So right now I'm displaying an TrainingEvents Index page that contains all events for every location. What I'm trying to do is create an TrainingEvents Index page just for that specific region.

My models look like:

class TrainingEvents
 belongs_to :location, optional: true

class Locations
 belongs_to :region, optional: true
 belongs_to :user, optional: true
 has_many :careers, dependent: :destroy
 has_many :training_events, dependent: :destroy

class Regions
 has_many :locations, dependent: :destroy
 has_many :zipcodes, dependent: :destroy
 has_many :careers, through: :locations
 has_many :training_events, through: :locations
 has_and_belongs_to_many :logos
 has_and_belongs_to_many :employees

My TrainingEventsController looks like:

class TrainingEventsController < ApplicationController
 respond_to :json, :html
 before_action :filter_time

 def index
 @events = TrainingEvent.by_month(@time.month).ascending
 @events = @events.by_state(params[:state]) if params[:state].present?
 @events = @events.by_city(params[:city]) if params[:city].present?
 end

 def show
 @event = TrainingEvent.find_by!(url_name: params[:id])
 add_breadcrumb 'Home', root_path
 add_breadcrumb 'Training & Events', training_events_path
 add_breadcrumb @event.name
 end

 def region_index
 @events = TrainingEvent.by_month(@time.month).ascending
 end

 private

 def filter_time
 @time = if params[:month].present?
 params[:month].to_datetime
 else
 Time.zone.now
 end
 end
end

The thought here was to create a separate method, region_index, to then pass along the new route. So in my Region's show page I have the following:

<%= link_to 'View Region', region_index_path(@region) %>

The link goes to the correct page but loading the data is where I'm stuck. Here's the view (in Slim):

= content_for :body do
 .container.banner-container
 .row.mt-4
 .col-sm-12
 = link_to 'Training Policies', '/training_policies', class: 'custom-button float-right'
 = form_tag :training_events, method: :get, id: 'filter-form' do
 .row.event-filter.align-items-center
 .col-lg-7.col-md-5
 = hidden_field_tag :month, params[:month]
 .month-selector
 = fa_icon 'chevron-left', data: month: @time.last_month 
 h3 #@time.strftime('%B %Y')
 = fa_icon 'chevron-right', data: month: @time.next_month 
 .col-lg-5.col-md-3.filter-select
 =link_to 'View All Trainings', training_events_path, class: 'custom-button float-right'
 - (@time.beginning_of_month.to_date..@time.end_of_month.to_date).each do |date|
 - events = @events.select event.time_start.to_date == date 
 - if events.count.positive?
 .row
 .col-sm-12
 .event-header
 span.date #date.strftime('%d')
 span #date.strftime('%A')
 - events.each do |event|
 .row.event-row
 .col-sm-8
 label.event-title #event.name
 .event-col-details
 - if event.time_start.present? && event.time_end.present?
 = fa_icon 'clock-o'
 p #event.time_start.strftime('%l:%M %p') - #event.time_end.strftime('%l:%M %p')
 - if event.street_address.present?
 = fa_icon 'map-marker'
 p #event.street_address
 - if event.city.present? && event.state.present?
 = fa_icon 'map-marker'
 p #event.city, #event.state
 .col-sm-4.details-cont
 = link_to 'view details', training_event_path(event.url_name)
 .row
 .col-sm-12
 .border

I know I need to hit @events.select and probably hit the locations then regions but I'm hitting my head on the wall. I've tried various methods of doing @events.locations.select, which gets a NoMethodError, or even an @events.regions.select, which gets the same.

So how do I pull in the through relationship and display only those results?

Edit:
I've also tried throwing into my TrainingEvents a scope thinking I might be able to query out the location id matching to the region.location_id with the following:

scope :region_index, -> where(location_id: region.location_id)

I end up with

undefined local variable or method `region' for

Did you mean? relation

region is not defined in your scope's context. I see you are already familiar with scopes using variables, looks like you only forgot that detail and needed fresh eyes.

scope :region_index, -> (region) where(location_id: region.location_id)