update_realtime_stats.rb

# frozen_string_literal: true

module StatsApi
  module Operations
    module UpdateRealtimeStatsViews
      class UpdateLastShareTimestamps < Operations::BaseOperation
        include Dry::Monads::Try::Mixin

        include Import[
          :application_config,
          :logger
        ]

        def call(_input = {})
          if pg.views(materialized: true).include? view_name
            update_view
          else
            create_view
          end
        end

        private

        def update_view
          Try() { pg.execute "REFRESH MATERIALIZED VIEW CONCURRENTLY #{view_name}" }
            .fmap { logger.info "#{view_name} materialized view updated" }
        end

        def pg
          StatsApi::Container[:pg]
        end

        def create_view
          Try() do
            logger.info "Creating #{view_name} materialized view"
            pg.create_view view_name, query, materialized: true
            logger.info "Created #{view_name} materialized view"
            logger.info "Creating #{view_name} index"
            pg.add_index view_name, %i[wallet worker coin], unique: true
            logger.info "Created #{view_name} index"
          end
        end

        def query
          max_lit = Sequel.lit('max(shares.created_at)')
          join = { miner: :miner, worker_id: :worker_id, created_at: :created_at }
          pg[:shares].join(max_ts, join)
                     .group_append { Sequel.lit('shares.miner') }
                     .group_append { Sequel.lit('shares.worker_id') }
                     .group_append(:coin)
                     .select { Sequel.lit('shares.miner').as :wallet }
                     .select_append { Sequel.lit('shares.worker_id').as :worker }
                     .select_append(:coin)
                     .select_append { Sequel.extract(:epoch, max_lit).as(:timestamp) }
        end

        def max_ts
          sql_lit = <<~LITERAL
            shares.created_at >= (now() - '#{application_config.short_window_duration} s'::interval)
          LITERAL

          time_lit = Sequel.lit(sql_lit)
          Share.select { max(created_at).as(:created_at) }
               .select_append(:miner)
               .select_append(:worker_id)
               .group(:miner)
               .group_append(:worker_id)
               .where { time_lit }
        end

        def view_name
          application_config.last_share_timestamps_view_name
        end
      end
    end
  end
end