(ns tcp-bin
  (:require [clojure.tools.logging :refer :all]))

(defn- i2b [i] (byte (if (< i 128) i (- i 256))))
(defn- b2i [b] (let [i (int b)] (if (< i 0) (+ i 256) i)))

(defn oi
 "Send `cmd` bytes to `port` of `host` and receive `len` bytes response from it
  with `timeout` [ms] timeout."
  [{:keys [host port]} cmd len timeout]
  (try
    (with-open [s (java.net.Socket. ^String host ^int port)
                ^java.io.OutputStream os (.getOutputStream s)
                ^java.io.InputStream is (.getInputStream s)]
      (let [^bytes obuf (byte-array (map i2b cmd))
            _ (trace "tcp-bin:oi:send:" (seq obuf))
            _ (.write os obuf 0 (count cmd))
            _ (.flush os)
            ^bytes ibuf (byte-array len)
            u (quot timeout 10)
            n (loop [m 0 t 0]
                (if (and (< m len) (< t u))
                    (let [l (if (.available is)
                                (.read is ibuf m (- len m))
                                (do (Thread/sleep 10) 0))]
                      (recur (+ m (long l)) (inc t)))
                    m))
            ]
        (trace "tcp-bin:oi:recv: [" n "]" (seq ibuf))
        (map b2i (take n (seq ibuf)))))
    (catch Throwable t (warn t) (debug t t))))