Add stats endpoint

Gemfile

@@ -20,3 +20,5 @@ group :development, :test do
 end
 
 gem "faraday", "~> 2.14"
+
+gem "jbuilder", "~> 2.14"

Gemfile.lock

@@ -102,6 +102,9 @@ GEM
       pp (>= 0.6.0)
       rdoc (>= 4.0.0)
       reline (>= 0.4.2)
+    jbuilder (2.14.1)
+      actionview (>= 7.0.0)
+      activesupport (>= 7.0.0)
     json (2.15.1)
     logger (1.7.0)
     loofah (2.24.1)
@@ -252,6 +255,7 @@ PLATFORMS
 DEPENDENCIES
   debug
   faraday (~> 2.14)
+  jbuilder (~> 2.14)
   puma (>= 5.0)
   rails (~> 8.0.3)
   rspec-rails (~> 8.0)

app/controllers/api/v1/stats_controller.rb

@@ -0,0 +1,9 @@
+module Api::V1
+  class StatsController < BaseController
+    def index
+      @park_count = Park.count
+      @alert_count = Alert.count
+      @park_with_most_alerts = Alert.group(:park_code).count.max
+    end
+  end
+end

app/views/api/v1/stats/index.json.jbuilder

@@ -0,0 +1,6 @@
+json.park_count @park_count
+json.alert_count @alert_count
+json.most_alerts do
+  json.park_code @park_with_most_alerts[0]
+  json.alert_count @park_with_most_alerts[1]
+end

config/routes.rb

@@ -1,9 +1,10 @@
 Rails.application.routes.draw do
   namespace :api do
-    namespace :v1 do
+    namespace :v1, defaults: { format: :json } do
       resources :parks, only: %i[index show], param: :code do
         resources :alerts, only: %i[index], module: :parks
       end
+      resources :stats, only: %i[index]
     end
   end
   # Define your application routes per the DSL in https://guides.rubyonrails.org/routing.html

spec/requests/api/v1/stats_spec.rb

@@ -0,0 +1,21 @@
+require 'rails_helper'
+
+RSpec.describe "Api::V1::Stats", type: :request do
+  describe "GET /stats" do
+    it "returns summary stats" do
+      alerts(:two).update!(park_code: parks(:one).code)
+
+      get api_v1_stats_url
+
+      expect(response).to have_http_status(:success)
+      expect(response.parsed_body).to match(
+        park_count: 2,
+        alert_count: 2,
+        most_alerts: {
+          park_code: "crla",
+          alert_count: 2
+        }
+      )
+    end
+  end
+end