// Weather Station 3 from AliExpress / TaoBao
// 
// Highly inspired by https://github.com/kquinsland/ws3-to-esphome-bridge/
// 
// Maybe the code is not optimal but it works.
// 
// Configuration of WS3 :
//
// JP1 toggle betwen ARS inch mode and professional metric mode
//     short : inch
//     open  : metric
//
// JP2 baud rate
//     short : 2400
//     open  : 9600
//
// Configuration used for this code :
// JP1 : open
// JP2 : closed
//
// Data is in the form :
//
// A4095B000C0000D0000E0000F0000G0000H0000I0000J0000K0000L0218M515N09654O.....*52
//
//
// Serial connection used there (hardcoded using AltSoftSerial) :
// Only TX has to be connected, RX is not used by WS3. 
//
// Board            Receive
// -----            -------
// Teensy 3.0 & 3.1  20
// Teensy 2.0        10
// Teensy++ 2.0       4
// Arduino Uno        8
// EtherTen           8
// Arduino Leonardo  13
// Arduino Mega      48
// Wiring-S           6
// Sanguino          14
//
// This code was tested and developped on EtherTen board which
// is Arduino Uno compatible with some additions.
//
// Use following libraries:
//  - AltSoftSerial
//  - Adafruit_MQTT
//

// soft or alt
// AltSerial takes more global variables.
#define ALTSERIAL
#ifdef ALTSERIAL
#include <AltSoftSerial.h>
#else 
#include <SoftwareSerial.h>
#endif
// Ethernet
#include <SPI.h>
#include <Ethernet.h>
// MQTT
#include <PubSubClient.h>

// Define the mac address.
const byte mac[] PROGMEM = {
  0xDE, 0xAA, 0xBE, 0xEC, 0xAF, 0x02
};

// Domoticz MQTT configuration
#define mqtt_server     "192.168.20.253"
#define mqtt_port       1883
// Domoticz Indexes (virtual devices has to be created)
#define domoticz_windir 160
#define domoticz_temp   161
#define domoticz_hum    162
#define domoticz_rain   163
#define domoticz_pres   164
// Definitions
const char* Mqtt_clientid = "51WS3Wether";
const char* dom_in        = "domoticz/in";


// Defines
#define DEBUG

#ifdef DEBUG
 #define debug(x)   Serial.print(x)
 #define debugln(x) Serial.println(x)
#else /* DEBUG */
 #define debug(x)
 #define debugln(x)
#endif /* DEBUG */
// Baud used to read see JP2
#define WS3_BAUD  2400
// Toggle support for PM2.5 sensor
//#define SUPPORT_PM25_SENSOR 

// Define the length of data
#ifdef SUPPORT_PM25_SENSOR
  // There is 88 bytes per packets
  #define WS3_PKT_LEN 78
  // And the checksum is the last 2 bytes 
  #define WS3_CHK_LEN 2
  #define CHK_SUM_DELINEATOR 75
#else /* SUPPORT_PM25_SENSOR */
  // There is 88 bytes per packets
  #define WS3_PKT_LEN 78
  // And the checksum is the last 2 bytes 
  #define WS3_CHK_LEN 2
  #define CHK_SUM_DELINEATOR 75
#endif /* SUPPRT_PM25_SENSOR */

// Seems the Metric format does not have a correct checksum
// In this case we should not test the checksum, just see
// if we have a correct dataline
#define DONT_CHKSUM

// Place holder for the packet received
String pkt_str = "";

// Flag for packet OK
bool pkt_ok = false;

#ifdef ALTSERIAL
AltSoftSerial WS3;
#else
SoftwareSerial WS3(8,9);
#endif
EthernetClient ethClient;
//PubSubClient client(ethClient);

// After parsing the string of bytes, we'll have an easier to use struct
// TODO: this should be it's own file?
struct WS3Packet {

  // The 1st field is "A0000" - Wind direction AD value in real time (0-4096)
  int wind_dir;  
  // The 2nd field is "B000" - Wind direct angle value (16 direction)
  int wind_angle;  // new
  // The 3rd field is "C0000" - Real time wind speed frequency 1Hz
  int wind_freq;  // New
  // The 4th field is "D0000" - Real time wind speed, unit: 0.1 m/s
  float wind_speed;
  // The 5th field is "E0000" - Avg wind speed in the previous minute, unit: 0.1m/s
  float wind_speed_1m;
  // The 6th field is "F0000" - the highest wind speed in the last 5 minutes, unit: 0.1m/s
  float wind_speed_5m;
  // The 7th field is "G0000" - Real time rain bucket (0-9999), loop-count
  int rain_bucket_cnt; // New
  // The 8th field is "H0000" - Number of rain bucket in the last minute, (0-9999)
  int rt_rain_bucket;
  // The 9th field is "I0000" - Rain fall in 1 minute, unit: 0.1mm
  float rain_1m;
  // The 10th field is "J0000" - the previous hour's rainfall ( 0.1 mm)
  float rain_1h;
  // The 11th field is "K0000" - rainfall during the first 24 hours ( 0.1 mm)
  float rain_24h;
  // The 12th field is "L0000" - temperature, unit: degree C (unit 0.1 Degree)
  float temp_f;
  // The 13th field is "M000" - humidity ( 00 % - 99 %), unit 0.1% 
  float humidity;
  // The 14th field is "M10020" - air pressure ( 0.1 hpa )
  float air_pressure;    
};

// Setup the stuff.
void setup() {
  // You can use Ethernet.init(pin) to configure the CS pin
  //Ethernet.init(10);  // Most Arduino shields
  //Ethernet.init(5);   // MKR ETH shield
  //Ethernet.init(0);   // Teensy 2.0
  //Ethernet.init(20);  // Teensy++ 2.0
  //Ethernet.init(15);  // ESP8266 with Adafruit Featherwing Ethernet
  //Ethernet.init(33);  // ESP32 with Adafruit Featherwing Ethernet
  
  Serial.begin(57600);
  while (!Serial) ; // wait for Arduino Serial Monitor to open
  Serial.println("Weather Station 3 Adapter by Kiwi");

  // Wait for eternet to initialize
   // start the Ethernet connection:
  Serial.println("Initialize Ethernet with DHCP:");
  if (Ethernet.begin(mac) == 0) {
    Serial.println("Failed to configure Ethernet using DHCP");
    if (Ethernet.hardwareStatus() == EthernetNoHardware) {
      Serial.println("Ethernet shield was not found.  Sorry, can't run without hardware. :(");
    } else if (Ethernet.linkStatus() == LinkOFF) {
      Serial.println("Ethernet cable is not connected.");
    }
    // no point in carrying on, so do nothing forevermore:
    while (true) {
      delay(1);
    }
  }
  // print your local IP address:
  Serial.print("My IP address: ");
  Serial.println(Ethernet.localIP());

  // Start the Software Serial for WS3
  WS3.begin(WS3_BAUD);
  debugln("WS3 UART is ready...");

  // Allocate memory for packet
  pkt_str.reserve(WS3_PKT_LEN);
  //payload.reserve(WS3_PKT_LEN-WS3_CHK_LEN);
  debugln(" -> Packet memory allocated!");
}

#ifdef DONT_CHKSUM
// Validate packet using the checksum.
// Work only APRS data on this 51W3 board. 
// Maybe the code on the board does not make the correct checksum ?
bool validate_packet(String pay, unsigned long chk) {
  // Print the payload and the checksum we want
  debugln("validate_packet:");
  debug(pay);
  debug(" * ");
  debugln(chk);

  // TEST DATA (actual packets)
  // c000s000g000t075r000p019h43b09940*32
  // String pay = "c000s000g000t075r000p019h43b09940";
  // byte chk = 0x32; // this will be in HEX)

  // c000s000g000t075r000p019h42b09940*33
  // String pay = "c000s000g000t075r000p019h42b09940";
  // byte chk = 0x33; // this will be in HEX)
  
  // c000s000g000t075r000p019h42b09939*3D
  // String pay = "c000s000g000t075r000p019h42b09939";
  // byte chk = 0x3D; // this will be in HEX)

  // SUPER grateful for the helpful https://toolslick.com/math/bitwise/xor-calculator to validate my
  // code!

  // Current byte
  byte i1=0;

  // the intermediate checksum
  byte tmp = 0;

  // starting from the second character, we begin XORing
  for (int x = 0; x < pay.length() ; x++) {

    i1=pay[x];
        
    // Do the xOR
    tmp = tmp^i1;

  }

  // do the check
  if(tmp == chk){
    return true;
  } else {
    debugln("INVALID!");
    debug("calculated:");
    debugln(tmp);
    return false;
  }
}
#endif /* DONT_CHKSUM */


// Parse the packet and fill the structure with data
void parse_packet(String payload, WS3Packet* p) { 

  // E.G.: A4095 B000 C0000 D0000 E0000 F0000 G0000 H0000 I0000 J0000 K0000 L0237 M502 N09810 O.....
  
  // Parse in order, starting with A0000 (wind dir real time, 0-4096)
  int wind_dir_idx = payload.indexOf('A');
  p->wind_dir = payload.substring(wind_dir_idx+1, wind_dir_idx+5).toInt();

  // Then move on to B000 - wind direction angle (16 direction)
  int wind_angle_idx = payload.indexOf('B');
  p->wind_angle = payload.substring(wind_angle_idx+1, wind_angle_idx+4).toInt();

  // Then move on to C0000 - wind speed frequency (1 Hz)
  int wind_freq_idx = payload.indexOf('C');
  p->wind_freq = payload.substring(wind_freq_idx+1, wind_freq_idx+5).toInt();

  // Then move on to D0000 - wind speed real time (unit 0.1 m/s)
  int wind_speed_idx = payload.indexOf('D');
  p->wind_speed = payload.substring(wind_speed_idx+1, wind_speed_idx+5).toInt() / 10;

  // Then move on to E0000 - wind speed avg in the last minute (unit 0.1 m/s)
  int wind_speed_1m_idx = payload.indexOf('D');
  p->wind_speed_1m = payload.substring(wind_speed_1m_idx+1, wind_speed_1m_idx+5).toInt() / 10;

  // Then move on to F0000 - wind speed over the last 5 min
  int wind_speed_5_idx = payload.indexOf('F');
  p->wind_speed_5m = payload.substring(wind_speed_5_idx+1, wind_speed_5_idx+5).toInt() / 10;

  // Then move on to G0000 - Rain in Realtime (0-9999 counter) bucket
  int rain_bucket_cnt_idx = payload.indexOf('G');
  p->rain_bucket_cnt = payload.substring(rain_bucket_cnt_idx+1, rain_bucket_cnt_idx+5).toInt();

  // Then move on to H0000 - Rain bucket in the last 1 minute (0-9999 counter)
  int rt_rain_bucket_idx = payload.indexOf('H');
  p->rt_rain_bucket = payload.substring(rt_rain_bucket_idx+1, rt_rain_bucket_idx+5).toInt();

  // Then move on to I0000 - rain last minute (0.1mm)
  int rain1m_idx = payload.indexOf('I');
  p->rain_1m = payload.substring(rain1m_idx+1, rain1m_idx+5).toInt() *.1;

  // Then move on to J0000 - rain last hour (0.1mm)
  int rain1h_idx = payload.indexOf('J');
  p->rain_1h = payload.substring(rain1h_idx+1, rain1h_idx+5).toInt() *.1;

  // Then move on to K0000 - rain last 24h (0.1mm)
  int rain24h_idx = payload.indexOf('K');
  p->rain_24h = payload.substring(rain24h_idx+1, rain24h_idx+5).toInt()*.1;

  // Then move on to L0200 - temp (0.1°C) 
  // XXX: Check with minus zero temperatures
  int temp_idx = payload.indexOf('L');
  p->temp_f = payload.substring(temp_idx+1, temp_idx+5).toInt()*.1;

  // Then move on to M611 - Humidity
  int humidity_idx = payload.indexOf('M');
//  p->humidity = payload.substring(humidity_idx+1, humidity_idx+3).toInt()*.1;
  p->humidity = payload.substring(humidity_idx+1, humidity_idx+3).toInt();

  // Then move on to N10020 - air pressure
  int pressure_idx = payload.indexOf('N');
  p->air_pressure = payload.substring(pressure_idx+1, pressure_idx+6).toInt()*.1;

}

// Clear the packet before working on the next
void clear_pkt(WS3Packet* p) {
  p->wind_dir        = 0;
  p->wind_angle      = 0;
  p->wind_freq       = 0;
  p->wind_speed      = 0;
  p->wind_speed_1m   = 0;
  p->wind_speed_5m   = 0;
  p->rain_bucket_cnt = 0;
  p->rt_rain_bucket  = 0;
  p->rain_1m         = 0;
  p->rain_1h         = 0;
  p->rain_24h        = 0;
  p->temp_f          = 0;
  p->humidity        = 0;
  p->air_pressure    = 0;
}

// Print the data
void print_weather(WS3Packet* p){
  Serial.print("Wind Direction (realtime): ");
  Serial.println(p->wind_dir, DEC);
  //Serial.println(" degrees");
  Serial.print("Wind direction angle : ");
  Serial.print(p->wind_angle, DEC);
  Serial.println(" degree");
  Serial.print("Wind speed Frequency: ");
  Serial.print(p->wind_freq, DEC);
  Serial.println(" Hz");
  Serial.print("Wind speed: ");
  Serial.print(p->wind_speed, DEC);
  Serial.println(" m/s");
  Serial.print("Wind speed 1m: ");
  Serial.print(p->wind_speed_1m, DEC);
  Serial.println(" m/s");
  Serial.print("Wind speed 5m: ");
  Serial.print(p->wind_speed_5m, DEC);
  Serial.println(" m/s");
  Serial.print("temp_f: ");
  Serial.print(p->temp_f, DEC); 
  Serial.println(" deg. C.");

  Serial.print("Rain buckets / buckets 1m: ");
  Serial.print(p->rain_bucket_cnt, DEC); 
  Serial.print(" / ");
  Serial.println(p->rt_rain_bucket, DEC); 
  
  Serial.print("Rain 1m / 1H / 24H: ");
  Serial.print(p->rain_1m, DEC); 
  Serial.print(" / ");
  Serial.print(p->rain_1h, DEC); 
  Serial.print(" / ");
  Serial.print(p->rain_24h, DEC); 
  Serial.println(" mm");

  Serial.print("humidity: ");
  Serial.print(p->humidity, DEC); 
  Serial.println(" %");

  Serial.print("air_pressure: ");
  Serial.print(p->air_pressure, DEC); 
  Serial.println(" hpa");
 }

// Processing the packet.
bool process_packet(String pkt, WS3Packet* p) {
  debugln("[D] process_packet - ALive!");
  debugln(pkt);

  // Allocate bytes for the payload
  String payload;
  payload.reserve(WS3_PKT_LEN-WS3_CHK_LEN);

  #ifdef DONT_CHKSUM
  // everything after the * is checksum (2 char long)
  unsigned long chksum;
  #endif /* DONT_CHKSUM */
 
  // Check if the 75rd character is *
  if (pkt.charAt(CHK_SUM_DELINEATOR) != '*') {
    debugln("Packed invalid; no * character at position 75!");    
    return false;
  #ifdef DONT_CHKSUM
  } else {
    // The character indicating the checksum is coming is in the correct place. Yay.
    // Now, we need to pull the two ascii characters that are transmitted to us
    // and turn them into a single byte. E.G. Char 3, Char D should convert to 0x3D.
    //
    // We can do this with the strtoul() function; we indicate that we wante base 16
    
    chksum = strtoul(pkt.substring(CHK_SUM_DELINEATOR+1, CHK_SUM_DELINEATOR+2).c_str(),NULL,16);
    //Serial.print("Checksum :");
    //Serial.println(pkt.substring(CHK_SUM_DELINEATOR+1, CHK_SUM_DELINEATOR+2).c_str());
  }
  #endif /* DONT_CHKSUM */

  // We have the checksum, Now we can bother to get the payload
  payload = pkt.substring(0, CHK_SUM_DELINEATOR);

  // And try to validate...
  #ifndef DONT_CHKSUM
  if(!validate_packet(payload, chksum)){
    debugln("invalid packet! :(");
    return false;
  } else {
    debugln("Valid packet!");
  }
  #endif /* DONT_CHKSUM */
  parse_packet(payload, p);
  return true;
}

void loop() {
  // While data comes in and we don't have a pending packet to process...
  while (WS3.available() && pkt_ok !=true) {
    
    // Pull the bytes off the stream
    char inChar = (char)WS3.read();

    // And build up the packet
    pkt_str += inChar;
    
    // Until we hit the end
    if (inChar == '\n') {
      pkt_ok = true;
    }
  }

  // Yay, we now have a packet! 
  // Now, we attempt to parse out the string into a packet that we can work with
  if (pkt_ok) {
    debugln("pkt_ok!");

    // At this point, we have a string of characters that was probably a valid packet
    // We set get some memory and attempt to parse the string into the struct
    WS3Packet p = {};
  
    // Validate the payload, then parse it. 
    if (process_packet(pkt_str, &p)) {
      // print results if parse OK
      print_weather(&p);
      debugln("processed");
    } else {
      debugln("unable to parse packet :(");
    }

   
    // clear so we can start again
    pkt_str = "";
    pkt_ok = false;
    clear_pkt(&p); 
 }
}

// MQTT Stuff
#ifdef MQTT
void callback(char* topic, byte* payload, unsigned int length) {
  debug("Message arrived [");
  Serial.print(topic);
  debug("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  debug(" ");
}
void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    debug("Attempting MQTT connection...");
    // Attempt to connect
    if (client.connect(Mqtt_clientid)) {
      debugln("connected");
      // ... and resubscribe
      client.subscribe(dom_in);
    } else {
      debug("failed, rc=");
      debug(client.state());
      debugln(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      for(int i = 0; i<5000; i++){
        delay(1);
      }
    }
  }
}
#endif