;; 0 represents short signal
;; 1 represents long signal
;; Intermational morse from http://en.wikipedia.org/wiki/Morse_code
(def letters-2-bits {\a [0 1]
                     \b [1 0 0 0]
                     \c [1 0 1 0]
                     \d [1 0 0]
                     \e [0]
                     \f [0 0 1 0]
                     \g [1 1 0]
                     \h [0 0 0 0]
                     \i [0 0]
                     \j [0 1 1 1]
                     \k [1 0 1]
                     \l [0 1 0 0]
                     \m [1 1]
                     \n [1 0]
                     \o [1 1 1]
                     \p [0 1 1 0]
                     \q [1 1 0 1]
                     \r [0 1 0]
                     \s [0 0 0]
                     \t [1]
                     \u [0 0 1]
                     \v [0 0 0 1]
                     \w [0 1 1]
                     \x [1 0 0 1]
                     \y [1 0 1 1]
                     \z [1 1 0 0]})

;; circuit: Just a led on the 13 pin.

;; time
(def short-pulse 100)
(def long-pulse 250)
(def letter-delay 500)

;; pin number
(def pin-led 13)

;; functions

(defn blink
  "Given a board and time, make the led blink a given time"
  [board time]
  (digital-write board pin-led HIGH)
  (Thread/sleep time)
  (digital-write board pin-led LOW)
  (Thread/sleep time))

(defn blink-letter
  "Given a letter, blink according to the sequence of 0 (short pulse) and 1 (long pulse)"
  [board letter]
  (doseq [i letter]
    (if (= i 0)
      (blink board short-pulse)
      (blink board long-pulse)))
  (Thread/sleep letter-delay))

(defn write-morse
  "Given a word, make the led blink in morse for each letter (no upper case, no punctuation)"
  [board word]
  (doseq [l word]
    (blink-letter board (m/letters-2-bits l))))

(defn main-write-morse
  "Given a serial device entry:
- open the board
- make the led blink in morse the word word
- then close the board"
  [board-serial-port word]
  (let [board (arduino :firmata board-serial-port)]
    ;;allow arduino to boot
    (Thread/sleep 5000)
    (pin-mode board pin-led OUTPUT)

    (write-morse board word)

    (close board)))

;; define the device according to your env setup (this may vary)
(def device-board "/dev/ttyACM0")

;; this is a limitation on the underlying lib clodiuno uses. Indeed, it searches only for /dev/ttySxx serial devices
;; and on ubuntu GNU/Linux it's named /dev/ACM0
(System/setProperty "gnu.io.rxtx.SerialPorts" device-board)

;; now declaring the board
(def board (arduino :firmata device-board))

;; the led must be set in output mode
(pin-mode board pin-led OUTPUT)

;; Now the heart of the program
(write-morse board "hello world")

;; just to show you that it works (as almost everybody knows at least that sos is 3 short 3 long 3 short)
(write-morse board "sos")

;; do not forget to free the board
(close board)