describe Procedure do

  let(:context) { clean_context }

  it "executes its body and leaves state in the program context" do
    poner_cmd = Poner.new rojo
    body = CommandBlock.new [poner_cmd]
    procedure = Procedure.new 'MyProcedure', no_arguments, body
    procedure.evaluate context
    expect(context.head.are_there_balls?(rojo)).to be true
  end

  it "fails getting a variable which is in the outer context" do
    var_name = 'var'.to_var_name
    context.set var_name, verde

    poner_cmd = Poner.new var_name
    body = CommandBlock.new [poner_cmd]
    procedure = Procedure.new 'MyProcedure', no_arguments, body
    expect { procedure.evaluate context }.to raise_error(UndefinedVariableError)
  end

  it "sets arguments in the new context so they can be used" do
    a_color = 'a_color'.to_var_name
    a_direction = 'a_direction'.to_var_name
    args = VarTuple.new [a_color, a_direction]
    mover_cmd = Mover.new a_direction
    poner_cmd = Poner.new a_color
    body = CommandBlock.new [mover_cmd, poner_cmd]
    procedure = Procedure.new 'MyProc', args, body

    procedure.evaluate context, [negro, norte]

    expect(context.head.are_there_balls?(negro)).to be true
    expect(context.head.y_pos).to eq(1)
  end

  it "does not set arguments as var names in outer context" do
    a_direction = 'a_direction'.to_var_name
    args = VarTuple.new [a_direction]
    procedure = Procedure.new 'MyProc', args, empty_body

    procedure.evaluate context, [oeste]

    expect(context.has_variable_named?('a_direction')).to be false
  end

  it "fails if it is executed with more arguments than expected" do
    procedure = Procedure.new 'MyProcedure', no_arguments, empty_body
    error_message = "Wrong number of arguments in procedure 'MyProcedure': expected 0, got 1"
    expect { procedure.evaluate context, [norte] }
      .to raise_error(WrongArgumentsError, error_message)
  end

  it "fails if it is executed with less arguments than expected" do
    args = VarTuple.new ['arg1'.to_var_name, 'arg2'.to_var_name]
    procedure = Procedure.new 'MyProcedure2', args, empty_body
    error_message = "Wrong number of arguments in procedure 'MyProcedure2': expected 2, got 1"
    expect { procedure.evaluate context, [verde] }
      .to raise_error(WrongArgumentsError, error_message)
  end

end