// MQTT PUBLISH implementation for LOXONE
// Version 0.1 ... 2017-11-04 ... kianusch@gmail.com
// Version 0.2 ... 2017-11-08 ... kianusch@gmail.com
// Version 0.3 ... 2017-11-14 ... kianusch@gmail.com

#define CONNECT    0x10
#define CONNACK    0x20
#define PUBLISH    0x30
#define PINGREQ    0xC0
#define PINGRESP   0xD0
#define DISCONNECT 0xE0

#define KEEPALIVE  30

// #define CLIENTID "iobroker"

#define DEVICE "/dev/tcp/192.168.x.x/1883"

#define USERNAME "user"
#define PASSWORD "passwd"

char* topic[13];

topic[0]="esp01/gpio/12";
topic[1]="esp02/gpio/12";
topic[2]="esp03/gpio/12";
topic[3]="esp04/gpio/12";
topic[4]="esp05/pwm/12";
topic[5]="";
topic[6]="";
topic[7]="";
topic[8]="";
topic[9]="";
topic[10]="";
topic[11]="";
topic[12]="";

char conHeader[2] = {CONNECT, 0};
char conMessage[10] = {0, 4, 'M', 'Q', 'T', 'T', 4, 2, 0, KEEPALIVE};
char conPayload[128];
char disCon[2] = {DISCONNECT, 0};
char pingReq[2] = {PINGREQ, 0};
char pubHeader[2] = {PUBLISH, 0};

int nEvents;
int input;
char inputStr[8];
STREAM* stream = NULL;
int keepalive;

void tostring(char *str, int num)
{
    int i, rem, len = 0, n;
 
    n = num;
    while (n != 0)
    {
        len++;
        n /= 10;
    }
    for (i = 0; i < len; i++)
    {
        rem = num % 10;
        num = num / 10;
        str[len - (i + 1)] = rem + '0';
    }
    str[len] = '\0';
}

void setConMessage() {
   char *ppayload;
   conMessage[7] |= 0x02;
   int len;
   int tmpLen;

   ppayload=conPayload;

   // set Client Identifier to blank
   *(ppayload++)=0;
   *(ppayload++)=0;
   len=2;

   if (USERNAME != NULL) {
     conMessage[7] |= 0x80;
     tmpLen=strlen(USERNAME);
     *(ppayload++)=0;
     *(ppayload++)=tmpLen;
     strcpy(ppayload, USERNAME);     
     ppayload+=tmpLen; 
     len+=(tmpLen+2);
   }   

   if (PASSWORD != NULL) {
     conMessage[7] |= 0x40;
     tmpLen=strlen(PASSWORD);
     *(ppayload++)=0;
     *(ppayload++)=tmpLen;
     strcpy(ppayload, PASSWORD);
     ppayload+=tmpLen;
     len+=(tmpLen+2);
   }   

   conHeader[1]=10+len;
}

STREAM* connect() {
   STREAM* mystream;
   char response[2];
   int len;

   mystream = stream_create(DEVICE,0,0);
   if (mystream != NULL) {
      stream_write(mystream,conHeader,2);
      stream_write(mystream,conMessage,10);
      len=conHeader[1]-10;
      stream_write(mystream,conPayload,len);
      stream_flush(mystream);

      len=stream_read(mystream,response,2,1000);
      if (len==2 && response[0] == CONNACK && response[1] == 2) {
         stream_read(mystream,response,2,1000);
         if (response[0] == 0 && response[1] == 0) {
            return mystream;
         }
         printf("MQTT: ACK failed. [Session Present: %02x / Code: %02x]", response[0], response[1]);
      } else {
         printf("MQTT: ACK failed. [len: %d / code: %02x]", len, response[0]);
      }
      stream_write(mystream,disConHeader,2);
      stream_flush(mystream);
      stream_close(mystream);
   }
   return NULL;
}

void publish(STREAM* stream, char* topic, char* message) {
   char payload[128];
   char payloadLen[2];

   strcpy(payload,topic);
   strcat(payload,message);

   pubHeader[1]=strlen(payload)+2;
   stream_write(stream,pubHeader,2);

   payloadLen[0]=0;
   payloadLen[1]=strlen(topic);
   stream_write(stream,payloadLen,2);

   stream_write(stream,payload,strlen(payload));
   stream_flush(stream);
}


int ping(STREAM* stream) {
   int len;
   stream_write(stream,pingReq,2);
   stream_flush(stream);
   char response[2];

   len=stream_read(stream,response,2,1000);
   if (len==2 && response[0] == PINGRESP && response[1] == 0) {
      return 1;
   } else {
      printf("MQTT: ACK failed. [len: %d / code: %02x]", len, response[0]);
      stream_close(stream);
      return 0;
   }
}

/*
void disconnect(STREAM* stream) {
   stream_write(stream,disConHeader,2);
   stream_flush(stream);
   stream_close(stream);
}
*/

setConMessage();

// Main loop
while(TRUE) {
   if (stream == NULL) {
      stream = connect();
      keepalive=KEEPALIVE;
   }
   if (stream != NULL) {
      nEvents = getinputevent();
      if (nEvents & 0xFFF8) {
         for (input=0;input<13;input++) {
            if (nEvents & (0x8 << input)) {
               float inMsg = getinput(input);
                  tostring(inputStr,(int)inMsg);
               publish(stream,topic[input],inputStr);
            }            
         }
         sleep(100);
         keepalive=KEEPALIVE;
      } else {
         keepalive--;
         if (! keepalive) {
            keepalive=KEEPALIVE;
            if (!ping(stream)) {
               stream = NULL;
            }
         }
         sleep (500);
      }
   } else {
      sleep (500);
   }
   
}