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

const STATUSES = ['draft', 'blocked', 'published'];
const STATUS_TIMESTAMP = { published: 'published_at', blocked: 'blocked_at' };

// GET /api/questions
router.get('/', async (req, res, next) => {
  try {
    const { status, sentence_de, limit = 50, offset = 0 } = req.query;
    const params = [Math.min(parseInt(limit), 500), parseInt(offset)];
    const conditions = [];
    if (status) { conditions.push(`status = $${params.length + 1}`); params.push(status); }
    if (sentence_de) { conditions.push(`lower(sentence_de) = lower($${params.length + 1})`); params.push(sentence_de); }
    const where = conditions.length ? `WHERE ${conditions.join(' AND ')}` : '';
    const result = await query(
      `SELECT * FROM questions ${where} ORDER BY created_at DESC LIMIT $1 OFFSET $2`,
      params
    );
    res.json(result.rows);
  } catch (err) { next(err); }
});

// GET /api/questions/:id
router.get('/:id', async (req, res, next) => {
  try {
    const result = await query('SELECT * FROM questions WHERE id = $1', [req.params.id]);
    if (!result.rows.length) return res.status(404).json({ error: 'Not found' });
    res.json(result.rows[0]);
  } catch (err) { next(err); }
});

// POST /api/questions
router.post('/', async (req, res, next) => {
  try {
    const { sentence_de, sentence_en, sentence_sv, blocked_topic } = req.body;
    const result = await query(
      `INSERT INTO questions (sentence_de, sentence_en, sentence_sv, blocked_topic)
       VALUES ($1, $2, $3, $4) RETURNING *`,
      [sentence_de || null, sentence_en || null, sentence_sv || null, blocked_topic || null]
    );
    res.status(201).json(result.rows[0]);
  } catch (err) { next(err); }
});

// PATCH /api/questions/:id
router.patch('/:id', async (req, res, next) => {
  try {
    const allowed = ['status', 'sentence_de', 'sentence_en', 'sentence_sv',
                     'blocked_topic', 'published_at', 'blocked_at'];
    const fields = Object.keys(req.body).filter(k => allowed.includes(k));
    if (!fields.length) return res.status(400).json({ error: 'No valid fields provided' });

    if (req.body.status && !STATUSES.includes(req.body.status))
      return res.status(400).json({ error: `status must be one of: ${STATUSES.join(', ')}` });

    const tsField = STATUS_TIMESTAMP[req.body.status];
    if (tsField && !req.body[tsField]) {
      fields.push(tsField);
      req.body[tsField] = new Date().toISOString();
    }

    const setClauses = fields.map((f, i) => `${f} = $${i + 1}`).join(', ');
    const values = [...fields.map(f => req.body[f]), req.params.id];
    const result = await query(
      `UPDATE questions SET ${setClauses} WHERE id = $${fields.length + 1} RETURNING *`,
      values
    );
    if (!result.rows.length) return res.status(404).json({ error: 'Not found' });
    res.json(result.rows[0]);
  } catch (err) { next(err); }
});

// DELETE /api/questions/:id
router.delete('/:id', async (req, res, next) => {
  try {
    const result = await query('DELETE FROM questions WHERE id = $1 RETURNING id', [req.params.id]);
    if (!result.rows.length) return res.status(404).json({ error: 'Not found' });
    res.status(204).end();
  } catch (err) { next(err); }
});

module.exports = router;