# frozen_string_literal: true

module Mihari
  module Analyzers
    class Base
      extend Dry::Initializer

      include Mixins::AutonomousSystem
      include Mixins::Configurable
      include Mixins::Database
      include Mixins::Retriable

      attr_accessor :ignore_old_artifacts, :ignore_threshold

      def initialize(*args, **kwargs)
        super

        @ignore_old_artifacts = false
        @ignore_threshold = 0
      end

      # @return [Array<String>, Array<Mihari::Artifact>]
      def artifacts
        raise NotImplementedError, "You must implement #{self.class}##{__method__}"
      end

      # @return [String]
      def title
        self.class.to_s.split("::").last.to_s
      end

      # @return [String]
      def description
        raise NotImplementedError, "You must implement #{self.class}##{__method__}"
      end

      # @return [String]
      def source
        self.class.to_s.split("::").last.to_s
      end

      # @return [Array<String>]
      def tags
        []
      end

      #
      # Set artifacts & run emitters in parallel
      #
      # @return [Mihari::Alert, nil]
      #
      def run
        unless configured?
          class_name = self.class.to_s.split("::").last
          raise ConfigurationError, "#{class_name} is not configured correctly"
        end

        with_db_connection do
          set_enriched_artifacts

          responses = Parallel.map(valid_emitters) do |emitter|
            run_emitter emitter
          end

          # returns Mihari::Alert created by the database emitter
          responses.find { |res| res.is_a?(Mihari::Alert) }
        end
      end

      #
      # Run emitter
      #
      # @param [Mihari::Emitters::Base] emitter
      #
      # @return [nil]
      #
      def run_emitter(emitter)
        emitter.run(title: title, description: description, artifacts: enriched_artifacts, source: source, tags: tags)
      rescue StandardError => e
        Mihari.logger.info "Emission by #{emitter.class} is failed: #{e}"
      end

      class << self
        def inherited(child)
          super
          Mihari.analyzers << child
        end
      end

      #
      # Normalize artifacts
      # - Convert data (string) into an artifact
      # - Reject an invalid artifact
      # - Uniquefy artifacts by data
      #
      # @return [Array<Mihari::Artifact>]
      #
      def normalized_artifacts
        @normalized_artifacts ||= artifacts.compact.sort.map do |artifact|
          # No need to set data_type manually
          # It is set automatically in #initialize
          artifact.is_a?(Artifact) ? artifact : Artifact.new(data: artifact, source: source)
        end.select(&:valid?).uniq(&:data)
      end

      private

      #
      # Uniquefy artifacts
      #
      # @return [Array<Mihari::Artifact>]
      #
      def unique_artifacts
        @unique_artifacts ||= normalized_artifacts.select do |artifact|
          artifact.unique?(ignore_old_artifacts: ignore_old_artifacts, ignore_threshold: ignore_threshold)
        end
      end

      #
      # Enriched artifacts
      #
      # @return [Array<Mihari::Artifact>]
      #
      def enriched_artifacts
        @enriched_artifacts ||= Parallel.map(unique_artifacts) do |artifact|
          artifact.enrich_all
          artifact
        end
      end

      #
      # Set enriched artifacts
      #
      # @return [nil]
      #
      def set_enriched_artifacts
        retry_on_error { enriched_artifacts }
      end

      #
      # Select valid emitters
      #
      # @return [Array<Mihari::Emitters::Base>]
      #
      def valid_emitters
        @valid_emitters ||= Mihari.emitters.filter_map do |klass|
          emitter = klass.new
          emitter.valid? ? emitter : nil
        end.compact
      end
    end
  end
end