Implement slide PageView and progress indicator
epic-annual-impact-summary-orchestration-task-009 — Implement the PageView inside WrappedSummaryScreen that renders each slide widget (StatCard, MilestoneBadge, ActivityTypeBreakdown) based on the current BLoC state. Add a segmented progress indicator at the top of the screen that highlights the active slide and responds to NavigateSlide BLoC events. Integrate the WrappedAnimationController for entrance animations per slide.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 5 - 253 tasks
Can start after Tier 4 completes
Implementation Notes
Sync the PageController with the BLoC's currentSlideIndex using a BlocListener — do NOT use the PageView's onPageChanged as the source of truth (BLoC state is the source of truth). Pattern: BlocListener listens for index changes and calls pageController.animateToPage(). The PageView's onPageChanged callback dispatches NavigateSlide to the BLoC so the BLoC stays in sync. Use IgnorePointer wrapping the PageView when the BLoC is in a loading or sharing state to prevent mid-transition user input.
For the WrappedAnimationController, create one AnimationController per slide and run it in didUpdateWidget when the active index changes. Use a factory or map keyed by slideIndex to avoid recreating controllers unnecessarily. The segmented progress indicator is a Row of Expanded containers with AnimatedContainer for smooth width/colour transitions.
Testing Requirements
Widget tests: (1) seed BLoC with WrappedSummaryLoaded containing 3 slides and verify PageView has 3 children, (2) simulate swipe right and verify NavigateSlide(forward) was dispatched, (3) emit currentSlideIndex=1 from BLoC and verify progress segment 1 is active, (4) seed with WrappedSummaryLoading and verify shimmer is shown and PageView physics are NeverScrollableScrollPhysics. Golden tests (optional): capture the progress indicator at indices 0, 1, and 2 for a 3-slide set. Accessibility: confirm each slide widget has semantic labels readable by screen readers.
If the device transitions between online and offline states while the user is mid-session in the wrapped screen, the BLoC may emit conflicting state transitions (loaded → error → offline) that cause visual flickering or an inconsistent UI state such as showing the offline banner over an already-loaded summary.
Mitigation & Contingency
Mitigation: Implement a connectivity stream listener in the BLoC that only triggers a state re-evaluation when transitioning from online to offline, not on every connectivity event. Once a summary is in the Loaded state, the BLoC should not transition to error/offline unless the user explicitly requests a refresh. Store the last-loaded data in BLoC state so it survives connectivity changes.
Contingency: If state flickering is observed in testing, add a minimum 3-second debounce on connectivity state changes before the BLoC reacts, and display a non-blocking top banner rather than replacing the entire screen state.
The push notification deep-link to the wrapped-summary-screen must work correctly whether the app is in the foreground, background, or terminated state. Handling all three app launch states on both iOS and Android is a common source of edge-case bugs, particularly when authentication state must be restored before the deep link can be resolved.
Mitigation & Contingency
Mitigation: Implement deep-link handling through the existing notification-deep-link-handler component which already manages app-state-aware routing. Define the wrapped-summary route in the navigation config early in the epic so the router is ready before notification dispatch is wired. Test all three app states (foreground, background, terminated) explicitly in the QA checklist.
Contingency: If terminated-state deep-linking fails on specific platforms, fall back to launching the app to the home screen with an in-app notification banner prompting the user to open their summary, rather than direct deep-link navigation.
The wrapped-summary-screen manages a large number of AnimationController instances (one or more per slide) via the wrapped-animation-controller. If disposal is not triggered correctly when the user exits mid-flow (e.g., via system back gesture or deep-link away), memory leaks will accumulate across session navigation.
Mitigation & Contingency
Mitigation: Implement screen disposal via Flutter's dispose() lifecycle method calling a single wrapped-animation-controller.disposeAll() method that iterates the named controller registry. Write a test that navigates to the screen, starts animations, then navigates away and verifies no active AnimationController listeners remain using Flutter's test binding.
Contingency: If disposal bugs are detected in production via memory profiling, patch by converting all AnimationControllers to use AutomaticKeepAliveClientMixin false and wrap each slide in a widget that disposes its own controller when removed from the widget tree.