FEATURE REQUEST : Sync Countdown + "What Changed" diff popup after each leaderboard sync

[manjiri27]

feat: Sync Countdown + "What Changed" diff popup after each leaderboard sync

Problem Statement

The leaderboard currently shows:
[SYS_STATUS]: LAST SYNC JUN 05, 12:13 AM GMT+5:30
[NEXT_SYNC]: ≈2 MIN
While this is informative, the sync itself is a silent background event - the page just quietly updates with no indication of what actually changed. Users have no way to know:

Did my rank change?
Did someone overtake me?
How many problems were solved across the board since last sync?

This makes the leaderboard feel static even though it's actively updating every few minutes.

Proposed Solution
After each sync completes, show a non-intrusive toast/diff popup at the bottom of the screen summarizing what changed, styled to match the existing terminal aesthetic.
Example popup content:
[SYNC_COMPLETE] ─────────────────────────────
↑ harsh-0_2 moved #4 → #3 (+8 pts)
↑ anuragmuley moved #5 → #4
● 12 new problems solved across 6 users
● 2 new users joined the leaderboard
───────────────────────────── [dismiss] [view]

Behaviour Details

Toast appears automatically after the sync polling detects new data
Stays visible for 8–10 seconds, then auto-dismisses
Has a [dismiss] button and a [view] button that scrolls to the leaderboard
If the current user's rank changed, highlight that line specifically:

★ You moved #12 → #10 (+15 pts)

If nothing changed (no rank shifts, no new problems), show a minimal:

[SYNC_COMPLETE] No changes detected.

[manjiri27]

Hi @jagdish-15 Sir, Please Assign me this Issue under GSSoC'26

[github-actions]

Thank you for opening an issue.

Please review our CONTRIBUTING.md guidelines before getting started.

A maintainer will review this issue shortly. If you would like to work on the issue yourself, please leave a comment requesting assignment.

[jagdish-15]

This seems like a fair feature addition overall.

One implementation direction I’d suggest is handling the diff generation during the sync workflow itself rather than computing everything on the frontend.

For example, the sync process could generate a small changes.json file in the data repo containing the latest sync summary (rank movements, new users, solve count changes, etc.), and the frontend could simply fetch and render that.

Also, please try to keep the popup relatively lightweight/non-noisy, especially since syncs happen every few minutes.

[manjiri27]

Thank you for the assignment @jagdish-15 .

I'll follow the suggested approach - generating a changes.json during the sync workflow and having the frontend fetch + render it as a lightweight toast.

Planned implementation:

• Backend: Extend the sync script to compute diffs (rank movements, new users, solve count delta) and write a changes.json to the data repo
• Frontend: After each poll detects new data, fetch changes.json and display a terminal-styled toast for 8–10s with auto-dismiss
• Keep the popup minimal/non-noisy as noted - only surface meaningful changes, show "No changes detected" otherwise

Will open a draft PR once the basic structure is ready.