refactor(flutter): extract shared AudioProcessingPanel widget (TODO-013)

Deduplicate audio processing toggle UI from voice_compact.dart and
voice_settings.dart into shared AudioProcessingPanel widget in
voice_settings_controls.dart. Centralize platform detection getters
in voice_platform.dart.

apps/chanora_flutter/lib/widgets/voice_compact.dart

@@ -26,21 +26,6 @@ import 'voice_settings_controls.dart';
 import 'voice_status_summary.dart';
 import '../src/rust/api.dart' as rust;
 
-bool get _isIos {
-  if (kIsWeb) return false;
-  return Platform.isIOS;
-}
-
-bool get _isMacOS {
-  if (kIsWeb) return false;
-  return Platform.isMacOS;
-}
-
-bool get _isDesktopSileroVadHost {
-  if (kIsWeb) return false;
-  return Platform.isWindows || Platform.isLinux;
-}
-
 /// Two-line status chip that summarises the current voice state.
 /// Tap to open the voice details modal.
 class VoiceStatusChip extends StatelessWidget {
@@ -737,130 +722,12 @@ class _VoiceSheetBodyState extends State<_VoiceSheetBody> {
               ),
             ),
             const SizedBox(height: 4),
-
+ 
-            // Android HW/SW selector.
+            AudioProcessingPanel(
-            if (Platform.isAndroid) ...[
+              config: _audioProcessing,
-              const VoiceSubHeader('Processing backend'),
+              dense: true,
-              SegmentedButton<bool>(
+              update: (mutation) {
-                style: voiceSegmentedButtonStyle(theme),
+                setState(mutation);
-                segments: androidProcessingSegments,
-                selected: {_audioProcessing.preferHardware},
-                onSelectionChanged: (s) {
-                  setState(() => _audioProcessing.preferHardware = s.first);
-                  _notifyAudioConfig();
-                },
-              ),
-              const SizedBox(height: 4),
-              Text(
-                _audioProcessing.preferHardware
-                    ? 'Hardware mode still keeps per-stage WebRTC fallback, so these controls remain effective.'
-                    : 'Software mode applies the full WebRTC APM stage set.',
-                style: theme.textTheme.bodySmall?.copyWith(
-                  color: theme.colorScheme.onSurfaceVariant,
-                ),
-              ),
-            ],
-
-            if (_isIos) ...[
-              Text(
-                'iOS uses Apple VoiceProcessingIO. WebRTC APM controls are '
-                'hidden here; only settings that still affect the shipping '
-                'iOS path are shown.',
-                style: theme.textTheme.bodySmall?.copyWith(
-                  color: theme.colorScheme.onSurfaceVariant,
-                ),
-              ),
-              const SizedBox(height: 4),
-            ],
-            if (!_isIos &&
-                (!Platform.isAndroid ||
-                    androidShowsNsControl(_audioProcessing)))
-              AudioProcessingToggleRow(
-                dense: true,
-                label: 'Noise suppression',
-                subtitle: 'Wiener filter',
-                value: _audioProcessing.nsEnabled,
-                onChanged: (v) {
-                  setState(() => _audioProcessing.nsEnabled = v);
-                  _notifyAudioConfig();
-                },
-              ),
-            if (!_isIos &&
-                (!Platform.isAndroid ||
-                    androidShowsAecControl(_audioProcessing)))
-              AudioProcessingToggleRow(
-                dense: true,
-                label: 'Echo cancellation',
-                subtitle: Platform.isAndroid
-                    ? (_audioProcessing.preferHardware
-                          ? 'Prefers device/OS effect; falls back to WebRTC AEC3'
-                          : 'WebRTC AEC3 · adaptive filter')
-                    : (_isMacOS
-                          ? 'Managed by platform VPIO'
-                          : 'WebRTC AEC3 · adaptive filter'),
-                value: _isMacOS ? true : _audioProcessing.aecEnabled,
-                onChanged: _isMacOS
-                    ? null
-                    : (v) {
-                        setState(() => _audioProcessing.aecEnabled = v);
-                        _notifyAudioConfig();
-                      },
-              ),
-            if (!_isIos &&
-                (!Platform.isAndroid ||
-                    androidShowsAgcControl(_audioProcessing)))
-              AudioProcessingToggleRow(
-                dense: true,
-                label: 'Auto gain control',
-                subtitle: 'AGC2 · -18 dBFS target',
-                value: _audioProcessing.agcEnabled,
-                onChanged: (v) {
-                  setState(() => _audioProcessing.agcEnabled = v);
-                  _notifyAudioConfig();
-                },
-              ),
-            if (!Platform.isAndroid || androidShowsHpfControl(_audioProcessing))
-              AudioProcessingToggleRow(
-                dense: true,
-                label: 'High-pass filter',
-                subtitle: '80 Hz · DC removal',
-                value: _audioProcessing.hpfEnabled,
-                onChanged: (v) {
-                  setState(() => _audioProcessing.hpfEnabled = v);
-                  _notifyAudioConfig();
-                },
-              ),
-            if (!_isIos &&
-                (!Platform.isAndroid ||
-                    androidShowsLimiterControl(_audioProcessing)))
-              AudioProcessingToggleRow(
-                dense: true,
-                label: 'Peak limiter',
-                subtitle: '-1 dBFS soft-knee · 2 ms look-ahead',
-                value: _audioProcessing.limiterEnabled,
-                onChanged: (v) {
-                  setState(() => _audioProcessing.limiterEnabled = v);
-                  _notifyAudioConfig();
-                },
-              ),
-
-            // VAD backend.
-            const SizedBox(height: 8),
-            Text(
-              'Voice activity detection (VAD)',
-              style: theme.textTheme.labelLarge?.copyWith(
-                color: theme.colorScheme.onSurfaceVariant,
-              ),
-            ),
-            const SizedBox(height: 2),
-            SegmentedButton<rust.BridgeVadBackend>(
-              style: voiceSegmentedButtonStyle(theme),
-              segments: _isDesktopSileroVadHost
-                  ? desktopVadBackendSegments
-                  : vadBackendSegments,
-              selected: {_audioProcessing.vadBackend},
-              onSelectionChanged: (s) {
-                setState(() => _audioProcessing.vadBackend = s.first);
                 _notifyAudioConfig();
               },
             ),

apps/chanora_flutter/lib/widgets/voice_platform.dart

@@ -2,9 +2,17 @@ import 'dart:io' show Platform;
 
 import 'package:flutter/foundation.dart' show kIsWeb;
 
-/// True when the host is a touch-only mobile platform without a
+// TODO(refactor): Scattered Platform.isX checks exist across ~6 Dart files.
-/// hardware keyboard the user would bind a PTT key on.
+// Centralize all platform checks here and update call sites to use these
-bool get isTouchOnlyPttHost {
+// getters instead of raw Platform.isAndroid/isIOS/etc.
-  if (kIsWeb) return false;
+bool get _notWeb => !kIsWeb;
-  return Platform.isIOS || Platform.isAndroid;
+
-}
+bool get isTouchOnlyPttHost => _notWeb && (Platform.isIOS || Platform.isAndroid);
+
+bool get isAndroidHost => _notWeb && Platform.isAndroid;
+
+bool get isIosHost => _notWeb && Platform.isIOS;
+
+bool get isMacOsHost => _notWeb && Platform.isMacOS;
+
+bool get isDesktopSileroVadHost => _notWeb && (Platform.isWindows || Platform.isLinux);

apps/chanora_flutter/lib/widgets/voice_settings.dart

@@ -7,9 +7,6 @@
 //   - VAD backend
 //   - platform audio-processing mode selection where available
 
-import 'dart:io' show Platform;
-
-import 'package:flutter/foundation.dart' show kIsWeb;
 import 'package:flutter/material.dart';
 
 import '../l10n/generated/app_localizations.dart';
@@ -22,26 +19,6 @@ import 'voice_platform.dart';
 import 'voice_settings_controls.dart';
 import '../src/rust/api.dart' as rust;
 
-bool get _isAndroid {
-  if (kIsWeb) return false;
-  return Platform.isAndroid;
-}
-
-bool get _isIos {
-  if (kIsWeb) return false;
-  return Platform.isIOS;
-}
-
-bool get _isMacOS {
-  if (kIsWeb) return false;
-  return Platform.isMacOS;
-}
-
-bool get _isDesktopSileroVadHost {
-  if (kIsWeb) return false;
-  return Platform.isWindows || Platform.isLinux;
-}
-
 /// Result returned by [VoiceSettingsDialog].
 class VoiceSettingsResult {
   const VoiceSettingsResult({
@@ -106,7 +83,7 @@ class _VoiceSettingsDialogState extends State<VoiceSettingsDialog> {
   rust.BridgeAudioProcessingConfig _buildConfig() {
     return _audioProcessing.buildConfig(
       base: widget.initialAudioConfig,
-      isAndroid: _isAndroid,
+      isAndroid: isAndroidHost,
     );
   }
 
@@ -189,92 +166,10 @@ class _VoiceSettingsDialogState extends State<VoiceSettingsDialog> {
               const Divider(height: 24),
               const VoiceSectionHeader('Audio processing'),
 
-              // Android HW/SW selector
+              AudioProcessingPanel(
-              if (_isAndroid) ...[
+                config: _audioProcessing,
-                const VoiceSubHeader('Processing backend'),
+                update: (mutation) => setState(mutation),
-                SegmentedButton<bool>(
+              ),
-                  style: voiceSegmentedButtonStyle(theme),
-                  segments: androidProcessingSegments,
-                  selected: {_audioProcessing.preferHardware},
-                  onSelectionChanged: (s) =>
-                      setState(() => _audioProcessing.preferHardware = s.first),
-                ),
-                const SizedBox(height: 4),
-                Text(
-                  _audioProcessing.preferHardware
-                      ? 'Android hardware mode still falls back to WebRTC APM per stage when device effects are missing, so these controls remain available.'
-                      : 'Android software mode applies the full WebRTC APM control set.',
-                  style: theme.textTheme.bodySmall?.copyWith(
-                    color: theme.colorScheme.onSurfaceVariant,
-                  ),
-                ),
-                const SizedBox(height: 8),
-              ],
-
-              // DSP toggles
-              const VoiceSubHeader('DSP stages'),
-              if (_isIos) ...[
-                Text(
-                  'iOS uses Apple VoiceProcessingIO. WebRTC APM controls are '
-                  'hidden here; only settings that still affect the shipping '
-                  'iOS path are shown.',
-                  style: theme.textTheme.bodySmall?.copyWith(
-                    color: theme.colorScheme.onSurfaceVariant,
-                  ),
-                ),
-                const SizedBox(height: 8),
-              ],
-              if (!_isIos &&
-                  (!_isAndroid || androidShowsNsControl(_audioProcessing)))
-                AudioProcessingToggleRow(
-                  label: 'Noise suppression (NS)',
-                  subtitle: 'Wiener filter · stationary noise',
-                  value: _audioProcessing.nsEnabled,
-                  onChanged: (v) =>
-                      setState(() => _audioProcessing.nsEnabled = v),
-                ),
-              if (!_isIos &&
-                  (!_isAndroid || androidShowsAecControl(_audioProcessing)))
-                AudioProcessingToggleRow(
-                  label: 'Echo cancellation (AEC3)',
-                  subtitle: _isAndroid
-                      ? (_audioProcessing.preferHardware
-                            ? 'Prefers device/OS effect; WebRTC AEC3 fallback when binding is unavailable'
-                            : 'WebRTC AEC3 · adaptive filter')
-                      : (_isMacOS
-                            ? 'Managed by platform VPIO'
-                            : 'WebRTC AEC3 · adaptive filter'),
-                  value: _isMacOS ? true : _audioProcessing.aecEnabled,
-                  onChanged: _isMacOS
-                      ? null
-                      : (v) => setState(() => _audioProcessing.aecEnabled = v),
-                ),
-              if (!_isIos &&
-                  (!_isAndroid || androidShowsAgcControl(_audioProcessing)))
-                AudioProcessingToggleRow(
-                  label: 'Auto gain control (AGC2)',
-                  subtitle: 'RNN VAD-gated · -18 dBFS target',
-                  value: _audioProcessing.agcEnabled,
-                  onChanged: (v) =>
-                      setState(() => _audioProcessing.agcEnabled = v),
-                ),
-              if (!_isAndroid || androidShowsHpfControl(_audioProcessing))
-                AudioProcessingToggleRow(
-                  label: 'High-pass filter (HPF)',
-                  subtitle: '80 Hz Butterworth · DC removal',
-                  value: _audioProcessing.hpfEnabled,
-                  onChanged: (v) =>
-                      setState(() => _audioProcessing.hpfEnabled = v),
-                ),
-              if (!_isIos &&
-                  (!_isAndroid || androidShowsLimiterControl(_audioProcessing)))
-                AudioProcessingToggleRow(
-                  label: 'Peak limiter',
-                  subtitle: '-1 dBFS soft-knee · 2 ms look-ahead',
-                  value: _audioProcessing.limiterEnabled,
-                  onChanged: (v) =>
-                      setState(() => _audioProcessing.limiterEnabled = v),
-                ),
 
               if (isTalkPowerBlocked(
                 talkPower: widget.talkPower,
@@ -289,22 +184,6 @@ class _VoiceSettingsDialogState extends State<VoiceSettingsDialog> {
                 ),
               ],
 
-              // ── VAD ────────────────────────────────────────────────
-              const Divider(height: 24),
-              const VoiceSectionHeader('Voice activity detection (VAD)'),
-
-              const VoiceSubHeader('Backend'),
-              SegmentedButton<rust.BridgeVadBackend>(
-                style: voiceSegmentedButtonStyle(theme),
-                segments: _isDesktopSileroVadHost
-                    ? desktopVadBackendSegments
-                    : vadBackendSegments,
-                selected: {_audioProcessing.vadBackend},
-                onSelectionChanged: (s) =>
-                    setState(() => _audioProcessing.vadBackend = s.first),
-              ),
-              const SizedBox(height: 8),
-
               // ── PTT capability badge ────────────────────────────────
               if (_mode == rust.BridgeTransmitMode.ptt &&
                   widget.pttLevel.isNotEmpty) ...[
@@ -318,14 +197,14 @@ class _VoiceSettingsDialogState extends State<VoiceSettingsDialog> {
               ],
 
               // ── Audio output route picker (mobile only) ─────────────
-              if (_isAndroid || _isIos) ...[
+              if (isAndroidHost || isIosHost) ...[
                 const Divider(height: 24),
                 const VoiceSectionHeader('Audio output'),
                 const AudioOutputTile(),
               ],
 
               // ── Audio devices (desktop only, SRS-026) ──────────────
-              if (!_isAndroid && !_isIos) ...[
+              if (!isAndroidHost && !isIosHost) ...[
                 const Divider(height: 24),
                 const VoiceSectionHeader('Audio devices'),
                 const AudioDeviceListTile(

apps/chanora_flutter/lib/widgets/voice_settings_controls.dart

@@ -3,6 +3,8 @@ import 'dart:io' show Platform;
 import 'package:flutter/foundation.dart' show kIsWeb;
 import 'package:flutter/material.dart';
 
+import 'audio_processing_config_state.dart';
+import 'voice_platform.dart';
 import '../src/rust/api.dart' as rust;
 
 /// Shared compact style for voice settings segmented buttons.
@@ -230,3 +232,173 @@ class AudioProcessingToggleRow extends StatelessWidget {
     );
   }
 }
+
+typedef AudioFieldUpdater = void Function(VoidCallback mutation);
+
+class AudioProcessingPanel extends StatelessWidget {
+  const AudioProcessingPanel({
+    super.key,
+    required this.config,
+    required this.update,
+    this.dense = false,
+  });
+
+  final AudioProcessingConfigState config;
+  final AudioFieldUpdater update;
+  final bool dense;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final isAndroid = isAndroidHost;
+    final isIos = isIosHost;
+    final isMacOS = isMacOsHost;
+    final isDesktopSilero = isDesktopSileroVadHost;
+
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.stretch,
+      children: [
+        if (isAndroid) ...[
+          if (!dense) const VoiceSubHeader('Processing backend'),
+          if (dense) _compactLabel(context, 'Processing backend'),
+          SegmentedButton<bool>(
+            style: voiceSegmentedButtonStyle(theme),
+            segments: androidProcessingSegments,
+            selected: {config.preferHardware},
+            onSelectionChanged: (s) {
+              update(() => config.preferHardware = s.first);
+            },
+          ),
+          const SizedBox(height: 4),
+          Text(
+            config.preferHardware
+                ? (dense
+                    ? 'Hardware mode still keeps per-stage WebRTC fallback, so these controls remain effective.'
+                    : 'Android hardware mode still falls back to WebRTC APM per stage when device effects are missing, so these controls remain available.')
+                : (dense
+                    ? 'Software mode applies the full WebRTC APM stage set.'
+                    : 'Android software mode applies the full WebRTC APM control set.'),
+            style: theme.textTheme.bodySmall?.copyWith(
+              color: theme.colorScheme.onSurfaceVariant,
+            ),
+          ),
+          if (!dense) const SizedBox(height: 8),
+        ],
+
+        if (!dense) const VoiceSubHeader('DSP stages'),
+
+        if (isIos) ...[
+          Text(
+            'iOS uses Apple VoiceProcessingIO. WebRTC APM controls are '
+            'hidden here; only settings that still affect the shipping '
+            'iOS path are shown.',
+            style: theme.textTheme.bodySmall?.copyWith(
+              color: theme.colorScheme.onSurfaceVariant,
+            ),
+          ),
+          const SizedBox(height: 4),
+        ],
+
+        if (!isIos &&
+            (!isAndroid || androidShowsNsControl(config)))
+          AudioProcessingToggleRow(
+            dense: dense,
+            label: dense ? 'Noise suppression' : 'Noise suppression (NS)',
+            subtitle: dense
+                ? 'Wiener filter'
+                : 'Wiener filter · stationary noise',
+            value: config.nsEnabled,
+            onChanged: (v) => update(() => config.nsEnabled = v),
+          ),
+        if (!isIos &&
+            (!isAndroid || androidShowsAecControl(config)))
+          AudioProcessingToggleRow(
+            dense: dense,
+            label: dense ? 'Echo cancellation' : 'Echo cancellation (AEC3)',
+            subtitle: _aecSubtitle(isAndroid, isMacOS, config),
+            value: isMacOS ? true : config.aecEnabled,
+            onChanged:
+                isMacOS ? null : (v) => update(() => config.aecEnabled = v),
+          ),
+        if (!isIos &&
+            (!isAndroid || androidShowsAgcControl(config)))
+          AudioProcessingToggleRow(
+            dense: dense,
+            label: dense ? 'Auto gain control' : 'Auto gain control (AGC2)',
+            subtitle: dense
+                ? 'AGC2 · -18 dBFS target'
+                : 'RNN VAD-gated · -18 dBFS target',
+            value: config.agcEnabled,
+            onChanged: (v) => update(() => config.agcEnabled = v),
+          ),
+        if (!isAndroid || androidShowsHpfControl(config))
+          AudioProcessingToggleRow(
+            dense: dense,
+            label: dense ? 'High-pass filter' : 'High-pass filter (HPF)',
+            subtitle: dense
+                ? '80 Hz · DC removal'
+                : '80 Hz Butterworth · DC removal',
+            value: config.hpfEnabled,
+            onChanged: (v) => update(() => config.hpfEnabled = v),
+          ),
+        if (!isIos &&
+            (!isAndroid || androidShowsLimiterControl(config)))
+          AudioProcessingToggleRow(
+            dense: dense,
+            label: 'Peak limiter',
+            subtitle: '-1 dBFS soft-knee · 2 ms look-ahead',
+            value: config.limiterEnabled,
+            onChanged: (v) => update(() => config.limiterEnabled = v),
+          ),
+
+        if (!dense) ...[
+          const Divider(height: 24),
+          const VoiceSectionHeader('Voice activity detection (VAD)'),
+          const VoiceSubHeader('Backend'),
+        ] else ...[
+          const SizedBox(height: 8),
+          Text(
+            'Voice activity detection (VAD)',
+            style: theme.textTheme.labelLarge?.copyWith(
+              color: theme.colorScheme.onSurfaceVariant,
+            ),
+          ),
+          const SizedBox(height: 2),
+        ],
+        SegmentedButton<rust.BridgeVadBackend>(
+          style: voiceSegmentedButtonStyle(theme),
+          segments:
+              isDesktopSilero ? desktopVadBackendSegments : vadBackendSegments,
+          selected: {config.vadBackend},
+          onSelectionChanged: (s) {
+            update(() => config.vadBackend = s.first);
+          },
+        ),
+        if (!dense) const SizedBox(height: 8),
+      ],
+    );
+  }
+
+  String _aecSubtitle(bool isAndroid, bool isMacOS, AudioProcessingConfigState c) {
+    if (isAndroid) {
+      return c.preferHardware
+          ? 'Prefers device/OS effect; falls back to WebRTC AEC3'
+          : 'WebRTC AEC3 · adaptive filter';
+    }
+    if (isMacOS) return 'Managed by platform VPIO';
+    return 'WebRTC AEC3 · adaptive filter';
+  }
+
+  Widget _compactLabel(BuildContext context, String text) {
+    final theme = Theme.of(context);
+    return Padding(
+      padding: const EdgeInsets.only(bottom: 2),
+      child: Text(
+        text,
+        style: theme.textTheme.labelLarge?.copyWith(
+          color: theme.colorScheme.onSurfaceVariant,
+        ),
+      ),
+    );
+  }
+}