defmodule FarmbotCeleryScript.Compiler.Execute do
  import FarmbotCeleryScript.Compiler.Utils
  alias FarmbotCeleryScript.Compiler

  @iterables [:point_group, :every_point]

  # Compiles an `execute` block.
  # This one is actually pretty complex and is split into two parts. 
  def execute(%{body: parameter_applications} = ast, env) do
    # if there is an iterable AST here, 
    # we need to compile _many_ sequences, not just one.

    loop_parameter_appl_ast =
      Enum.find_value(parameter_applications, fn
        # check if this parameter_application is a iterable type
        %{kind: :parameter_application, args: %{data_value: %{kind: kind}}} = iterable
        when kind in @iterables ->
          iterable

        _other ->
          false
      end)

    if loop_parameter_appl_ast,
      do: compile_execute_iterable(loop_parameter_appl_ast, ast, env),
      else: compile_execute(ast, env)
  end

  def compile_execute_iterable(loop_parameter_appl_ast, ast, env)

  def compile_execute_iterable(
        _loop_parameter_appl_ast,
        %{args: %{sequence_id: sequence_id}, body: param_appls},
        env
      ) do
    quote location: :keep do
      case FarmbotCeleryScript.SysCalls.get_sequence(unquote(sequence_id)) do
        %FarmbotCeleryScript.AST{kind: :sequence} = celery_ast ->
          celery_args =
            celery_ast.args
            |> Map.put(:sequence_name, celery_ast.args[:name] || celery_ast.meta[:sequence_name])
            |> Map.put(:locals, %{
              celery_ast.args.locals
              | body: celery_ast.args.locals.body ++ unquote(param_appls)
            })

          celery_ast = %{celery_ast | args: celery_args}
          Compiler.compile(celery_ast, unquote(env))

        error ->
          error
      end
    end
  end

  def compile_execute(%{args: %{sequence_id: id}, body: parameter_applications}, env) do
    quote location: :keep do
      # We have to lookup the sequence by it's id.
      case FarmbotCeleryScript.SysCalls.get_sequence(unquote(id)) do
        %FarmbotCeleryScript.AST{} = ast ->
          # compile the ast
          env = unquote(compile_params_to_function_args(parameter_applications, env))
          FarmbotCeleryScript.Compiler.compile(ast, env)

        error ->
          error
      end
    end
  end
end