import { Router } from 'express';
import db from '../db/index.js';
import { requireAuth } from '../auth/middleware.js';
import { getGame } from '../games/registry.js';

const router = Router();

// GET /api/puzzles/:slug/progress
// Returns the highest contiguous level the signed-in user has cleared.
router.get('/:slug/progress', requireAuth, (req, res) => {
  const { slug } = req.params;
  if (!getGame(slug)) return res.status(400).json({ error: 'Unknown game slug.' });

  const row = db
    .prepare('SELECT levels_completed FROM puzzle_progress WHERE user_id = ? AND slug = ?')
    .get(req.user.id, slug);

  res.json({ levelsCompleted: row?.levels_completed ?? 0 });
});

// POST /api/puzzles/:slug/complete  body: { level }
// Records completion of `level`. Levels must be cleared in order, so this only
// advances progress when level === current + 1; replaying an earlier level is a
// no-op that still returns the current high-water mark.
router.post('/:slug/complete', requireAuth, (req, res) => {
  const { slug } = req.params;
  const { level } = req.body ?? {};

  if (!getGame(slug)) return res.status(400).json({ error: 'Unknown game slug.' });
  if (!Number.isInteger(level) || level < 1) {
    return res.status(400).json({ error: 'Invalid level.' });
  }

  const row = db
    .prepare('SELECT levels_completed FROM puzzle_progress WHERE user_id = ? AND slug = ?')
    .get(req.user.id, slug);
  const current = row?.levels_completed ?? 0;

  if (level !== current + 1) {
    return res.json({ levelsCompleted: current });
  }

  db.prepare(
    `INSERT INTO puzzle_progress (user_id, slug, levels_completed, updated_at)
     VALUES (?, ?, ?, datetime('now'))
     ON CONFLICT(user_id, slug)
     DO UPDATE SET levels_completed = excluded.levels_completed,
                   updated_at = excluded.updated_at`,
  ).run(req.user.id, slug, level);

  res.json({ levelsCompleted: level });
});

// POST /api/puzzles/:slug/reset
// Clears the signed-in user's progress for this puzzle (back to level 0).
router.post('/:slug/reset', requireAuth, (req, res) => {
  const { slug } = req.params;
  if (!getGame(slug)) return res.status(400).json({ error: 'Unknown game slug.' });

  db.prepare('DELETE FROM puzzle_progress WHERE user_id = ? AND slug = ?').run(req.user.id, slug);
  res.json({ levelsCompleted: 0 });
});

export default router;