defmodule PrivacyRevolver.Router do
  use Plug.Router

  plug :match
  plug :dispatch

  get "/ping" do
    # Useful for app healthcheck
    {:ok, resp} = Redix.command(:redix, ["PING"])
    send_resp(conn, 200, resp)
  end

  get "/:service/*glob" do
    full_path = "/" <> Enum.join(glob, "/")
    {:ok, instances} = Redix.command(:redix, ["LRANGE", service, "0", "-1"])

    # Either pick a random available instance, or fall back to the default one
    instance = if Enum.count(instances) > 0 do
      Enum.random(instances)
    else
      Redix.command(:redix, ["GET", service <> "-fallback"])
    end

    # Redirect to the available instance
    conn |>
    Plug.Conn.resp(:found, "") |>
    Plug.Conn.put_resp_header("location", instance <> full_path)
  end
end