# frozen_string_literal: true

require_relative '../sampling/ext'
require_relative '../utils'

module Datadog
  module Tracing
    module Distributed
      # Helpers module provides common helper functions for distributed tracing data
      module Helpers
        # Base provides common methods for distributed helper classes
        def self.clamp_sampling_priority(sampling_priority)
          # B3 doesn't have our -1 (USER_REJECT) and 2 (USER_KEEP) priorities so convert to acceptable 0/1
          if sampling_priority < 0
            sampling_priority = Sampling::Ext::Priority::AUTO_REJECT
          elsif sampling_priority > 1
            sampling_priority = Sampling::Ext::Priority::AUTO_KEEP
          end

          sampling_priority
        end

        def self.parse_decimal_id(value)
          return unless value

          value = value.to_s

          num   = value.to_i

          # Ensure the parsed number is the same as the original string value
          # e.g. We want to make sure to throw away `'nan'.to_i == 0`
          return unless num.to_s(10) == value

          num
        end

        def self.parse_hex_id(value)
          return unless value

          # Lowercase if we want to parse base16 e.g. 3E8 => 3e8
          # DEV: Ruby will parse `3E8` just fine, but to test
          #      `num.to_s(base) == value` we need to lowercase
          value = value.to_s.downcase

          # Remove any leading zeros
          # DEV: When we call `num.to_s(16)` later Ruby will not add leading zeros
          #      for us so we want to make sure the comparision will work as expected
          # DEV: regex, remove all leading zeros up until we find the last 0 in the string
          #      or we find the first non-zero, this allows `'0000' -> '0'` and `'00001' -> '1'`
          value = value.sub(/^0*(?=(0$)|[^0])/, '')

          # Convert value to an integer
          # DEV: Ruby `.to_i` will return `0` if a number could not be parsed
          num = value.to_i(16)

          # Ensure the parsed number is the same as the original string value
          # e.g. We want to make sure to throw away `'nan'.to_i == 0`
          return unless num.to_s(16) == value

          num
        end
      end
    end
  end
end