defmodule BitcoinLib.Script.Opcode do
  @moduledoc """
  Opcode behaviour, allowing execution and returning the opcode's integer value
  """

  @doc """
  Returns the opcode's value
  """
  @callback v() :: byte()

  @doc """
  Attemps to execute the opcode against the stack given as an argument,
  returning either the altered stack or an error
  """
  @callback execute(any(), list()) :: {:ok, list()} | {:error, binary()}

  alias BitcoinLib.Script.Opcodes.Data

  @type t :: Data

  @spec execute(Data.t(), list()) :: {:ok, list()}
  def execute(%Data{value: value}, stack) do
    {:ok, [value | stack]}
  end

  @spec execute(module(), list()) :: {:ok, list()}
  def execute(opcode, stack) do
    opcode.__struct__.execute(opcode, stack)
  end
end