feat(): LibraryViewModel performance improvements

[phobos665]

Description

• Reduce sorting cpu time & memory usage (Cpu is now O(n) instead of O (n log n) e.g. exponential complexity for sorting) - Did this by creating a sortName on entry creation, rather than manipulating both the comparitor and the name on comparison.
• Created a Job & cache for fetching results so that we can cancel and check the cache before we fetch again. This way we don't have issues with multiple processes trying to receive the results and causing excessive redraws on the UI.

Overall, the UI should be vastly more responsive on initial and further retrievals for games going forward. This also means Carousel should be much more usable.

Recording

Type of Change

• Bug fix
• Performance / stability improvement
• Compatibility improvements
• Other (requires prior approval)

Checklist

• If I have access to #code-changes, I have discussed this change there and it has been green-lighted. If I do not have access, I have still provided clear context in this PR. If I skip both, I accept that this change may face delays in review, may not be reviewed at all, or may be closed.
• This change aligns with the current project scope (core functionality, stability, or performance). If not, it has been explicitly approved beforehand.
• I have attached a recording of the change.
• I have read and agree to the contribution guidelines in CONTRIBUTING.md.

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Summary by cubic

Speeds up LibraryViewModel filtering, sorting, and pagination to reduce CPU work and UI redraws. The library and carousel feel more responsive on first load and when paging; pagination now cancels stale work.

• Performance
  • Cache filtered results and slice pages via applyPagination, avoiding re-filter/re-sort on page changes.
  • Add pageJob and filterJob to cancel stale work; guard commits with ensureActive() to prevent outdated UI updates.
  • Precompute sortName per entry for cheaper sorting.
  • Cache Steam size per app/branch in ConcurrentHashMap.
  • Batch installed-branch lookup via SteamService.getAllInstalledApps().
  • Check GOG/Epic/Amazon credentials once per run.
  • Clear caches on refresh and when the Steam app list changes.

^{Written for commit 0761185. Summary will update on new commits.}

Summary by CodeRabbit

• Performance
  • Improved library filtering and pagination speed by reusing cached filtered+sorted results and re-applying pagination-specific adjustments without re-running the full pipeline.
  • Faster refreshes and page transitions, with improved responsiveness by canceling superseded filtering work.
• Bug Fixes
  • Improved correctness and consistency of Steam-related filtering and size estimates.
  • More reliable source availability indicators (including badge counts) by evaluating credential checks once per filtering run.

[coderabbitai]

📝 Walkthrough

Walkthrough

LibraryViewModel now cancels superseded filtering jobs, caches filtered results for pagination, memoizes Steam size calculations, precomputes sorting and credential data, and centralizes recommendation insertion.

Changes

Library filtering pipeline

Layer / File(s)	Summary
Filter cancellation and cached pagination app/src/main/java/app/gamenative/ui/model/LibraryViewModel.kt	Filtering jobs are synchronized and cancellable, while pagination reuses the cached filtered list and applies recommendation insertion through applyPagination.
Steam filtering and size memoization app/src/main/java/app/gamenative/ui/model/LibraryViewModel.kt	Steam processing precomputes installed branches and lowercase sort names, memoizes size calculations, and clears the size cache when Steam data or refresh state changes.
Credential-gated source inclusion app/src/main/java/app/gamenative/ui/model/LibraryViewModel.kt	GOG, Epic, and Amazon credential checks are evaluated once per run and reused for source inclusion and badge counts; cancellation checks are added around sorting and state updates.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Sequence Diagram(s)

sequenceDiagram
  participant FilterRequest
  participant LibraryViewModel
  participant PaginationState
  FilterRequest->>LibraryViewModel: start filtering
  LibraryViewModel->>LibraryViewModel: cancel prior filter and page jobs
  LibraryViewModel->>PaginationState: cache full filtered list
  FilterRequest->>LibraryViewModel: change page
  LibraryViewModel->>PaginationState: slice cached list and apply pagination

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🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title is concise and accurately summarizes the main change: LibraryViewModel performance improvements.
Description check	✅ Passed	The PR follows the template and covers the change, type, and checklist; only the recording attachment appears missing.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[cubic-dev-ai]

All reported issues were addressed across 1 file

<sub>Reply with feedback, questions, or to request a fix.

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