[MBL-17287][Teacher] Add dashboard card reordering functionality

[kristofnemere]

refs: MBL-17287
affects: Teacher
release note: Teachers can now reorder their dashboard cards by dragging them.

Summary

Adds drag-and-drop reordering functionality for dashboard cards in the Teacher app, matching the Student app implementation.

Changes

• Added ItemTouchHelper for drag-and-drop card reordering in DashboardFragment
• Added position persistence via API with cache invalidation strategy
• Added cancelCardDrag() safety method to handle tab switching during drag
• Updated DashboardPresenter with moveCourse(), saveDashboardPositions(), and isOnline() methods
• Dragging only enabled when online

Test plan

Drag and reorder dashboard cards, verify positions persist after app restart and dragging is disabled offline.

🤖 Generated with Claude Code

[claude]

PR Review Summary

This PR implements drag-and-drop reordering for dashboard cards in the Teacher app. The implementation is generally well-structured with proper dependency injection using Hilt. Here are my findings:

Positives

✅ Good use of Hilt for dependency injection
✅ Proper bounds checking in moveCourse()
✅ Network connectivity check before enabling drag
✅ Online/offline state handling
✅ Clean separation of concerns between Fragment and Presenter

Areas for Improvement

Code Quality:

• Performance issue with notifyDataSetChanged() after move (consider removing)
• GlobalScope.launch usage in presenter should be replaced with lifecycle-aware scope
• Missing error logging when dashboard position save fails

Potential Bugs:

• Possible race condition with draggedFromPosition (likely safe but needs verification)
• No null safety comment for fragment lookup in InitActivity
• MotionEvent.obtain() could potentially leak native memory without recycle()

Testing:

• Need unit tests for moveCourse() and saveDashboardPositions()
• UI tests for drag-and-drop would prevent regressions

The drag-and-drop feature looks solid overall. The main concerns are the performance optimization opportunity and ensuring proper coroutine lifecycle management. The functionality should work correctly but could be refined for better performance and maintainability.

[Copilot]

Pull Request Overview

This PR implements drag-and-drop reordering functionality for dashboard course cards in the Teacher app, allowing users to manually reorganize their course cards and persist the new order to the backend.

• Added dependency injection support via Hilt to the DashboardFragment and DashboardPresenter
• Implemented ItemTouchHelper for drag-and-drop course card reordering with visual feedback
• Integrated API calls to save dashboard positions to the server after reordering

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
DashboardPresenter.kt	Added constructor parameters for UserAPI and NetworkStateProvider; implemented course movement logic and dashboard position persistence
DashboardFragment.kt	Added Hilt annotations, ItemTouchHelper for drag-and-drop, and touch cancellation for tab switching
DashboardPresenterFactory.kt	Updated to pass injected dependencies to DashboardPresenter constructor
InitActivity.kt	Added logic to cancel active drag operations when switching tabs

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[github-actions]

📊 Code Coverage Report

✅ Student

• PR Coverage: 43.97%
• Master Coverage: 43.97%
• Delta: +0.00%

⚠️ Teacher

• PR Coverage: 25.52%
• Master Coverage: 25.58%
• Delta: -0.06%

✅ Pandautils

• PR Coverage: 22.54%
• Master Coverage: 22.54%
• Delta: +0.00%

---

📈 Overall Average

• PR Coverage: 30.67%
• Master Coverage: 30.70%
• Delta: -0.02%

[claude]

Overall Review Summary

This PR implements drag-and-drop reordering for dashboard course cards. The implementation is solid overall with good use of modern Android patterns like Hilt dependency injection and coroutines. Here are the key findings:

✅ Strengths

• Good architecture: Proper separation of concerns with presenter pattern
• Modern Android practices: Uses Hilt for DI, coroutines for async operations
• Defensive programming: Good null checks and validation
• User experience: Disables dragging when offline and cancels drag on tab switch

⚠️ Areas for Improvement

High Priority:

1. Potential duplicate ItemTouchHelper attachments - addItemTouchHelperForCardReorder() could be called multiple times (DashboardFragment.kt:170)
2. Inconsistent state on API failure - If the API call fails, the local UI remains reordered but the server state doesn't match (DashboardFragment.kt:323)
3. Memory leak risk - MotionEvent not properly recycled if exception occurs (DashboardFragment.kt:338)

Medium Priority:
4. Performance concern - Using notifyDataSetChanged() after drag may cause unnecessary rebinding (DashboardFragment.kt:321)
5. Side effects in presenter - Cache clearing happens inside saveDashboardPositions() which may have unintended consequences (DashboardPresenter.kt:147)

Low Priority:
6. Consider adding user feedback when dragging is disabled due to offline status
7. Add documentation for thread safety assumptions around draggedFromPosition

🧪 Testing Recommendations

• Test fragment recreation scenarios (rotation, background/foreground)
• Test rapid tab switching during drag operations
• Test network failure scenarios to ensure UI consistency
• Test with large course lists for performance
• Verify cache clearing doesn't cause excessive network requests

Overall, this is well-structured code that follows good practices. The inline comments provide specific suggestions for addressing the identified issues.

[inst-danger]

Teacher Install Page

[tamaskozmer]

QA + 1

[adamNagy56]

QA +1