feat(#1121): add multiplexed gateway awareness (#1127)

app/src/main/java/com/m57/hermescontrol/data/model/GatewayMigration.kt

@@ -0,0 +1,43 @@
+package com.m57.hermescontrol.data.model
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class GatewayMigrationPlan(
+    @SerialName("default_home") val defaultHome: String? = null,
+    val profiles: List<GatewayMigrationProfile> = emptyList(),
+    @SerialName("multiplex_flag_on") val multiplexFlagOn: Boolean = false,
+    @SerialName("live_served") val liveServed: List<String>? = null,
+    @SerialName("already_multiplexed") val alreadyMultiplexed: Boolean = false,
+    val interrupted: Boolean = false,
+    val blockers: List<String> = emptyList(),
+    val notices: List<String> = emptyList(),
+    val eligible: Boolean = false,
+    val command: String? = null,
+)
+
+@Serializable
+data class GatewayMigrationProfile(
+    val profile: String? = null,
+    val home: String? = null,
+    val pid: Int? = null,
+    val service: GatewayMigrationService? = null,
+    val services: List<GatewayMigrationService> = emptyList(),
+    @SerialName("run_as_user") val runAsUser: String? = null,
+    val uid: Int? = null,
+    @SerialName("runtime_home") val runtimeHome: String? = null,
+)
+
+@Serializable
+data class GatewayMigrationService(
+    val kind: String? = null,
+    val system: Boolean? = null,
+)
+
+@Serializable
+data class GatewayMigrationStartResponse(
+    val ok: Boolean = false,
+    val pid: Int? = null,
+    val name: String? = null,
+)

app/src/main/java/com/m57/hermescontrol/data/model/MessagingPlatform.kt

@@ -17,6 +17,7 @@ data class MessagingPlatform(
     @SerialName("env_vars") val envVars: List<EnvVarField>? = null,
     @SerialName("updated_at") val updatedAt: String? = null,
     @SerialName("home_channel") val homeChannel: HomeChannelInfo? = null,
+    @SerialName("ingress_url") val ingressUrl: String? = null,
 )
 
 @Serializable
@@ -64,6 +65,13 @@ data class MessagingPlatformTestResult(
     val message: String,
 )
 
+@Serializable
+data class MessagingPlatformUpdateResponse(
+    val ok: Boolean = false,
+    val platform: String? = null,
+    @SerialName("hot_served") val hotServed: Boolean = false,
+)
+
 // ── Telegram onboarding ─────────────────────────────────────────────────
 
 @Serializable

app/src/main/java/com/m57/hermescontrol/data/model/StatusResponse.kt

@@ -1,4 +1,5 @@
 package com.m57.hermescontrol.data.model
+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
 @Serializable
@@ -8,6 +9,8 @@ data class StatusResponse(
     val active_sessions: Int? = null,
     val auth_required: Boolean? = null,
     val gateway_platforms: Map<String, PlatformStatus?>? = null,
+    @SerialName("gateway_shared_with")
+    val gatewaySharedWith: List<String>? = null,
     val memory: MemoryPressureStatus? = null,
     val disk: DiskPressureStatus? = null,
 )

app/src/main/java/com/m57/hermescontrol/data/remote/HermesApiService.kt

@@ -33,6 +33,8 @@ import com.m57.hermescontrol.data.model.EnvVarDeleteRequest
 import com.m57.hermescontrol.data.model.EnvVarRevealRequest
 import com.m57.hermescontrol.data.model.EnvVarRevealResponse
 import com.m57.hermescontrol.data.model.EnvVarUpdate
+import com.m57.hermescontrol.data.model.GatewayMigrationPlan
+import com.m57.hermescontrol.data.model.GatewayMigrationStartResponse
 import com.m57.hermescontrol.data.model.HealthStatus
 import com.m57.hermescontrol.data.model.HookResponse
 import com.m57.hermescontrol.data.model.InstantiateBlueprintRequest
@@ -65,6 +67,7 @@ import com.m57.hermescontrol.data.model.MemoryResponse
 import com.m57.hermescontrol.data.model.MessagingPlatformResponse
 import com.m57.hermescontrol.data.model.MessagingPlatformTestResult
 import com.m57.hermescontrol.data.model.MessagingPlatformUpdate
+import com.m57.hermescontrol.data.model.MessagingPlatformUpdateResponse
 import com.m57.hermescontrol.data.model.MoaConfigResponse
 import com.m57.hermescontrol.data.model.ModelAssignmentRequest
 import com.m57.hermescontrol.data.model.ModelAssignmentResponse
@@ -390,6 +393,12 @@ interface HermesApiService : KanbanApiService {
     @POST("api/gateway/restart")
     suspend fun restartGateway(): Response<Unit>
 
+    @GET("api/gateway/migrate/plan")
+    suspend fun getGatewayMigrationPlan(): Response<GatewayMigrationPlan>
+
+    @POST("api/gateway/migrate")
+    suspend fun startGatewayMigration(): Response<GatewayMigrationStartResponse>
+
     @GET("api/profiles")
     suspend fun getProfiles(): Response<ProfilesResponse>
 
@@ -677,7 +686,7 @@ interface HermesApiService : KanbanApiService {
     suspend fun configurePlatform(
         @Path("platform_id") platformId: String,
         @Body config: MessagingPlatformUpdate,
-    ): Response<Unit>
+    ): Response<MessagingPlatformUpdateResponse>
 
     @POST("api/messaging/platforms/{platform_id}/test")
     suspend fun testMessagingPlatform(

app/src/main/java/com/m57/hermescontrol/ui/channels/ChannelsViewModel.kt

@@ -125,7 +125,8 @@ class ChannelsViewModel :
                 }
             },
             onStart = {},
-            onSuccess = {
+            onSuccess = { response ->
+                val hotServed = response.hotServed
                 _uiState.update { state ->
                     state.copy(
                         platforms =
@@ -133,16 +134,28 @@ class ChannelsViewModel :
                                 if (p.id == platformId) {
                                     p.copy(
                                         enabled = enabled,
-                                        state = if (enabled) "pending_restart" else "disabled",
+                                        state =
+                                            when {
+                                                !enabled -> "disabled"
+                                                hotServed -> "connected"
+                                                else -> "pending_restart"
+                                            },
                                     )
                                 } else {
                                     p
                                 }
                             },
-                        restartNeeded = true,
+                        restartNeeded = !hotServed,
                         togglingId = null,
+                        toastMessage =
+                            if (hotServed) {
+                                "$platformId updated live"
+                            } else {
+                                null
+                            },
                     )
                 }
+                loadPlatforms()
             },
             onError = { error ->
                 _uiState.update {
@@ -201,12 +214,18 @@ class ChannelsViewModel :
                     it.copy(isLoading = true, errorMessage = null)
                 }
             },
-            onSuccess = {
-                val message = "$platformId configured successfully — restart the gateway for changes to take effect"
+            onSuccess = { response ->
+                val hotServed = response.hotServed
+                val message =
+                    if (hotServed) {
+                        "$platformId configured and reloaded live"
+                    } else {
+                        "$platformId configured successfully — restart the gateway for changes to take effect"
+                    }
                 _uiState.update {
                     it.copy(
                         isLoading = false,
-                        restartNeeded = true,
+                        restartNeeded = !hotServed,
                         toastMessage = message,
                     )
                 }

app/src/main/java/com/m57/hermescontrol/ui/channels/components/PlatformCard.kt

@@ -1,5 +1,6 @@
 package com.m57.hermescontrol.ui.channels.components
 
+import android.content.ClipData
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
@@ -12,6 +13,7 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.CheckCircle
+import androidx.compose.material.icons.filled.ContentCopy
 import androidx.compose.material.icons.filled.Delete
 import androidx.compose.material.icons.filled.QrCode
 import androidx.compose.material.icons.filled.RadioButtonChecked
@@ -34,18 +36,23 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.platform.ClipEntry
+import androidx.compose.ui.platform.LocalClipboard
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontFamily
 import androidx.compose.ui.unit.dp
 import com.m57.hermescontrol.R
 import com.m57.hermescontrol.data.model.MessagingPlatform
 import com.m57.hermescontrol.data.model.MessagingPlatformUpdate
 import com.m57.hermescontrol.theme.LocalHermesStatusColors
 import com.m57.hermescontrol.ui.channels.ConfigureForm
+import kotlinx.coroutines.launch
 
 private enum class StatusRole { SUCCESS, WARNING, ERROR, NEUTRAL }
 
@@ -110,6 +117,8 @@ internal fun PlatformCard(
 ) {
     var showConfigureForm by remember { mutableStateOf(false) }
     var showRemoveConfirm by remember { mutableStateOf(false) }
+    val clipboard = LocalClipboard.current
+    val scope = rememberCoroutineScope()
     val style = platformStateStyle(platform.state)
 
     Card(modifier = Modifier.fillMaxWidth()) {
@@ -166,6 +175,40 @@ internal fun PlatformCard(
                 )
             }
 
+            platform.ingressUrl?.takeIf { it.isNotBlank() }?.let { ingressUrl ->
+                Spacer(modifier = Modifier.height(8.dp))
+                Text(
+                    text = stringResource(R.string.channels_ingress_url),
+                    style = MaterialTheme.typography.labelSmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+                Row(
+                    modifier = Modifier.fillMaxWidth(),
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    Text(
+                        text = ingressUrl,
+                        style = MaterialTheme.typography.bodySmall.copy(fontFamily = FontFamily.Monospace),
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        modifier = Modifier.weight(1f),
+                    )
+                    IconButton(
+                        onClick = {
+                            scope.launch {
+                                clipboard.setClipEntry(ClipEntry(ClipData.newPlainText(null, ingressUrl)))
+                            }
+                        },
+                        modifier = Modifier.size(32.dp),
+                    ) {
+                        Icon(
+                            imageVector = Icons.Filled.ContentCopy,
+                            contentDescription = stringResource(R.string.channels_copy_ingress_url),
+                            modifier = Modifier.size(18.dp),
+                        )
+                    }
+                }
+            }
+
             // ── Error message ──
             if (!platform.errorMessage.isNullOrBlank()) {
                 Spacer(modifier = Modifier.height(4.dp))

app/src/main/java/com/m57/hermescontrol/ui/profiles/ProfilesScreen.kt

@@ -54,6 +54,7 @@ import androidx.compose.ui.draw.clip
 import androidx.compose.ui.platform.ClipEntry
 import androidx.compose.ui.platform.LocalClipboard
 import androidx.compose.ui.platform.testTag
+import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.font.FontFamily
@@ -232,8 +233,15 @@ fun ProfilesScreen(
                                 contentPadding = PaddingValues(16.dp),
                                 verticalArrangement = Arrangement.spacedBy(12.dp),
                             ) {
+                                if (state.sharedGatewayProfiles.isNotEmpty()) {
+                                    item(key = "shared_gateway_summary") {
+                                        SharedGatewaySummary(state.sharedGatewayProfiles)
+                                    }
+                                }
+
                                 items(state.displayProfiles, key = { it.name }) { profile ->
                                     val isActive = profile.name == state.activeProfileName
+                                    val isProfileShared = profile.name in state.sharedGatewayProfiles
                                     Card(
                                         modifier = Modifier.fillMaxWidth(),
                                         colors =
@@ -293,6 +301,29 @@ fun ProfilesScreen(
                                                                 )
                                                             }
                                                         }
+                                                        if (isProfileShared) {
+                                                            val sharedGatewayContainer =
+                                                                MaterialTheme.colorScheme.secondaryContainer
+                                                            val onSharedGatewayContainer =
+                                                                MaterialTheme.colorScheme.onSecondaryContainer
+                                                            val sharedGatewayLabel =
+                                                                stringResource(R.string.profiles_shared_gateway_badge)
+                                                            Spacer(modifier = Modifier.width(8.dp))
+                                                            Box(
+                                                                modifier =
+                                                                    Modifier
+                                                                        .clip(RoundedCornerShape(4.dp))
+                                                                        .background(sharedGatewayContainer)
+                                                                        .padding(horizontal = 6.dp, vertical = 2.dp),
+                                                            ) {
+                                                                Text(
+                                                                    text = sharedGatewayLabel,
+                                                                    color = onSharedGatewayContainer,
+                                                                    style = MaterialTheme.typography.labelSmall,
+                                                                    fontWeight = FontWeight.Bold,
+                                                                )
+                                                            }
+                                                        }
                                                     }
                                                     val descriptionText =
                                                         if (!profile.description.isNullOrBlank()) {
@@ -971,6 +1002,43 @@ fun ProfilesScreen(
     }
 }
 
+@Composable
+private fun SharedGatewaySummary(profiles: List<String>) {
+    Card(
+        modifier = Modifier.fillMaxWidth(),
+        colors =
+            CardDefaults.cardColors(
+                containerColor = MaterialTheme.colorScheme.secondaryContainer,
+            ),
+    ) {
+        Column(modifier = Modifier.padding(16.dp)) {
+            Text(
+                text = stringResource(R.string.profiles_shared_gateway_title),
+                style = MaterialTheme.typography.titleMedium,
+                fontWeight = FontWeight.Bold,
+                color = MaterialTheme.colorScheme.onSecondaryContainer,
+            )
+            Spacer(modifier = Modifier.height(4.dp))
+            Text(
+                text =
+                    pluralStringResource(
+                        R.plurals.profiles_shared_gateway_count,
+                        profiles.size,
+                        profiles.size,
+                    ),
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSecondaryContainer,
+            )
+            Spacer(modifier = Modifier.height(4.dp))
+            Text(
+                text = profiles.joinToString(" · "),
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSecondaryContainer,
+            )
+        }
+    }
+}
+
 // ---------------------------------------------------------------------
 // Profile Builder Wizard
 // ---------------------------------------------------------------------

app/src/main/java/com/m57/hermescontrol/ui/profiles/ProfilesViewModel.kt

@@ -34,6 +34,7 @@ data class ProfilesUiState(
     val isLoading: Boolean = false,
     val profiles: List<ProfileInfo> = emptyList(),
     val activeProfileName: String? = null,
+    val sharedGatewayProfiles: List<String> = emptyList(),
     val selectedSoulContent: String? = null,
     val isLoadingSoul: Boolean = false,
     val errorMessage: String? = null,
@@ -67,6 +68,15 @@ data class ProfilesUiState(
             }
 }
 
+private fun normalizeSharedGatewayProfiles(names: List<String>?): List<String> =
+    names
+        .orEmpty()
+        .asSequence()
+        .map(String::trim)
+        .filter(String::isNotEmpty)
+        .distinct()
+        .toList()
+
 class ProfilesViewModel(
     private val ioDispatcher: CoroutineDispatcher = Dispatchers.IO,
 ) : ViewModel(),
@@ -110,6 +120,7 @@ class ProfilesViewModel(
                     val profilesDeferred = async(ioDispatcher) { safeApiCall { ApiClient.hermesApi.getProfiles() } }
                     val activeDeferred =
                         async(ioDispatcher) { safeApiCall { ApiClient.hermesApi.getActiveProfile() } }
+                    val statusDeferred = async(ioDispatcher) { safeApiCall { ApiClient.hermesApi.getStatus() } }
 
                     val profilesResult = profilesDeferred.await()
                     val activeResult = activeDeferred.await()
@@ -120,9 +131,20 @@ class ProfilesViewModel(
                                 isLoading = false,
                                 profiles = profilesResult.data.profiles.orEmpty(),
                                 activeProfileName = activeResult.data.active,
+                                sharedGatewayProfiles = emptyList(),
                                 hiddenProfiles = AuthManager.getHiddenProfiles().toSet(),
                             )
                         }
+
+                        val statusResult = statusDeferred.await()
+                        if (statusResult is NetworkResult.Success) {
+                            _uiState.update {
+                                it.copy(
+                                    sharedGatewayProfiles =
+                                        normalizeSharedGatewayProfiles(statusResult.data.gatewaySharedWith),
+                                )
+                            }
+                        }
                     } else {
                         val profilesError = (profilesResult as? NetworkResult.Failure)?.error?.message ?: "Success"
                         val activeError = (activeResult as? NetworkResult.Failure)?.error?.message ?: "Success"

app/src/main/java/com/m57/hermescontrol/ui/system/SystemScreen.kt

@@ -133,6 +133,10 @@ fun SystemScreen(
         controller = resolvedViewModel.actionProgress,
         title = stringResource(R.string.system_update_progress_title),
     )
+    ActionProgressDialog(
+        controller = resolvedViewModel.migrationProgress,
+        title = stringResource(R.string.system_migration_progress_title),
+    )
 
     // Credential remove confirmation using ConfirmDialog
     var credToRemove by remember { mutableStateOf<Pair<String, Int>?>(null) }

app/src/main/java/com/m57/hermescontrol/ui/system/SystemViewModel.kt

@@ -15,6 +15,7 @@ import com.m57.hermescontrol.data.model.CredentialPoolProvider
 import com.m57.hermescontrol.data.model.CuratorResponse
 import com.m57.hermescontrol.data.model.DebugShareResponse
 import com.m57.hermescontrol.data.model.DoctorResponse
+import com.m57.hermescontrol.data.model.GatewayMigrationPlan
 import com.m57.hermescontrol.data.model.HookResponse
 import com.m57.hermescontrol.data.model.PortalResponse
 import com.m57.hermescontrol.data.model.StatusResponse
@@ -26,6 +27,7 @@ import com.m57.hermescontrol.data.remote.NetworkResult
 import com.m57.hermescontrol.data.remote.safeApiCall
 import com.m57.hermescontrol.ui.common.ActionProgressController
 import com.m57.hermescontrol.ui.common.ToastHost
+import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.async
@@ -53,6 +55,8 @@ data class SystemUiState(
     val updateInfo: UpdateCheckResponse? = null,
     val status: StatusResponse? = null,
     val doctorReport: DoctorResponse? = null,
+    val migrationPlan: GatewayMigrationPlan? = null,
+    val migrationSupported: Boolean? = null,
     val activeAction: String? = null,
     val actionLog: ActionStatusResponse? = null,
     val backupArchive: String? = null,
@@ -88,6 +92,7 @@ data class SystemUiState(
 
 class SystemViewModel(
     application: Application,
+    private val migrationDispatcher: CoroutineDispatcher = Dispatchers.IO,
 ) : AndroidViewModel(application),
     ToastHost {
     companion object {
@@ -114,12 +119,22 @@ class SystemViewModel(
             onFinished = { status -> onActionFinished(status) },
         )
 
+    /** Progress popup for the optional gateway migration action. */
+    val migrationProgress =
+        ActionProgressController(
+            scope = viewModelScope,
+            onFinished = { status -> onMigrationFinished(status) },
+        )
+
     private var actionPollingJob: Job? = null
     private var downloadJob: Job? = null
 
     // ── Full parallel data load ────────────────────────────────────────
 
     fun loadAll() {
+        // Migration support is optional; probe it independently so an older or
+        // slow backend cannot hold up the required System data.
+        loadMigrationPlan()
         viewModelScope.launch {
             _uiState.update { it.copy(isLoading = true, errorMessage = null) }
 
@@ -138,6 +153,7 @@ class SystemViewModel(
 
                 val statsResult = statsDeferred.await()
                 val statusResult = statusDeferred.await()
+
                 val portalResult = portalDeferred.await()
                 val curatorResult = curatorDeferred.await()
 
@@ -224,6 +240,66 @@ class SystemViewModel(
         }
     }
 
+    /** Load optional migration capability state without affecting other System data. */
+    fun loadMigrationPlan() {
+        viewModelScope.launch {
+            val result =
+                withContext(migrationDispatcher) {
+                    safeApiCall { ApiClient.hermesApi.getGatewayMigrationPlan() }
+                }
+            _uiState.update {
+                it.copy(
+                    migrationPlan = (result as? NetworkResult.Success)?.data,
+                    migrationSupported = migrationSupport(result),
+                )
+            }
+        }
+    }
+
+    /**
+     * Start the backend migration only after the Gateway section's confirmation.
+     * The POST starts an asynchronous `gateway-migrate` action; completion is
+     * owned by [migrationProgress], not by the trigger response.
+     */
+    fun startMigration() {
+        val plan = _uiState.value.migrationPlan ?: return
+        if (plan.alreadyMultiplexed) {
+            _uiState.update { it.copy(toastMessage = "Gateway is already multiplexed") }
+            return
+        }
+        if (plan.blockers.isNotEmpty()) {
+            _uiState.update { it.copy(toastMessage = "Migration is blocked by the preflight plan") }
+            return
+        }
+
+        migrationProgress.open()
+        viewModelScope.launch {
+            val result =
+                withContext(migrationDispatcher) {
+                    safeApiCall { ApiClient.hermesApi.startGatewayMigration() }
+                }
+            when (result) {
+                is NetworkResult.Success -> {
+                    val response = result.data
+                    val actionName = response.name
+                    if (!response.ok) {
+                        migrationProgress.fail("Migration was rejected by the backend")
+                    } else if (actionName != null) {
+                        migrationProgress.markStarted(actionName)
+                    } else {
+                        migrationProgress.fail(
+                            "Migration was accepted but the backend did not report an action name",
+                        )
+                    }
+                }
+
+                is NetworkResult.Failure -> {
+                    migrationProgress.fail("Failed to start migration: ${result.error.message}")
+                }
+            }
+        }
+    }
+
     /**
      * Fired when [actionProgress] finishes tracking a backend action. For the
      * `hermes-update` action we additionally fetch the durable update receipt
@@ -242,6 +318,12 @@ class SystemViewModel(
         loadAll()
     }
 
+    private fun onMigrationFinished(status: ActionStatusResponse?) {
+        if (status?.exit_code == 0) {
+            loadAll()
+        }
+    }
+
     /**
      * Pull `GET /api/hermes/update/receipt` and render a compact summary block
      * for the popup. Returns an empty list when the endpoint is unavailable
@@ -862,3 +944,15 @@ class SystemViewModel(
         _uiState.update { it.copy(toastMessage = null) }
     }
 }
+
+private fun migrationSupport(result: NetworkResult<GatewayMigrationPlan>): Boolean? =
+    when (result) {
+        is NetworkResult.Success -> {
+            true
+        }
+
+        is NetworkResult.Failure -> {
+            val code = (result.error as? NetworkError.Http)?.code
+            if (code == 404 || code == 405) false else null
+        }
+    }

app/src/main/java/com/m57/hermescontrol/ui/system/components/GatewaySection.kt

@@ -22,12 +22,19 @@ import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import com.m57.hermescontrol.R
+import com.m57.hermescontrol.data.model.GatewayMigrationPlan
 import com.m57.hermescontrol.theme.Spacing
+import com.m57.hermescontrol.ui.common.ConfirmDialog
 import com.m57.hermescontrol.ui.common.InfoRow
 import com.m57.hermescontrol.ui.common.SectionHeader
 import com.m57.hermescontrol.ui.common.StatusBadge
@@ -183,5 +190,134 @@ fun LazyListScope.gatewaySection(
                 }
             }
         }
+
+        state.migrationPlan?.let { plan ->
+            item {
+                GatewayMigrationCard(
+                    plan = plan,
+                    onStartMigration = viewModel::startMigration,
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun GatewayMigrationCard(
+    plan: GatewayMigrationPlan,
+    onStartMigration: () -> Unit,
+) {
+    var showConfirmation by remember(plan) { mutableStateOf(false) }
+    val profileNames =
+        plan.profiles
+            .mapNotNull { it.profile?.takeIf(String::isNotBlank) }
+            .ifEmpty { plan.liveServed.orEmpty() }
+
+    Card(
+        modifier = Modifier.fillMaxWidth(),
+        colors =
+            CardDefaults.cardColors(
+                containerColor = MaterialTheme.colorScheme.surfaceContainer,
+            ),
+    ) {
+        Column(modifier = Modifier.padding(16.dp)) {
+            Text(
+                text = stringResource(R.string.system_migration_title),
+                style = MaterialTheme.typography.titleMedium,
+            )
+            Text(
+                text = stringResource(R.string.system_migration_description),
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+
+            if (profileNames.isNotEmpty()) {
+                InfoRow(
+                    label = stringResource(R.string.system_migration_profiles),
+                    value = profileNames.joinToString(" · "),
+                )
+            }
+            InfoRow(
+                label = stringResource(R.string.system_migration_automatic_eligibility),
+                value =
+                    stringResource(
+                        if (plan.eligible) {
+                            R.string.system_migration_yes
+                        } else {
+                            R.string.system_migration_no
+                        },
+                    ),
+            )
+
+            if (plan.alreadyMultiplexed) {
+                Spacer(modifier = Modifier.height(8.dp))
+                StatusBadge(
+                    text = stringResource(R.string.system_migration_already_multiplexed),
+                    status = StatusBadgeType.SUCCESS,
+                )
+            }
+            if (plan.interrupted) {
+                Spacer(modifier = Modifier.height(8.dp))
+                StatusBadge(
+                    text = stringResource(R.string.system_migration_interrupted),
+                    status = StatusBadgeType.WARNING,
+                )
+            }
+
+            if (plan.blockers.isNotEmpty()) {
+                Spacer(modifier = Modifier.height(8.dp))
+                Text(
+                    text = stringResource(R.string.system_migration_blockers),
+                    style = MaterialTheme.typography.labelLarge,
+                    color = MaterialTheme.colorScheme.error,
+                )
+                plan.blockers.forEach { blocker ->
+                    Text(
+                        text = "• $blocker",
+                        style = MaterialTheme.typography.bodySmall,
+                        color = MaterialTheme.colorScheme.error,
+                    )
+                }
+            }
+
+            if (plan.notices.isNotEmpty()) {
+                Spacer(modifier = Modifier.height(8.dp))
+                Text(
+                    text = stringResource(R.string.system_migration_notices),
+                    style = MaterialTheme.typography.labelLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+                plan.notices.forEach { notice ->
+                    Text(
+                        text = "• $notice",
+                        style = MaterialTheme.typography.bodySmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                }
+            }
+
+            if (!plan.alreadyMultiplexed && plan.blockers.isEmpty()) {
+                Spacer(modifier = Modifier.height(12.dp))
+                Button(
+                    onClick = { showConfirmation = true },
+                    modifier = Modifier.fillMaxWidth(),
+                ) {
+                    Text(stringResource(R.string.system_migration_start))
+                }
+            }
+        }
+    }
+
+    if (showConfirmation) {
+        ConfirmDialog(
+            title = stringResource(R.string.system_migration_confirm_title),
+            message = stringResource(R.string.system_migration_confirm_description),
+            onConfirm = {
+                showConfirmation = false
+                onStartMigration()
+            },
+            onDismiss = { showConfirmation = false },
+            confirmText = stringResource(R.string.system_migration_start),
+        )
     }
 }