RoR interview themes and examples

ror interview.txt

theory
  OOP

  ruby
    inheritance
    classes
    modules
    objects
    private/public/protected
    super
    common methods
    meta
    

  rails
    model
    view
    controller
    routes
    middleware
    rack
    arel
    method_missing?
    hdtm
    polymorph
    delegate
    

  debugging
    pry
    bybug
    ide?
  problem solving
    way to solve(instruments, questions)


  db
    sql
      mysql
      postgresql
      sqlite
    explain
    mongodb
    indexes
    STI
    view
    
  tdd/bdd
    rspec/minitest
    Faker
    FactoryBot
    database cleaner
    capybara
    cucumber
    

  other
    SOA/SOP
    sidekiq/rescue
    http
    cors
    local storages
    cookies
    session
    tokens
    ssl

  small talk
    monkey patch?
    fat model or controller
    rails way
    follow famous
    pet projects
    keira knightley or natalie portman?

practice
  refactor model
  inject 
  sql query 
  
  
class Appointment < ApplicationRecord

  scope :pending, -> { where(status: APPOINTMENT_STATUS[0]) }
  scope :rescheduled, -> { where(status: APPOINTMENT_STATUS[3]) }
  scope :canceled, -> { where(status: APPOINTMENT_STATUS[2]) }
  scope :confirmed, -> { where(status: APPOINTMENT_STATUS[1]) }

  belongs_to :offer
  belongs_to :stylist
  belongs_to :user

  validates :user_id, presence: true
  validates :offer_id, presence: true
  validates_uniqueness_of :time, scope: [:offer_id, :date], conditions: -> { where.not(status: [APPOINTMENT_STATUS[2], APPOINTMENT_STATUS[3]]) }, if: Proc.new { |a| a.date and a.time }

  before_validation :appointment_date_time
  before_create :add_initial_call_status
  after_create :alert_on_appointment_creation
  before_update :status_change_alert
  after_create :generate_barcode
  before_update :refund_if_cancelled_by_s_or_a

  def appointment_date_time
    if self.date_time.present?
      self.date = self.date_time.to_date
      self.time = self.date_time.to_time.strftime("%H:%M")
    end
  end

  def add_initial_call_status
    self.call_status = 'not called'
  end

  def toggle_call_status
    if self.call_status == 'not called'
      self.call_status = 'called'
    elsif self.call_status == 'called'
      self.call_status = 'no answer'
    elsif self.call_status == 'no answer'
      self.call_status = 'not called'
    else
      self.call_status = 'not called'
    end
    self.save
  end

  def refund_if_cancelled_by_s_or_a
    if self.cancelled_by_admin?
      self.allow_refund = true
    end
  end

  #notifications about appointment state [pending, confirmed, cancelled, rescheduled]
  def alert_on_appointment_creation
    if self.status == APPOINTMENT_STATUS[0] and !self.date.blank?
      user = User.find(self.user_id) if !self.is_private?
      if user.present?
        msg = I18n.t('pending_status_alert', locale: 'ur')

        if self.date and self.time
          msg = msg.gsub('stylist', ("#{self.stylist.translations.last.title.present? ? self.stylist.translations.last.title+' ': nil}#{self.stylist.translations.last.name}")).gsub('dd', self.date.strftime("%d-%m-%Y")).gsub('tt', self.time.strftime("%l:%M %p"))
        else
          msg = msg.gsub('stylist', ("#{self.stylist.translations.last.title.present? ? self.stylist.translations.last.title+' ': nil}#{self.stylist.translations.last.name}")).gsub('dd', '').gsub('tt', '')
        end

        user.user_devices.each do |user_device|
          device_id = user_device.device_id
          Notification.send_appointment_status_change_notification(msg,1, device_id)
        end
      end
    end
  end

  def status_change_alert
    appointment = Appointment.find(self.id) if self.persisted?
    user = User.find(self.user_id) if !self.is_private?
    if appointment && (appointment.status != self.status) && user.present?
      if self.status == APPOINTMENT_STATUS[1] # confirmed

        msg = I18n.t('confirm_status_alert', locale: 'ur')
        if self.date and self.time
          msg = msg.gsub('stylist', ("#{self.stylist.translations.last.title.present? ? self.stylist.translations.last.title+' ': nil}#{self.stylist.translations.last.name}")).gsub('dd', self.date.strftime("%d-%m-%Y")).gsub('tt', self.time.strftime("%l:%M %p"))
        else
          msg = msg.gsub('stylist', ("#{self.stylist.translations.last.title.present? ? self.stylist.translations.last.title+' ': nil}#{self.stylist.translations.last.name}")).gsub('dd', '').gsub('tt', '')
        end

        user.user_devices.each do |user_device|
          device_id = user_device.device_id
          key = 1
          if appointment.offer_id and !appointment.offer_id.blank?
            key = appointment.offer_id
          end
          Notification.send_appointment_status_change_notification(msg,key, device_id)
        end

      elsif self.status == APPOINTMENT_STATUS[2] # canceled
        msg = I18n.t('cancel_status_alert', locale: 'ur')

        if self.date and self.time
          msg = msg.gsub('stylist', ("#{self.stylist.translations.last.title.present? ? self.stylist.translations.last.title+' ': nil}#{self.stylist.translations.last.name}")).gsub('dd', self.date.strftime("%d-%m-%Y")).gsub('tt', self.time.strftime("%l:%M %p"))
        else
          msg = msg.gsub('stylist', ("#{self.stylist.translations.last.title.present? ? self.stylist.translations.last.title+' ': nil}#{self.stylist.translations.last.name}")).gsub('dd', '').gsub('tt', '')
        end


        user.user_devices.each do |user_device|
          device_id = user_device.device_id
          Notification.send_appointment_status_change_notification(msg,1, device_id)
        end
      elsif self.status == APPOINTMENT_STATUS[3] #rescheduled
        if self.date and self.time
          msg = I18n.t('reschedule_status_alert', locale: 'ur')

          if self.date and self.time
            msg = msg.gsub('stylist', ("#{self.stylist.translations.last.title.present? ? self.stylist.translations.last.title+' ': nil}#{self.stylist.translations.last.name}")).gsub('dd', self.date.strftime("%d-%m-%Y")).gsub('tt', self.time.strftime("%l:%M %p"))
          else
            msg = msg.gsub('stylist', ("#{self.stylist.translations.last.title.present? ? self.stylist.translations.last.title+' ': nil}#{self.stylist.translations.last.name}")).gsub('dd', '').gsub('tt', '')
          end

          user.user_devices.each do |user_device|
            device_id = user_device.device_id
            Notification.send_appointment_status_change_notification(msg,1, device_id)
          end
        end
      end
      self.status_changed_at = Time.now
    end
  end

  #alert methods: reminding user about appointments
  def self.appointment_alerts
    curr_time = Time.now.in_time_zone("Asia/Karachi")
    curr_time_1_hour = (curr_time + 1.hours).strftime("2000-01-01 %H:%M:00")
    curr_time_12_hour = (curr_time + 2.hours).strftime("2000-01-01 %H:%M:00")
    curr_time_24_hour = (curr_time + 24.hours).strftime("2000-01-01 %H:%M:00")
    user_ids = Appointment.includes(:user).where("is_alert= ? AND time >= ? AND date >= ?  AND status = ?", true, curr_time, Time.now.in_time_zone("Asia/Karachi").to_date, 'confirmed' ).collect{|app| [app.user_id]}
    user_ids.each do |id|
      user = User.find_by(id: id)
      if user.present? && user.alert_setting.present? && user.alert_setting.is_alert_1_hour?
        send_user_appointment_alert(user, curr_time_1_hour, 1 )
      end
      if user.present? && user.alert_setting.present? && user.alert_setting.is_alert_12_hour?
        send_user_appointment_alert(user, curr_time_12_hour, 12)
      end
      if user.present? && user.alert_setting.present? && user.alert_setting.is_alert_24_hour?
        send_user_appointment_alert(user, curr_time_24_hour, 24)
      end
    end
  end

  def self.send_user_appointment_alert(user, alert_time, alert_type)

    if alert_type == 1
      appointments = user.appointments.where("is_alert= ? AND time = ? AND date = ? AND status = ? AND is_1_hour = ?", true, alert_time , Time.now.in_time_zone("Asia/Karachi").to_date, 'confirmed', false ).collect{|app| [app.id]}
      appointments.each do |appointment_id|
        appointment = Appointment.find_by(id: appointment_id)
        send_appointment(user, appointment)
        appointment.update(is_1_hour: true)
      end
    elsif alert_type == 12
      appointments = user.appointments.where("is_alert= ? AND time = ? AND date = ? AND status = ? AND is_12_hour = ?", true, alert_time , Time.now.in_time_zone("Asia/Karachi").to_date, 'confirmed', false ).collect{|app| [app.id]}
      appointments.each do |appointment_id|
        appointment = Appointment.find_by(id: appointment_id)
        send_appointment(user, appointment)
        appointment.update(is_12_hour: true)
      end
    elsif alert_type == 24
      appointments = user.appointments.where("is_alert= ? AND time = ? AND date = ? AND status = ? AND is_24_hour = ?", true, alert_time , Time.now.in_time_zone("Asia/Karachi").to_date, 'confirmed', false ).collect{|app| [app.id]}
      appointments.each do |appointment_id|
        appointment = Appointment.find_by(id: appointment_id)
        send_appointment(user, appointment)
        appointment.update(is_24_hour: true)
      end
    end

  end

  def self.send_appointment(user, appointment)

    msg = "You have an appointment with  #{appointment.stylist.translations.first.title+' '+ appointment.stylist.translations.first.name}"
    msg = msg+" at #{appointment.time.strftime("%H:%M")} on #{appointment.date}" if appointment.date and appointment.time
    user.user_devices.each do |user_device|
      device_id = user_device.device_id
      key = 1
      if appointment.offer_id and !appointment.offer_id.blank?
        key = appointment.offer_id
      end
      Notification.send_appointment_alerts(msg, key, device_id)
    end

  end

  #get barcode for receipt
  def generate_barcode
    #require 'barby'
    require 'barby/barcode/code_128'
    require 'barby/outputter/png_outputter'

    dir = File.dirname(Rails.root.join('/path_to_folder/create.log'))
    FileUtils.mkdir_p(dir) unless File.directory?(dir)

    barcode = Barby::Code128B.new('appointment'+self.id.to_s)
    blob = Barby::PngOutputter.new(barcode).to_png #Raw PNG data
    File.open(Rails.root.join('/path_to_folder/'+self.id.to_s+'.png'), 'wb'){|f| f.write blob }
  end

  def get_barcode
    barcode = Rails.root.join('public/barcodes/appointments/a'+self.id.to_s+'.png')
    barcode_out = '/path_to_folder/'+self.id.to_s+'.png'
    unless File.exists? barcode
      self.generate_barcode
    end
    barcode_out
  end

end