Allow users to withdraw job applications

lib/algora/jobs/jobs.ex

@@ -213,6 +213,13 @@ defmodule Algora.Jobs do
     end
   end
 
+  def withdraw_application(job_id, user) do
+    case JobApplication |> where([a], a.job_id == ^job_id and a.user_id == ^user.id) |> Repo.one() do
+      nil -> {:error, :not_found}
+      application -> Repo.delete(application)
+    end
+  end
+
   def list_user_applications(user) do
     JobApplication
     |> where([a], a.user_id == ^user.id)

lib/algora_web/live/org/jobs_live.ex

@@ -178,9 +178,19 @@ defmodule AlgoraWeb.Org.JobsLive do
                         <% end %>
                       </div>
                     </div>
-                    <.button phx-click="apply_job" phx-value-job-id={job.id}>
-                      I'm interested
-                    </.button>
+                    <%= if MapSet.member?(@user_applications, job.id) do %>
+                      <.button
+                        variant="secondary"
+                        phx-click="withdraw_application"
+                        phx-value-job-id={job.id}
+                      >
+                        Withdraw
+                      </.button>
+                    <% else %>
+                      <.button phx-click="apply_job" phx-value-job-id={job.id}>
+                        I'm interested
+                      </.button>
+                    <% end %>
                   </div>
                 <% end %>
               </div>
@@ -254,6 +264,27 @@ defmodule AlgoraWeb.Org.JobsLive do
     end
   end
 
+  @impl true
+  def handle_event("withdraw_application", %{"job-id" => job_id}, socket) do
+    current_user = socket.assigns[:current_user]
+    org = socket.assigns.current_org
+
+    if current_user do
+      case Jobs.withdraw_application(job_id, current_user) do
+        {:ok, _application} ->
+          {:noreply, assign_user_applications(socket)}
+
+        {:error, :not_found} ->
+          {:noreply, put_flash(socket, :error, "Application not found.")}
+
+        {:error, _changeset} ->
+          {:noreply, put_flash(socket, :error, "Failed to withdraw application. Please try again.")}
+      end
+    else
+      {:noreply, push_navigate(socket, to: "/#{org.handle}/job/#{job_id}/apply")}
+    end
+  end
+
   @impl true
   def handle_event(_event, _params, socket) do
     {:noreply, socket}

test/algora/jobs_test.exs

@@ -0,0 +1,34 @@
+defmodule Algora.JobsTest do
+  use Algora.DataCase
+
+  import Algora.Factory
+
+  alias Algora.Jobs
+  alias Algora.Jobs.JobApplication
+  alias Algora.Repo
+
+  describe "withdraw_application/2" do
+    test "deletes the current user's application" do
+      user = insert!(:user)
+      job = insert!(:job_posting, user: insert!(:user))
+
+      assert {:ok, application} = Jobs.create_application(job.id, user)
+      assert MapSet.member?(Jobs.list_user_applications(user), job.id)
+
+      assert {:ok, deleted_application} = Jobs.withdraw_application(job.id, user)
+      assert deleted_application.id == application.id
+      refute MapSet.member?(Jobs.list_user_applications(user), job.id)
+      refute Repo.get(JobApplication, application.id)
+    end
+
+    test "does not delete another user's application" do
+      owner = insert!(:user)
+      other_user = insert!(:user)
+      job = insert!(:job_posting, user: insert!(:user))
+
+      assert {:ok, application} = Jobs.create_application(job.id, owner)
+      assert {:error, :not_found} = Jobs.withdraw_application(job.id, other_user)
+      assert Repo.get(JobApplication, application.id)
+    end
+  end
+end

test/algora_web/live/org/jobs_live_test.exs

@@ -0,0 +1,38 @@
+defmodule AlgoraWeb.Org.JobsLiveTest do
+  use AlgoraWeb.ConnCase
+
+  import Algora.Factory
+  import Phoenix.LiveViewTest
+
+  alias Algora.Jobs
+  alias AlgoraWeb.UserAuth
+
+  setup %{conn: conn} do
+    {:ok, conn: Phoenix.ConnTest.init_test_session(conn, %{})}
+  end
+
+  test "lets a user withdraw an existing job application", %{conn: conn} do
+    user = insert!(:user)
+    org = insert!(:organization)
+    job = insert!(:job_posting, user: org)
+
+    assert {:ok, _application} = Jobs.create_application(job.id, user)
+
+    {:ok, view, html} =
+      conn
+      |> UserAuth.put_current_user(user)
+      |> live("/#{org.handle}/jobs")
+
+    assert html =~ "Withdraw"
+    assert has_element?(view, "button[phx-click=withdraw_application]", "Withdraw")
+    refute has_element?(view, "button[phx-click=apply_job]", "I'm interested")
+
+    view
+    |> element("button[phx-click=withdraw_application]")
+    |> render_click()
+
+    assert has_element?(view, "button[phx-click=apply_job]", "I'm interested")
+    refute has_element?(view, "button[phx-click=withdraw_application]", "Withdraw")
+    assert {:error, :not_found} = Jobs.withdraw_application(job.id, user)
+  end
+end