Dealing with Recursive Models

User wants to search for classes nearby according to date similar to classpass

Backend

Form fields for creating class by admin::
1) Name
2) Start Date ( Class start date)
3) End Date
4) Recursive?

class Fpclass < ActiveRecord::Base
   after_create :build_ice_cube_params
   has_many :recursivedates

 private
  # This method is used to push dates between start date to end date (weekly) to recursivedates
  def build_ice_cube_params
            search_dates.each do |date|
        recursivedates << Recursivedate.create(:ondate => date)
     end
     end
end

Frontend ref

Implemented search using Ransack

class FiltersController < ApplicationController
  def search
    @c = Fpclass.ransack(params[:q])  # params[:q][:recursivedates_ondate_eq]
    @fpclasses = @c.result(distinct: true)
  end
end

Example how it'll work

1) Admin creates class that'll held on every sunday until 2 months using (start date and end date )
2) Fpclass saves all data (name, startdate, enddate etc.,) and creates recursivedates (Between dates like 1st of july, 8th july, 15th july ....)
3) Getting fpclasses at search page using ransack on (recursivedates model)

Problems i've facing
1) When admin edits form then all fresh dates dumped into recursivedates model along with old ones
2) When admin gives longer dates(from 2015 to 2020) (Sql insertions are more)
3) Searching kills time
4) Hard to implement conditions at Reserve button as shown in ref image

Can there be any alternative approach or can you let me know if any mistakes i've done ?

Recurring events get complicated quickly! :)

You may need to do a find_or_create for all the recursivedates when you do an edit. It also might be easier to delete all the existing ones before adding the new dates. That will save you some trouble. I'd take a look at how Google Calendar does it and work backwards from there if you like the way it works.

I think they may calculate on the fly the recurring ones so they don't have to insert records for X years into the future and your calendar will always work. They probably separate individual dates and recurring ones and query for both each time the page renders.