bdfr-browser/lib/bdfr_browser/subreddit.ex

defmodule BdfrBrowser.Subreddit do
  use Ecto.Schema

  import Ecto.Query, only: [from: 2]

  alias BdfrBrowser.Post

  schema "subreddits" do
    field :name, :string

    has_many :posts, Post
  end

  def multiple_names(names) do
    from(s in __MODULE__, where: s.name in ^names)
  end

  def names do
    from(s in __MODULE__, select: s.name, order_by: [asc: fragment("lower(?)", s.name)])
  end

  def names_without(hidden) do
    from(s in __MODULE__, select: s.name, where: s.name not in ^hidden, order_by: [asc: fragment("lower(?)", s.name)])
  end

  def statistics(subreddit) when is_binary(subreddit), do: statistics([subreddit])

  def statistics(subreddits) when is_list(subreddits) do
    from(s in __MODULE__,
      join: p in assoc(s, :posts),
      left_join: c in assoc(p, :comments),
      select: {s.name, count(p.id), count(c.id)},
      where: s.name in ^subreddits,
      group_by: [s.name]
    )
  end
end