class Opal::Nodes::EnsureNode

def body_sexp
  if wrap_in_closure?
    sexp = compiler.returns(begn)
    # 'rescue' is an edge case that should be compiled to
    # try { return function(){ ..rescue through try/catch.. }() }
    sexp.type == :rescue ? s(:js_return, sexp) : sexp
  else
    sexp = begn
  end
end

def compile
  push "try {"
  in_ensure do
    line compiler.process(body_sexp, @level)
  end
  line "} finally {"
  indent do
    if has_rescue_else?
      # $no_errors indicates thate there were no error raised
      unshift "var $no_errors = true; "
      # when there's a begin;rescue;else;ensure;end statement,
      # ruby returns a result of the 'else' branch
      # but invokes it before 'ensure'.
      # so, here we
      # 1. save the result of calling else to $rescue_else_result
      # 2. call ensure
      # 2. return $rescue_else_result
      line "var $rescue_else_result;"
      line "if ($no_errors) { "
      indent do
        line "$rescue_else_result = (function() {"
        indent do
          line compiler.process(compiler.returns(scope.rescue_else_sexp), @level)
        end
        line "})();"
      end
      line "}"
      line compiler.process(ensr_sexp, @level)
      line "if ($no_errors) { return $rescue_else_result; }"
    else
      line compiler.process(ensr_sexp, @level)
    end
  end
  line "}"
  wrap '(function() { ', '; })()' if wrap_in_closure?
end

def ensr_sexp
  ensr || s(:nil)
end

def wrap_in_closure?
  recv? or expr? or has_rescue_else?
end