Set current donation goal

Add DonationGoalsManager

Integrate manager into controller

Add current donation goal migration and project tests

lib/code_corps/donation_goals_manager.ex

@@ -0,0 +1,115 @@
+defmodule CodeCorps.DonationGoalsManager do
+  @moduledoc """
+  Handles CRUD operations for donation goals.
+
+  When operations happen on `CodeCorps.DonationGoal`, we need to set
+  the current donation goal on `CodeCorps.Project`.
+
+  The current donation goal should be the smallest value that is
+  greater than the project's current total donations, _or_ falls back to
+  the largest donation goal.
+  """
+
+  import Ecto.Query
+
+  alias CodeCorps.{DonationGoal, Project, Repo}
+  alias Ecto.Multi
+
+  def create(attributes) do
+    changeset = %DonationGoal{} |> DonationGoal.create_changeset(attributes)
+
+    multi = Multi.new
+    |> Multi.insert(:donation_goal, changeset)
+    |> Multi.run(:update_related_goals, &update_related_goals/1)
+
+    case Repo.transaction(multi) do
+      {:ok, %{donation_goal: donation_goal, update_related_goals: _}} ->
+        {:ok, donation_goal}
+      {:error, :donation_goal, %Ecto.Changeset{} = changeset, %{}} ->
+        {:error, changeset}
+      {:error, _failed_operation, _failed_value, _changes_so_far} ->
+        {:error, :unhandled}
+    end
+  end
+
+  def update(%DonationGoal{} = donation_goal, attributes) do
+    changeset = donation_goal |> DonationGoal.create_changeset(attributes)
+
+    multi = Multi.new
+    |> Multi.update(:donation_goal, changeset)
+    |> Multi.run(:update_related_goals, &update_related_goals/1)
+
+    case Repo.transaction(multi) do
+      {:ok, %{donation_goal: donation_goal, update_related_goals: _}} ->
+        {:ok, Repo.get(DonationGoal, donation_goal.id)}
+      {:error, :donation_goal, %Ecto.Changeset{} = changeset, %{}} ->
+        {:error, changeset}
+      {:error, _failed_operation, _failed_value, _changes_so_far} ->
+        {:error, :unhandled}
+    end
+  end
+
+  def set_current_goal_for_project(%Project{} = project) do
+    project
+    |> find_current_goal
+    |> set_to_current(project)
+  end
+
+  defp update_related_goals(%{donation_goal: %DonationGoal{project_id: project_id}}) do
+    Project
+    |> Repo.get(project_id)
+    |> set_current_goal_for_project
+  end
+
+  defp find_current_goal(%Project{} = project) do
+    amount_donated = get_amount_donated(project)
+    case find_lowest_not_yet_reached(project, amount_donated) do
+      nil -> find_largest_goal(project)
+      %DonationGoal{} = donation_goal -> donation_goal
+    end
+  end
+
+  defp get_amount_donated(%Project{id: project_id}) do
+    # TODO: This should be simplified by having
+    # subscriptions relate to projects instead of plans
+    # and by caching the total amount on the project itself
+
+    CodeCorps.StripeConnectPlan
+    |> Repo.get_by(project_id: project_id)
+    |> aggregate_donations
+    |> default_to_zero
+  end
+
+  defp aggregate_donations(nil), do: 0
+  defp aggregate_donations(%CodeCorps.StripeConnectPlan{id: plan_id}) do
+    CodeCorps.StripeConnectSubscription
+    |> where([s], s.stripe_connect_plan_id == ^plan_id)
+    |> Repo.aggregate(:sum, :quantity)
+  end
+
+  defp default_to_zero(nil), do: 0
+  defp default_to_zero(value), do: value
+
+  defp find_lowest_not_yet_reached(%Project{id: project_id}, amount_donated) do
+    DonationGoal
+    |> where([d], d.project_id == ^project_id and d.amount > ^amount_donated)
+    |> order_by(asc: :amount)
+    |> limit(1)
+    |> Repo.one
+  end
+
+  defp find_largest_goal(%Project{id: project_id}) do
+    DonationGoal
+    |> where([d], d.project_id == ^project_id)
+    |> order_by(desc: :amount)
+    |> limit(1)
+    |> Repo.one
+  end
+
+  defp set_to_current(%DonationGoal{} = donation_goal, %Project{} = project) do
+    attrs = %{current_donation_goal_id: donation_goal.id}
+    project
+    |> Project.set_current_donation_goal_changeset(attrs)
+    |> Repo.update
+  end
+end

priv/repo/migrations/20161126045705_add_current_donation_goal.exs

@@ -0,0 +1,27 @@
+defmodule CodeCorps.Repo.Migrations.AddCurrentDonationGoal do
+  use Ecto.Migration
+
+  def up do
+    alter table(:projects) do
+      add :current_donation_goal_id, references(:donation_goals)
+    end
+
+    create unique_index(:projects, [:current_donation_goal_id])
+
+    alter table(:donation_goals) do
+      remove(:current)
+    end
+  end
+
+  def down do
+    drop_if_exists unique_index(:projects, [:current_donation_goal_id])
+
+    alter table(:projects) do
+      remove(:current_donation_goal_id)
+    end
+
+    alter table(:donation_goals) do
+      add :current, :boolean, default: false
+    end
+  end
+end

test/controllers/donation_goal_controller_test.exs

@@ -1,7 +1,7 @@
 defmodule CodeCorps.DonationGoalControllerTest do
   use CodeCorps.ApiCase, resource_name: :donation_goal
 
-  @valid_attrs %{amount: 200, current: false, description: "A description"}
+  @valid_attrs %{amount: 200, description: "A description"}
   @invalid_attrs %{description: nil}
 
   describe "index" do
@@ -67,7 +67,9 @@ defmodule CodeCorps.DonationGoalControllerTest do
   describe "update" do
     @tag authenticated: :admin
     test "updates and renders chosen resource when data is valid", %{conn: conn} do
-      assert conn |> request_update(@valid_attrs) |> json_response(200)
+      project = insert(:project)
+      attrs = @valid_attrs |> Map.merge(%{project: project})
+      assert conn |> request_update(attrs) |> json_response(200)
     end
 
     @tag authenticated: :admin

test/lib/code_corps/donation_goals_manager_test.exs

@@ -0,0 +1,167 @@
+defmodule CodeCorps.DonationGoalsManagerTest do
+  use ExUnit.Case, async: true
+
+  use CodeCorps.ModelCase
+
+  alias CodeCorps.DonationGoal
+  alias CodeCorps.DonationGoalsManager
+  alias CodeCorps.Project
+
+  defp assert_current_goal_id(goal_id) do
+    project =
+      Project
+      |> Repo.get_by(current_donation_goal_id: goal_id)
+      |> Repo.preload([:current_donation_goal])
+    assert project.current_donation_goal.id == goal_id
+  end
+
+  defp donate(plan, amount) do
+    insert(:stripe_connect_subscription, quantity: amount, stripe_connect_plan: plan)
+  end
+
+  describe "create/1" do
+    test "inserts new goal, returns {:ok, record}" do
+      project = insert(:project)
+      insert(:stripe_connect_plan, project: project)
+
+      {:ok, %DonationGoal{} = donation_goal} = DonationGoalsManager.create(%{amount: 10, description: "Test", project_id: project.id})
+      assert_current_goal_id(donation_goal.id)
+    end
+
+    test "returns {:error, changeset} if there are validation errors" do
+      {:error, %Ecto.Changeset{} = changeset} = DonationGoalsManager.create(%{amount: 10})
+      refute changeset.valid?
+    end
+
+    test "sets current goal correctly" do
+      project = insert(:project)
+      plan = insert(:stripe_connect_plan, project: project)
+
+      {:ok, first_goal} = DonationGoalsManager.create(%{amount: 10, description: "Test", project_id: project.id})
+
+      # total donated is 0,
+      # only goal inserted is the first goal
+      assert_current_goal_id(first_goal.id)
+
+      {:ok, second_goal} = DonationGoalsManager.create(%{amount: 20, description: "Test", project_id: project.id})
+
+      # total donated is still 0
+      # first goal larger than 0 is the very first goal
+      assert_current_goal_id(first_goal.id)
+
+      insert(:stripe_connect_subscription, quantity: 15, stripe_connect_plan: plan)
+
+      {:ok, _} = DonationGoalsManager.create(%{amount: 30, description: "Test", project_id: project.id})
+
+      # total donated is 15.
+      # first applicable goal is second goal, with an amount of 20
+      # third goal has an amount of 30, which is not applicable
+      assert_current_goal_id(second_goal.id)
+
+      insert(:stripe_connect_subscription, quantity: 30, stripe_connect_plan: plan)
+
+      {:ok, fourth_goal} = DonationGoalsManager.create(%{amount: 40, description: "Test", project_id: project.id})
+
+      # total donated is 45, which is more than any defined goal
+      # largest goal inserted after change the fourth goal, with an amount of 40
+      assert_current_goal_id(fourth_goal.id)
+    end
+  end
+
+  describe "update/2" do
+    test "updates existing goal, returns {:ok, record}" do
+      project = insert(:project)
+      insert(:stripe_connect_plan, project: project)
+      donation_goal = insert(:donation_goal, amount: 10, project: project)
+
+      {:ok, %DonationGoal{} = updated_goal} = DonationGoalsManager.update(donation_goal, %{amount: 15})
+      assert_current_goal_id(updated_goal.id)
+      assert updated_goal.id == donation_goal.id
+    end
+    test "returns {:error, changeset} if there are validation errors" do
+      project = insert(:project)
+      insert(:stripe_connect_plan, project: project)
+      donation_goal = insert(:donation_goal, amount: 10, project: project)
+
+      {:error, %Ecto.Changeset{} = changeset} = DonationGoalsManager.update(donation_goal, %{amount: nil})
+      refute changeset.valid?
+    end
+
+    test "sets current goal correctly" do
+      project = insert(:project)
+      plan = insert(:stripe_connect_plan, project: project)
+      goal_1 = insert(:donation_goal, amount: 10, project: project)
+      goal_2 = insert(:donation_goal, amount: 15, project: project)
+      insert(:donation_goal, amount: 20, project: project)
+
+      DonationGoalsManager.update(goal_1, %{amount: 11})
+
+      # amount donated is 0, first goal above that is still goal 1
+      assert_current_goal_id(goal_1.id)
+
+      DonationGoalsManager.update(goal_1, %{amount: 21})
+
+      # amount donated is still 0, first goal above that is now goal 2
+      assert_current_goal_id(goal_2.id)
+
+      insert(:stripe_connect_subscription, quantity: 25, stripe_connect_plan: plan)
+
+      DonationGoalsManager.update(goal_1, %{amount: 21})
+
+      # amount donated is now 25
+      # this is more than any current goal
+      # largest goal is goal 1, with 21
+      assert_current_goal_id(goal_1.id)
+
+      DonationGoalsManager.update(goal_2, %{amount: 22})
+
+      # amount donated is now 25
+      # this is more than any current goal
+      # largest goal is goal 2, with 22
+      assert_current_goal_id(goal_2.id)
+
+      DonationGoalsManager.update(goal_1, %{amount: 27})
+
+      # amount donated is still 25
+      # first goal higher than that is goal 1, with 27
+      assert_current_goal_id(goal_1.id)
+    end
+  end
+
+
+
+  describe "set_current_goal_for_project/1" do
+    test "sets current goal correctly" do
+      project = insert(:project)
+      plan = insert(:stripe_connect_plan, project: project)
+
+      goal_1 = insert(:donation_goal, amount: 10, project: project)
+      goal_2 = insert(:donation_goal, amount: 15, project: project)
+      goal_3 = insert(:donation_goal, amount: 20, project: project)
+
+      plan |> donate(5)
+      DonationGoalsManager.set_current_goal_for_project(project)
+      assert_current_goal_id(goal_1.id)
+
+      plan |> donate(5) # total is now 10
+      DonationGoalsManager.set_current_goal_for_project(project)
+      assert_current_goal_id(goal_2.id)
+
+      plan |> donate(5) # total is now 15
+      DonationGoalsManager.set_current_goal_for_project(project)
+      assert_current_goal_id(goal_3.id)
+
+      plan |> donate(5) # total is now 20
+      DonationGoalsManager.set_current_goal_for_project(project)
+      assert_current_goal_id(goal_3.id)
+
+      plan |> donate(5) # total is now 25
+      DonationGoalsManager.set_current_goal_for_project(project)
+      assert_current_goal_id(goal_3.id)
+
+      goal_4 = insert(:donation_goal, amount: 30, project: project) # 30 is more than the current 25 total
+      DonationGoalsManager.set_current_goal_for_project(project)
+      assert_current_goal_id(goal_4.id)
+    end
+  end
+end

test/models/donation_goal_test.exs

@@ -4,18 +4,17 @@ defmodule CodeCorps.DonationGoalTest do
   alias CodeCorps.DonationGoal
 
   describe "%create_changeset/2" do
-    test "requires amount, current, description and project_id" do
+    test "requires amount, description and project_id" do
       changeset = DonationGoal.create_changeset(%DonationGoal{}, %{})
 
       refute changeset.valid?
       assert changeset.errors[:amount] == {"can't be blank", []}
-      assert changeset.errors[:current] == {"can't be blank", []}
       assert changeset.errors[:description] == {"can't be blank", []}
       assert changeset.errors[:project_id] == {"can't be blank", []}
     end
 
     test "ensures project with specified id actually exists" do
-      attrs = %{amount: 100, current: true, description: "Bar", project_id: -1}
+      attrs = %{amount: 100, description: "Bar", project_id: -1}
       { result, changeset } =
         DonationGoal.create_changeset(%DonationGoal{}, attrs)
         |> Repo.insert
@@ -27,14 +26,13 @@ defmodule CodeCorps.DonationGoalTest do
   end
 
   describe "&update_changeset/2" do
-    test "requires amount, current, description" do
-      attrs = %{amount: nil, current: nil, description: nil}
+    test "requires amount, description" do
+      attrs = %{amount: nil, description: nil}
       donation_goal = insert(:donation_goal)
       changeset = DonationGoal.update_changeset(donation_goal, attrs)
 
       refute changeset.valid?
       assert changeset.errors[:amount] == {"can't be blank", []}
-      assert changeset.errors[:current] == {"can't be blank", []}
       assert changeset.errors[:description] == {"can't be blank", []}
     end
   end