[Affiliations] Hide bad data and add metadata validation (#13131)

## Summary of the problem
<!-- Why are these changes being made? What problem does it solve? Link
any related issues to provide more details. -->

https://appsignal.com/hack-club/sites/6596247683eb67648f30f807/exceptions/incidents/2761
Our frontend validations seem to have been bypassed, and affiliations
with metadata `{}` were created.

## Describe your changes
<!-- Explain your thought process to the solution and provide a quick
summary of the changes. -->
- Adds a `nonempty` scope to `Event::Affiliation` to hide any existing
affiliations with empty metadata
- Adds a `metadata_contains_required_fields` validation to ensure that
all affiliation types have backend validations that match their frontend
validations

<!-- If there are any visual changes, please attach images, videos, or
gifs. -->

Author: polypixeldev

app/models/event/affiliation.rb

@@ -27,6 +27,9 @@ class Affiliation < ApplicationRecord
     store_accessor :metadata, :league, :team_number, :size, :venue_name
 
     scope :robotics, -> { where(name: %w[first vex]) }
+    scope :nonempty, -> { where.not(metadata: {}) }
+
+    validate :metadata_contains_required_fields
 
     def display_name
       case name
@@ -59,6 +62,26 @@ def to_s
       [display_name, league&.upcase, team_number, size&.positive? ? pluralize(size, "people") : nil].compact.join(" – ")
     end
 
+    private
+
+    def metadata_contains_required_fields
+      required_fields = case name
+                        when "first"
+                          ["league", "team_number", "size"]
+                        when "vex"
+                          ["league", "team_number", "size"]
+                        when "hack_club"
+                          ["venue_name", "size"]
+                        else
+                          return errors.add(:name, "is not a valid affiliation")
+                        end
+
+      missing_fields = required_fields.select { |field| metadata[field].nil? }
+      if missing_fields.any?
+        errors.add(:metadata, "is missing fields: #{missing_fields.to_sentence}")
+      end
+    end
+
   end
 
 end

app/views/event/applications/project_info.html.erb

@@ -143,7 +143,7 @@
     <% end %>
   </div>
 
-  <%= render partial: "events/settings/affiliation", collection: @application.affiliations %>
+  <%= render partial: "events/settings/affiliation", collection: @application.affiliations.nonempty %>
 <% end %>
 </div>
 

app/views/events/settings/_affiliations.html.erb

@@ -12,5 +12,5 @@
   <% unless event.affiliations.none? %>
     <h3 class="mb2"><%= possessive(event.name) %> affiliations</h3>
   <% end %>
-  <%= render partial: "events/settings/affiliation", collection: event.affiliations %>
+  <%= render partial: "events/settings/affiliation", collection: event.affiliations.nonempty %>
 <% end %>