# frozen_string_literal: true

require 'tacview_client/base_processor'
require 'time'
require 'concurrent-ruby'
require_relative 'cache'

module TacScribe
  # Processes the events emitted by the Ruby Tacview Client
  class EventProcessor
    @@ignored_units = Concurrent::Set.new

    attr_accessor :events_processed, :events_ignored

    def initialize(cache:, datastore:, event_queue:, whitelist: nil)
      @cache = cache
      @datastore = datastore
      @event_queue = event_queue
      @whitelist = whitelist
      self.events_processed = 0
      self.events_ignored = 0
    end

    def start
      loop do
        wrapped_event = @event_queue.shift
        process_event(wrapped_event)
      rescue StandardError => e
        puts wrapped_event
        puts e.inspect
        puts e.backtrace
        next
      end
    end

    def process_event(wrapped_event)
      case wrapped_event[:type]
      when :update_object
        update_object(wrapped_event[:event], wrapped_event[:time])
      when :delete_object
        delete_object(wrapped_event[:object_id])
      when :set_latitude
        update_latitude wrapped_event[:value]
      when :set_longitude
        update_longitude wrapped_event[:value]
      end
    end

    private

    # Process an update event for an object
    #
    # On the first appearance of the object there are usually more fields
    # including pilot names, object type etc.
    #
    # For existing objects these events are almost always lat/lon/alt updates
    # only
    #
    # @param event [Hash] A parsed ACMI line. This hash will always include
    #   the fields listed below but may also include others depending on the
    #   source line.
    # @option event [String] :object_id The hexadecimal format object ID.
    # @option event [BigDecimal] :latitude The object latitude in WGS 84 format.
    # @option event [BigDecimal] :longitude The object latitude in WGS 84
    #   format.
    # @option event [BigDecimal] :altitude The object altitude above sea level
    #   in meters to 1 decimal place.
    def update_object(event, time)
      return if ignore_unit?(event)

      # Hack to make sure the :name field is present so that it is included
      # in the SQL
      event[:name] = nil unless event.has_key?(:name)
      event[:game_time] = time

      self.events_processed += 1
      @cache.write_object(event)
    end

    def ignore_unit?(event)
      if @@ignored_units.include?(event[:object_id])
        self.events_ignored += 1
        return true
      end

      if @whitelist && event[:type] && !@whitelist.include?(event[:type])
        @@ignored_units << event[:object_id]
        self.events_ignored += 1
        return true
      end

      false
    end

    # Process a delete event for an object
    #
    # @param id [String] A hexadecimal number representing the object ID
    def delete_object(id)
      if @@ignored_units.delete?(id)
        nil
      else
        @cache.delete_object(id)
      end
      self.events_processed += 1
    end

    def update_latitude(value)
      Cache.instance.reference_latitude = value
    end

    def update_longitude(value)
      Cache.instance.reference_longitude = value
    end
  end
end