defmodule Rsh26pool.Voting.Vote do
  @moduledoc """
  A single vote cast by a participant for an idea. A participant may vote for a
  given idea at most once (enforced by a unique index).
  """
  use Ecto.Schema
  import Ecto.Changeset

  alias Rsh26pool.Voting.{Idea, Participant}

  schema "votes" do
    belongs_to :idea, Idea
    belongs_to :participant, Participant

    timestamps(type: :utc_datetime)
  end

  def changeset(vote, attrs) do
    vote
    |> cast(attrs, [:idea_id, :participant_id])
    |> validate_required([:idea_id, :participant_id])
    |> unique_constraint([:idea_id, :participant_id],
      name: :votes_idea_id_participant_id_index,
      message: "は既に投票済みです"
    )
    |> foreign_key_constraint(:idea_id)
    |> foreign_key_constraint(:participant_id)
  end
end