const express = require('express');
const { query, getRow } = require('../db');
const { authenticate, requireRole } = require('../middleware/auth');

const router = express.Router();

router.get('/', authenticate, async (req, res) => {
  const polls = await query('SELECT id, title, description, active, created_at FROM polls ORDER BY created_at DESC');
  res.json(polls);
});

router.get('/active', authenticate, async (req, res) => {
  const polls = await query('SELECT id, title, description, active, created_at FROM polls WHERE active = 1 ORDER BY created_at DESC');
  for (const p of polls) {
    p.options = JSON.parse(p.options || '[]');
    const rows = await query('SELECT option_index, COUNT(*) as count FROM poll_votes WHERE poll_id = ? GROUP BY option_index', [p.id]);
    p.votes = {};
    let total = 0;
    for (const r of rows) { p.votes[r.option_index] = r.count; total += r.count; }
    p.total = total;
    const myVote = await getRow('SELECT option_index FROM poll_votes WHERE poll_id = ? AND user_id = ?', [p.id, req.user.id]);
    p.my_vote = myVote ? myVote.option_index : null;
  }
  res.json(polls);
});

router.post('/', authenticate, requireRole('owner'), async (req, res) => {
  const { title, description, options } = req.body;
  if (!title || !options || !Array.isArray(options) || options.length < 2) return res.status(400).json({ error: '标题和至少2个选项为必填' });
  const r = await query('INSERT INTO polls(title, description, options, created_by) VALUES (?,?,?,?)', [title, description||'', JSON.stringify(options), req.user.id]);
  res.status(201).json({ id: r.insertId, message: '创建成功' });
});

router.put('/:id', authenticate, requireRole('owner'), async (req, res) => {
  const p = await getRow('SELECT * FROM polls WHERE id = ?', [req.params.id]);
  if (!p) return res.status(404).json({ error: '投票不存在' });
  const fields = {};
  if (req.body.title) fields.title = req.body.title;
  if (req.body.description !== undefined) fields.description = req.body.description;
  if (req.body.active !== undefined) fields.active = req.body.active ? 1 : 0;
  if (req.body.options) fields.options = JSON.stringify(req.body.options);
  if (!Object.keys(fields).length) return res.status(400).json({ error: '无更新内容' });
  const sets = Object.keys(fields).map(k => `${k} = ?`).join(', ');
  await query(`UPDATE polls SET ${sets} WHERE id = ?`, [...Object.values(fields), req.params.id]);
  res.json({ message: '更新成功' });
});

router.delete('/:id', authenticate, requireRole('owner'), async (req, res) => {
  await query('DELETE FROM poll_votes WHERE poll_id = ?', [req.params.id]);
  await query('DELETE FROM polls WHERE id = ?', [req.params.id]);
  res.json({ message: '已删除' });
});

router.post('/:id/vote', authenticate, async (req, res) => {
  const p = await getRow('SELECT * FROM polls WHERE id = ? AND active = 1', [req.params.id]);
  if (!p) return res.status(404).json({ error: '投票不存在或已关闭' });
  const { option_index } = req.body;
  if (option_index === undefined || option_index === null) return res.status(400).json({ error: '请选择选项' });
  const opts = JSON.parse(p.options || '[]');
  if (option_index < 0 || option_index >= opts.length) return res.status(400).json({ error: '无效选项' });
  await query('INSERT INTO poll_votes(poll_id, user_id, option_index) VALUES (?,?,?) ON DUPLICATE KEY UPDATE option_index = VALUES(option_index)', [req.params.id, req.user.id, option_index]);
  res.json({ message: '投票成功' });
});

module.exports = router;