if Code.ensure_loaded?(Ecto) do
  defmodule AntlUtils.Ecto.Queryable do
    @callback queryable() :: Ecto.Queryable.t()
    @callback paginate(Ecto.Queryable.t(), integer, keyword) :: Ecto.Queryable.t()
    @callback sort(Ecto.Queryable.t(), map) :: Ecto.Queryable.t()
    @callback filter(Ecto.Queryable.t(), map) :: Ecto.Queryable.t()
    @callback search(Ecto.Queryable.t(), binary) :: Ecto.Queryable.t()

    defmacro __using__(opts) do
      quote do
        @behaviour unquote(__MODULE__)
        @before_compile unquote(__MODULE__)

        import Ecto.Query

        @sortable_fields Keyword.get(unquote(opts), :sortable_fields, [:inserted_at, :updated_at])
        @searchable_fields Keyword.get(unquote(opts), :searchable_fields, [:id])

        def queryable(), do: Keyword.get(unquote(opts), :base_schema, __MODULE__)
        defoverridable queryable: 0

        def paginate(queryable, page, opts \\ []),
          do: unquote(__MODULE__).paginate(queryable, page, opts)

        def sort(queryable, sort_params \\ %{})

        def sort(queryable, %{field: field, order: _order} = sort_params) do
          handle_sort(queryable, sort_params)
        end

        def sort(queryable, %{}) do
          sort(queryable, %{field: List.first(@sortable_fields), order: :desc})
        end

        defp handle_sort(queryable, %{field: field, order: _order} = sort_params)
             when field in @sortable_fields do
          unquote(__MODULE__).sort(queryable, sort_params)
        end

        def filter(queryable, filters),
          do: Enum.reduce(filters, queryable, &filter_by_field(&1, &2))

        def search(queryable, search_query, metadata \\ [])
        def search(queryable, nil, _metadata), do: queryable

        def search(queryable, search_query, metadata)
            when is_binary(search_query) and is_list(metadata),
            do: where(queryable, ^search_where_query(search_query, metadata))

        defp search_where_query(search_query, []) do
          Enum.reduce(
            @searchable_fields,
            Ecto.Query.dynamic(false),
            &search_by_field({&1, search_query}, &2)
          )
        end

        defp search_where_query(search_query, metadata) when length(metadata) > 0 do
          Enum.reduce(
            @searchable_fields,
            Ecto.Query.dynamic(false),
            &search_by_field({&1, search_query}, &2, metadata)
          )
        end
      end
    end

    defmacro __before_compile__(_env) do
      quote do
        defp filter_by_field(field, queryable),
          do: unquote(__MODULE__).filter_by_field(field, queryable)

        defp search_by_field(field, dynamic),
          do: unquote(__MODULE__).search_by_field(field, dynamic)

        defp search_by_field(field, dynamic, metadata),
          do: unquote(__MODULE__).search_by_field(field, dynamic, metadata)
      end
    end

    import Ecto.Query

    @spec paginate(Ecto.Queryable.t(), number, keyword) :: Ecto.Queryable.t()
    def paginate(queryable, page, opts \\ []) do
      queryable |> AntlUtils.Ecto.Paginator.paginate(page, opts)
    end

    @spec sort(any, map) :: Ecto.Queryable.t()
    def sort(queryable, %{field: field, order: order})
        when is_atom(field) and order in [:asc, :desc] do
      queryable |> AntlUtils.Ecto.Query.order_by(field, order)
    end

    @spec filter_by_field({any, any}, any) :: Ecto.Queryable.t()
    def filter_by_field({key, value}, queryable) do
      queryable |> AntlUtils.Ecto.Query.where(key, value)
    end

    @spec search_by_field({any, binary}, any) :: Ecto.Query.DynamicExpr.t()
    def search_by_field({key, value}, dynamic) do
      like_value = "%#{String.replace(value, "%", "\\%")}%"
      dynamic([q], ^dynamic or like(field(q, ^key), ^like_value))
    end

    @spec search_by_field({any, binary}, any, list()) :: Ecto.Query.DynamicExpr.t()
    def search_by_field({key, value}, dynamic, metadata) when is_list(metadata) do
      like_value = "%#{String.replace(value, "%", "\\%")}%"
      dynamic([q], ^dynamic or like(field(q, ^key), ^like_value))
    end
  end
end