# Copyright (c) 2022 Contrast Security, Inc. See https://www.contrastsecurity.com/enduser-terms-0317a for more details.
# frozen_string_literal: true

require 'contrast/agent/reporting/reporting_events/finding_event_object'
require 'contrast/agent/reporting/reporting_events/finding_event_parent_object'
require 'contrast/agent/reporting/reporting_events/finding_event_property'
require 'contrast/agent/reporting/reporting_events/finding_event_signature'
require 'contrast/agent/reporting/reporting_events/finding_event_source'
require 'contrast/agent/reporting/reporting_events/finding_event_stack'
require 'contrast/agent/reporting/reporting_events/finding_event_taint_range'

module Contrast
  module Agent
    module Reporting
      # This is the new FindingEvent class which will include all the needed information for the new reporting system
      # to relay this information in the Finding/Trace messages. These FindingEvents are used by TeamServer to
      # construct the vulnerability information for the assess feature. They represent the operation the application
      # underwent that transformed data during the dataflow.
      class FindingEvent
        # @return [Symbol] what the event did; CREATION, A2O, A2P, A2A, A2R, O2A, O2O, O2P, O2R, P2A, P2O, P2P, P2R,
        #   TAG, TRIGGER.
        attr_reader :action
        # @return [Array<Contrast::Agent::Reporting::FindingEventObject>] the arguments passed to the method.
        attr_reader :args
        # @return [nil] unused.
        attr_reader :code
        # @return [Integer] the id of this event.
        attr_reader :event_id
        # @return [Array<Contrast::Agent::Reporting::FindingEventSource>] the source of taint
        attr_reader :event_sources
        # @return [nil] unused.
        attr_reader :field_name
        # @return [Contrast::Agent::Reporting::FindingEventObject] the object this method was invoked on.
        attr_reader :object
        # @@return [Array<Contrast::Agent::Reporting::FindingEventParentObject>] the ids of all the events directly
        #   preceding this
        attr_reader :parent_object_ids
        # @return [Array<Contrast::Agent::Reporting::FindingEventProperty>]
        attr_reader :properties
        # @return  [Contrast::Agent::Reporting::FindingEventObject] the return of the method.
        attr_reader :ret
        # @return [Contrast::Agent::Reporting::FindingEventSignature] the signature of the method.
        attr_reader :signature
        # @return [String] the source of the taint from the method; ^(O|R|P\d+)$
        attr_reader :source
        # @return [Array<Contrast::Agent::Reporting::FindingEventStack>]
        attr_reader :stack
        # @return [String] comma separated list of descriptions of what's happened to the data
        attr_reader :tags
        # @return [Array<Contrast::Agent::Reporting::FindingEventTaintRange>] the tags and spans of the source that are
        #   tracked
        attr_reader :taint_ranges
        # @return [String] the target of the taint from the method; ^(O|R|P\d+)$
        attr_reader :target
        # @return [String] the id of the thread on which the method was invoked
        attr_reader :thread
        # @return [Integer] the time, in ms, when the event was generated
        attr_reader :time
        # @return [String] the type of event; METHOD, PROPAGATION, TAG
        attr_reader :type

        class << self
          # Find all the events leading up to the given source and return an array of FindingEvents
          #
          # @param source [Object] something that may have been tracked
          # @return [Array<Contrast::Agent::Reporting::FindingEvent>]
          def from_source source
            return unless source && (props = Contrast::Agent::Assess::Tracker.properties(source))

            build_events([], props.event) if props.event
          end

          # @param event [Contrast::Agent::Assess::ContrastEvent]
          # @return [Contrast::Agent::Reporting::FindingEvent]
          def convert event
            report = new
            report.attach_data(event)
            report
          end

          private

          # Pull the parent events from the given event, generating an array of FindingEvents, passing back the given
          # array of events after populating it.
          #
          # @param events [Array<Contrast::Agent::Reporting::FindingEvent>]
          # @param event [Contrast::Agent::Assess::ContrastEvent]
          # @return [Array<Contrast::Agent::Reporting::FindingEvent>]
          def build_events events, event
            return unless event

            event.parent_events&.each do |parent_event|
              build_events(events, parent_event)
            end
            events << convert(event)
            events
          end
        end

        # Parse the data from a Contrast::Agent::Assess::ContrastEvent to attach what is required for reporting to
        # TeamServer to this Contrast::Agent::Reporting::FindingEvent
        #
        # @param event [Contrast::Agent::Assess::ContrastEvent]
        def attach_data event
          @event_id = event.event_id
          @time = event.time.to_i
          @thread = event.thread.to_s
          display_params!(event)
          dataflow!(event)
          event_sources!(event)
          @signature = Contrast::Agent::Reporting::FindingEventSignature.convert(event)
          stack!(event)
          parent_ids!(event)
          properties!(event)
        end

        # Convert the instance variables on the class, and other information, into the identifiers required for
        # TeamServer to process the JSON form of this message.
        #
        # @return [Hash]
        # @raise [ArgumentError]
        def to_controlled_hash # rubocop:disable Metrics/AbcSize
          validate
          {
              action: action,
              args: args.map(&:to_controlled_hash),
              # code: code, # Unused by our agent
              objectId: event_id,
              eventSources: event_sources.map(&:to_controlled_hash),
              # fieldName: field_name, # Unused by our agent
              object: object.to_controlled_hash,
              parentObjectIds: parent_object_ids.map(&:to_controlled_hash),
              properties: properties.map(&:to_controlled_hash),
              ret: ret&.to_controlled_hash,
              signature: signature.to_controlled_hash,
              source: source || '',
              stack: stack.map(&:to_controlled_hash),
              tags: tags.join(','),
              taintRanges: taint_ranges.map(&:to_controlled_hash),
              target: target || '',
              thread: thread,
              time: time,
              type: type
          }
        end

        # @raise [ArgumentError]
        def validate
          validate_base
          validate_dataflow
        end

        private

        # Find the action and type of this event, used by TeamServer to display type of the event and the
        # transformation if made.
        #
        # @param event [Contrast::Agent::Assess::ContrastEvent]
        def display_params! event
          @action = event.policy_node.build_action
          @type = case event.policy_node.node_type
                  when :TYPE_TAG
                    'TAG'
                  when :TYPE_PROPAGATION
                    'PROPAGATION'
                  else # :TYPE_METHOD
                    'METHOD'
                  end
        end

        # Build the dataflow components of this FindingEvent.
        #
        # @param event [Contrast::Agent::Assess::ContrastEvent]
        def dataflow! event
          taint_target = taint_target!(event)
          truncate_obj = Contrast::Utils::ObjectShare::OBJECT_KEY != taint_target
          @object = Contrast::Agent::Reporting::FindingEventObject.convert(event.object, truncate_obj)
          truncate_ret = Contrast::Utils::ObjectShare::RETURN_KEY != taint_target
          @ret = Contrast::Agent::Reporting::FindingEventObject.convert(event.ret, truncate_ret)
          event_args!(event, taint_target)
          taint_ranges!(event)
        end

        # Convert the arguments of the given ContrastEvent to the reportable form for this FindingEvent. We'll
        # truncate any argument that isn't the taint target of this event.
        #
        # @param event [Contrast::Agent::Assess::ContrastEvent]
        # @param taint_target [String,nil] the target of the taint in this event.
        def event_args! event, taint_target
          @args = []
          idx = 0
          while idx < event.args.length
            @args << Contrast::Agent::Reporting::FindingEventObject.convert(event.args[idx], taint_target != idx)
            idx += 1
          end
        end

        # Convert the sources of the event to sources here
        #
        # @param event [Contrast::Agent::Assess::ContrastEvent]
        def event_sources! event
          @event_sources = []
          return unless event.cs__is_a?(Contrast::Agent::Assess::Events::SourceEvent)

          source = Contrast::Agent::Reporting::FindingEventSource.convert(event)
          event_sources << source if source
        end

        # Convert the parent id's of the given ContrastEvent to the reportable form for this FindingEvent.
        #
        # @param event [Contrast::Agent::Assess::ContrastEvent]
        def parent_ids! event
          @parent_object_ids = []
          event.parent_events&.each do |parent_event|
            parent_object_ids << Contrast::Agent::Reporting::FindingEventParentObject.new(parent_event.event_id.to_i)
          end
        end

        # Convert the properties of the given ContrastEvent to the reportable form for this FindingEvent.
        # TODO: RUBY-99999 How do properties get to events? Do they? I thought Stored-XSS needed it.
        #
        # @param _event [Contrast::Agent::Assess::ContrastEvent]
        def properties! _event
          @properties = []
        end

        # Convert the stack of the given ContrastEvent to the reportable form for this FindingEvent.
        #
        # @param event [Contrast::Agent::Assess::ContrastEvent]
        def stack! event
          @stack = []
          event.stack_trace.each do |stack_event|
            if (report = Contrast::Agent::Reporting::FindingEventStack.convert(stack_event))
              stack << report
            end
          end
        end

        # Convert the taint ranges of the given ContrastEvent to the reportable form for this FindingEvent.
        #
        # @param event [Contrast::Agent::Assess::ContrastEvent]
        def taint_ranges! event
          @tags = []
          @taint_ranges = []
          event&.tags&.each_pair do |tag_key, tag_ranges|
            tags << tag_key
            tag_ranges.each do |range|
              taint_ranges << Contrast::Agent::Reporting::FindingEventTaintRange.convert(range)
            end
          end
        end

        # Find the source and target for this FindingEvent based on the provided event.
        #
        # @param event [Contrast::Agent::Assess::ContrastEvent]
        # @return [String,nil] the target of the taint in this event.
        def taint_target! event
          return unless (node = event.policy_node)

          @source = node.source_string if node.source_string
          @target = node.target_string if node.target_string
          return node.targets[0] if node.targets&.any?

          node.sources[0] if node.sources&.any?
        end

        # @raise [ArgumentError]
        def validate_base
          raise(ArgumentError, "#{ self } did not have a proper action. Unable to continue.") unless action
          raise(ArgumentError, "#{ self } did not have a proper eventId. Unable to continue.") unless event_id
          raise(ArgumentError, "#{ self } did not have a proper thread. Unable to continue.") unless thread
          raise(ArgumentError, "#{ self } did not have a proper time. Unable to continue.") unless time
          raise(ArgumentError, "#{ self } did not have a proper type. Unable to continue.") unless type
        end

        # @raise [ArgumentError]
        def validate_dataflow
          unless parent_object_ids
            raise(ArgumentError, "#{ self } did not have a proper parentObjectIds. Unable to continue.")
          end
          raise(ArgumentError, "#{ self } did not have a proper taintRanges. Unable to continue.") unless taint_ranges
          raise(ArgumentError, "#{ self } did not have a proper args. Unable to continue.") unless args
          raise(ArgumentError, "#{ self } did not have a proper object. Unable to continue.") unless object
          raise(ArgumentError, "#{ self } did not have a proper signature. Unable to continue.") unless signature
          raise(ArgumentError, "#{ self } did not have a proper stack. Unable to continue.") unless stack
          raise(ArgumentError, "#{ self } did not have a proper tags. Unable to continue.") unless tags
        end
      end
    end
  end
end