Task 3

.gitignore

@@ -2,3 +2,4 @@
 /tmp
 /log
 /public
+/profile

.rspec

@@ -0,0 +1 @@
+--require spec_helper

Gemfile

@@ -9,6 +9,21 @@ gem 'puma'
 gem 'listen'
 gem 'bootsnap'
 gem 'rack-mini-profiler'
+gem 'rubocop', require: false
+gem 'pghero'
+gem 'benchmark'
+gem 'ruby-prof'
+gem 'stackprof'
+gem 'oj'
+gem 'strong_migrations'
+
+group :development, :test do
+  gem 'rspec-rails', '~> 7.1.1'
+  gem 'factory_bot_rails', '~> 6.4.4'
+  gem 'rails-controller-testing'
+  gem 'rspec-rake'
+  gem 'rspec-benchmark'
+end
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

Gemfile.lock

@@ -72,8 +72,12 @@ GEM
       securerandom (>= 0.3)
       tzinfo (~> 2.0, >= 2.0.5)
       uri (>= 0.13.1)
+    ast (2.4.2)
     base64 (0.2.0)
     benchmark (0.4.0)
+    benchmark-malloc (0.2.0)
+    benchmark-perf (0.6.0)
+    benchmark-trend (0.4.0)
     bigdecimal (3.1.9)
     bootsnap (1.18.4)
       msgpack (~> 1.2)
@@ -82,8 +86,14 @@ GEM
     connection_pool (2.5.0)
     crass (1.0.6)
     date (3.4.1)
+    diff-lcs (1.6.0)
     drb (2.2.1)
     erubi (1.13.1)
+    factory_bot (6.5.1)
+      activesupport (>= 6.1.0)
+    factory_bot_rails (6.4.4)
+      factory_bot (~> 6.5)
+      railties (>= 5.0.0)
     ffi (1.17.1-arm64-darwin)
     globalid (1.2.1)
       activesupport (>= 6.1)
@@ -94,6 +104,9 @@ GEM
       pp (>= 0.6.0)
       rdoc (>= 4.0.0)
       reline (>= 0.4.2)
+    json (2.10.1)
+    language_server-protocol (3.17.0.4)
+    lint_roller (1.1.0)
     listen (3.9.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
@@ -122,7 +135,17 @@ GEM
     nio4r (2.7.4)
     nokogiri (1.18.2-arm64-darwin)
       racc (~> 1.4)
+    oj (3.16.9)
+      bigdecimal (>= 3.0)
+      ostruct (>= 0.2)
+    ostruct (0.6.1)
+    parallel (1.26.3)
+    parser (3.3.7.1)
+      ast (~> 2.4.1)
+      racc
     pg (1.5.9)
+    pghero (3.6.1)
+      activerecord (>= 6.1)
     pp (0.6.2)
       prettyprint
     prettyprint (0.2.0)
@@ -156,6 +179,10 @@ GEM
       activesupport (= 8.0.1)
       bundler (>= 1.15.0)
       railties (= 8.0.1)
+    rails-controller-testing (1.0.5)
+      actionpack (>= 5.0.1.rc1)
+      actionview (>= 5.0.1.rc1)
+      activesupport (>= 5.0.1.rc1)
     rails-dom-testing (2.2.0)
       activesupport (>= 5.0.0)
       minitest
@@ -171,20 +198,72 @@ GEM
       rake (>= 12.2)
       thor (~> 1.0, >= 1.2.2)
       zeitwerk (~> 2.6)
+    rainbow (3.1.1)
     rake (13.2.1)
     rb-fsevent (0.11.2)
     rb-inotify (0.11.1)
       ffi (~> 1.0)
     rdoc (6.12.0)
       psych (>= 4.0.0)
+    regexp_parser (2.10.0)
     reline (0.6.0)
       io-console (~> 0.5)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-benchmark (0.6.0)
+      benchmark-malloc (~> 0.2)
+      benchmark-perf (~> 0.6)
+      benchmark-trend (~> 0.4)
+      rspec (>= 3.0)
+    rspec-core (3.13.3)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.3)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.2)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-rails (7.1.1)
+      actionpack (>= 7.0)
+      activesupport (>= 7.0)
+      railties (>= 7.0)
+      rspec-core (~> 3.13)
+      rspec-expectations (~> 3.13)
+      rspec-mocks (~> 3.13)
+      rspec-support (~> 3.13)
+    rspec-rake (0.0.4)
+      rake
+      rspec-core
+    rspec-support (3.13.2)
+    rubocop (1.72.1)
+      json (~> 2.3)
+      language_server-protocol (~> 3.17.0.2)
+      lint_roller (~> 1.1.0)
+      parallel (~> 1.10)
+      parser (>= 3.3.0.2)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 2.9.3, < 3.0)
+      rubocop-ast (>= 1.38.0, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 2.4.0, < 4.0)
+    rubocop-ast (1.38.0)
+      parser (>= 3.3.1.0)
+    ruby-prof (1.7.1)
+    ruby-progressbar (1.13.0)
     securerandom (0.4.1)
+    stackprof (0.2.27)
     stringio (3.1.2)
+    strong_migrations (2.2.0)
+      activerecord (>= 7)
     thor (1.3.2)
     timeout (0.4.3)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
+    unicode-display_width (3.1.4)
+      unicode-emoji (~> 4.0, >= 4.0.4)
+    unicode-emoji (4.0.4)
     uri (1.0.2)
     useragent (0.16.11)
     websocket-driver (0.7.7)
@@ -194,15 +273,28 @@ GEM
     zeitwerk (2.7.1)
 
 PLATFORMS
+  arm64-darwin-21
   arm64-darwin-24
 
 DEPENDENCIES
+  benchmark
   bootsnap
+  factory_bot_rails (~> 6.4.4)
   listen
+  oj
   pg
+  pghero
   puma
   rack-mini-profiler
   rails (~> 8.0.1)
+  rails-controller-testing
+  rspec-benchmark
+  rspec-rails (~> 7.1.1)
+  rspec-rake
+  rubocop
+  ruby-prof
+  stackprof
+  strong_migrations
   tzinfo-data
 
 RUBY VERSION

app/controllers/trips_controller.rb

@@ -1,7 +1,23 @@
 class TripsController < ApplicationController
+  before_action :set_pagination_params, :set_cities, only: :index
+
   def index
+    @total_count = Trip.where(from: @from, to: @to).count
+    @trips = Trip.where(from: @from, to: @to)
+                 .order(:start_time)
+                 .limit(@per).offset(@per * (@page - 1))
+                 .preload(bus: [:services])
+  end
+
+  private
+
+  def set_pagination_params
+    @page = params[:page].present? ? params[:page].to_i : 1
+    @per = params[:per].present? ? params[:per].to_i : 100
+  end
+
+  def set_cities
     @from = City.find_by_name!(params[:from])
     @to = City.find_by_name!(params[:to])
-    @trips = Trip.where(from: @from, to: @to).order(:start_time)
   end
 end

app/models/bus.rb

@@ -13,7 +13,8 @@ class Bus < ApplicationRecord
   ].freeze
 
   has_many :trips
-  has_and_belongs_to_many :services, join_table: :buses_services
+  has_many :buses_services
+  has_many :services, through: :buses_services
 
   validates :number, presence: true, uniqueness: true
   validates :model, inclusion: { in: MODELS }

app/models/buses_service.rb

@@ -0,0 +1,4 @@
+class BusesService < ApplicationRecord
+  belongs_to :bus
+  belongs_to :service
+end

app/models/service.rb

@@ -12,7 +12,8 @@ class Service < ApplicationRecord
     'Можно не печатать билет',
   ].freeze
 
-  has_and_belongs_to_many :buses, join_table: :buses_services
+  has_many :buses_services
+  has_many :buses, through: :buses_services
 
   validates :name, presence: true
   validates :name, inclusion: { in: SERVICES }

app/services/data_loader.rb

@@ -0,0 +1,105 @@
+# frozen_string_literal: true
+
+class DataLoader
+  TRIPS_COMMAND =
+    "copy trips (from_id, to_id, start_time, duration_minutes, price_cents, bus_id) from stdin with csv delimiter ';'"
+  CITIES_COMMAND = "copy cities (id, name) from stdin with csv delimiter ';'"
+  BUSES_COMMAND = "copy buses (id, number, model) from stdin with csv delimiter ';'"
+  SERVICES_COMMAND = "copy services (id, name) from stdin with csv delimiter ';'"
+  BUSES_SERVICES_COMMAND = "copy buses_services (bus_id, service_id) from stdin with csv delimiter ';'"
+
+  def self.load(filename)
+    new(filename).load
+  end
+
+  def initialize(filename)
+    @stream = JsonStreamer.stream(filename)
+    @cities = {}
+    @services = {}
+    @buses = {}
+    @buses_services = []
+  end
+
+  def load
+    ActiveRecord::Base.transaction do
+      clean_database
+      connection = ActiveRecord::Base.connection.raw_connection
+
+      ActiveRecord::Base.connection.raw_connection.copy_data TRIPS_COMMAND do
+        stream.each do |trip|
+          from = city(trip['from'])
+          to = city(trip['to'])
+
+          if buses[trip['bus']['number']].nil?
+            bus_services = []
+            trip['bus']['services'].each do |name|
+              bus_services << service(name)
+            end
+
+            create_bus(trip['bus']['number'], trip['bus']['model'])
+            create_bus_services(buses[trip['bus']['number']], bus_services)
+          end
+
+          bus = buses[trip['bus']['number']]
+
+          connection.put_copy_data("#{from[:id]};#{to[:id]};#{trip['start_time']};#{trip['duration_minutes']};#{trip['price_cents']};#{bus[:id]}\n")
+        end
+      end
+
+      ActiveRecord::Base.connection.raw_connection.copy_data CITIES_COMMAND do
+        cities.each do |name, attrs|
+          connection.put_copy_data("#{attrs[:id]};#{name}\n")
+        end
+      end
+
+      ActiveRecord::Base.connection.raw_connection.copy_data BUSES_COMMAND do
+        buses.each do |number, attrs|
+          connection.put_copy_data("#{attrs[:id]};#{number};#{attrs[:model]}\n")
+        end
+      end
+
+      ActiveRecord::Base.connection.raw_connection.copy_data SERVICES_COMMAND do
+        services.each do |name, attrs|
+          connection.put_copy_data("#{attrs[:id]};#{name}\n")
+        end
+      end
+
+      ActiveRecord::Base.connection.raw_connection.copy_data BUSES_SERVICES_COMMAND do
+        buses_services.each do |bus_id, service_id|
+          connection.put_copy_data("#{bus_id};#{service_id}\n")
+        end
+      end
+    end
+  end
+
+  private
+
+  attr_reader :stream
+  attr_accessor :cities, :services, :buses, :buses_services
+
+  def clean_database
+    City.delete_all
+    Bus.delete_all
+    Service.delete_all
+    Trip.delete_all
+    ActiveRecord::Base.connection.execute('delete from buses_services;')
+  end
+
+  def city(name)
+    cities[name] ||= { id: cities.size + 1 }
+  end
+
+  def service(name)
+    services[name] ||= { id: services.size + 1 }
+  end
+
+  def create_bus(number, model)
+    buses[number] = { id: buses.size + 1, model: }
+  end
+
+  def create_bus_services(bus, services)
+    services.map do |service|
+      @buses_services << [bus[:id], service[:id]]
+    end
+  end
+end

app/services/json_streamer.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+class JsonStreamer
+  def self.stream(filename)
+    new(filename).stream
+  end
+
+  def initialize(filename)
+    @file = File.open(filename, 'r:UTF-8')
+  end
+
+  def stream
+    Enumerator.new do |yielder|
+      loop do
+        yielder << Oj.load(object)
+      rescue Oj::ParseError, TypeError => _e
+        break
+      end
+    end
+  end
+
+  private
+
+  attr_reader :file
+
+  def object
+    nesting = 0
+    str = +''
+
+    while nesting > 0 || str.empty?
+      ch = file.getc
+
+      return if file.eof?
+
+      nesting += 1 if ch == '{'
+      str << ch if nesting >= 1
+      nesting -= 1 if ch == '}'
+
+      str
+    end
+
+    str
+  end
+end