# frozen_string_literal: true

require 'json'

# Converts the current world-state into something we can send to a client.
class Serialiser
  def initialize(cid)
    @cid = cid
    @last_snapshot = ''
  end

  # NOTE: "full" is a hint that we're OK to send stuff we might otherwise omit.
  def snapshot(world, full: false)
    actors = Hash[world.actors.map { |a| [a.object_id, actor_json(a, full)] }]
    result = { actors: actors }.to_json

    return nil if @last_snapshot == result

    @last_snapshot = result
  end

  private

  # TODO: A better idea would be to only include "full" details if they change.
  def actor_json(actor, full)
    json = actor.as_json # This includes EVERYTHING, which we dont always send.

    user = json.delete('user')
    position = json.delete('position')

    result = { x: position[0], y: position[1] }
    result.merge!(json) if full # <-- This is what the comment above refers to.
    user == @cid ? result.merge(yours: true) : result
  end
end