module Semantic
  module Subscribers
    # LogSubscriber for event_group :active_record
    class ActiveRecord < LogSubscriber
      include AnsiColors

      IGNORE_PAYLOAD_NAMES = %w[SCHEMA EXPLAIN].freeze
      TRANSACTION_TAINT = AnsiColors::DARK_TEXT_CYAN

      def sql(event)
        name = event.payload[:name]
        return if IGNORE_PAYLOAD_NAMES.include?(name)

        category, model, *remaining = name.split.reverse
        return if category == 'TRANSACTION'

        statement_taint = AnsiColors::TEXT_GRAY_300
        case category
        when 'Count'
          name = "#{category} #{model}"
        when 'Load'
          if event.payload[:cached]
            name = "Cache #{model}"
            no_stats = true
          else
            statement_taint = TEXT_BLUE
            row_count = event.payload[:row_count]
            name = "#{category} #{row_count} #{model.pluralize(row_count)}"
          end
        when 'Update', 'Create', 'Destroy'
          statement_taint = TEXT__PINK
          name = "#{category} #{model}"
          category_taint = TRANSACTION_TAINT
          increment_transaction_local(event.payload[:transaction].uuid, category.downcase.to_sym, event.duration)
        else raise "unknown sql category: <#{category}>"
        end

        name = "#{name} #{stats_event(event.duration)}" unless no_stats
        name = "#{name} #{remaining.join(' ')}" if remaining.any?
        name = colorize(name, category_taint) if category_taint
        statement = colorize(event.payload[:sql], statement_taint)

        logger.debug("#{name} #{statement}")
      end

      def start_transaction(_event)
        logger.info(colorize('Begin', TRANSACTION_TAINT))
      end

      def transaction(event)
        outcome = colorize(event.payload[:outcome].capitalize, TRANSACTION_TAINT)
        transaction = event.payload[:transaction]
        summary = transaction_summary(transaction)
        stats = stats_event(event.duration - transaction_internal_duration(transaction))
        logger.info("#{outcome} #{summary} #{stats}")
      end

      def instantiation(event); end

      def strict_loading_violation(event) = any_hook event

      private

      def stats_event(duration)= colorize("(#{number_to_ms(duration)})", TEXT_GRAY_400)
      def number_to_ms(number) = "#{::ActionController::Base.helpers.number_with_precision(number, precision: 1)}ms"
      def transaction_internal_duration(transaction) = transaction_local(transaction.uuid)[:total_duration]

      def transaction_summary(transaction)
        transaction_local(transaction.uuid)
          .except(:total_duration)
          .select { |_, value| value.positive? }
          .map { |k, v| "#{v} #{k.to_s.pluralize(v)}" }
          .join(',')
      end

      def increment_transaction_local(transaction_id, sql_command, duration)
        transaction_local(transaction_id)[sql_command] += 1
        transaction_local(transaction_id)[:total_duration] += duration
      end

      def thread_local = Thread.current[self.class.to_s] ||= {}

      def transaction_local(transaction_id)
        thread_local[transaction_id] ||= { update: 0, create: 0, destroy: 0, total_duration: 0 }
      end
    end
  end
end