98 lines
3.1 KiB
Ruby
98 lines
3.1 KiB
Ruby
class EmailDigestArticleCollector
|
|
include Instrumentation
|
|
|
|
ARTICLES_TO_SEND = "EmailDigestArticleCollector#articles_to_send".freeze
|
|
|
|
def initialize(user)
|
|
@user = user
|
|
end
|
|
|
|
def articles_to_send
|
|
# rubocop:disable Metrics/BlockLength
|
|
instrument ARTICLES_TO_SEND, tags: { user_id: @user.id } do
|
|
return [] unless should_receive_email?
|
|
|
|
articles = if user_has_followings?
|
|
experience_level_rating = (@user.experience_level || 5)
|
|
experience_level_rating_min = experience_level_rating - 3.6
|
|
experience_level_rating_max = experience_level_rating + 3.6
|
|
|
|
@user.followed_articles
|
|
.select(:title, :description, :path)
|
|
.published
|
|
.where("published_at > ?", cutoff_date)
|
|
.where(email_digest_eligible: true)
|
|
.where.not(user_id: @user.id)
|
|
.where("score > ?", 12)
|
|
.where("experience_level_rating > ? AND experience_level_rating < ?",
|
|
experience_level_rating_min, experience_level_rating_max)
|
|
.order(score: :desc)
|
|
.limit(6)
|
|
else
|
|
Article.select(:title, :description, :path)
|
|
.published
|
|
.where("published_at > ?", cutoff_date)
|
|
.where(featured: true, email_digest_eligible: true)
|
|
.where.not(user_id: @user.id)
|
|
.where("score > ?", 25)
|
|
.order(score: :desc)
|
|
.limit(6)
|
|
end
|
|
|
|
articles.length < 3 ? [] : articles
|
|
end
|
|
# rubocop:enable Metrics/BlockLength
|
|
end
|
|
|
|
private
|
|
|
|
def should_receive_email?
|
|
return true unless last_email_sent_at
|
|
|
|
# Has it been at least x days since @user received an email?
|
|
Time.current - last_email_sent_at >= days_until_next_email
|
|
end
|
|
|
|
def days_until_next_email
|
|
# Relies on hyperbolic tangent function to model the frequency of the digest email
|
|
max_day = SiteConfig.periodic_email_digest_max
|
|
min_day = SiteConfig.periodic_email_digest_min
|
|
result = max_day * (1 - Math.tanh(2 * open_rate))
|
|
result = result.round
|
|
|
|
[result, min_day].max
|
|
end
|
|
|
|
def open_rate
|
|
email_count = last_user_emails.count
|
|
|
|
# Will stick with 50% open rate if @user has no/not-enough email digest history
|
|
return 0.5 if email_count < 10
|
|
|
|
past_opened_emails_count = last_user_emails.count { |msg| msg.opened_at.present? }
|
|
past_opened_emails_count / email_count
|
|
end
|
|
|
|
def last_email_sent_at
|
|
last_user_emails.last&.sent_at
|
|
end
|
|
|
|
def cutoff_date
|
|
a_few_days_ago = 4.days.ago.utc
|
|
return a_few_days_ago unless last_email_sent_at
|
|
|
|
[a_few_days_ago, last_email_sent_at].max
|
|
end
|
|
|
|
def user_has_followings?
|
|
@user.following_users_count.positive? || @user.cached_followed_tag_names.any?
|
|
end
|
|
|
|
def last_user_emails
|
|
@last_user_emails ||= @user
|
|
.email_messages
|
|
.select(:sent_at, :opened_at)
|
|
.where(mailer: "DigestMailer#digest_email")
|
|
.limit(10)
|
|
end
|
|
end
|