add steps

lib/memex/pipelines/pipeline.ex

@@ -6,7 +6,7 @@ defmodule Memex.Pipelines.Pipeline do
   import Ecto.Changeset
   import MemexWeb.Gettext
   alias Ecto.{Changeset, UUID}
-  alias Memex.{Accounts.User, Pipelines.Step}
+  alias Memex.{Accounts.User, Pipelines.Steps.Step}
 
   @primary_key {:id, :binary_id, autogenerate: true}
   @foreign_key_type :binary_id

lib/memex/pipelines/step.ex

@@ -1,4 +1,4 @@
-defmodule Memex.Pipelines.Step do
+defmodule Memex.Pipelines.Steps.Step do
   @moduledoc """
   Represents a step taken while executing a pipeline
   """
@@ -46,16 +46,25 @@ defmodule Memex.Pipelines.Step do
     |> validate_required([:title, :content, :user_id, :position])
   end
 
-  @spec update_changeset(t(), attrs :: map(), position :: non_neg_integer(), User.t()) ::
+  @spec update_changeset(t(), attrs :: map(), User.t()) ::
           changeset()
   def update_changeset(
         %{user_id: user_id} = step,
         attrs,
-        position,
         %User{id: user_id}
       ) do
     step
     |> cast(attrs, [:title, :content])
+    |> validate_required([:title, :content, :user_id, :position])
+  end
+
+  @spec position_changeset(t(), position :: non_neg_integer(), User.t()) :: changeset()
+  def position_changeset(
+        %{user_id: user_id} = step,
+        position,
+        %User{id: user_id}
+      ) do
+    step
     |> change(position: position)
     |> validate_required([:title, :content, :user_id, :position])
   end

lib/memex/pipelines/steps.ex

@@ -4,8 +4,9 @@ defmodule Memex.Pipelines.Steps do
   """
 
   import Ecto.Query, warn: false
+  alias Ecto.Multi
   alias Memex.{Accounts.User, Repo}
-  alias Memex.Pipelines.{Pipeline, Step}
+  alias Memex.Pipelines.{Pipeline, Steps.Step}
 
   @doc """
   Returns the list of steps.
@@ -105,11 +106,11 @@ defmodule Memex.Pipelines.Steps do
       {:error, %Ecto.Changeset{}}
 
   """
-  @spec update_step(Step.t(), attrs :: map(), position :: non_neg_integer(), User.t()) ::
+  @spec update_step(Step.t(), attrs :: map(), User.t()) ::
           {:ok, Step.t()} | {:error, Step.changeset()}
-  def update_step(%Step{} = step, attrs, position, user) do
+  def update_step(%Step{} = step, attrs, user) do
     step
-    |> Step.update_changeset(attrs, position, user)
+    |> Step.update_changeset(attrs, user)
     |> Repo.update()
   end
 
@@ -130,11 +131,31 @@ defmodule Memex.Pipelines.Steps do
   """
   @spec delete_step(Step.t(), User.t()) :: {:ok, Step.t()} | {:error, Step.changeset()}
   def delete_step(%Step{user_id: user_id} = step, %{id: user_id}) do
-    step |> Repo.delete()
+    delete_step(step)
   end
 
   def delete_step(%Step{} = step, %{role: :admin}) do
-    step |> Repo.delete()
+    delete_step(step)
+  end
+
+  defp delete_step(step) do
+    Multi.new()
+    |> Multi.delete(:delete_step, step)
+    |> Multi.update_all(
+      :reorder_steps,
+      fn %{delete_step: %{position: position, pipeline_id: pipeline_id}} ->
+        from s in Step,
+          where: s.pipeline_id == ^pipeline_id,
+          where: s.position > ^position,
+          update: [set: [position: s.position - 1]]
+      end,
+      []
+    )
+    |> Repo.transaction()
+    |> case do
+      {:ok, %{delete_step: step}} -> {:ok, step}
+      {:error, :delete_step, changeset, _changes_so_far} -> {:error, changeset}
+    end
   end
 
   @doc """
@@ -149,11 +170,69 @@ defmodule Memex.Pipelines.Steps do
       %Ecto.Changeset{data: %Step{}}
 
   """
-  @spec change_step(Step.t(), position :: non_neg_integer(), Pipeline.t(), User.t()) ::
-          Step.changeset()
-  @spec change_step(Step.t(), attrs :: map(), position :: non_neg_integer(), User.t()) ::
-          Step.changeset()
-  def change_step(%Step{} = step, attrs \\ %{}, position, user) do
-    step |> Step.update_changeset(attrs, position, user)
+  @spec change_step(Step.t(), User.t()) :: Step.changeset()
+  @spec change_step(Step.t(), attrs :: map(), User.t()) :: Step.changeset()
+  def change_step(%Step{} = step, attrs \\ %{}, user) do
+    step |> Step.update_changeset(attrs, user)
+  end
+
+  @spec reorder_step(Step.t(), :up | :down, User.t()) ::
+          {:ok, Step.t()} | {:error, Step.changeset()}
+  def reorder_step(%Step{position: 0} = step, :up, _user), do: {:error, step}
+
+  def reorder_step(
+        %Step{position: position, pipeline_id: pipeline_id, user_id: user_id} = step,
+        :up,
+        %{id: user_id} = user
+      ) do
+    Multi.new()
+    |> Multi.update_all(
+      :reorder_steps,
+      from(s in Step,
+        where: s.pipeline_id == ^pipeline_id,
+        where: s.position == ^position - 1,
+        update: [set: [position: ^position]]
+      ),
+      []
+    )
+    |> Multi.update(
+      :update_step,
+      step |> Step.position_changeset(position - 1, user)
+    )
+    |> Repo.transaction()
+    |> case do
+      {:ok, %{update_step: step}} -> {:ok, step}
+      {:error, :update_step, changeset, _changes_so_far} -> {:error, changeset}
+    end
+  end
+
+  def reorder_step(
+        %Step{pipeline_id: pipeline_id, position: position, user_id: user_id} = step,
+        :down,
+        %{id: user_id} = user
+      ) do
+    Multi.new()
+    |> Multi.one(
+      :step_count,
+      from(s in Step, where: s.pipeline_id == ^pipeline_id, distinct: true, select: count(s.id))
+    )
+    |> Multi.update_all(
+      :reorder_steps,
+      from(s in Step,
+        where: s.pipeline_id == ^pipeline_id,
+        where: s.position == ^position + 1,
+        update: [set: [position: ^position]]
+      ),
+      []
+    )
+    |> Multi.update(:update_step, fn %{step_count: step_count} ->
+      new_position = if position >= step_count - 1, do: position, else: position + 1
+      step |> Step.position_changeset(new_position, user)
+    end)
+    |> Repo.transaction()
+    |> case do
+      {:ok, %{update_step: step}} -> {:ok, step}
+      {:error, :update_step, changeset, _changes_so_far} -> {:error, changeset}
+    end
   end
 end