# Copyright (c) 2023 Contrast Security, Inc. See https://www.contrastsecurity.com/enduser-terms-0317a for more details.
# frozen_string_literal: true

require 'contrast/agent/protect/rule/input_classification/encoding_rates'
require 'contrast/agent/telemetry/input_analysis_encoding_event'
require 'contrast/components/logger'

module Contrast
  module Agent
    module Protect
      module Rule
        module InputClassification
          # This class will safe all the information for the Base64 decoding matches per input type.
          class Base64Statistic
            include Contrast::Components::Logger::InstanceMethods

            # @return [Hash<Contrast::Agent::Protect::Rule::InputClassification::EncodingRates>]
            attr_reader :data

            # Capacity for request context life cycle.
            CAPACITY = 1000

            def initialize
              @data = {}
            end

            # Add a match for the given input type.
            #
            # @param input_type [Symbol]
            def match! input_type
              return @data[input_type]&.increase_match_base64 if @data[input_type]

              @data[input_type] = Contrast::Agent::Protect::Rule::InputClassification::EncodingRates.new(input_type)
              @data[input_type].increase_match_base64
            end

            # Add a mismatch for the given input type.
            #
            # @param input_type [Symbol]
            def mismatch! input_type
              return @data[input_type]&.increase_mismatch_base64 if @data[input_type]

              @data[input_type] = Contrast::Agent::Protect::Rule::InputClassification::EncodingRates.new(input_type)
              @data[input_type].increase_mismatch_base64
            end

            # Clears statistic data.
            def clear
              @data.clear
            end

            # @return [Array<Contrast::Agent::Telemetry::InputAnalysisCacheEvent>] the events to be sent.
            def to_events
              events = []
              data.each do |_input_type, encoding_rate|
                event = Contrast::Agent::Telemetry::InputAnalysisEncodingEvent.new(nil, encoding_rate)
                next if event.empty?

                events << event
              end
              events
            rescue StandardError => e
              logger.error("[Telemetry] Error while creating events: #{ e }", stacktrace: e.backtrace)
              []
            end
          end
        end
      end
    end
  end
end