I’ve using a calendar gem that uses start_time for the date (YYYY-MM-DD).

For example purposes I’ve got Meeting, which has start_time string and postponed boolean attributes.

@meeting.start_time must be at least one day in the future (the day after today), but you can’t set a new start_time (Meeting Date) if @meeting.postponed, only if @meeting.postponed == false

I would like validations so when updating the Meeting (if @meeting was previously postponed), I want to unselect the @meeting.postponed checkbox and submit a new @meeting.start_date in the form, and have it pass in the same submission.

if in the controller, something like:

@meeting.attributes = meeting_params

if @meeting.start_time != ""
  if @meeting.start_time_changed?
    if @meeting.posteponed
      @error = "Can't change the Meeting Date if the Meeting is still postponed."
    else
      if @meeting.start_time.to_date <= Date.today
        @error = "Meeting must be at least one day in the future."
      end
    end
  end
else
  @error = "Meeting Date cannot be blank."
end

How can I do this with validations?