feat: add a `GET /api/stats` endpoint to `server.js` that returns aggregate leaderboard statistics — the dashboard currently shows no summary metrics (total users, total problems solved, most active week, etc.)

[divyanshim27]

🚀 Problem Statement

The leaderboard frontend shows a table of individual student rankings but has no aggregate statistics panel. A student or club admin visiting the site cannot immediately see:

• Total number of registered students
• Total problems solved across all students
• Average problems solved per student
• How many students solved at least one problem this week
• The most popular difficulty level (Easy/Medium/Hard ratio)

These summary stats would make the leaderboard feel alive and motivating — rather than just a static sorted table. They also give the CodePVG club admins a quick pulse check on overall club activity.

Proposed Fix

Backend — add GET /api/stats to server.js

// server.js

app.get('/api/stats', async (req, res) => {
  try {
    const users = await loadLeaderboardData(); // existing function

    const stats = users.reduce((acc, user) => {
      acc.totalUsers++;
      acc.totalSolved += (user.easySolved || 0) + (user.mediumSolved || 0) + (user.hardSolved || 0);
      acc.totalEasy += user.easySolved || 0;
      acc.totalMedium += user.mediumSolved || 0;
      acc.totalHard += user.hardSolved || 0;
      if ((user.easySolved + user.mediumSolved + user.hardSolved) > 0) acc.activeUsers++;
      return acc;
    }, { totalUsers: 0, totalSolved: 0, totalEasy: 0, totalMedium: 0, totalHard: 0, activeUsers: 0 });

    res.json({
      ...stats,
      avgSolvedPerUser: stats.totalUsers > 0
        ? (stats.totalSolved / stats.totalUsers).toFixed(1)
        : 0,
      difficultyRatio: {
        easy: ((stats.totalEasy / stats.totalSolved) * 100).toFixed(1) + '%',
        medium: ((stats.totalMedium / stats.totalSolved) * 100).toFixed(1) + '%',
        hard: ((stats.totalHard / stats.totalSolved) * 100).toFixed(1) + '%',
      },
      lastUpdated: new Date().toISOString(),
    });
  } catch (err) {
    res.status(500).json({ error: 'Failed to compute stats' });
  }
});

Frontend — add a stats banner above the leaderboard table

<!-- frontend/ — add above the leaderboard table -->
<div id="stats-banner" class="stats-grid">
  <div class="stat-card">
    <span class="stat-value" id="stat-total-users">—</span>
    <span class="stat-label">Registered Students</span>
  </div>
  <div class="stat-card">
    <span class="stat-value" id="stat-total-solved">—</span>
    <span class="stat-label">Problems Solved</span>
  </div>
  <div class="stat-card">
    <span class="stat-value" id="stat-avg-solved">—</span>
    <span class="stat-label">Avg per Student</span>
  </div>
  <div class="stat-card">
    <span class="stat-value" id="stat-active-users">—</span>
    <span class="stat-label">Active Students</span>
  </div>
</div>

// Fetch and display stats
fetch('/api/stats')
  .then(r => r.json())
  .then(stats => {
    document.getElementById('stat-total-users').textContent = stats.totalUsers;
    document.getElementById('stat-total-solved').textContent = stats.totalSolved.toLocaleString();
    document.getElementById('stat-avg-solved').textContent = stats.avgSolvedPerUser;
    document.getElementById('stat-active-users').textContent = stats.activeUsers;
  });

Files to Modify

File	Change
server.js	Add GET /api/stats endpoint
frontend/ (leaderboard HTML)	Add stats banner with 4 stat cards
frontend/ (leaderboard JS)	Fetch stats and populate cards
frontend/ (leaderboard CSS)	Style .stats-grid and .stat-card

Suggested labels: enhancement, frontend, backend, level: beginner

I would like to work on this. Could you please assign it to me?

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[divyanshim27]

Hey @codepvg ,
Please assign it to me under GSSOC 2026.
/assign /claim /claim-assignment

[jagdish-15]

I do think a statistics panel would be a nice addition to the leaderboard, but I don't think introducing a new /api/stats endpoint is the right approach here.

Instead, I'd prefer a completely frontend-based implementation using the leaderboard data that's already available.

For the UI, let's add a small button beside the Compare Peers button. Clicking it should open a responsive popup/modal (working well on both desktop and mobile, like the compare users popup) displaying statistics. The popup should also provide buttons to switch between the different leaderboard modes (Overall, Monthly, Weekly, or Daily) without closing it.

I think this would provide a much cleaner user experience while keeping the implementation consistent with the current architecture.