rails_exercise.rb

# Background:
#after full refactor of the provided code to make it more efficient I added comments to improve readability. 
#I'll also address your questions about the 'distinct_groups' variable and what it contains.



start_range = Date.today.beginning_of_month
end_range = Date.today.end_of_month

# Fetch users with the given role efficiently using the database query.
users = User.where(role: role)

employers = []
partners = []
controller_resources = []

distinct_groups = {}

# Iterate through users.
users.each do |user|
  times = []
  last_time = nil
  user_name = nil

  # Fetch user events within the specified date range.
  user_events_filtered = user.user_events.where(created_at: start_range..end_range).order(:created_at).to_a

  # Iterate through filtered user events.
  user_events_filtered.each do |event|
    user_name ||= event.user_name
    last_known_session = event.last_known_session
    controller_params = event.data["params"]

    if last_known_session.present?
      employers << last_known_session["employer"]
      partners << last_known_session["partner"]
    end

    controller_resources << controller_params["controller"]

    # Calculate time intervals between events.
    if last_time.nil? || last_time + 10.minutes < event.created_at
      times << 0
    else
      times << event.created_at - last_time
    end

    last_time = event.created_at
  end

  # Calculate the sum of time intervals for this user.
  sum = times.sum
  distinct_groups[user_name] = sum
end

# 2. Please explain what the variable 'distinct_groups' will contain by the end of the execution and what
#    this data would be useful for.

# The 'distinct_groups' variable is a hash where the keys are user names, and the values are the total time intervals
# spent between their user events within the specified date range. It will contains information about how much time each
# user has spent interacting with the system during the specified time period. This data can be useful for various
# analytics and reporting purposes, such as identifying which users are the most active or which areas of the
# application are getting the most user engagement.