Wizard Progress Indicator widget
epic-cognitive-accessibility-foundation-task-008 — Implement the WizardProgressIndicator Flutter widget displaying current step position within the ≤5 step constraint. Show numbered step dots with completed/active/upcoming states, accessible semantic labels for screen readers (e.g., 'Step 2 of 4, Date selection'), and a step title below the indicator. Widget must reject configurations with more than 5 steps by asserting in debug mode via the CognitiveLoadRuleEngine.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 2 - 518 tasks
Can start after Tier 1 completes
Implementation Notes
Build as a StatelessWidget with const constructor. Use Row of StepDot widgets separated by thin connector lines (use Container with fixed height). StepDot state is derived from comparing index to currentStep — no internal state needed. Apply design tokens via Theme.of(context) extension or a DesignTokens static class — never hardcode hex colours or pixel sizes.
The Semantics label for the full row should NOT use a live region — screen readers should navigate dots individually. Use debugCheckHasFlutterMediaQuery in tests to ensure MediaQuery is available for font scale tests. For the connector line between dots, use a thin horizontal Divider-like Container (height: 2, colour: design token borderSubtle) — hide it from semantics with ExcludeSemantics.
Testing Requirements
Widget tests with flutter_test. Golden tests for: 1-step wizard (only active), 3-step wizard at step 1 (1 active, 2 upcoming), 3-step wizard at step 2 (1 completed, 1 active, 1 upcoming), 3-step wizard at step 3 (2 completed, 1 active), 5-step wizard at step 5 (max allowed). Test semantics tree with tester.getSemantics() — verify each dot has correct label. Test font scale 2.0x renders without overflow.
Test AssertionError for totalSteps = 6. Test AssertionError for currentStep = 0 and currentStep > totalSteps. No integration or e2e tests needed.
The error message registry and help content registry both depend on bundled JSON assets loaded at startup. If asset loading fails silently (e.g. malformed JSON, missing pubspec asset declaration), the entire plain-language layer falls back to empty strings or raw error codes, breaking the accessibility guarantee app-wide.
Mitigation & Contingency
Mitigation: Implement eager validation of both assets during app initialisation with an assertion failure in debug mode and a structured error log in release mode. Add integration tests that verify asset loading in the Flutter test harness on every CI run.
Contingency: Ship a hardcoded minimum-viable fallback message set directly in Dart code so the app always has at least a safe generic message, preventing a blank or code-only error surface.
The AccessibilityDesignTokenEnforcer relies on dart_code_metrics custom lint rules. If the lint toolchain is not already configured in the project's CI pipeline, integrating a new linting plugin may cause unexpected build failures or require significant CI configuration work beyond the estimated scope.
Mitigation & Contingency
Mitigation: Audit the existing dart_code_metrics configuration in the project before starting implementation. Scope the lint rules to a separate Dart package that can be integrated incrementally, starting with the most critical rule (hard-coded colors) and adding others in subsequent iterations.
Contingency: Fall back to Flutter test-level assertions (using the cognitive-accessibility-audit utility) to catch violations in CI if the lint plugin integration is delayed, preserving enforcement coverage without blocking the epic.
WizardDraftRepository must choose between shared_preferences and Hive for local persistence. Choosing the wrong store for the data volume (e.g. shared_preferences for complex nested wizard state) can lead to serialisation bugs or performance degradation, particularly on lower-end Android devices used by some NHF members.
Mitigation & Contingency
Mitigation: Define a clean repository interface first and implement shared_preferences as the initial backend. Profile serialisation round-trip time with a realistic wizard state payload (≈10 fields) before committing to either store.
Contingency: Swap the persistence backend behind the repository interface without touching wizard UI code, which is possible precisely because the repository abstraction isolates the storage detail.
The AccessibilityDesignTokenEnforcer scope could expand significantly if a large portion of existing widgets use hard-coded values. Discovering widespread violations during this epic would force either a major refactor or a decision to exclude legacy components, potentially reducing the enforcer's coverage and value.
Mitigation & Contingency
Mitigation: Run a preliminary audit of existing widgets using a simple grep for hard-coded hex colors and raw pixel values before implementation begins. Use the results to set a realistic remediation boundary for this epic and log all out-of-scope violations as tracked tech-debt items.
Contingency: Scope the enforcer to new and modified components only (via file-path filters in dart_code_metrics config), shipping a partial but immediately valuable coverage rather than blocking the epic on full-codebase remediation.