events.ex

defmodule Rsvp.Events do
	use Ecto.Schema
	import Ecto.Changeset

	schema "events" do
		field :title, :string
		field :location, :string
		field :date, Ecto.DateTime
		field :description, :string
		timestamps()
	end

	# @required_fields ~w(title location date)a
    # @optional_fields ~w(description)a


 	@required_fields [:title,:location,:date]
  	@optional_fields [:description]

	def changeset(event, params \\ %{}) do
		event
		|> cast(params, @required_fields ++ @optional_fields)
		|> validate_required(@required_fields)
		|> validate_change(:date, fn(s, x) -> must_be_future(s,x) end)  
	end
		# validate_change(:date, &must_be_future/2)
	defp must_be_future(_ , value) do
		Ecto.DateTime.compare(value, Ecto.DateTime.utc)
		|> get_error
	end

	defp get_error(comparison) when comparison == :lt do
		[date: "cant be in the past"]
	end

	defp get_error(_), do: []
end