module JamRuby
  class EmailBatchNewMusician < EmailBatchPeriodic

    BATCH_SIZE = 500

    SINCE_WEEKS = 2

    VAR_MUSICIAN_COUNT = "@MUSICIAN_COUNT"
    VAR_MUSICIAN_TABLE = "@MUSICIAN_TABLE"

    def self.subject
      "New musicians with good Internet connections to you have joined JamKazam!"
    end

    def fetch_recipients(since=nil)
      since ||= Time.now - SINCE_WEEKS.weeks
      User.geocoded_users
        .email_opt_in
        .where(['created_at < ?', since])
        .find_in_batches(batch_size: EmailBatchNewMusician::BATCH_SIZE) do |users|
        new_musicians = users.inject({}) do |hh, uu|
          if 0 < (nearby = uu.nearest_musicians).count
            hh[uu] = nearby
          end
          hh
        end
        yield(new_musicians) if block_given?
      end
    end

    def deliver_batch_sets!
      self.opt_in_count = 0
      sent = 0
      self.fetch_recipients(self.time_since_last_batch(SINCE_WEEKS)) do |new_musicians|
        self.opt_in_count += new_musicians.count
        self.email_batch_sets << (bset = EmailBatchSet.load_set(self, new_musicians.keys.map(&:id)))
        new_musicians.each do |uu, nearby|
          UserMailer.new_musicians(uu, nearby).deliver
          sent += 1
        end
      end
      self.sent_count = sent
      self.save
      self.did_batch_run!
    end

  end
end