add type specs and fix id issues

lib/workload_service/aggregates/task.ex

@@ -10,6 +10,15 @@ defmodule WorkloadService.Aggregates.Task do
     end
   """
 
+  @type t :: %__MODULE__{
+    id: WorkloadService.Aggregates.TaskId.t() | nil,
+    application_id: WorkloadService.Aggregates.ApplicationId.t() | nil,
+    task_info: map() | nil,
+    submission: map() | nil,
+    attachments: [String.t()],
+    status: String.t() | nil
+  }
+
   @callback validate_submission(map()) :: :ok | {:error, term()}
 
   defmacro __using__(opts) do
@@ -55,8 +64,6 @@ defmodule WorkloadService.Aggregates.Task do
       def execute(%__MODULE__{status: status}, %SubmitResponse{} = cmd)
           when status in [nil, "created", "draft", "approved"] do
         with :ok <- validate_submission(cmd.submission) do
-          new_status = if status == "approved", do: "draft", else: "draft"
-
           %WorkloadService.Events.SubmissionUpdated{
             id: cmd.id,
             submission: cmd.submission,
@@ -78,9 +85,9 @@ defmodule WorkloadService.Aggregates.Task do
       end
 
       @impl Aggregate
-      def execute(%__MODULE__{status: "approved"}, %CompleteTask{} = cmd) do
+      def execute(%__MODULE__{status: "approved", id: id}, %CompleteTask{} = cmd) do
         %WorkloadService.Events.TaskCompleted{
-          id: cmd.id,
+          id: id,
           completed_by: cmd.completed_by
         }
       end