
      params.push(parent_id || null);
    }

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

    updates.push(`updated_at = NOW()`);
    params.push(id);

    const query = `
      UPDATE bins
      SET ${updates.join(', ')}
      WHERE id = $${paramCount}
      RETURNING *
    `;

    const result = await pool.query(query, params);

    if (result.rows.length === 0) {
      return res.status(404).json({ error: 'Bin not found' });
    }

    res.json(result.rows[0]);
  } catch (err) {
    next(err);
  }
});

// DELETE /:id - Delete bin
router.delete('/:id', async (req, res, next) => {
  try {
    const { id } = req.params;

    const result = await pool.query(
      'DELETE FROM bins WHERE id = $1 RETURNING *',
      [id]
    );

    if (result.rows.length === 0) {
      return res.status(404).json({ error: 'Bin not found' });
    }

    res.json({ message: 'Bin deleted', bin: result.rows[0] });
  } catch (err) {
    next(err);
  }
});

// POST /:id/assets - Add asset to bin
router.post('/:id/assets', async (req, res, next) => {
  try {
    const { id } = req.params;
    const { asset_id } = req.body;

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

    // Verify bin exists
    const binCheck = await pool.query('SELECT id FROM bins WHERE id = $1', [id]);
    if (binCheck.rows.length === 0) {
      return res.status(404).json({ error: 'Bin not found' });
    }

    // Update asset's bin_id
    const result = await pool.query(
      'UPDATE assets SET bin_id = $1, updated_at = NOW() WHERE id = $2 RETURNING *',
      [id, asset_id]
    );

    if (result.rows.length === 0) {
      return res.status(404).json({ error: 'Asset not found' });
    }

    res.json(result.rows[0]);
  } catch (err) {
    next(err);
  }
});

// DELETE /:id/assets/:assetId - Remove asset from bin
router.delete('/:id/assets/:assetId', async (req, res, next) => {
  try {
    const { id, assetId } = req.params;

    // Verify bin exists
    const binCheck = await pool.query('SELECT id FROM bins WHERE id = $1', [id]);
    if (binCheck.rows.length === 0) {
      return res.status(404).json({ error: 'Bin not found' });
    }

    // Remove asset from bin
    const result = await pool.query(
      'UPDATE assets SET bin_id = NULL, updated_at = NOW() WHERE id = $1 AND bin_id = $2 RETURNING *',
      [assetId, id]
    );

    if (result.rows.length === 0) {
      return res.status(404).json({ error: 'Asset not found in this bin' });
    }

    res.json({ message: 'Asset removed from bin', asset: result.rows[0] });
  } catch (err) {
    next(err);
  }
});

export default router;