Add availability-based visibility logic to microphone button
epic-speech-to-text-input-user-interface-task-002 — Implement the conditional rendering logic in DictationMicrophoneButton so the widget fully hides itself when DictationScopeGuard reports dictation as unavailable (e.g., unsupported OS version, missing permissions, disabled org feature flag). Use Riverpod provider watch to reactively update visibility without requiring a rebuild of the parent field.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 1 - 540 tasks
Can start after Tier 0 completes
Implementation Notes
The cleanest approach is a dedicated `dictationAvailableProvider(fieldId)` (or a non-family global if availability is org-wide rather than per-field) that DictationScopeGuard exposes. Inside DictationMicrophoneButton, wrap the existing button in: `final isAvailable = ref.watch(dictationAvailableProvider); if (!isAvailable) return const SizedBox.shrink();`. Avoid `Visibility` widget with `maintainState: true` as it keeps the provider subscription alive unnecessarily. Consider whether `AnimatedSize` is appropriate for the appear animation — a simple fade is preferred over a sliding expand to avoid layout jumps.
If the parent TextField uses `suffixIcon`, note that Flutter's InputDecoration does not handle null suffixIcon gracefully in all themes — test on both material and the app's custom theme.
Testing Requirements
Widget tests: (1) Override dictationAvailabilityProvider with false — verify find.byType(IconButton) returns zero matches and find.byType(SizedBox) with zero size is present. (2) Override with true — verify IconButton is present. (3) Use StreamProvider or StateProvider in test to simulate a runtime availability change — pump after change and verify widget appears. (4) Override availability provider to throw an exception — verify widget renders SizedBox.shrink() and no exception propagates to the widget tree.
(5) Verify that when hidden, the Semantics tree contains no node with 'dictation' in the label.
Merging dictated text at the current cursor position in a TextField that already contains user-typed content is non-trivial in Flutter — TextEditingController cursor offsets can behave unexpectedly with IME composition, emoji, or RTL characters, potentially corrupting the user's existing notes.
Mitigation & Contingency
Mitigation: Implement the merge logic using TextEditingController.value replacement with explicit selection range calculation rather than direct text manipulation. Write targeted widget tests covering edge cases: cursor at start, cursor at end, cursor mid-word, existing content with emoji, and content that was modified during an active partial-results stream.
Contingency: If cursor-position merging proves too fragile for the initial release, scope the merge behaviour to always append dictated text at the end of the existing field content and add the cursor-position insertion as a follow-on task after the feature is in TestFlight with real user feedback.
VoiceOver on iOS and TalkBack on Android handle rapid sequential live region announcements differently. If recording start, partial-result, and recording-stop announcements arrive within a short window, they may queue, overlap, or be dropped, leaving screen reader users without critical state information.
Mitigation & Contingency
Mitigation: Implement announcement queuing in AccessibilityLiveRegionAnnouncer with a minimum inter-announcement delay and priority ordering (assertive recording start/stop always takes precedence over polite partial-result updates). Test announcement behaviour on physical iOS and Android devices with VoiceOver/TalkBack enabled as part of the acceptance test plan.
Contingency: If platform differences make reliable queuing impossible, reduce partial-result announcements to a single 'transcription updating' message with debouncing, preserving the critical start/stop announcements. Coordinate with the screen-reader-support feature team to leverage the existing SemanticsServiceFacade patterns already established in the codebase.
The DictationMicrophoneButton must integrate with the dynamic-field-renderer which generates form fields from org-specific schemas at runtime. If the renderer does not expose a stable field metadata API for dictation eligibility checks, the scope guard and button visibility logic will require invasive changes to the report form architecture.
Mitigation & Contingency
Mitigation: Coordinate with the post-session report feature team early in the epic to confirm that dynamic-field-renderer exposes a field metadata interface including field type and sensitivity flags. Add a dictation_eligible flag to the field schema that the renderer passes to DictationMicrophoneButton as a constructor parameter.
Contingency: If the renderer cannot be modified without breaking changes, implement dictation eligibility as a separate lookup against org-field-config-loader using the field key as the lookup identifier, bypassing the renderer integration and keeping the dictation components fully decoupled from the report form architecture.