How can I scope created_at between two times and use said scope on an instance? - class

Question

I'm trying to create a scope, active, that queries for entries of a class, Shift, that are 5 hours old. I'm then trying to take the scope and apply it to an instance of Shift so I can have the shifts controller redirect to show the active shift. Here's shift.rb:
class Shift < ActiveRecord::Base
scope :active, -> { where(created_at: (Time.now.ago(5.hours)..Time.now)) }
validates :created_at, uniqueness: true
validates_time :created_at, :between => ['9:30pm', '2:30am']
validate :active_shift_limit
private
def active_shift_limit
if Shift.active.count >= 1
errors.add(:base, "Shift already exists for tonight")
end
end
end
First off, I'm having problems with the scope. I created a shift 8 hours ago and am querying for it in the console.
Shift.active.exists?
Shift Exists (0.2ms) SELECT 1 AS one FROM "shifts" WHERE ("shifts"."created_at" BETWEEN '2015-09-14 22:48:35.929658' AND '2015-09-15 03:48:35.929768') LIMIT 1
=> true
So I take a look at the entry.
Shift.active
Shift Load (0.2ms) SELECT "shifts".* FROM "shifts" WHERE ("shifts"."created_at" BETWEEN '2015-09-14 23:03:38.195154' AND '2015-09-15 04:03:38.195191')
=> #<ActiveRecord::Relation [#<Shift id: 32, shift_id: nil, vehicle_id: nil, user_id: nil, created_at: "2015-09-15 00:11:32", updated_at: "2015-09-15 00:11:32">]>
The scope is registering a range into tomorrow, I don't know why, so I try entering the range I've given the scope into the console to see if the problem is there:
Time.now.ago(5.hours)..Time.now
=> 2015-09-14 16:08:35 -0700..2015-09-14 21:08:35 -0700
Alright. At this point I'm stumped. Where am I going wrong?
As for the second part of the question, calling the scope on an instance of Shift, I'm also stumped. I've realized, after some tinkering, that scope is a class method. So I figured calling it on the method and putting that inside an instance variable would work. No cigar. I get this error:
ActiveRecord::RecordNotFound in ShiftsController#create
"Couldn't find Shift without an ID"
Here's my shifts_controller.rb:
class ShiftsController < ApplicationController
skip_before_filter :verify_authenticity_token, :only => :create
def show
#shift = Shift.find(params[:id])
end
def create
#active_shift = Shift.active
if Shift.active.exists?
redirect_to shift_path(#active_shift)
else
#shift = Shift.new
#shift.save
redirect_to shift_path(#shift)
end
end
end
I'm using this gem for validates_time in shift.rb:
gem 'jc-validates_timeliness', '~> 3.1.1'. I heavily referenced this in figuring out the scope: How do I validate one post per day?