filter.ex

defmodule Whatever.Filter do

  alias Whatever.Filter, as: Filter
  alias Ecto.Query, as: Query

  require Ecto.Query
  
  defstruct valid?: true, query: nil, limit: 1000, errors: []

  def filter(%Filter{} = s, { "id", id }) do
    filter(s, { "id.eq", id })
  end
  def filter(%Filter{} = s, { "id.eq", id }) do
    case s.valid? do
      true  -> %{ s | query: Query.dynamic([t], t.id == ^id and ^s.query) }
      false -> s
    end
  end
  def filter(%Filter{} = s, { "id.in", ids }) do
    ids = ids |> String.split(",")
    case s.valid? do
      true  -> %{ s | query: Query.dynamic([t], t.id in ^ids and ^s.query) }
      false -> s
    end
  end
  def filter(%Filter{} = s, { "key", key }) do
    filter(s, { "key.eq", key })
  end
  def filter(%Filter{} = s, { "key.eq", key }) do
    case s.valid? do
      true  -> %{ s | query: Query.dynamic([t], t.key == ^key and ^s.query) }
      false -> s
    end
  end
  def filter(%Filter{} = s, { "key.in", keys }) do
    keys = keys |> String.split(",")
    case s.valid? do
      true  -> %{ s | query: Query.dynamic([t], t.key in ^keys and ^s.query) }
      false -> s
    end
  end
  
end