work on steps

lib/memex/pipelines/steps.ex

@@ -0,0 +1,159 @@
+defmodule Memex.Pipelines.Steps do
+  @moduledoc """
+  The context for steps within a pipeline
+  """
+
+  import Ecto.Query, warn: false
+  alias Memex.{Accounts.User, Repo}
+  alias Memex.Pipelines.{Pipeline, Step}
+
+  @doc """
+  Returns the list of steps.
+
+  ## Examples
+
+      iex> list_steps(%User{id: 123})
+      [%Step{}, ...]
+
+      iex> list_steps("my step", %User{id: 123})
+      [%Step{title: "my step"}, ...]
+
+  """
+  @spec list_steps(Pipeline.t(), User.t()) :: [Step.t()]
+  def list_steps(%{id: pipeline_id}, %{id: user_id}) do
+    Repo.all(
+      from s in Step,
+        where: s.pipeline_id == ^pipeline_id,
+        where: s.user_id == ^user_id,
+        order_by: s.position
+    )
+  end
+
+  def list_steps(%{id: pipeline_id, visibility: visibility}, _invalid_user)
+      when visibility in [:unlisted, :public] do
+    Repo.all(
+      from s in Step,
+        where: s.pipeline_id == ^pipeline_id,
+        order_by: s.position
+    )
+  end
+
+  @doc """
+  Preloads the `:steps` field on a Memex.Pipelines.Pipeline
+  """
+  @spec preload_steps(Pipeline.t(), User.t()) :: Pipeline.t()
+  def preload_steps(pipeline, user) do
+    %{pipeline | steps: list_steps(pipeline, user)}
+  end
+
+  @doc """
+  Gets a single step.
+
+  Raises `Ecto.NoResultsError` if the Step does not exist.
+
+  ## Examples
+
+      iex> get_step!(123, %User{id: 123})
+      %Step{}
+
+      iex> get_step!(456, %User{id: 123})
+      ** (Ecto.NoResultsError)
+
+  """
+  @spec get_step!(Step.id(), User.t()) :: Step.t()
+  def get_step!(id, %{id: user_id}) do
+    Repo.one!(from n in Step, where: n.id == ^id, where: n.user_id == ^user_id)
+  end
+
+  def get_step!(id, _invalid_user) do
+    Repo.one!(
+      from n in Step,
+        where: n.id == ^id,
+        where: n.visibility in [:public, :unlisted]
+    )
+  end
+
+  @doc """
+  Creates a step.
+
+  ## Examples
+
+      iex> create_step(%{field: value}, %User{id: 123})
+      {:ok, %Step{}}
+
+      iex> create_step(%{field: bad_value}, %User{id: 123})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  @spec create_step(position :: non_neg_integer(), Pipeline.t(), User.t()) ::
+          {:ok, Step.t()} | {:error, Step.changeset()}
+  @spec create_step(attrs :: map(), position :: non_neg_integer(), Pipeline.t(), User.t()) ::
+          {:ok, Step.t()} | {:error, Step.changeset()}
+  def create_step(attrs \\ %{}, position, pipeline, user) do
+    Step.create_changeset(attrs, position, pipeline, user) |> Repo.insert()
+  end
+
+  @doc """
+  Updates a step.
+
+  ## Examples
+
+      iex> update_step(step, %{field: new_value}, %User{id: 123})
+      {:ok, %Step{}}
+
+      iex> update_step(step, %{field: bad_value}, %User{id: 123})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  @spec update_step(Step.t(), attrs :: map(), position :: non_neg_integer(), User.t()) ::
+          {:ok, Step.t()} | {:error, Step.changeset()}
+  def update_step(%Step{} = step, attrs, position, user) do
+    step
+    |> Step.update_changeset(attrs, position, user)
+    |> Repo.update()
+  end
+
+  @doc """
+  Deletes a step.
+
+  ## Examples
+
+      iex> delete_step(%Step{user_id: 123}, %User{id: 123})
+      {:ok, %Step{}}
+
+      iex> delete_step(%Step{}, %User{role: :admin})
+      {:ok, %Step{}}
+
+      iex> delete_step(%Step{}, %User{id: 123})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  @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()
+  end
+
+  def delete_step(%Step{} = step, %{role: :admin}) do
+    step |> Repo.delete()
+  end
+
+  @doc """
+  Returns an `%Ecto.Changeset{}` for tracking step changes.
+
+  ## Examples
+
+      iex> change_step(step, %User{id: 123})
+      %Ecto.Changeset{data: %Step{}}
+
+      iex> change_step(step, %{title: "new title"}, %User{id: 123})
+      %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)
+  end
+end