Building an order booking system in Rails

I want to create a mail-order booking application with the following characteristics: - Users can be service providers or buyers - Service providers set their capabilities (but can only set their capabilities 6 months in advance) - Buyers can then book appointments based on these capabilities - each meeting based on type of service takes a different amount of time - Based on the appointment the buyer chooses, a different set of options is displayed depending on how long the service takes

What I have created is the following: - A model TimeSlot

where I create some generic 30 minute time slots based on the start_time

and attributes end_time

. To make these time slots 6 months in the future, I have a background job running every day that creates all the new time slots needed

class TimeSlot < ActiveRecord::Base
  has_many :user_time_slots
  # ... more methods below
end

      

        
        
        
      

    

- A UserTimeSlots

, which basically represents the service provider's availability that they can establish. So when they create user_time_slot, they essentially say they are available at that time.

class UserTimeSlot < ActiveRecord::Base 
    belongs_to :time_slot
    belongs_to :service_provider, :class_name => "User"
    belongs_to :appointment
end

      

        
        
        
      

    

- A model Appointment

that has many user_time_slots. It has a lot because the assignment belongs to a service that takes a certain amount of time (attribute time_required

for services) and it can span the number of consecutive user_time_slots.

class Appointment < ActiveRecord::Base
  has_many :user_time_slots
  belongs_to :buyer, :class_name => "User"
  belongs_to :service_provider, :class_name => "User"
  belongs_to :service
end

      

        
        
        
      

    

- A Service

, which has multiple purposes and belongs to the service provider who creates this service.

class Service < ActiveRecord::Base
  has_many :appointments
  belongs_to :service_provider, :class_name => "User"
end

      

        
        
        
      

    

This domain model works; however I am wondering if there is a better way to do this because of the following:

• It seems a bit uncomfortable for me to create TimeSlot entries every day on my backend using background work - TimeSlots really have a single purpose - to have start and end times and then be associated with.

  • Once the user (buyer) selects the service they want, I do not know how I could efficiently find x the number of consecutive and long users, and therefore available to book an appointment (for example, if I have 30 minutes time slots and the user selects an appointment which will take 3 hours, I will need to find 6 consecutive time slots). For example, if a user clicks on an instance of a service, I would need to 1) get the time it takes for that service (easy enough to do) and 2) I would need to find ALL of the user's user_time_slots and collect their associated time_slots and then compare each start time and the end of the time interval with each other to find consecutive. It just looks like too many iterations for me and it looks likethat it will swallow my application!

Does anyone have a better way or solution to do this (especially around the topic of finding consecutive timeslots)?