module Youtube
  class BroadcastService
    class Error < StandardError; end

    def initialize(team, youtube_channel: nil)
      @team = team
      @resolver = CredentialResolver.new(team, channel: youtube_channel)
      @credential = @resolver.resolve
    end

    def create_broadcast!(title:, privacy_status: "public", scheduled_at: nil)
      return mock_broadcast if @credential.blank? || missing_oauth_config?

      client = authorized_client
      start_time = normalize_scheduled_start_time(scheduled_at)
      broadcast = Google::Apis::YoutubeV3::LiveBroadcast.new(
        snippet: Google::Apis::YoutubeV3::LiveBroadcastSnippet.new(
          title: title,
          scheduled_start_time: start_time.iso8601
        ),
        status: Google::Apis::YoutubeV3::LiveBroadcastStatus.new(
          privacy_status: privacy_status,
          self_declared_made_for_kids: false
        ),
        content_details: Google::Apis::YoutubeV3::LiveBroadcastContentDetails.new(
          enable_auto_start: true,
          enable_auto_stop: true
        )
      )
      result = client.insert_live_broadcast("snippet,status,contentDetails", broadcast)

      stream = Google::Apis::YoutubeV3::LiveStream.new(
        snippet: Google::Apis::YoutubeV3::LiveStreamSnippet.new(title: "#{title} stream"),
        cdn: Google::Apis::YoutubeV3::CdnSettings.new(
          frame_rate: "30fps",
          ingestion_type: "rtmp",
          resolution: "720p"
        )
      )
      stream_result = client.insert_live_stream("snippet,cdn", stream)
      client.bind_live_broadcast(result.id, "id,contentDetails", stream_id: stream_result.id)

      {
        broadcast_id: result.id,
        stream_id: stream_result.id,
        stream_key: stream_result.cdn.ingestion_info.stream_name,
        rtmp_url: stream_result.cdn.ingestion_info.ingestion_address
      }
    rescue Google::Apis::Error => e
      raise Error, friendly_api_error(e)
    end

    # Porta in onda appena c’è ingest su YouTube (non attendere scheduledStartTime).
    def activate_broadcast!(broadcast_id)
      return if broadcast_id.blank?
      return if @credential.blank? || missing_oauth_config?

      client = authorized_client
      item = client.list_live_broadcasts("status", id: broadcast_id).items&.first
      return unless item

      status = item.status.life_cycle_status.to_s
      return if status == "live"

      if %w[ready created].include?(status)
        client.transition_live_broadcast("testing", broadcast_id, "id,status")
        status = "testing"
      end
      client.transition_live_broadcast("live", broadcast_id, "id,status") if status == "testing"
    rescue Google::Apis::Error => e
      Rails.logger.warn("[Youtube::BroadcastService] activate #{broadcast_id}: #{e.message}")
      nil
    end

    def complete_broadcast!(broadcast_id)
      return if broadcast_id.blank?
      return if @credential.blank? || missing_oauth_config?

      client = authorized_client
      client.transition_live_broadcast("complete", broadcast_id, "id,status")
    rescue Google::Apis::Error
      nil
    end

    def viewer_count(broadcast_id)
      return 0 if @credential.blank? || missing_oauth_config?

      client = authorized_client
      resp = client.list_live_broadcasts("statistics", id: broadcast_id)
      resp.items&.first&.statistics&.concurrent_viewers.to_i
    rescue Google::Apis::Error
      0
    end

    private

    def mock_broadcast
      {
        broadcast_id: "mock_#{SecureRandom.hex(8)}",
        stream_id: "mock_stream",
        stream_key: ENV.fetch("YOUTUBE_MOCK_STREAM_KEY", "mock-stream-key"),
        rtmp_url: "rtmp://a.rtmp.youtube.com/live2"
      }
    end

    def missing_oauth_config?
      ENV["YOUTUBE_CLIENT_ID"].blank?
    end

    def authorized_client
      OauthRefresh.new(@credential).apply!(Google::Apis::YoutubeV3::YouTubeService.new)
    end

    def friendly_api_error(error)
      msg = error.message.to_s
      return "Il canale YouTube non ha la diretta attiva. Apri YouTube Studio con l’account del canale Match Live TV, abilita la live (verifica telefono se richiesto) e riprova." if msg.include?("liveStreamingNotEnabled")
      return "Credenziali YouTube non valide. Ricollega il canale dalla sezione Admin → YouTube." if msg.match?(/Unauthorized|invalid_grant/i)
      if msg.match?(/invalidScheduledStartTime|scheduledStartTimeRequired/i)
        return "Orario programmazione YouTube non valido. Riprova: la diretta partirà appena invii il segnale RTMP."
      end

      msg
    end

    # YouTube richiede scheduledStartTime nel futuro; per «vai subito» usiamo ~1 min (auto_start al RTMP).
    def normalize_scheduled_start_time(scheduled_at)
      now = Time.current.utc
      minimum = now + 90.seconds
      maximum = now + 7.days

      candidate =
        if scheduled_at.blank?
          minimum
        else
          scheduled_at.utc
        end

      candidate = minimum if candidate < minimum
      candidate = maximum if candidate > maximum
      candidate
    end
  end
end