# frozen_string_literal: true

module Streams
  # Assegna un StreamNode a una nuova sessione (least-loaded tra i ready).
  # Garantisce il nodo "home" derivato dagli ENV MediaMTX attuali.
  class NodeRegistry
    class NoCapacityError < StandardError; end

    HOME_SLUG = "home"

    class << self
      def ensure_home_from_env!
        StreamNode.find_or_initialize_by(slug: HOME_SLUG).tap do |node|
          node.assign_attributes(
            hostname: home_hostname,
            role: "home",
            status: "ready",
            provider: "local",
            rtmp_base_url: MatchLiveTv.mediamtx_rtmp_url,
            hls_base_url: MatchLiveTv.hls_public_url,
            api_base_url: MatchLiveTv.mediamtx_api_url,
            internal_rtmp_url: ENV.fetch("MEDIAMTX_INTERNAL_RTMP_URL", "rtmp://mediamtx:1935"),
            internal_hls_url: ENV.fetch("MEDIAMTX_HLS_URL", "http://mediamtx:8888"),
            max_publishers: ENV.fetch("STREAM_NODE_HOME_MAX_PUBLISHERS", "6").to_i,
            max_relays: ENV.fetch("STREAM_NODE_HOME_MAX_RELAYS", "6").to_i
          )
          node.save!
        end
      end

      def allocate!
        ensure_home_from_env!

        node = StreamNode.ready
          .to_a
          .select(&:allocatable?)
          .min_by { |n| [n.active_publishers, n.role == "home" ? 1 : 0, n.slug] }

        raise NoCapacityError, "Nessun nodo streaming con slot liberi" if node.nil?

        node
      end

      private

      def home_hostname
        ENV["STREAM_NODE_HOME_HOSTNAME"].presence ||
          begin
            uri = URI.parse(MatchLiveTv.mediamtx_rtmp_url.sub(/\Artmps?:\/\//, "http://"))
            uri.host.presence
          rescue URI::InvalidURIError
            nil
          end || "home"
      end
    end
  end
end