defmodule Guesswork do
  @moduledoc """
  Guesswork allows the creation of logical statements and knowledge databases
  which then can be used together to figure out answers to questions stated
  in those logical systems.
  """

  alias Guesswork.Ast.Statement
  alias Guesswork.Answer.Result
  alias Guesswork.Query

  defmodule EmptyCollection do
    @moduledoc """
    A collection with no facts, falsehoods, or rules.
    """
    use Guesswork.KnowledgeBase.Collection
  end

  @doc """
  Takes a logical statement, a knowledge base, and a target number of answer sets,
  and then returns all entity bindings for which the statement is true, according
  to the knowledge base.

  Available Options:

  #{NimbleOptions.docs(Query.opts_schema())}
  """
  @spec query(Statement.t(), integer(), Query.opts_list()) :: Result.t()
  def query(statement, n, opts \\ []) do
    Query.new(statement, opts)
    |> Query.run(n)
  end
end