module Byebug::Helpers::FrameHelper

def adjust_frame(new_frame)
  return frame_err('too_low') if new_frame >= context.stack_size
  return frame_err('too_high') if new_frame < 0
  context.frame = new_frame
  processor.prev_line = nil
end

def direction(step)
  step / step.abs
end

def frame_err(msg)
  errmsg(pr("frame.errors.#{msg}"))
end

def index_from_start(i)
  i >= 0 ? i : context.stack_size + i
end

def jump_frames(steps)
  adjust_frame(navigate_to_frame(steps))
end

def navigate_to_frame(jump_no)
  current_jumps = 0
  current_pos = context.frame.pos
  loop do
    current_pos += direction(jump_no)
    break if out_of_bounds?(current_pos)
    next if Frame.new(context, current_pos).c_frame?
    current_jumps += 1
    break if current_jumps == jump_no.abs
  end
  current_pos
end

def out_of_bounds?(pos)
  !(0...context.stack_size).cover?(pos)
end

def switch_to_frame(frame)
  new_frame = index_from_start(frame)
  return frame_err('c_frame') if Frame.new(context, new_frame).c_frame?
  adjust_frame(new_frame)
end