# typed: true
require 'set'

module Datadog
  module Contrib
    module Redis
      # Quantize contains Redis-specific resource quantization tools.
      module Quantize
        PLACEHOLDER = '?'.freeze
        TOO_LONG_MARK = '...'.freeze
        VALUE_MAX_LEN = 50
        CMD_MAX_LEN = 500

        MULTI_VERB_COMMANDS = Set.new(
          %w[
            ACL
            CLIENT
            CLUSTER
            COMMAND
            CONFIG
            DEBUG
            LATENCY
            MEMORY
          ]
        ).freeze

        module_function

        def format_arg(arg)
          str = arg.is_a?(Symbol) ? arg.to_s.upcase : arg.to_s
          str = Utils.utf8_encode(str, binary: true, placeholder: PLACEHOLDER)
          Utils.truncate(str, VALUE_MAX_LEN, TOO_LONG_MARK)
        rescue => e
          Datadog.logger.debug("non formattable Redis arg #{str}: #{e}")
          PLACEHOLDER
        end

        def format_command_args(command_args)
          command_args = resolve_command_args(command_args)
          return 'AUTH ?' if auth_command?(command_args)

          cmd = command_args.map { |x| format_arg(x) }.join(' ')
          Utils.truncate(cmd, CMD_MAX_LEN, TOO_LONG_MARK)
        end

        def get_verb(command_args)
          return unless command_args.is_a?(Array)

          return get_verb(command_args.first) if command_args.first.is_a?(Array)

          arg = command_args.first
          verb = arg.is_a?(Symbol) ? arg.to_s.upcase : arg.to_s
          return verb unless MULTI_VERB_COMMANDS.include?(verb) && command_args[1]

          "#{verb} #{command_args[1]}"
        end

        def auth_command?(command_args)
          return false unless command_args.is_a?(Array) && !command_args.empty?

          command_args.first.to_sym == :auth
        end

        # Unwraps command array when Redis is called with the following syntax:
        #   redis.call([:cmd, 'arg1', ...])
        def resolve_command_args(command_args)
          return command_args.first if command_args.is_a?(Array) && command_args.first.is_a?(Array)

          command_args
        end

        private_class_method :auth_command?, :resolve_command_args
      end
    end
  end
end