#include "Arduino.h"
#include "ArduinoUniqueID.h"
#include "Adler16.h"

#define SERIAL_PORT_SPEED 2000000
#define CompileDate __DATE__
#define CompileTime __TIME__

struct MQTTTopicMessageStuct
{
  const PROGMEM String topic;            // Full MQTT topic (this is used to calculate the Adler16 topic ID) [remove once adler16 is pre-calculated]
  String adler_topic;                    // Adler16 MQTT topic ID as string
  const bool direction;                  // input from serial = 0, output to serial = 1
  String message;                        // Current message  
  String last_message;                   // Last message sent
  const PROGMEM String default_message;  // Default message (used to initialize the message at startup and set home positions on shutdown etc)
  const uint16_t period_ms;              // Period to re-transmit the message after (maximum period is 65,535 ~ 65 seconds)
  long next_sent_ms;                     // Next sent time in milliseconds
};

const String device_path = "Adeept";     // root for DUT in MQTT messages)
const String device_idn = "Adeept Hat";  // IDN response
const String software_version = String(CompileDate) + " " + String(CompileTime); // Software version string

// topic,                              adler_topic, direction, message, last_message, default_message,  period_ms, last_sent_ms, description (comment),
MQTTTopicMessageStuct MQTTTopicMessageData[] =
{
  {"board/idn",                        "",          1,         "0",     "0",          device_idn,       60000,      0},           // Board ID
  {"board/sn",                         "",          1,         "0",     "0",          "0",              60000,      0},           // Board Serial Number
  {"board/sw",                         "",          1,         "0",     "0",          software_version, 60000,      0},           // Software Version
  {"board/heartbeat",                  "",          1,         "0",     "0",          "0",              1000,       0},           // an Incramental number between 0-255
  {"input/analogue/battery/raw",       "",          1,         "0",     "0",          "0",              1000,       0},           // Analog channel 0: Battery Level
  {"input/analogue/light_tracker/raw", "",          1,         "0",     "0",          "0",              1000,       0},           // Analog channel 1: Light Tracker
  {"input/analogue/2/raw",             "",          1,         "0",     "0",          "0",              1000,       0},           // Analog channel 2: un-used
  {"input/analogue/3/raw",             "",          1,         "0",     "0",          "0",              1000,       0},           // Analog channel 3: un-used
  {"input/analogue/4/raw",             "",          1,         "0",     "0",          "0",              1000,       0},           // Analog channel 4: un-used
  {"input/analogue/5/raw",             "",          1,         "0",     "0",          "0",              1000,       0},           // Analog channel 5: un-used
  {"input/analogue/6/raw",             "",          1,         "0",     "0",          "0",              1000,       0},           // Analog channel 6: un-used
  {"input/analogue/7/raw",             "",          1,         "0",     "0",          "0",              1000,       0},           // Analog channel 7: un-used
};

const char delimiter = ':';             // use '' NOT ""
uint8_t heartbeat;
uint16_t topicSize;

Adler16 adler16;

void setup() {
  Serial.begin(SERIAL_PORT_SPEED);
  while (!Serial);
  delay(1000);

  topicSize = sizeof(MQTTTopicMessageData) / sizeof(MQTTTopicMessageData[0]);   // get the size of the MQTTTopicMessageData array (number of rows/topics)
   for (int i = 0; i < topicSize; i++) {
    MQTTTopicMessageStuct& current_topic = MQTTTopicMessageData[i];             // The & is important to create a reference to the array element rather than a copy! -- https://www.reddit.com/r/arduino/comments/1qno8ko/comment/o1vlejc/

    // Calculate the adler16 topic ID
    String device_path_lower = device_path;
    device_path_lower.toLowerCase();
    String full_topic = device_path_lower + "/" + current_topic.topic;
    adler16.begin();
    for (int j = 0; full_topic[j] != 0; j++) {
      adler16.add(full_topic[j]);
    }
    String adler16_topic = String(adler16.getAdler(), HEX);
    adler16_topic.toUpperCase();
    current_topic.adler_topic = adler16_topic;
    
    current_topic.message = current_topic.default_message;                      // Initialize the message to the default message 

    if (current_topic.topic == "board/serial_number")                           // Generate the serial number adler16 value
    {
      String Serial_Number;
      for (size_t i = 0; i < UniqueIDsize; i++) 
      {
        Serial_Number += String(UniqueID[i], HEX);
      }
      Serial_Number.toUpperCase();
      current_topic.message = Serial_Number;

      adler16.begin();
      for (int j = 0; Serial_Number[j] != 0; j++) 
      {
        adler16.add(Serial_Number[j]);
      }

      String adler16_serial = String(adler16.getAdler(), HEX);
      adler16_serial.toUpperCase();
      current_topic.message = adler16_serial;
    }



    // At the end of Setup topic5 should look like:
    //   "adeept/input/analogue/light_tracker/raw -> C5A4:0
    Serial.print(full_topic);
    Serial.print(" -> ");
    Serial.println(current_topic.adler_topic + delimiter + current_topic.message);
 }
  delay(5000);            // this is just a temp thing for debug
}

void loop()
{

  // these don't need global scope, so move them in here, I don't know if it helps with memory managment; but it can't hurt?
  
  String serialResponse;
  String MQTTtopic;
  String MQTTmessage;
  int delimiterLocation;

  if (Serial.available() > 0)
  {
    serialResponse = Serial.readStringUntil('\n');                                      // read the incoming data as string until newline character
    delimiterLocation = serialResponse.indexOf(delimiter);                              // find the location of the delimiter character  
    if (delimiterLocation != -1)                                                        // make sure the delimiter was found
    {
      MQTTtopic = serialResponse.substring(0, delimiterLocation);                       // extract the topic
      MQTTmessage = serialResponse.substring(delimiterLocation + 1);                    // extract the message
    }

    for (int i = 0; i < topicSize; i++)                                                 // loop the array of topics
    {
      MQTTTopicMessageStuct& current_topic = MQTTTopicMessageData[i]; 
      if (current_topic.direction == 0 && MQTTtopic == current_topic.adler_topic)       // is it an input topic from serial and a topic we care about?
      {
        current_topic.message = MQTTmessage;                                            // update the message     
      }
    }
  }
  
  for (int i = 0; i < topicSize; i++) 
  {
    MQTTTopicMessageStuct& current_topic = MQTTTopicMessageData[i];                     // The & is important to create a reference to the array element rather than a copy

    if (current_topic.direction == 1 && (current_topic.last_message != current_topic.message || millis() >= current_topic.next_sent_ms)) // is it an output topic to serial AND has it changed or time to resend it?
    {
      current_topic.last_message = current_topic.message;                             // update the last message sent
      Serial.println(current_topic.adler_topic + delimiter + current_topic.message);  // send the topic and message to serial
      current_topic.next_sent_ms = millis() + current_topic.period_ms + random(100);  // Reset the next sent time with a small random delay to avoid collisions

      if (current_topic.topic == "board/heartbeat")                                     // heartbeat is a special case
      {
        heartbeat ++;                                                                   // increment the heartbeat, hearbeat is an unsigned 8 bit int; so will overflow at 255 wrapping back to 0
        current_topic.message = current_topic.last_message = heartbeat;                // update the heartbeat message
      }
     }
  }
  
}