defmodule Posterize.Extensions.EPGSQL.Date do
  @moduledoc false
  import Postgrex.BinaryUtils
  use Postgrex.BinaryExtension, send: "date_send"

  @gd_epoch :calendar.date_to_gregorian_days({2000, 1, 1})
  @date_max_year 5874897

  def encode(_, {year, month, day}, _, _)
  when year <= @date_max_year do
    date = {year, month, day}
    <<:calendar.date_to_gregorian_days(date) - @gd_epoch :: int32>>
  end
  def encode(type_info, value, _, _) do
    raise ArgumentError, encode_msg(type_info, value, "date")
  end

  def decode(_, <<days :: int32>>, _, _) do
    :calendar.gregorian_days_to_date(days + @gd_epoch)
  end

  def encode_msg(%Postgrex.TypeInfo{type: type}, observed, expected) do
    "Postgrex expected #{expected} that can be encoded/cast to " <>
    "type #{inspect type}, got #{inspect observed}. Please make sure the " <>
    "value you are passing matches the definition in your table or in your " <>
    "query or convert the value accordingly."
  end
end