exmr/lib/exmr_web/live/exam_live/index.ex

defmodule ExmrWeb.ExamLive.Index do
  use ExmrWeb, :live_view

  alias Exmr.Exams
  alias Exmr.Exams.Exam

  @impl true
  def mount(_params, _session, socket) do
    socket =
      socket
      |> assign(:exams, Exams.list_exams())
      |> assign(:sort_by, "date")
      |> assign(:live_action, :index)
      |> assign(exam: %{})

    {:ok, socket}
  end

  @impl true
  def handle_params(params, _url, socket) do
    {:noreply, apply_action(socket, socket.assigns.live_action, params)}
  end

  defp apply_action(socket, :edit, %{"id" => id}) do
    socket
    |> assign(:page_title, "Edit Exam")
    |> assign(:exam, Exams.get_exam!(id))
  end

  defp apply_action(socket, :new, _params) do
    socket
    |> assign(:page_title, gettext("New Exam"))
    |> assign(:exam, %Exam{})
  end

  defp apply_action(socket, :index, _params) do
    socket
    |> assign(:page_title, "Listing Exams")
    |> assign(:exam, nil)
  end

  @impl true
  def handle_info({ExmrWeb.ExamLive.FormComponent, {:saved, exam}}, socket) do
    socket =
      socket
      |> assign(:exams, [exam | socket.assigns.exams])

    {:noreply, socket}
  end

  @impl true
  def handle_event("remove", %{"id" => id}, socket) do
    exam = Exams.get_exam!(id)
    {:ok, _} = Exams.delete_exam(exam)

    socket =
      socket
      |> update(:exams, fn exams ->
        Enum.reject(exams, fn l -> l.id == exam.id end)
      end)

    {:noreply, socket}
  end

  def handle_event("sort", %{"by" => sort_by}, socket) do
    exams = sort_items(socket.assigns.exams, sort_by)
    {:noreply, assign(socket, exams: exams, sort_by: sort_by)}
  end

  def handle_event("edit", %{"id" => id}, socket) do
    exam = Exams.get_exam!(id)

    socket =
      socket
      |> assign(live_action: :edit, exam: exam)

    {:noreply, socket}
  end

  defp sort_items(items, "subject") do
    Enum.sort_by(items, & &1.subject)
  end

  defp sort_items(items, "date") do
    Enum.sort_by(items, & &1.date, &Date.before?/2)
  end
end