[MBL-19925][Student] NGC Module Extraction and Dashboard Navigation Refactor

[tamaskozmer]

Summary

This PR extracts the Next Generation Canvas (NGC) code into a dedicated module (libs/ngc) and introduces a unified navigation event pattern for dashboard widgets. This architectural change prepares the codebase for the NGC experience while maintaining the classic Student app functionality.

Architecture Overview

Module Structure

canvas-api-2
     ↑
pandautils (shared: DashboardBody, DashboardViewModel, navigation handlers, widgets)
     ↑
    ngc (NGC-specific: NGCActivity, NGCDashboardScreen, design system, splash)
     ↑
  student (app: launches NGCActivity, provides RouteMatcherNavigationHandler)

Key Architectural Decisions

1. NGC Module (libs/ngc)

A standalone library module containing all NGC-specific code:

• NGCActivity - Main entry point for NGC experience
• NGCTheme - Compose theme using NGC typography and colors
• NGCDashboardScreen - Dashboard with scrollable header
• Design System - Standalone implementation (NGCTypography, NGCColors, NGCIconButton) without Horizon dependencies
• Splash Screen - Initial loading screen with theme setup
• Navigation - Compose Navigation with NGCComposeNavigationHandler

The NGC module depends only on pandautils (NOT on Horizon), allowing independent evolution of the NGC design system.

2. Dashboard Navigation Events Pattern

Replaced scattered router interfaces with a unified event-based navigation system:

// Sealed interface hierarchy for type-safe navigation
sealed interface DashboardNavigationEvent {
    sealed interface Dashboard : DashboardNavigationEvent { ... }
    sealed interface Courses : DashboardNavigationEvent { ... }
    sealed interface Todo : DashboardNavigationEvent { ... }
    // ... other widget navigation events
}

// Single handler interface
interface DashboardNavigationHandler {
    fun handleDashboardNavigation(event: Dashboard)
    fun handleCoursesNavigation(event: Courses)
    // ...
}

Implementations:

• RouteMatcherNavigationHandler - For classic Student app (uses RouteMatcher/Fragments)
• NGCComposeNavigationHandler - For NGC experience (uses Compose Navigation)

3. Shared Dashboard Components

Moved to pandautils for sharing between Student and NGC:

• DashboardBody - Main content area with pull-to-refresh and widgets
• DashboardViewModel - Widget loading and state management
• DashboardUiState - UI state model
• All widget composables (Courses, Todo, Forecast, Progress, Conferences, etc.)

4. Design System Abstraction

The NGC module includes an abstract design system layer for future NGC vs Legacy Canvas switching:

• DSIconButton, DSTypography - Abstract interfaces
• NGCIconButton, NGCTypography - NGC implementations
• DesignSystem enum with NextGenCanvas and LegacyCanvas values

Benefits

1. Separation of Concerns - NGC code is isolated from classic app code
2. Independent Evolution - NGC design system can evolve without affecting Horizon
3. Code Reuse - Dashboard widgets and logic shared via pandautils
4. Type Safety - Navigation events provide compile-time safety
5. Testability - Navigation handlers can be easily mocked

---

Test plan:

1. Launch Student app normally → verify classic dashboard works
2. Enable NGC flag and login → verify NGC dashboard launches
3. Test all dashboard widgets in both experiences
4. Verify pull-to-refresh works
5. Test navigation from widgets (courses, assignments, etc.)

refs: MBL-19925
affects: Student
release note: Internal architecture improvements for the upcoming NGC experience

• Follow-up e2e test ticket created or not needed
• Tested in dark mode
• Tested in light mode
• Test in landscape mode and/or tablet
• A11y checked
• Approve from product

🤖 Generated with Claude Code

Co-Authored-By: Claude [email protected]

[github-actions]

🧪 Unit Test Results

✅ 📱 Student App

• Tests: 1210 total, 0 failed, 0 skipped
• Duration: 0.000s
• Success Rate: 100%

✅ 🌅 Horizon

• Tests: 790 total, 0 failed, 0 skipped
• Duration: 36.434s
• Success Rate: 100%

✅ 📦 Submodules

• Tests: 3406 total, 0 failed, 0 skipped
• Duration: 63.223s
• Success Rate: 100%

---

📊 Summary

• Total Tests: 5406
• Failed: 0
• Skipped: 0
• Status: ✅ All tests passed!

Last updated: Mon, 13 Apr 2026 14:08:47 GMT

[claude]

PR Review Update — Synchronize Push

This push introduces the libs/ngc module (NGC activity, theme, navigation, dashboard, and design system) alongside completing the dashboard refactoring that replaces DashboardRouter with DashboardNavigationHandler.

Summary of Changes

• New libs/ngc module — NGCActivity, NGCTheme, NGCNavigation, NGCDashboardScreen, design system components (NGCIconButton, NGCTypography, NGCColors, DSIconButton, DSTypography, DesignSystem), splash screen + VM
• Dashboard refactoring completed — DashboardBody, DashboardViewModel, DashboardUiState moved to pandautils; all widgets now emit SharedFlow<DashboardNavigationEvent> instead of calling routers with FragmentActivity
• Login flow extended with Experience.NextGenCanvas backed by NEXT_GEN_CANVAS remote config
• New use cases — LoadSplashDataUseCase, SetupPendoTrackingUseCase; ThemeRepository and FeaturesRepository added

---

Issues Requiring Changes

• Incorrect accessibility content descriptions — cloud-download button announces "Notebook", edit button announces "Inbox" (strings.xml lines 23–24, NGCDashboardScreen.kt lines 170 & 180)
• forceRefresh = true default in LoadSplashDataUseCase — will force-refresh all startup data on every cold launch; should be false (line 35)
• Duplicate ngc_dashboardTitle string — defined in both libs/ngc and libs/pandares; will cause aapt2 duplicate resource error (pandares line 2479)
• Unreferenced proguard-rules.txt — not referenced by build.gradle.kts, contains unrelated Amazon/AWS rules; should be deleted
• Unused @Serializable on NGCNavigationRoute — string-based routing is used throughout; annotation creates false impression of type-safe navigation (NGCNavigation.kt line 32)

Positive Notes

• The DashboardNavigationHandler + DashboardNavigationEvent pattern is well-structured and testable. The accompanying test updates (switching from verify to SharedFlow collection assertions) are thorough and correct.
• Removing FragmentActivity from all widget callback signatures is a clean improvement — widgets are now properly decoupled from the Android framework.
• RouteMatcherNavigationHandler correctly centralises all student-app routing in one place, making future navigation changes easier to track.

[github-actions]

Student Install Page

[claude]

PR Review Update — Synchronize Event

Summary of Changes

This is a large, well-structured PR with two primary goals:

1. Navigation architecture refactor: Replaces the DashboardRouter + per-widget *Router/*Behavior pattern with a unified DashboardNavigationHandler + DashboardNavigationEvent sealed interface. All FragmentActivity references are removed from widget composables and ViewModels — a clean move toward proper Compose-first design.

2. New NGC (Next Gen Canvas) module: Introduces libs/ngc with its own NGCActivity, design system, navigation scaffold, and splash screen, gated behind a new Experience.NextGenCanvas remote-config flag.

The architecture is significantly cleaner after this refactor. Test coverage was maintained and updated throughout.

---

Issues Requiring Changes

Severity	Issue
🔴	Wrong accessibility content descriptions on NGC top bar buttons ("Notebook" for offline content, "Inbox" for customize dashboard)
🔴	LoadSplashDataUseCase defaults forceRefresh = true with a TODO — will force a network call on every cold start
🟡	ngc_dashboardTitle string defined in both libs/ngc and libs/pandares — duplicate resource
🟡	NGCActivity.loginWithToken is public with no @VisibleForTesting guard or debug-build check
🟡	libs/ngc/proguard-rules.txt is unreferenced and should be deleted
🟡	NGCComposeNavigationHandler is entirely stub — worth documenting this is intentional in the PR description

Inline comments mark the specific locations. The accessibility issues are the blocking ones; the rest are improvements.

---

Positive Changes

• FragmentActivity cleanly removed from all widget callbacks
• DashboardViewModel, DashboardUiState, and DashboardBody moved to pandautils for proper reuse by both Student and NGC
• Navigation events use typed sealed interfaces — exhaustive when prevents missed cases
• All unit tests updated to assert on emitted navigation events rather than mock verify calls
• Old per-widget router/behavior classes fully deleted with no dead code left behind

[github-actions]

📊 Code Coverage Report

⚠️ Student

• PR Coverage: 42.64%
• Master Coverage: 42.65%
• Delta: -0.01%

⚠️ Teacher

• PR Coverage: 25.31%
• Master Coverage: 25.37%
• Delta: -0.07%

✅ Pandautils

• PR Coverage: 23.88%
• Master Coverage: 23.69%
• Delta: +0.19%

---

📈 Overall Average

• PR Coverage: 30.61%
• Master Coverage: 30.57%
• Delta: +0.04%

[claude]

PR Review Summary

This PR implements a significant architectural improvement: replacing callback-based widget routers with an event-driven navigation system (DashboardNavigationEvent sealed interface + DashboardNavigationHandler), and introduces a new ngc library module with NGCActivity as the entry point for Next Generation Canvas.

The direction is sound and the sealed interface hierarchy is well-structured. A few concerns need attention before merging:

Issues Requiring Changes

1. MutableSharedFlow missing backpressure config — All five widget ViewModels declare MutableSharedFlow<...>() with no replay or extraBufferCapacity. Events emitted before a collector subscribes are silently dropped. See inline comment on TodoWidgetViewModel.kt.

2. SplashViewModel has 6 critical TODOs — Unread counts, user settings, launch definitions, and to-do counts are all stubbed out. These affect visible UI (nav badges, course appearance) and feature gating. These should be tracked as explicit tickets or addressed before shipping. See inline comment on SplashViewModel.kt.

3. DashboardNavigationHandler has no safety net for missing implementations — The interface has 6 required methods; a missing handler silently swallows navigation events. A no-op default with debug logging would make gaps detectable. See inline comment on DashboardNavigationEvent.kt.

4. Deleted app-layer behaviour tests have no replacement — StudentCoursesWidgetBehaviorTest (144 lines) and StudentTodoWidgetBehaviorTest (175 lines) are deleted. The Student-app-specific handler that performs actual routing should have equivalent coverage. See inline comment.

Positive Notes

• The sealed interface hierarchy for DashboardNavigationEvent is clean and exhaustive — all widget navigation cases are covered.
• NGCActivity is correctly marked android:exported="false" in the manifest.
• Moving DashboardViewModel to pandautils improves reusability across apps.
• The switch from FragmentActivity parameters in callbacks to stateless event objects is the right call for testability.

[adamNagy56]

QA +1

Issues fixed

[kristofnemere]

We should have test for this

[kristofnemere]

We should have test for this