defmodule Ami.Event do
  use Ecto.Schema

  import Ecto.{
    Query
  }

  alias Ami.{
    User,
    Repo,
    # Community,
    CommunityEvent
  }

  schema "events" do
    @timestamps_opts [type: :naive_datetime_usec]
    
    field(:title, :string)
    field(:body, :string)
    field(:event_type, :integer)
    field(:starts_on, :utc_datetime_usec)
    field(:ends_on, :utc_datetime_usec)
    field(:created_at, :utc_datetime_usec)
    field(:updated_at, :utc_datetime_usec)
    field(:weekly_recurrence, :boolean, default: false)
    field(:whole_community, :boolean, default: false)

    belongs_to(:author, User, foreign_key: :user_id)
    has_many(:community_events, CommunityEvent)
    has_many(:communities, through: [:community_events, :community])
  end

  defp start_date_for(frequency) do
    case frequency do
      "daily" ->
        Timex.beginning_of_day(Timex.now())

      "weekly" ->
        Timex.beginning_of_week(Timex.now())

      "monthly" ->
        Timex.beginning_of_month(Timex.now())
    end
  end

  def fetch_nonmember_news(frequency) do
    start_date = start_date_for(frequency)

    Repo.all(
      from(
        e in __MODULE__,
        where: e.event_type == 0 and e.starts_on >= ^start_date,
        or_where: e.event_type == 0 and e.weekly_recurrence == true
      )
    )
  end

  def fetch_member_news(%Ami.User{} = user, frequency) do
    user = Repo.preload(user, [:communities])
    user_communities_ids = Enum.map(user.communities, fn com -> com.id end)

    start_date = start_date_for(frequency)

    community_news =
      Repo.all(
        from(
          e in __MODULE__,
          where: e.event_type == 1,
          where: e.starts_on >= ^start_date,
          where: e.whole_community == true,
          or_where: e.whole_community == true and e.weekly_recurrence == true
        )
      )
      |> Enum.concat(
        Repo.all(
          from(
            e in __MODULE__,
            where: e.event_type == 1,
            where: e.weekly_recurrence == false,
            join: c in assoc(e, :communities),
            where: c.id in ^user_communities_ids,
            where: e.starts_on >= ^start_date
          )
        )
      )
      |> Enum.concat(
        Repo.all(
          from(
            e in __MODULE__,
            where: e.event_type == 1,
            join: c in assoc(e, :communities),
            where: c.id in ^user_communities_ids,
            where: e.weekly_recurrence == true
          )
        )
      )
      |> Enum.uniq()

    if length(community_news) == 0, do: fetch_nonmember_news(frequency), else: community_news
  end
end