(local fcntl (require "posix.fcntl"))
(local posix (require "posix"))
(local { : read : write } (require "posix.unistd"))
(local {: tcgetattr : tcsetattr : tcdrain
        : CLOCAL : CREAD
        : ICANON : ECHO : ECHOE : ISIG
        : OPOST
        } (require "posix.termio"))
(local { : nanosleep } (require "posix.time"))
(local { : view  } (require "fennel"))

(local gsm-char (require :unicode-to-gsm))

(fn escape-for-logging [s]
  (s:gsub "%c" (fn [x] (.. "{" (string.byte x) "}"))))

(fn tx [fd s]
  (write fd s)
  (print (.. ">>> " (escape-for-logging s)))
  (nanosleep {:tv_sec 0 :tv_nsec (* 10 1000 1000)}))

(fn chars [i]
  (if (not i)
      ""
      (< i 256)
      (string.char i)
      (.. (string.char (rshift i 8)) (string.char (band i 0xff)))))

(fn unicode-to-gsm [s]
  (s:gsub "." (fn [c] (chars (. gsm-char (string.byte c))))))

;(print (escape-for-logging (unicode-to-gsm "hello")))
;(print (escape-for-logging (unicode-to-gsm "{he@llo}€")))


(fn expect [fd pattern]
  (let [b (read fd 1024)]
    (if (> (# b) 0)
        (do
          (print (.. "<<< " (escape-for-logging b)))
          (if (string.find b pattern)
              (do (print "found" pattern) true)
              (expect fd pattern)))
        nil)))

(fn send-sms [number body]
  (let [fd (fcntl.open "/dev/serial/by-id/usb-HUAWEI_HUAWEI_HiLink-if00-port0" posix.O_RDWR)
        termios (tcgetattr fd)]
    (tset termios :cflag (bor termios.cflag CLOCAL CREAD))
    (tset termios :lflag (band termios.lflag
                               (bnot ICANON)
                               (bnot ECHO)
                               (bnot ECHOE)
                               (bnot ISIG)))
    (tset termios :oflag (band termios.oflag ( bnot OPOST)))
    (tcsetattr fd 0 termios)
    ;; opt->c_cc[VMIN]  = 1;
    ;; opt->c_cc[VTIME] = 10;
    (tcdrain fd)
    (doto fd
      (tx  "AT\r\n")
      (expect "OK")

      (tx  "AT&F\r\n")
      (expect "OK")

      (tx  "ATE0\r\n")                  ;disable command echo
      (expect "OK")

      (tx "AT+CMEE=1\r\n")              ;print CME errors
      (expect "OK")

      (tx "AT+CMGF=1\r\n")              ;SMS text mode (not PDU mode)
      (expect "OK")

      (tx "AT+CSCS=\"GSM\"\r\n")        ; default character set
      (expect "OK")

      (tx "AT+CSMP=17,12,0,0\r\n")      ; message valid for 12*5 minutes
      (expect "OK")

      (tx "AT+CSCA=\"+447958879879\",145\r\n") ;set SMSC
      (expect "OK")

      (tx (.. "AT+CMGS=\"" number "\"\r\n"))
      (expect ">")

      ;;      (tx (unicode-to-gsm body))
      (tx body)
      (tx "\026\r\n")
      (expect "OK"))))


{  :send send-sms }