[Feature Request]: Add rating range filter to the Problem Explorer

[Sandesh282]

Description:

The Problem List currently supports filtering by text search and tag selection, but there is no way to filter problems by difficulty rating. For competitive programmers, filtering by rating range (e.g., 800–1200) is essential for targeted practice sessions.

Feature Requirements:

• Add a set of rating range chip buttons near the existing tag filter bar (e.g., [800-1000], [1000-1200], [1200-1400], [1400-1800], [1800+]).
• Tapping a chip selects it (highlighted with the neon gradient). Tapping again deselects it.
• The rating filter should work in combination with the existing text search and tag filter.
• Problems with a nil rating should be excluded when a rating range is active.
• When no rating range is selected, all problems are displayed (preserving current behavior).

Steps to Implement:

1. Add a @State private var selectedRatingRange property in ProblemListView.
2. Create rating chip UI components below the tag filter bar, following the same visual style as the existing tag chips.
3. Update ProblemFilterEngine.filter() in CForge/Domain/ProblemFilterEngine.swift to accept an optional rating range parameter.
4. Update ProblemListViewModel.filterProblems() in CForge/ViewModels/ProblemListViewModel.swift to pass the rating range through.
5. Wire the UI state to trigger filtering via the existing .task(id:) pattern.

Key Files:

File	Change
CForge/Domain/ProblemFilterEngine.swift	Add rating range filtering logic
CForge/ViewModels/ProblemListViewModel.swift	Update filterProblems() method signature
CForge/Views/Problem/ProblemListView.swift	Add rating chip UI and state management

Expected Outcome:

• Users can filter problems by selecting a rating range chip.
• The filter integrates seamlessly with the existing search and tag filters.
• The UI is consistent with the app's neon dark theme.

[momedul]

https://needlecode.com/blog/web-dev/data-driven-woocommerce-development-analytics.html

[Sandesh282]

Hey @momedul, thanks for sharing this.

Could you clarify how this applies to the current issue? Specifically, we’re looking to implement rating range filtering with UI chips and integrate it into the existing filtering pipeline (ProblemFilterEngine, ProblemListViewModel, etc.).

If you have a concrete approach or plan based on this, it would be great if you could outline it here.

[mvanhorn]

Opened a PR for this in #13.

Approach: new RatingRange enum in CForge/Domain/ for the five buckets, optional ratingRange: parameter added to ProblemFilterEngine.filter (defaults to nil, AND-ed after the query and tag filters, drops nil-rated problems when active), threaded through ProblemListViewModel.filterProblems, and a ratingFilterBar in ProblemListView mirroring the existing tag chip styling. Three Swift Testing cases for the engine.

Will add Simulator screenshots before review.