feat: filter deployment targets by operation type (#1015)

Add operation-aware filtering for deployment campaign targets

Previously, the deployment target computation logic treated all
operations the same way, selecting all deployable devices based
only on system model compatibility.

This ensures that lifecycle operations can only be performed on
devices where the release is already deployed, preventing invalid
operations on devices without the target release.

Signed-off-by: Omar <omar.brbutovic@secomind.com>

Author: OmarBrbutovic

backend/lib/edgehog/deployment_campaigns/deployment_campaign/changes/compute_deployment_targets.ex

@@ -23,6 +23,12 @@ defmodule Edgehog.DeploymentCampaigns.DeploymentCampaign.Changes.ComputeDeployme
   Change to compute deployment targets.
 
   It starts from the channel of the campaign and finds the suitable targets for the campaign.
+
+  For deploy operations, all devices in the channel that match the system model requirements
+  are included as targets.
+
+  For other operations (start, stop, upgrade, delete), only devices that already have the
+  specified release deployed are included as targets.
   """
   use Ash.Resource.Change
 
@@ -37,9 +43,11 @@ defmodule Edgehog.DeploymentCampaigns.DeploymentCampaign.Changes.ComputeDeployme
 
     with {:ok, release} <- fetch_release(changeset, tenant),
          {:ok, channel} <- fetch_channel(changeset, tenant) do
+      operation_type = Ash.Changeset.get_attribute(changeset, :operation_type)
       channel = Ash.load!(channel, deployable_devices: [release: release])
 
-      deployable_devices = channel.deployable_devices
+      deployable_devices =
+        filter_devices_by_operation(channel.deployable_devices, operation_type, release, tenant)
 
       if Enum.empty?(deployable_devices) do
         changeset
@@ -104,4 +112,24 @@ defmodule Edgehog.DeploymentCampaigns.DeploymentCampaign.Changes.ComputeDeployme
   end
 
   defp start_campaign_executor(transaction_result), do: transaction_result
+
+  # For deploy operations, return all deployable devices
+  defp filter_devices_by_operation(devices, :deploy, _release, _tenant) do
+    devices
+  end
+
+  # For other operations (start, stop, upgrade, delete), filter devices that have the release deployed
+  defp filter_devices_by_operation(devices, _operation_type, release, tenant) do
+    devices_with_release = Ash.load!(devices, [:application_deployments], tenant: tenant)
+
+    Enum.filter(devices_with_release, fn device ->
+      has_release_deployed?(device, release)
+    end)
+  end
+
+  defp has_release_deployed?(device, release) do
+    Enum.any?(device.application_deployments, fn deployment ->
+      deployment.release_id == release.id
+    end)
+  end
 end