/*
 
Copyright  2018 Oliver Brandmueller <ob@sysadm.in>
Copyright  2018 Klaus Wilting <verkehrsrot@arcor.de>

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

NOTICE: 
Parts of the source files in this repository are made available under different licenses.
Refer to LICENSE.txt file in repository for more details.

*/

// Basic Config
#include "globals.h"

// Does nothing and avoid any compilation error with I2C
#include <Wire.h> 

// LMIC-Arduino LoRaWAN Stack
#include "loraconf.h"
#include <lmic.h>
#include <hal/hal.h>

// ESP32 lib Functions
#include <esp_event_loop.h>         // needed for Wifi event handler
#include <esp_spi_flash.h>          // needed for reading ESP32 chip attributes
#include <esp32-hal-log.h>          // needed for ESP_LOGx on arduino framework

// Initialize global variables
configData_t cfg;                   // struct holds current device configuration
osjob_t sendjob;                    // LMIC job handler
uint64_t uptimecounter = 0;         // timer global for uptime counter
uint8_t DisplayState = 0;           // globals for state machine
uint16_t macs_total = 0, macs_wifi = 0, macs_ble = 0;   // MAC counters globals for display
uint8_t channel = 0;                // wifi channel rotation counter global for display
char display_lora[16], display_lmic[16]; // display buffers
led_states LEDState = LED_OFF;      // LED state global for state machine
led_states previousLEDState = LED_ON;    // This will force LED to be off at boot since State is OFF
unsigned long LEDBlinkStarted = 0;  // When (in millis() led blink started)
uint16_t LEDBlinkDuration = 0;      // How long the blink need to be
uint16_t LEDColor = COLOR_NONE;     // state machine variable to set RGB LED color
hw_timer_t * displaytimer = NULL;   // configure hardware timer used for cyclic display refresh
hw_timer_t * channelSwitch = NULL;  // configure hardware timer used for wifi channel switching

portMUX_TYPE timerMux = portMUX_INITIALIZER_UNLOCKED; // sync main loop and ISR when modifying shared variable DisplayIRQ

std::set<uint16_t> macs; // associative container holds total of unique MAC adress hashes (Wifi + BLE)

// this variables will be changed in the ISR, and read in main loop
static volatile int ButtonPressed = 0, DisplayTimerIRQ = 0, ChannelTimerIRQ = 0;

// local Tag for logging
static const char *TAG = "paxcnt";
// Note: Log level control seems not working during runtime,
// so we need to switch loglevel by compiler build option in platformio.ini

#ifndef VERBOSE
int redirect_log(const char * fmt, va_list args) {
   //do nothing
   return 0;
}
#endif

void reset_counters() {
    macs.clear();                           // clear all macs container
    macs_total = 0;                         // reset all counters
    macs_wifi = 0;
    macs_ble = 0;
}

/* begin LMIC specific parts ------------------------------------------------------------ */


#ifdef VERBOSE
    void printKeys(void);
#endif // VERBOSE

// LMIC callback functions
void os_getDevKey (u1_t *buf) { 
    memcpy(buf, APPKEY, 16);
}

void os_getArtEui (u1_t *buf) { 
    memcpy(buf, APPEUI, 8);
    RevBytes(buf, 8); // TTN requires it in LSB First order, so we swap bytes
}

void os_getDevEui (u1_t* buf) {
    int i=0, k=0;
    memcpy(buf, DEVEUI, 8); // get fixed DEVEUI from loraconf.h 
    for (i=0; i<8 ; i++) {
        k += buf[i];
    }
    if (k) {
        RevBytes(buf, 8); // use fixed DEVEUI and swap bytes to LSB format
    } else {
        gen_lora_deveui(buf); // generate DEVEUI from device's MAC
    }

    // Get MCP 24AA02E64 hardware DEVEUI (override default settings if found)
    #ifdef MCP_24AA02E64_I2C_ADDRESS
        get_hard_deveui(buf); 
        RevBytes(buf, 8); // swap bytes to LSB format
    #endif
}

// LMIC enhanced Pin mapping
const lmic_pinmap lmic_pins = {
    .mosi = PIN_SPI_MOSI,
    .miso = PIN_SPI_MISO,
    .sck = PIN_SPI_SCK,
    .nss = PIN_SPI_SS,
    .rxtx = LMIC_UNUSED_PIN,
    .rst = RST,
    .dio = {DIO0, DIO1, DIO2}
};


// LMIC FreeRTos Task
void lorawan_loop(void * pvParameters) {

    configASSERT( ( ( uint32_t ) pvParameters ) == 1 ); // FreeRTOS check

    //static uint16_t lorawait = 0;

    while(1) {
        
        // execute LMIC jobs
        os_runloop_once();

        /*
        // check if payload is sent
        while(LMIC.opmode & OP_TXRXPEND) {
            if(!lorawait) 
                sprintf(display_lora, "LoRa wait");
            lorawait++;
            // in case sending really fails: reset LMIC and rejoin network
            if( (lorawait % MAXLORARETRY ) == 0) {
                ESP_LOGI(TAG, "Payload not sent, resetting LMIC and rejoin");
                lorawait = 0;                
                LMIC_reset(); // Reset the MAC state. Session and pending data transfers will be discarded.
            };
            vTaskDelay(1000/portTICK_PERIOD_MS);
        }
        */

        vTaskDelay(10/portTICK_PERIOD_MS); // reset watchdog
    }    
}


/* end LMIC specific parts --------------------------------------------------------------- */


/* beginn hardware specific parts -------------------------------------------------------- */

#ifdef HAS_DISPLAY
    HAS_DISPLAY u8x8(OLED_RST, OLED_SCL, OLED_SDA);
    // Display Refresh IRQ
    void IRAM_ATTR DisplayIRQ() {
        portENTER_CRITICAL_ISR(&timerMux);
        DisplayTimerIRQ++;
        portEXIT_CRITICAL_ISR(&timerMux);
    }
#endif

#ifdef HAS_ANTENNA_SWITCH
    // defined in antenna.cpp
    void antenna_init();
    void antenna_select(const uint8_t _ant);
#endif

#ifndef BLECOUNTER
    bool btstop = btStop();
#endif

#ifdef HAS_BUTTON
    // Button IRQ
    // IRAM_ATTR necessary here, see https://github.com/espressif/arduino-esp32/issues/855
    void IRAM_ATTR ButtonIRQ() {
        ButtonPressed++;
    }
#endif

void IRAM_ATTR ChannelSwitchIRQ() {
    portENTER_CRITICAL(&timerMux);
    ChannelTimerIRQ++;
    portEXIT_CRITICAL(&timerMux);
}

/* end hardware specific parts -------------------------------------------------------- */


/* begin wifi specific parts ---------------------------------------------------------- */

// Sniffer Task
void sniffer_loop(void * pvParameters) {

    configASSERT( ( ( uint32_t ) pvParameters ) == 1 ); // FreeRTOS check

  	while (1) {

        if (ChannelTimerIRQ) {
            portENTER_CRITICAL(&timerMux);
            ChannelTimerIRQ--;
            portEXIT_CRITICAL(&timerMux);
            // rotates variable channel 1..WIFI_CHANNEL_MAX
            channel = (channel % WIFI_CHANNEL_MAX) + 1;
            wifi_sniffer_set_channel(channel);
            ESP_LOGD(TAG, "Wifi set channel %d", channel);

            vTaskDelay(10/portTICK_PERIOD_MS); // reset watchdog
        }

    } // end of infinite wifi channel rotation loop
}

/* end wifi specific parts ------------------------------------------------------------ */

// uptime counter 64bit to prevent millis() rollover after 49 days
uint64_t uptime() {
    static uint32_t low32, high32;
    uint32_t new_low32 = millis();
    if (new_low32 < low32) high32++;
    low32 = new_low32;
    return (uint64_t) high32 << 32 | low32;
}

#ifdef HAS_DISPLAY

    // Print a key on display
    void DisplayKey(const uint8_t * key, uint8_t len, bool lsb) {
        uint8_t start=lsb?len:0;
        uint8_t end = lsb?0:len;
        const uint8_t * p ;
        for (uint8_t i=0; i<len ; i++) {
            p = lsb ? key+len-i-1 : key+i;
            u8x8.printf("%02X", *p);
        }
        u8x8.printf("\n");
    }

    void init_display(const char *Productname, const char *Version) {
        uint8_t buf[32];
        u8x8.begin();
        u8x8.setFont(u8x8_font_chroma48medium8_r);
        u8x8.clear();
        u8x8.setFlipMode(0);
        u8x8.setInverseFont(1);
        u8x8.draw2x2String(0, 0, Productname);
        u8x8.setInverseFont(0);
        u8x8.draw2x2String(2, 2, Productname);
        delay(1500);
        u8x8.clear();
        u8x8.setFlipMode(1);
        u8x8.setInverseFont(1);
        u8x8.draw2x2String(0, 0, Productname);
        u8x8.setInverseFont(0);
        u8x8.draw2x2String(2, 2, Productname);
        delay(1500);

        u8x8.setFlipMode(0);
        u8x8.clear();

        #ifdef DISPLAY_FLIP
            u8x8.setFlipMode(1);
        #endif

        // Display chip information
        #ifdef VERBOSE
            esp_chip_info_t chip_info;
            esp_chip_info(&chip_info);
            u8x8.printf("ESP32 %d cores\nWiFi%s%s\n",
               chip_info.cores,
                (chip_info.features & CHIP_FEATURE_BT) ? "/BT" : "",
                (chip_info.features & CHIP_FEATURE_BLE) ? "/BLE" : "");
            u8x8.printf("ESP Rev.%d\n", chip_info.revision);
            u8x8.printf("%dMB %s Flash\n", spi_flash_get_chip_size() / (1024 * 1024),
                (chip_info.features & CHIP_FEATURE_EMB_FLASH) ? "int." : "ext.");
        #endif // VERBOSE

        u8x8.print(Productname);
        u8x8.print(" v");
        u8x8.println(PROGVERSION);
        u8x8.println("DEVEUI:");
        os_getDevEui((u1_t*) buf);
        DisplayKey(buf, 8, true);
        delay(5000);
        u8x8.clear();
    }

    void refreshDisplay() {
        // update counter display (lines 0-4)
        char buff[16];
        snprintf(buff, sizeof(buff), "PAX:%-4d", (int) macs.size()); // convert 16-bit MAC counter to decimal counter value
        u8x8.draw2x2String(0, 0, buff);          // display number on unique macs total Wifi + BLE
        u8x8.setCursor(0,4);
        u8x8.printf("WIFI:%-4d", macs_wifi);

        #ifdef BLECOUNTER
            u8x8.setCursor(0,3);
            if (cfg.blescan)
                u8x8.printf("BLTH:%-4d", macs_ble);
            else
                u8x8.printf("%s", "BLTH:off");
        #endif

        // update LoRa SF display (line 3)
        u8x8.setCursor(11,3);
        u8x8.printf("SF:%c%c", lora_datarate[LMIC.datarate * 2], lora_datarate[LMIC.datarate * 2 + 1]);

        // update wifi channel display (line 4)
        u8x8.setCursor(11,4);
        u8x8.printf("ch:%02d", channel);

        // update RSSI limiter status & free memory display (line 5)
        u8x8.setCursor(0,5);
        u8x8.printf(!cfg.rssilimit ? "RLIM:off " : "RLIM:%-4d", cfg.rssilimit);
        u8x8.setCursor(10,5);
        u8x8.printf("%4dKB", ESP.getFreeHeap() / 1024);
        
        // update LoRa status display (line 6)
        u8x8.setCursor(0,6);
        u8x8.printf("%-16s", display_lora);

        // update LMiC event display (line 7)
        u8x8.setCursor(0,7);
        u8x8.printf("%-16s", display_lmic);
    }    

    void updateDisplay() {
        // refresh display according to refresh cycle setting
        if (DisplayTimerIRQ) {
            portENTER_CRITICAL(&timerMux);
            DisplayTimerIRQ--;
            portEXIT_CRITICAL(&timerMux);

            refreshDisplay();
        
            // set display on/off according to current device configuration
            if (DisplayState != cfg.screenon) {
                DisplayState = cfg.screenon;
                u8x8.setPowerSave(!cfg.screenon);
            }
        }
    } // updateDisplay()
#endif // HAS_DISPLAY

#ifdef HAS_BUTTON
    void readButton() {
        if (ButtonPressed) {
            ButtonPressed--;
            ESP_LOGI(TAG, "Button pressed, resetting device to factory defaults");
            eraseConfig();
            esp_restart();
        }
    }
#endif

#if (HAS_LED != NOT_A_PIN) || defined (HAS_RGB_LED)

    void blink_LED(uint16_t set_color, uint16_t set_blinkduration) {
        LEDColor = set_color;                   // set color for RGB LED
        LEDBlinkDuration = set_blinkduration;   // duration 
        LEDBlinkStarted = millis();             // Time Start here
        LEDState = LED_ON;                      // Let main set LED on
    }

    void led_loop() {
        // Custom blink running always have priority other LoRaWAN led management
        if ( LEDBlinkStarted && LEDBlinkDuration) {

            //ESP_LOGI(TAG, "Start=%ld for %g",LEDBlinkStarted, LEDBlinkDuration );

            // Custom blink is finished, let this order, avoid millis() overflow
            if ( (millis() - LEDBlinkStarted) >= LEDBlinkDuration) {
                // Led becomes off, and stop blink 
                LEDState = LED_OFF;
                LEDBlinkStarted = 0;
                LEDBlinkDuration = 0;
                LEDColor = COLOR_NONE ;
            } else {
                // In case of LoRaWAN led management blinked off
                LEDState = LED_ON;
            }
            
        // No custom blink, check LoRaWAN state
        } else {

            // LED indicators for viusalizing LoRaWAN state
            if ( LMIC.opmode & (OP_JOINING | OP_REJOIN) )  {
                LEDColor = COLOR_YELLOW;
                // quick blink 20ms on each 1/5 second
                LEDState = ((millis() % 200) < 20) ? LED_ON : LED_OFF;   // TX data pending
            } else if (LMIC.opmode & (OP_TXDATA | OP_TXRXPEND)) {
                LEDColor = COLOR_BLUE;
                // small blink 10ms on each 1/2sec (not when joining)
                LEDState = ((millis() % 500) < 20) ? LED_ON : LED_OFF;
            // This should not happen so indicate a problem
            } else  if ( LMIC.opmode & (OP_TXDATA | OP_TXRXPEND | OP_JOINING | OP_REJOIN) == 0 ) {
                LEDColor = COLOR_RED;
                // heartbeat long blink 200ms on each 2 seconds
                LEDState = ((millis() % 2000) < 200) ? LED_ON : LED_OFF;
            } else {
                // led off
                LEDColor = COLOR_NONE;
                LEDState = LED_OFF;
            }            
        }

        //ESP_LOGI(TAG, "state=%d previous=%d Color=%d",LEDState, previousLEDState, LEDColor );
        // led need to change state? avoid digitalWrite() for nothing
        if (LEDState != previousLEDState) {
            if (LEDState == LED_ON) {
                rgb_set_color(LEDColor);
                #ifdef LED_ACTIVE_LOW
                  digitalWrite(HAS_LED, LOW); 
                #else
                  digitalWrite(HAS_LED, HIGH);
                #endif
            } else {
                rgb_set_color(COLOR_NONE);
                #ifdef LED_ACTIVE_LOW
                  digitalWrite(HAS_LED, HIGH); 
                #else
                  digitalWrite(HAS_LED, LOW);
                #endif
            }
            previousLEDState = LEDState;
        }
    }; // led_loop()

 #endif

/* begin Aruino SETUP ------------------------------------------------------------ */

void setup() {
    char features[64] = "";

    // disable brownout detection
#ifdef DISABLE_BROWNOUT
    // register with brownout is at address DR_REG_RTCCNTL_BASE + 0xd4
  (*((volatile uint32_t *)ETS_UNCACHED_ADDR((DR_REG_RTCCNTL_BASE+0xd4)))) = 0;
#endif

    // setup debug output or silence device
#ifdef VERBOSE
    Serial.begin(115200);
    esp_log_level_set("*", ESP_LOG_VERBOSE);
#else
    // mute logs completely by redirecting them to silence function
    esp_log_level_set("*", ESP_LOG_NONE);
    esp_log_set_vprintf(redirect_log);
#endif
    
    ESP_LOGI(TAG, "Starting %s %s", PROGNAME, PROGVERSION);
    
    // initialize system event handler for wifi task, needed for wifi_sniffer_init()
    esp_event_loop_init(NULL, NULL);

    // print chip information on startup if in verbose mode
#ifdef VERBOSE
    esp_chip_info_t chip_info;
    esp_chip_info(&chip_info);
    ESP_LOGI(TAG, "This is ESP32 chip with %d CPU cores, WiFi%s%s, silicon revision %d, %dMB %s Flash",
            chip_info.cores,
            (chip_info.features & CHIP_FEATURE_BT) ? "/BT" : "",
            (chip_info.features & CHIP_FEATURE_BLE) ? "/BLE" : "", 
            chip_info.revision, spi_flash_get_chip_size() / (1024 * 1024),
            (chip_info.features & CHIP_FEATURE_EMB_FLASH) ? "embedded" : "external");
    ESP_LOGI(TAG, "ESP32 SDK: %s", ESP.getSdkVersion());
#endif

    // read settings from NVRAM
    loadConfig(); // includes initialize if necessary

    // initialize led if needed
#if (HAS_LED != NOT_A_PIN) 
    pinMode(HAS_LED, OUTPUT);
    strcat(features, " LED");
#endif

#ifdef HAS_RGB_LED
    rgb_set_color(COLOR_PINK);
    strcat(features, " RGB");
    delay(1000);
#endif


    // initialize button handling if needed
#ifdef HAS_BUTTON
    strcat(features, " BTN_");
    #ifdef BUTTON_PULLUP
        strcat(features, "PU");
        // install button interrupt (pullup mode)
        pinMode(HAS_BUTTON, INPUT_PULLUP);
        attachInterrupt(digitalPinToInterrupt(HAS_BUTTON), ButtonIRQ, RISING); 
    #else
        strcat(features, "PD");
        // install button interrupt (pulldown mode)
        pinMode(HAS_BUTTON, INPUT_PULLDOWN);
        attachInterrupt(digitalPinToInterrupt(HAS_BUTTON), ButtonIRQ, FALLING); 
    #endif
#endif

    // initialize wifi antenna if needed
#ifdef HAS_ANTENNA_SWITCH
    strcat(features, " ANT");
    antenna_init();
#endif

#ifdef HAS_DISPLAY
    strcat(features, " OLED");
    // initialize display  
    init_display(PROGNAME, PROGVERSION);  
    DisplayState = cfg.screenon;   
    u8x8.setPowerSave(!cfg.screenon); // set display off if disabled
    u8x8.draw2x2String(0, 0, "PAX:0");
    u8x8.setCursor(0,4);
    u8x8.printf("WIFI:0");
    #ifdef BLECOUNTER
        u8x8.setCursor(0,3);
        u8x8.printf("BLTH:0");
    #endif
    u8x8.setCursor(0,5);
    u8x8.printf(!cfg.rssilimit ? "RLIM:off " : "RLIM:%d", cfg.rssilimit);
    
    sprintf(display_lora, "Join wait");

    // setup display refresh trigger IRQ using esp32 hardware timer 0 
    // for explanation see https://techtutorialsx.com/2017/10/07/esp32-arduino-timer-interrupts/
    displaytimer = timerBegin(0, 80, true);                        // prescaler 80 -> divides 80 MHz CPU freq to 1 MHz, timer 0, count up
    timerAttachInterrupt(displaytimer, &DisplayIRQ, true);         // interrupt handler DisplayIRQ, triggered by edge
    timerAlarmWrite(displaytimer, DISPLAYREFRESH_MS * 1000, true); // reload interrupt after each trigger of display refresh cycle
    timerAlarmEnable(displaytimer);                                // enable display interrupt
#endif

// setup channel rotation trigger IRQ using esp32 hardware timer 1
channelSwitch = timerBegin(1, 80, true);                        
timerAttachInterrupt(channelSwitch, &ChannelSwitchIRQ, true);
timerAlarmWrite(channelSwitch, cfg.wifichancycle * 10000, true);
timerAlarmEnable(channelSwitch);

// show compiled features
ESP_LOGI(TAG, "Features %s", features);

// output LoRaWAN keys to console
#ifdef VERBOSE
    printKeys();
#endif

// initialize LoRaWAN LMIC run-time environment
os_init(); 
// reset LMIC MAC state
LMIC_reset();
// This tells LMIC to make the receive windows bigger, in case your clock is 1% faster or slower.
LMIC_setClockError(MAX_CLOCK_ERROR * 1 / 100); 

// start lmic runloop in rtos task on core 1 (note: arduino main loop runs on core 1, too)
// https://techtutorialsx.com/2017/05/09/esp32-get-task-execution-core/

ESP_LOGI(TAG, "Starting Lora task on core 1");
xTaskCreatePinnedToCore(lorawan_loop, "loratask", 2048, ( void * ) 1,  ( 5 | portPRIVILEGE_BIT ), NULL, 1); 

// start wifi in monitor mode and start channel rotation task on core 0
ESP_LOGI(TAG, "Starting Wifi task on core 0");
wifi_sniffer_init(); 
// initialize salt value using esp_random() called by random() in arduino-esp32 core
// note: do this *after* wifi has started, since function gets it's seed from RF noise
reset_salt(); // get new 16bit for salting hashes
xTaskCreatePinnedToCore(sniffer_loop, "wifisniffer", 2048, ( void * ) 1, 1, NULL, 0);

// start BLE scan callback if BLE function is enabled in NVRAM configuration
#ifdef BLECOUNTER
    if (cfg.blescan) { 
        start_BLEscan();
    }
#endif
    
// kickoff sendjob -> joins network and rescedules sendjob for cyclic transmitting payload
do_send(&sendjob);

}

/* end Arduino SETUP ------------------------------------------------------------ */

/* begin Arduino main loop ------------------------------------------------------ */

void loop() {

  	while (1) {

        // simple state machine for controlling uptime, display, LED, button, memory.

        uptimecounter = uptime() / 1000;    // counts uptime in seconds (64bit)

        #if (HAS_LED != NOT_A_PIN) || defined (HAS_RGB_LED)
            led_loop();
        #endif
    
        #ifdef HAS_BUTTON
            readButton();
        #endif

        #ifdef HAS_DISPLAY
            updateDisplay();
        #endif

        // check free memory
        if (esp_get_minimum_free_heap_size() <= MEM_LOW) {
            ESP_LOGI(TAG, "Memory full, counter cleared (heap low water mark = %d Bytes / free heap = %d bytes)", \
                esp_get_minimum_free_heap_size(), ESP.getFreeHeap());
            do_send(&sendjob);  // send count
            reset_counters();   // clear macs container and reset all counters
            reset_salt();       // get new salt for salting hashes
        }

        vTaskDelay(10/portTICK_PERIOD_MS); // reset watchdog

    } // end of infinite main loop
}

/* end Arduino main loop ------------------------------------------------------------ */