defmodule Ami.CourseSearch do
  defstruct id: 0,
            title: "",
            description: "",
            teaser_description: "",
            slug: "",
            rank: 0.0,
            introduction: ""

  @doc """
  Search for open course periods matching given term accessible by given user
  Returns `{ :ok,
             %{courses: [course_period_struct], packages: [package_struct]}
            }`

  ## Examples
    iex> Ami.CourseSearch.search_for_user_with_term(user, "manage")
    {:ok, %courses: [%Ami.CoursePeriod{}], packages: [%Ami.Package{}]}
  """
  def search_for_user_with_term(user, term) do
    course_periods =
      search(term)
      |> Enum.map(fn course -> Ami.CoursePeriod.currents_for(course, user) |> List.first() end)

    packages = if user.status in [0, 1], do: Ami.Package.on_air(), else: []

    if length(course_periods) > 0 do
      {:ok, %{courses: course_periods, packages: packages}}
    else
      {:error, "no results found"}
    end
  end

  def search_for_user_with_term(term) do
    # course_periods =
    search(term)
    |> Enum.map(fn course -> Ami.CoursePeriod.currents_for(course) |> List.first() end)
  end

  def search_for_user_with_term_of_type(user, term, type) do
    course_periods =
      search(term)
      |> Enum.map(fn course ->
        Ami.CoursePeriod.currents_for(course, user) |> filter_by_type(type) |> List.first()
      end)

    packages = if user.status in [0, 1], do: Ami.Package.on_air(), else: []

    if length(course_periods) > 0 do
      {:ok, %{courses: course_periods, packages: packages}}
    else
      {:error, "no results found"}
    end
  end

  def search_for_community_with_term(community, term) do
    # course_periods =
    search(term)
    |> Enum.map(fn course ->
      Ami.CoursePeriod.currents_for(community, course)
      |> List.first()
    end)
    |> Enum.filter(&(!is_nil(&1)))
  end

  def search(term) do
    Ecto.Adapters.SQL.query!(Ami.Repo, "SELECT * FROM course_search($1)", [term])
    |> result_to_course_struct
  end

  # defp result_to_struct(res) do
  #   cols = Enum.map(res.columns, &String.to_atom(&1))
  #   Enum.map(res.rows, fn row -> struct(__MODULE__, Enum.zip(cols, row)) end)
  # end

  defp result_to_course_struct(res) do
    cols = Enum.map(res.columns, &String.to_atom(&1))
    Enum.map(res.rows, fn row -> struct(Ami.Course, Enum.zip(cols, row)) end)
  end

  defp filter_by_type(course_periods, type) do
    case type do
      "public" ->
        Enum.filter(course_periods, fn cp -> is_nil(cp.community_id) end)

      "community" ->
        Enum.filter(course_periods, fn cp -> !is_nil(cp.community_id) end)

      "learning_lab" ->
        Enum.filter(course_periods, fn cp -> cp.is_learning_lab == true end)

      nil ->
        course_periods
    end
  end
end