#include <lmic.h>
#include <hal/hal.h>
#include <SPI.h>
#include <LowPower.h>

const int wake_pin = 2;
const int done_pin = 7;
const int en_pin = 3;
const int trig_pin = A4;
const int echo_pin = A5;

//node_001_otaa (LSB)
static const u1_t PROGMEM APPEUI[8] = {};
void os_getArtEui (u1_t* buf) { memcpy_P(buf, APPEUI, 8);}

//node_001_otaa (LSB)
static const u1_t PROGMEM DEVEUI[8] = {};
void os_getDevEui (u1_t* buf) { memcpy_P(buf, DEVEUI, 8);}

//node_001_otaa (MSB)
static const u1_t PROGMEM APPKEY[16] = {};
void os_getDevKey (u1_t* buf) {  memcpy_P(buf, APPKEY, 16);}

uint8_t data[] = {0xFF,0xFF};
static osjob_t sendjob;
unsigned int sensor_data = 0x0000;

const lmic_pinmap lmic_pins = {
    .nss = 10,
    .rxtx = LMIC_UNUSED_PIN,
    .rst = LMIC_UNUSED_PIN,
    .dio = {0, 16, LMIC_UNUSED_PIN},
};

void wakeUp()
{
      detachInterrupt(0);
      do_send(&sendjob);
      os_runloop_once();
}

unsigned int get_distance(void)
{
    digitalWrite(trig_pin, LOW);
    delayMicroseconds(2);
    digitalWrite(trig_pin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trig_pin, LOW);
    unsigned int distance = pulseIn(echo_pin, HIGH);
    distance = distance/58;
    pinMode(echo_pin, INPUT);
    pinMode(trig_pin, OUTPUT);
    return distance;
}

void onEvent (ev_t ev) {
    os_getTime();
    switch(ev) {
        case EV_JOINED:
            done_pulse();
            digitalWrite(en_pin, LOW);
            attachInterrupt(0, wakeUp, RISING);
            LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF);
          break;
        case EV_TXCOMPLETE:
             done_pulse();
             digitalWrite(en_pin, LOW);
             attachInterrupt(0, wakeUp, RISING);
             LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF);
            break;
        default:
            break;
    }
}

void do_send(osjob_t* j){


    if (LMIC.opmode & OP_TXRXPEND) {
    } else {
        digitalWrite(en_pin, HIGH);
        sensor_data = get_distance();
        data[0] = sensor_data & 255;
        data[1] = (sensor_data >> 8) & 255;
        LMIC_setTxData2(1, data, sizeof(data), 0);
    }
}

void setup() {

    pinMode(echo_pin, INPUT);
    pinMode(trig_pin, OUTPUT);

    pinMode(en_pin, OUTPUT);
    digitalWrite(en_pin,LOW);

    pinMode(done_pin, OUTPUT);
    digitalWrite(done_pin,HIGH);

    attachInterrupt(0, wakeUp, RISING);

    os_init();
    LMIC_reset();
    LMIC_setClockError (MAX_CLOCK_ERROR * 15/100);
    LMIC_setLinkCheckMode(0);
    LMIC.dn2Dr = DR_SF12;
    LMIC_setDrTxpow (DR_SF12, 13);
    LMIC_startJoining();

}

void loop() {
   os_runloop_once();
}

void done_pulse(void) {
digitalWrite(done_pin,LOW);
delay(10);
digitalWrite(done_pin,HIGH);
}