defmodule Ami.Like do
  use Ecto.Schema

  import Ecto.{
    Query,
    Changeset
  }

  alias Ami.{
    User,
    Repo
  }

  schema "likes" do
    @timestamps_opts [type: :naive_datetime_usec]
    
    field(:likeable_id, :integer)
    field(:likeable_type, :string)
    field(:created_at, :utc_datetime_usec)
    field(:updated_at, :utc_datetime_usec)

    belongs_to(:user, User)
  end

  def preload_likes(struct, likeable_type) do
    query = from(l in __MODULE__, where: l.likeable_type == ^likeable_type, order_by: l.id)

    struct
    |> Repo.preload(likes: {query, [user: :profile]})
  end

  def changeset(like, params \\ %{}) do
    like
    |> cast(params, [:created_at, :updated_at, :likeable_type, :likeable_id, :user_id])
    |> validate_required([:user_id, :likeable_type, :likeable_id])
    |> unique_constraint(:likeable_id, name: :likes_likeable_id_likeable_type_user_id_index)
  end

  def count_for(%Ami.Post{} = post, user) do
    Repo.one(
      from(
        l in __MODULE__,
        where: l.likeable_type == "Post",
        where: l.likeable_id == ^post.id,
        where: l.user_id == ^user.id,
        select: count(l.id)
      )
    )
  end

  def count_for(%Ami.Tool{} = tool, user) do
    Repo.one(
      from(
        l in __MODULE__,
        where: l.likeable_type == "Tool",
        where: l.likeable_id == ^tool.id,
        where: l.user_id == ^user.id,
        select: count(l.id)
      )
    )
  end

  def count_for(%Ami.Toolkit{} = toolkit, user) do
    Repo.one(
      from(
        l in __MODULE__,
        where: l.likeable_type == "ToolKit",
        where: l.likeable_id == ^toolkit.id,
        where: l.user_id == ^user.id,
        select: count(l.id)
      )
    )
  end
end