discourse/app/models/email_log.rb

require_dependency 'distributed_mutex'

class EmailLog < ActiveRecord::Base
  CRITICAL_EMAIL_TYPES ||= Set.new %w{
    account_created
    admin_login
    confirm_new_email
    confirm_old_email
    forgot_password
    notify_old_email
    signup
    signup_after_approval
  }

  belongs_to :user
  belongs_to :post
  belongs_to :topic

  validates :email_type, :to_address, presence: true

  scope :sent,    -> { where(skipped: false) }
  scope :skipped, -> { where(skipped: true) }
  scope :bounced, -> { sent.where(bounced: true) }

  after_create do
    # Update last_emailed_at if the user_id is present and email was sent
    User.where(id: user_id).update_all("last_emailed_at = CURRENT_TIMESTAMP") if user_id.present? && !skipped
  end

  def self.unique_email_per_post(post, user)
    return yield unless post && user

    DistributedMutex.synchronize("email_log_#{post.id}_#{user.id}") do
      if where(post_id: post.id, user_id: user.id, skipped: false).exists?
        nil
      else
        yield
      end
    end
  end

  def self.reached_max_emails?(user, email_type = nil)
    return false if SiteSetting.max_emails_per_day_per_user == 0 || CRITICAL_EMAIL_TYPES.include?(email_type)

    count = sent.where('created_at > ?', 1.day.ago)
      .where(user_id: user.id)
      .count

    count >= SiteSetting.max_emails_per_day_per_user
  end

  def self.count_per_day(start_date, end_date)
    sent.where("created_at BETWEEN ? AND ?", start_date, end_date)
      .group("DATE(created_at)")
      .order("DATE(created_at)")
      .count
  end

  def self.for(reply_key)
    self.find_by(reply_key: reply_key)
  end

  def self.last_sent_email_address
    self.where(email_type: "signup")
      .order(created_at: :desc)
      .first
      .try(:to_address)
  end

  def bounce_key
    super&.delete('-')
  end

end

# == Schema Information
#
# Table name: email_logs
#
#  id             :integer          not null, primary key
#  to_address     :string           not null
#  email_type     :string           not null
#  user_id        :integer
#  created_at     :datetime         not null
#  updated_at     :datetime         not null
#  reply_key      :string(32)
#  post_id        :integer
#  topic_id       :integer
#  skipped        :boolean          default(FALSE)
#  skipped_reason :string
#  bounce_key     :string
#  bounced        :boolean          default(FALSE), not null
#  message_id     :string
#
# Indexes
#
#  idx_email_logs_user_created_filtered        (user_id,created_at) WHERE (skipped = false)
#  index_email_logs_on_created_at              (created_at)
#  index_email_logs_on_message_id              (message_id)
#  index_email_logs_on_post_id                 (post_id)
#  index_email_logs_on_reply_key               (reply_key)
#  index_email_logs_on_skipped_and_created_at  (skipped,created_at)
#  index_email_logs_on_topic_id                (topic_id)
#  index_email_logs_on_user_id_and_created_at  (user_id,created_at DESC)
#