# frozen_string_literal: true

require "active_support/core_ext/array/wrap"
require "stringio"

module DjiMqttConnect
  module Utils
    # Generates anonymised fixture data from MQTTX JSON Export Dumps
    class MqttxFixtureDataGenerator
      def self.from_file(file_path, **sanitizer_args)
        raw_data = File.read(file_path)
        new JSON.parse(raw_data), message_sanitizer: MessageSanitizer.new(**sanitizer_args)
      end

      def initialize(mqttx_data, message_sanitizer:)
        @mqttx_data = mqttx_data
        @message_sanitizer = message_sanitizer
      end

      # Generates fixture data using ALL found messages in the MQTTX export
      #
      # # Output is:
      # <topic 1>: <message 1 as json>
      # <topic 1>: <message 2 as json>
      def generate
        extracted_messages.each_with_object(StringIO.new) do |(topic, message), builder|
          builder.puts [topic, message.to_json].join(": ")
        end.string
      end

      # Generates fixture data using unique found messages in the MQTTX export
      #
      # A message is considered unique if the topic and schema does not match any other messages
      #
      # # Output is:
      # <topic 1>: <message 1 as json>
      def generate_unique(**schema_generator_args)
        message_schema_generator = MessageSchemaGenerator.new(**schema_generator_args)

        unique_messages = extracted_messages.each_with_object({}) do |(topic, message), found|
          message_schema = message_schema_generator.generate(message)
          found[[topic, message_schema]] ||= [topic, message]
        end.values

        unique_messages.each_with_object(StringIO.new) do |(topic, message), builder|
          builder.puts [topic, message.to_json].join(": ")
        end.string
      end

      private

      attr_reader :mqttx_data, :message_sanitizer

      def extracted_messages
        return enum_for(:extracted_messages) unless block_given?

        Array.wrap(mqttx_data).each do |client_output|
          client_messages = client_output["messages"]

          client_messages.each do |message|
            message_topic = message_sanitizer.sanitize_topic(message.fetch("topic"))
            message_payload = JSON.parse message.fetch("payload")
            yield(message_topic, message_sanitizer.sanitize_message(message_payload))
          end
        end
      end
    end
  end
end