feat(geom9 ch3 wave2 + final): §12 «Герон» + Финал Главы 3

backend/src/routes/exam-prep.js

@@ -0,0 +1,86 @@
+'use strict';
+const router = require('express').Router();
+const db = require('../db/db');
+const { authMiddleware } = require('../middleware/auth');
+
+router.use(authMiddleware);
+
+/* ── Statements (prepared once) ────────────────────────────────── */
+const SQL = {
+  listTracks: db.prepare(`
+    SELECT exam_key, title, subject_slug, grade, duration_min,
+           tasks_per_variant, variants_count, intro_html, sort_order
+      FROM exam_tracks
+     WHERE enabled = 1
+     ORDER BY sort_order, exam_key
+  `),
+  getTrack: db.prepare(`
+    SELECT exam_key, title, subject_slug, grade, duration_min,
+           tasks_per_variant, variants_count, scoring_json, intro_html
+      FROM exam_tracks
+     WHERE exam_key = ? AND enabled = 1
+  `),
+  countTasks: db.prepare(`
+    SELECT
+      COUNT(*) AS total,
+      COALESCE(SUM(CASE WHEN task_type = 'mc'   THEN 1 ELSE 0 END), 0) AS mc,
+      COALESCE(SUM(CASE WHEN task_type = 'open' THEN 1 ELSE 0 END), 0) AS open,
+      COALESCE(SUM(CASE WHEN task_type = 'long' THEN 1 ELSE 0 END), 0) AS long
+      FROM exam_tasks
+     WHERE exam_key = ?
+  `),
+  /* For each (user, task) — was the most-recent attempt correct?
+     A task counts as «solved» iff at least one historical attempt is_correct = 1. */
+  userProgress: db.prepare(`
+    SELECT
+      COUNT(DISTINCT exam_task_id) AS tasks_attempted,
+      COUNT(DISTINCT CASE WHEN is_correct = 1 THEN exam_task_id END) AS tasks_solved,
+      COUNT(*) AS total_attempts,
+      COALESCE(SUM(CASE WHEN is_correct = 1 THEN 1 ELSE 0 END), 0) AS correct_attempts
+      FROM exam_attempts a
+      JOIN exam_tasks t ON t.id = a.exam_task_id
+     WHERE a.user_id = ? AND t.exam_key = ?
+  `),
+};
+
+/* ── GET /api/exam-prep/tracks ──
+   Public list of enabled exam tracks (for a future landing page). */
+router.get('/tracks', (_req, res) => {
+  const tracks = SQL.listTracks.all();
+  res.json({ tracks });
+});
+
+/* ── GET /api/exam-prep/:examKey/info ──
+   Track metadata + global counts + this user's aggregate progress. */
+router.get('/:examKey/info', (req, res) => {
+  const { examKey } = req.params;
+  const track = SQL.getTrack.get(examKey);
+  if (!track) return res.status(404).json({ error: 'Unknown exam track' });
+
+  const counts   = SQL.countTasks.get(examKey);
+  const progress = SQL.userProgress.get(req.user.id, examKey);
+
+  // Parse scoring grid (JSON in DB). Tolerant of malformed values.
+  let scoring = null;
+  if (track.scoring_json) {
+    try { scoring = JSON.parse(track.scoring_json); } catch { scoring = null; }
+  }
+
+  res.json({
+    track: {
+      exam_key: track.exam_key,
+      title:    track.title,
+      subject:  track.subject_slug,
+      grade:    track.grade,
+      duration_min:      track.duration_min,
+      tasks_per_variant: track.tasks_per_variant,
+      variants_count:    track.variants_count,
+      intro_html:        track.intro_html,
+      scoring,
+    },
+    counts,
+    progress,
+  });
+});
+
+module.exports = router;