Ruby

require "json"
require "net/http"
require "uri"

class Pulse
  BASE = URI("https://api.thepulseapi.com/api/v1").freeze

  def initialize(api_key:, organization_id:)
    @api_key = api_key
    @organization_id = organization_id
  end

  def track(session_id, signals)
    post("/track", sessionId: session_id, signals: signals)
  end

  def ranked_catalog(session_id, limit: 24)
    post("/catalog/ranked", sessionId: session_id, limit: limit)
  end

  def session(session_id)
    post("/session", sessionId: session_id)
  end

  private

  def post(path, **body)
    # organizationId is required on nearly every endpoint and is read from the body,
    # not from the key.
    body[:organizationId] = @organization_id

    request = Net::HTTP::Post.new(BASE.path + path)
    request["Content-Type"] = "application/json"
    request["x-api-key"] = @api_key
    request.body = JSON.generate(body)

    response = Net::HTTP.start(
      BASE.host, BASE.port,
      use_ssl: true,
      open_timeout: 5,
      read_timeout: 5,
    ) { |http| http.request(request) }

    raise "PULSE #{path}: #{response.code}" unless response.is_a?(Net::HTTPSuccess)

    JSON.parse(response.body)
  end
end

PULSE = Pulse.new(
  api_key: ENV.fetch("PULSE_API_KEY"),
  organization_id: ENV.fetch("PULSE_ORG_ID"),
)

def show
  session_id = cookies[:pulse_session]
  @products = if session_id
    PULSE.ranked_catalog(session_id, limit: 24)["items"]
  end
rescue StandardError
  # Personalisation is an enhancement. Catalogue order is a working page.
  @products = nil
ensure
  @products ||= Product.where(category: params[:slug]).limit(24)
end