'use strict';
/* Dashboard aggregates. /api/dashboard/activity — per-day study activity of the
 * current user across ALL engagement types (not just tests), for the activity
 * heatmap. Each source contributes a per-day count by type. */
const express = require('express');
const router  = express.Router();
const db = require('../db/db');
const { authMiddleware } = require('../middleware/auth');

router.use(authMiddleware);

const WINDOW_DAYS = 182; // ~6 months (max heatmap scale)

/* GET /api/dashboard/activity → { days: { 'YYYY-MM-DD': { test, exam, cards, lesson, live, homework } } } */
router.get('/activity', (req, res) => {
  const uid = req.user.id;
  const days = {};
  const add = (d, type, n) => {
    if (!d || !n) return;
    (days[d] || (days[d] = {}))[type] = (days[d][type] || 0) + n;
  };
  // TEXT datetime sources use a SQL cutoff; exam_attempts stores epoch-ms.
  const txtCut = `datetime('now','-${WINDOW_DAYS} days')`;
  const epochCut = Date.now() - WINDOW_DAYS * 86400000;

  const sources = [
    ['test',     `SELECT DATE(started_at) d, COUNT(*) n FROM test_sessions
                    WHERE user_id=? AND status='completed' AND started_at >= ${txtCut} GROUP BY d`, [uid]],
    ['exam',     `SELECT DATE(created_at/1000,'unixepoch') d, COUNT(*) n FROM exam_attempts
                    WHERE user_id=? AND created_at >= ? GROUP BY d`, [uid, epochCut]],
    ['cards',    `SELECT DATE(last_reviewed) d, COUNT(*) n FROM flashcard_reviews
                    WHERE user_id=? AND last_reviewed IS NOT NULL AND last_reviewed >= ${txtCut} GROUP BY d`, [uid]],
    ['lesson',   `SELECT DATE(updated_at) d, COUNT(*) n FROM lesson_progress
                    WHERE user_id=? AND completed=1 AND updated_at >= ${txtCut} GROUP BY d`, [uid]],
    ['live',     `SELECT DATE(joined_at) d, COUNT(*) n FROM classroom_attendance
                    WHERE user_id=? AND joined_at >= ${txtCut} GROUP BY d`, [uid]],
    ['homework', `SELECT DATE(completed_at) d, COUNT(*) n FROM assignment_completion
                    WHERE user_id=? AND completed_at >= ${txtCut} GROUP BY d`, [uid]],
  ];
  for (const [type, sql, args] of sources) {
    try { db.prepare(sql).all(...args).forEach(r => add(r.d, type, r.n)); }
    catch (e) { /* tolerate a missing/legacy table — skip that source */ }
  }
  res.json({ days });
});

module.exports = router;