feat: run photo analysis and gaps on the device's own AI

composeApp/src/main/kotlin/com/github/worn/ui/screen/AddItemSheet.kt

@@ -86,7 +86,7 @@ import java.io.ByteArrayOutputStream
 @Composable
 fun AddItemSheet(
     isSaving: Boolean,
-    hasApiKey: Boolean,
+    isAiAvailable: Boolean,
     existingItem: ClothingItem? = null,
     onSave: (
         imageBytes: ByteArray, name: String, category: Category,
@@ -106,7 +106,7 @@ fun AddItemSheet(
     ) {
         AddItemForm(
             isSaving = isSaving,
-            hasApiKey = hasApiKey,
+            isAiAvailable = isAiAvailable,
             existingItem = existingItem,
             onSave = onSave,
         )
@@ -116,7 +116,7 @@ fun AddItemSheet(
 @Composable
 internal fun AddItemForm(
     isSaving: Boolean = false,
-    hasApiKey: Boolean = false,
+    isAiAvailable: Boolean = false,
     existingItem: ClothingItem? = null,
     onSave: (ByteArray, String, Category, List<String>, List<Season>, Subcategory?, Fit?, Material?) -> Unit =
         { _, _, _, _, _, _, _, _ -> },
@@ -215,7 +215,7 @@ internal fun AddItemForm(
         canSave = formState.hasPhoto && formState.name.isNotBlank() && formState.selectedCategory != null,
         isEditing = existingItem != null,
         onPhotoClick = { formState.showSourceChooser = true },
-        onAiBadgeClick = { if (!hasApiKey) formState.showAiLockedSheet = true },
+        onAiBadgeClick = { if (!isAiAvailable) formState.showAiLockedSheet = true },
         onSave = {
             val cat = formState.selectedCategory ?: return@AddItemFormContent
             val bytes = formState.photoBytes ?: ByteArray(0)

composeApp/src/main/kotlin/com/github/worn/ui/screen/GapsScreen.kt

@@ -123,7 +123,7 @@ fun GapsScreen(onTabSelected: (Tab) -> Unit) {
         val gap = addItemPreFill!!
         AddItemSheet(
             isSaving = false,
-            hasApiKey = state.hasApiKey,
+            isAiAvailable = state.isAiAvailable,
             existingItem = gap.toPreFilledItem(),
             onSave = { _, _, _, _, _, _, _, _ -> showAddItemSheet = false },
             onDismiss = { showAddItemSheet = false },
@@ -613,7 +613,7 @@ private fun GapsScreenPhonePreview() {
             state = GapsState(
                 recommendations = com.github.worn.domain.model.capsuleWardrobeSuggestions.take(6),
                 isAiMode = false,
-                hasApiKey = false,
+                isAiAvailable = false,
             ),
         )
     }
@@ -627,7 +627,7 @@ private fun GapsScreenTabletPreview() {
             state = GapsState(
                 recommendations = com.github.worn.domain.model.capsuleWardrobeSuggestions.take(6),
                 isAiMode = true,
-                hasApiKey = true,
+                isAiAvailable = true,
             ),
             isCompact = false,
         )
@@ -650,7 +650,7 @@ private fun GapsScreenErrorPreview() {
             state = GapsState(
                 error = "Invalid API key. Check your key in Settings.",
                 isAiMode = true,
-                hasApiKey = true,
+                isAiAvailable = true,
             ),
         )
     }

composeApp/src/main/kotlin/com/github/worn/ui/screen/SettingsScreen.kt

@@ -25,6 +25,7 @@ import androidx.compose.material.icons.automirrored.outlined.KeyboardArrowRight
 import androidx.compose.material.icons.outlined.AutoAwesome
 import androidx.compose.material.icons.outlined.Checkroom
 import androidx.compose.material.icons.outlined.Person
+import androidx.compose.material.icons.outlined.PhoneAndroid
 import androidx.compose.material.icons.outlined.Visibility
 import androidx.compose.material.icons.outlined.VisibilityOff
 import androidx.compose.material3.ExperimentalMaterial3Api
@@ -34,6 +35,8 @@ import androidx.compose.material3.IconButton
 import androidx.compose.material3.ModalBottomSheet
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Surface
+import androidx.compose.material3.Switch
+import androidx.compose.material3.SwitchDefaults
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextField
 import androidx.compose.material3.TextFieldDefaults
@@ -58,6 +61,7 @@ import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.input.PasswordVisualTransformation
 import androidx.compose.ui.text.input.VisualTransformation
+import androidx.annotation.StringRes
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
@@ -69,8 +73,11 @@ import com.github.worn.domain.model.AgeRange
 import com.github.worn.domain.model.BodyType
 import com.github.worn.domain.model.Climate
 import com.github.worn.domain.model.Lifestyle
+import com.github.worn.domain.model.OnDeviceAiAvailability
+import com.github.worn.domain.model.OnDeviceAiUnavailableReason
 import com.github.worn.domain.model.StyleProfile
 import com.github.worn.domain.model.UserProfile
+import com.github.worn.domain.model.isUsable
 import com.github.worn.presentation.viewmodel.SettingsEffect
 import com.github.worn.presentation.viewmodel.SettingsIntent
 import com.github.worn.presentation.viewmodel.SettingsState
@@ -111,6 +118,7 @@ fun SettingsScreen(onTabSelected: (Tab) -> Unit) {
         onProfileClick = { showProfileSheet = true },
         onApiKeyClick = { showApiKeySheet = true },
         onYouCamClick = { showYouCamSheet = true },
+        onOnDeviceAiChange = { viewModel.onIntent(SettingsIntent.SetOnDeviceAi(it)) },
     )
 
     if (showProfileSheet) {
@@ -161,6 +169,7 @@ private fun SettingsScaffold(
     onProfileClick: () -> Unit = {},
     onApiKeyClick: () -> Unit = {},
     onYouCamClick: () -> Unit = {},
+    onOnDeviceAiChange: (Boolean) -> Unit = {},
 ) {
     val contentPadding = if (isCompact) 24.dp else 32.dp
 
@@ -198,6 +207,17 @@ private fun SettingsScaffold(
             Spacer(Modifier.height(24.dp))
             SectionLabel(stringResource(R.string.settings_section_ai))
             Spacer(Modifier.height(10.dp))
+            // Listed before the key card: it is free and private, so it should be the first option.
+            SettingsToggleCard(
+                icon = { SettingsIcon(color = WornColors.AccentGreen, icon = Icons.Outlined.PhoneAndroid) },
+                title = stringResource(R.string.settings_on_device_ai_title),
+                subtitle = stringResource(state.onDeviceAiAvailability.subtitleRes()),
+                checked = state.onDeviceAiEnabled,
+                enabled = state.onDeviceAiAvailability.isUsable,
+                onCheckedChange = onOnDeviceAiChange,
+                modifier = Modifier.testTag("settings_on_device_ai_toggle"),
+            )
+            Spacer(Modifier.height(10.dp))
             SettingsCard(
                 icon = { SettingsIcon(color = WornColors.AccentIndigo, icon = Icons.Outlined.AutoAwesome) },
                 title = stringResource(R.string.settings_api_key_title),
@@ -260,6 +280,67 @@ private fun SettingsIcon(color: Color, icon: androidx.compose.ui.graphics.vector
     }
 }
 
+/**
+ * A [SettingsCard] whose trailing affordance is a switch instead of a chevron. The whole row is
+ * tappable so the target matches the other cards, and the switch is disabled — rather than hidden —
+ * when the capability is missing, so the subtitle can explain why.
+ */
+@Composable
+private fun SettingsToggleCard(
+    icon: @Composable () -> Unit,
+    title: String,
+    subtitle: String,
+    checked: Boolean,
+    enabled: Boolean,
+    onCheckedChange: (Boolean) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    Surface(
+        onClick = { onCheckedChange(!checked) },
+        enabled = enabled,
+        shape = RoundedCornerShape(16.dp),
+        color = WornColors.BgCard,
+        modifier = modifier,
+    ) {
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            modifier = Modifier.fillMaxWidth().padding(16.dp),
+        ) {
+            icon()
+            Spacer(Modifier.width(14.dp))
+            Column(modifier = Modifier.weight(1f)) {
+                Text(title, color = WornColors.TextPrimary, fontSize = 16.sp, fontWeight = FontWeight.Medium)
+                Text(subtitle, color = WornColors.TextSecondary, fontSize = 13.sp)
+            }
+            Spacer(Modifier.width(8.dp))
+            Switch(
+                checked = checked,
+                onCheckedChange = onCheckedChange,
+                enabled = enabled,
+                colors = SwitchDefaults.colors(
+                    checkedThumbColor = Color.White,
+                    checkedTrackColor = WornColors.AccentGreen,
+                ),
+            )
+        }
+    }
+}
+
+@StringRes
+private fun OnDeviceAiAvailability.subtitleRes(): Int = when (this) {
+    OnDeviceAiAvailability.Available -> R.string.settings_on_device_ai_available
+    OnDeviceAiAvailability.Downloadable -> R.string.settings_on_device_ai_downloading
+    is OnDeviceAiAvailability.Unavailable -> when (reason) {
+        OnDeviceAiUnavailableReason.UNSUPPORTED_DEVICE ->
+            R.string.settings_on_device_ai_unsupported_device
+        OnDeviceAiUnavailableReason.UNSUPPORTED_OS ->
+            R.string.settings_on_device_ai_unsupported_os
+        OnDeviceAiUnavailableReason.DISABLED_BY_USER ->
+            R.string.settings_on_device_ai_disabled_by_user
+        OnDeviceAiUnavailableReason.UNKNOWN -> R.string.settings_on_device_ai_unavailable
+    }
+}
+
 @Composable
 private fun SettingsCard(
     icon: @Composable () -> Unit,
@@ -919,14 +1000,34 @@ private const val LICENSE_URL = "https://github.com/jvsena42/worn/blob/main/LICE
 @Composable
 private fun SettingsScreenPhonePreview() {
     WornTheme {
-        SettingsScaffold(state = SettingsState())
+        SettingsScaffold(
+            state = SettingsState(
+                onDeviceAiEnabled = true,
+                onDeviceAiAvailability = OnDeviceAiAvailability.Available,
+            ),
+        )
     }
 }
 
 @Preview(showSystemUi = true, device = "id:pixel_tablet")
 @Composable
 private fun SettingsScreenTabletPreview() {
     WornTheme {
-        SettingsScaffold(state = SettingsState(), isCompact = false)
+        SettingsScaffold(
+            state = SettingsState(
+                onDeviceAiEnabled = true,
+                onDeviceAiAvailability = OnDeviceAiAvailability.Available,
+            ),
+            isCompact = false,
+        )
+    }
+}
+
+/** The default [SettingsState] already reports on-device AI as unavailable. */
+@Preview(showSystemUi = true, device = "id:pixel_8")
+@Composable
+private fun SettingsScreenOnDeviceAiUnavailablePreview() {
+    WornTheme {
+        SettingsScaffold(state = SettingsState())
     }
 }

composeApp/src/main/kotlin/com/github/worn/ui/screen/WardrobeScreen.kt

@@ -165,7 +165,7 @@ private fun WardrobeAddItemSheet(
 ) {
     AddItemSheet(
         isSaving = state.isSaving,
-        hasApiKey = state.hasApiKey,
+        isAiAvailable = state.isAiAvailable,
         existingItem = editItem,
         onSave = { imageBytes, name, category, colors, seasons, subcategory, fit, material ->
             if (editItem != null) {

composeApp/src/main/res/values-pt-rBR/strings.xml

@@ -88,6 +88,13 @@
     <string name="settings_your_profile">Seu Perfil</string>
     <string name="settings_profile_subtitle_empty">Toque para configurar</string>
     <string name="settings_profile_help">Ajude a IA a dar melhores sugestões</string>
+    <string name="settings_on_device_ai_title">IA no dispositivo</string>
+    <string name="settings_on_device_ai_available">Roda de forma privada neste aparelho, sem chave</string>
+    <string name="settings_on_device_ai_downloading">O modelo é baixado no primeiro uso</string>
+    <string name="settings_on_device_ai_unsupported_device">Não compatível com este aparelho</string>
+    <string name="settings_on_device_ai_unsupported_os">Requer uma versão mais recente do Android</string>
+    <string name="settings_on_device_ai_disabled_by_user">Ative o Gemini Nano nos ajustes do sistema</string>
+    <string name="settings_on_device_ai_unavailable">Indisponível no momento</string>
     <string name="settings_api_key_title">Chave da API Claude</string>
     <string name="settings_api_key_connected">Conectado</string>
     <string name="settings_api_key_required">Necessária para funções de IA</string>
@@ -173,7 +180,7 @@
 
     <!-- AI Locked Sheet -->
     <string name="ai_locked_title">Desbloquear funções de IA</string>
-    <string name="ai_locked_description">Adicione sua chave da API Claude nos Ajustes para habilitar.</string>
+    <string name="ai_locked_description">Ative a IA no dispositivo ou adicione sua chave da API Claude nos Ajustes.</string>
     <string name="ai_locked_cta">Ir para Ajustes</string>
 
     <!-- Filter -->

composeApp/src/main/res/values/strings.xml

@@ -88,6 +88,13 @@
     <string name="settings_your_profile">Your Profile</string>
     <string name="settings_profile_subtitle_empty">Tap to set up</string>
     <string name="settings_profile_help">Help AI give better suggestions</string>
+    <string name="settings_on_device_ai_title">On-device AI</string>
+    <string name="settings_on_device_ai_available">Runs privately on this device, no key needed</string>
+    <string name="settings_on_device_ai_downloading">The model downloads the first time you use it</string>
+    <string name="settings_on_device_ai_unsupported_device">Not supported by this device</string>
+    <string name="settings_on_device_ai_unsupported_os">Needs a newer Android version</string>
+    <string name="settings_on_device_ai_disabled_by_user">Turn on Gemini Nano in system settings</string>
+    <string name="settings_on_device_ai_unavailable">Unavailable right now</string>
     <string name="settings_api_key_title">Claude API Key</string>
     <string name="settings_api_key_connected">Connected</string>
     <string name="settings_api_key_required">Required for AI features</string>
@@ -173,7 +180,7 @@
 
     <!-- AI Locked Sheet -->
     <string name="ai_locked_title">Unlock AI features</string>
-    <string name="ai_locked_description">Add your Claude API key in Settings to enable this.</string>
+    <string name="ai_locked_description">Turn on on-device AI or add your Claude API key in Settings.</string>
     <string name="ai_locked_cta">Go to Settings</string>
 
     <!-- Filter -->

gradle/libs.versions.toml

@@ -21,6 +21,7 @@ turbine = "1.2.1"
 mockk = "1.14.11"
 datastore = "1.2.1"
 splashscreen = "1.2.0"
+mlkitGenaiPrompt = "1.0.0-beta2"
 mlkitSubjectSegmentation = "16.0.0-beta1"
 
 [libraries]
@@ -64,6 +65,7 @@ mockk = { module = "io.mockk:mockk", version.ref = "mockk" }
 datastore = { module = "androidx.datastore:datastore", version.ref = "datastore" }
 datastore-preferences = { module = "androidx.datastore:datastore-preferences", version.ref = "datastore" }
 androidx-splashscreen = { module = "androidx.core:core-splashscreen", version.ref = "splashscreen" }
+mlkit-genai-prompt = { module = "com.google.mlkit:genai-prompt", version.ref = "mlkitGenaiPrompt" }
 mlkit-subject-segmentation = { module = "com.google.android.gms:play-services-mlkit-subject-segmentation", version.ref = "mlkitSubjectSegmentation" }
 
 [plugins]

iosApp/Configuration/Config.xcconfig

@@ -4,4 +4,9 @@ PRODUCT_NAME=Worn
 PRODUCT_BUNDLE_IDENTIFIER=com.github.worn.Worn$(TEAM_ID)
 
 CURRENT_PROJECT_VERSION=1
-MARKETING_VERSION=1.0
+MARKETING_VERSION=1.0
+
+// FoundationModels (Apple Intelligence) only exists from iOS 26, but the app deploys back to
+// 18.2. Weak linking lets it launch on older systems, where OnDeviceAiService reports the
+// feature as unavailable via its #available guard.
+OTHER_LDFLAGS=$(inherited) -weak_framework FoundationModels

iosApp/iosApp/Screens/AddItemSheet.swift

@@ -4,7 +4,7 @@ import Shared
 
 struct AddItemSheet: View {
     let isSaving: Bool
-    let hasApiKey: Bool
+    let isAiAvailable: Bool
     var existingItem: ClothingItem?
     let onSave: (Data, String, Category, [String], [Season], Subcategory?, Fit?, Material?) -> Void
     let onDismiss: () -> Void
@@ -238,7 +238,7 @@ struct AddItemSheet: View {
 
     private var aiBadge: some View {
         Button {
-            if !hasApiKey { showAiLockedSheet = true }
+            if !isAiAvailable { showAiLockedSheet = true }
         } label: {
             HStack(spacing: 6) {
                 Text("✦")
@@ -565,10 +565,10 @@ struct AddItemSheet: View {
 }
 
 #Preview("iPhone") {
-    AddItemSheet(isSaving: false, hasApiKey: false, onSave: { _, _, _, _, _, _, _, _ in }, onDismiss: {})
+    AddItemSheet(isSaving: false, isAiAvailable: false, onSave: { _, _, _, _, _, _, _, _ in }, onDismiss: {})
 }
 
 #Preview("iPad Portrait") {
-    AddItemSheet(isSaving: false, hasApiKey: false, onSave: { _, _, _, _, _, _, _, _ in }, onDismiss: {})
+    AddItemSheet(isSaving: false, isAiAvailable: false, onSave: { _, _, _, _, _, _, _, _ in }, onDismiss: {})
         .previewDevice(PreviewDevice(rawValue: "iPad Pro (11-inch)"))
 }

iosApp/iosApp/Screens/GapsScreen.swift

@@ -72,7 +72,7 @@ struct GapsScreen: View {
             if let gap = addItemPreFill {
                 AddItemSheet(
                     isSaving: false,
-                    hasApiKey: viewModel.state.hasApiKey,
+                    isAiAvailable: viewModel.state.isAiAvailable,
                     existingItem: gap.toPreFilledItem(),
                     onSave: { _, _, _, _, _, _, _, _ in showAddItemSheet = false },
                     onDismiss: { showAddItemSheet = false }