// MIT License
// https://github.com/gonzalocasas/arduino-uno-dragino-lorawan/blob/master/LICENSE
// Based on examples from https://github.com/matthijskooijman/arduino-lmic
// Copyright (c) 2015 Thomas Telkamp and Matthijs Kooijman

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

/*************************************
 * TODO: Change the following keys
 * NwkSKey: network session key, AppSKey: application session key, and DevAddr: end-device address
 *************************************/
static const u1_t NWKSKEY[16] = {0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##};
static const u1_t APPSKEY[16] = {0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##, 0x##};
static const u4_t DEVADDR = 0x########;


// These callbacks are only used in over-the-air activation, so they are
// left empty here (we cannot leave them out completely unless
// DISABLE_JOIN is set in config.h, otherwise the linker will complain).
void os_getArtEui (u1_t* buf) { }
void os_getDevEui (u1_t* buf) { }
void os_getDevKey (u1_t* buf) { }

static osjob_t sendjob;

// Schedule TX every this many seconds (might become longer due to duty
// cycle limitations).
const unsigned TX_INTERVAL = 60;

// Pin mapping
const lmic_pinmap lmic_pins = {
    .nss = 10,
    .rxtx = LMIC_UNUSED_PIN,
    .rst = 9,
    .dio = {2, 6, 7},
};

void onEvent (ev_t ev) {
    if (ev == EV_TXCOMPLETE) {
      Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)"));
      if (LMIC.dataLen) {
        uint8_t downlink[LMIC.dataLen];
        memcpy(&downlink,&(LMIC.frame+LMIC.dataBeg)[0],LMIC.dataLen);
        // Turn on LED if we get the magic number
        digitalWrite(5, downlink[0] == 42);
      }
      // Schedule next transmission
      os_setTimedCallback(&sendjob, os_getTime()+sec2osticks(TX_INTERVAL), do_send);
    }
}

void do_send(osjob_t* j){
    // Payload to send (uplink)
    static uint8_t message[2];

    int value = analogRead(A0);
    message[0] = highByte(value);
    message[1] = lowByte(value);

    // Check if there is not a current TX/RX job running
    if (LMIC.opmode & OP_TXRXPEND) {
        Serial.println(F("OP_TXRXPEND, not sending"));
    } else {
        // Prepare upstream data transmission at the next possible time.
        LMIC_setTxData2(1, message, sizeof(message), 0);
        Serial.println(F("Sending uplink packet..."));
    }
    // Next TX is scheduled after TX_COMPLETE event.
}

void setup() {
    Serial.begin(115200);
    Serial.println(F("Starting..."));

    // LMIC init
    os_init();

    // Reset the MAC state. Session and pending data transfers will be discarded.
    LMIC_reset();

    // Set static session parameters.
    LMIC_setSession (0x1, DEVADDR, NWKSKEY, APPSKEY);

    // Disable link check validation
    LMIC_setLinkCheckMode(0);

    // TTN uses SF9 for its RX2 window.
    LMIC.dn2Dr = DR_SF9;

    // Set data rate and transmit power for uplink (note: txpow seems to be ignored by the library)
    LMIC_setDrTxpow(DR_SF7,14);

    // Start job
    do_send(&sendjob);
}

void loop() {
    os_runloop_once();
}