#include <Arduino.h>
#include <Wire.h>
#include <Ethernet.h>
#include <MQTT.h>
#include "credentials.h"

#define VERSION          "1.0"

#define MQTT_MONTOPIC    "admin/monitoring/client/%s/state"
#define MQTT_VERTOPIC    "admin/monitoring/client/%s/version"
#define MQTT_IPTOPIC     "admin/monitoring/client/%s/ipaddr"
#define MQTT_BROKER      "mqttbroker.scimonshouse.net"
#define MQTT_PORT        1883

#define MQTT_BASETOPIC   "sandbox/automation/attic/sensor/%s"

void(* resetFunc) (void) = 0;

EthernetClient net;
byte mac[] = { 0x0E, 0xBB, 0x00, 0x00, 0x00, 0x03 };

MQTTClient client;

String data = "";
bool dataAvailable = false;

void mqttInit() {
    client.begin(MQTT_BROKER, MQTT_PORT, net);

    if (mqttConnect() != 0) {
        resetFunc(); 
    }

    int verTopicLen = strlen(MQTT_VERTOPIC) - 1 + strlen(MQTT_USERNAME);
    char verTopic[verTopicLen];
    sprintf(verTopic, MQTT_VERTOPIC, MQTT_USERNAME);
    verTopic[verTopicLen - 1] = 0;
    client.publish(verTopic, VERSION, true, 1);
}

int mqttConnect() {
    digitalWrite(2, HIGH);

    int monTopicLen = strlen(MQTT_MONTOPIC) - 1 + strlen(MQTT_USERNAME);
    char monTopic[monTopicLen];
    sprintf(monTopic, MQTT_MONTOPIC, MQTT_USERNAME);
    monTopic[monTopicLen - 1] = 0;
    
    Serial.println(monTopic);
    client.setWill(monTopic, "missing", true, 1);

    int attempts = 10;

    while (!client.connect(MQTT_USERNAME, MQTT_USERNAME, MQTT_PASSWORD) && attempts > 0) {
        delay(1500);
        attempts--;
    }

    if (attempts == 0 && !client.connected()) {
        delay(500);
        resetFunc();
    }

    client.publish(monTopic, "connected", true, 1);
    digitalWrite(2, LOW);

    int ipTopicLen = strlen(MQTT_IPTOPIC) - 1 + strlen(MQTT_USERNAME);
    char ipTopic[ipTopicLen];
    sprintf(ipTopic, MQTT_IPTOPIC, MQTT_USERNAME);
    ipTopic[ipTopicLen - 1] = 0;
    
    IPAddress ip = Ethernet.localIP();
    client.publish(ipTopic, String(ip[0]) + "." + String(ip[1]) + "." + String(ip[2]) + "." + String(ip[3]), true, 1);  
}

String getToken(String data, char separator, int index) {
  int found = 0;
  int strIndex[] = {0, -1};
  int maxIndex = data.length() - 1;

  for(int i = 0; i <= maxIndex && found <= index; i++){
    if(data.charAt(i) == separator || i == maxIndex) {
        found++;
        strIndex[0] = strIndex[1] + 1;
        strIndex[1] = (i == maxIndex) ? i + 1 : i;
    }
  }

  return found > index ? data.substring(strIndex[0], strIndex[1]) : "";
}

void receiveEvent(int dataLength) {
    char localData[dataLength];
    int i;
    for(i = 0; Wire.available() > 0; i++) {
      localData[i] = Wire.read();
    }
          
    data = String(localData).substring(0, i);
    dataAvailable = true;
}

void setup() {    
    pinMode(2, OUTPUT);
    digitalWrite(2, HIGH);
  
    // connect to ethernet
    delay(250);
    if (Ethernet.begin(mac) == 0) {
        delay(5000);
        resetFunc();
    }

    // connect to MQTT broker
    mqttInit();

    Wire.begin(8);
    Wire.onReceive(receiveEvent);
}

void loop() {
    if (!client.connected()) {
        mqttConnect();
    }

    Ethernet.maintain();
    client.loop();

    if (dataAvailable) {
        String localData = data;
        dataAvailable = false;

        String temp = getToken(localData, '/', 0);
        String humid = getToken(localData, '/', 1);
        String pressure = getToken(localData, '/', 2);
    
        int topicLen = strlen(MQTT_BASETOPIC) - 1 + strlen("temperature");
        char topicTemp[topicLen];
        sprintf(topicTemp, MQTT_BASETOPIC, "temperature");
        topicTemp[topicLen - 1] = 0;
        client.publish(topicTemp, temp, false, 1);

        topicLen = strlen(MQTT_BASETOPIC) - 1 + strlen("humidity");
        char topicHumid[topicLen];
        sprintf(topicHumid, MQTT_BASETOPIC, "humidity");
        topicHumid[topicLen - 1] = 0;
        client.publish(topicHumid, humid, false, 1);

        topicLen = strlen(MQTT_BASETOPIC) - 1 + strlen("pressure");
        char topicPressure[topicLen];
        sprintf(topicPressure, MQTT_BASETOPIC, "pressure");
        client.publish(topicPressure, pressure, false, 1);
    }
}