/* There are 2 variables changeable for you to adjust as per requirements. 
1. B_variations  -> Available values options are: 1 or 2 or 3 or 4 or 6 (This this interval for 2 in hours I consider them sub cycle)
2. isC_present -> Available options are: true or false  (This is for confirmation of is C is present or not)

As you requested in program in to have 8 different options, my code can provide you 10 different options that can be as following:
1.  B = 1, C present
2.  B = 1, C not present
3.  B = 2, C present
4.  B = 2, C not present
5.  B = 3, C present
6.  B = 3, C not present
7.  B = 4, C present
8.  B = 4, C not present
9.  B = 6, C present
10. B = 6, C not present
*/

#include <LiquidCrystal.h>
#include "RTClib.h"

/********************** Changeable variables **********************/

bool isC_present = true; // Options available true or false
int B_variation = 1; // Options available 1, 2, 3, 4 or 5 hours

/********************** Changeable variables **********************/

int relay[4] = {2, 3, 4, 5};

RTC_DS1307 rtc;

char daysOfTheWeek[7][12] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};

LiquidCrystal lcd(12, 11, 10, 9, 8, 7);
DateTime now;

// program variables
bool relayStatus[4] = {false};
bool debug = true;
int lastSecond = 0;

void setup() {
  Serial.begin(115200);
  for(int i=0; i < 4; i++){
    pinMode(relay[i], OUTPUT);
    digitalWrite(relay[i], LOW);
  }
  // digitalWrite(relay[0], HIGH);
  lcd.begin(16, 2);
  lcd.print("    Welcome!");
  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    abort();
  }
  delay(2000);
  lcd.clear();
}

void loop() {
  now = rtc.now();
  displayTime();

  char currentCycle = getCycle();
  if (currentCycle == 'A') {
    ifPrint("Cycle A");
    long runTime = getRunningTime(currentCycle);
    Serial.println(runTime);
    // Relay B ON for 2 minutes. B can be turned ON with either 1,2,3 or 4 hours interval
    if (runTime < 120){
      if(relayStatus[0]){
        digitalWrite(relay[0], LOW);
        relayStatus[0] = false;
      }
      if(relayStatus[2]){
        digitalWrite(relay[2], LOW);
        relayStatus[2] = false;
      }
      if(relayStatus[3]){
        digitalWrite(relay[3], LOW);
        relayStatus[3] = false;
      }
      if(!relayStatus[1]){
        digitalWrite(relay[1], HIGH);
        relayStatus[1] = true;
      }
    }
    else if (runTime >= 120 && runTime < 240){  // checks from 2 to 4 minutes
      if(isC_present){  // if C is present then turn on it and turn off B
        if(relayStatus[0]){
          digitalWrite(relay[0], LOW);
          relayStatus[0] = false;
        }
        if(relayStatus[1]){
          digitalWrite(relay[1], LOW);
          relayStatus[1] = false;
        }
        if(relayStatus[3]){
          digitalWrite(relay[3], LOW);
          relayStatus[3] = false;
        }
        if(!relayStatus[2]){
          digitalWrite(relay[2], HIGH);
          relayStatus[2] = true;
        }
      }
      else{
        if(relayStatus[1]){   // if C is not present turn off B and turn on A and Fan
          digitalWrite(relay[1], LOW);
          relayStatus[1] = false;
        }
        if(relayStatus[2]){
          digitalWrite(relay[2], LOW);
          relayStatus[2] = false;
        }
        if(!relayStatus[0]){ 
          digitalWrite(relay[0], HIGH);
          relayStatus[0] = true;
        }
        if(!relayStatus[3]){ 
          digitalWrite(relay[3], HIGH);
          relayStatus[3] = true;
        }
      }
    }
    else if(runTime >= (B_variation * 3600) - 120) {   //last 2 minutes of subcycle Fan turns off
      if(relayStatus[3]){
        digitalWrite(relay[3], LOW);
        relayStatus[3] = false;
      }
    }
    else{  // Light A and Fan remains on when nothing is on or last 2 minutes of subcycle
      if(relayStatus[1]){  
        digitalWrite(relay[1], LOW);
        relayStatus[1] = false;
      }
      if(relayStatus[2]){
        digitalWrite(relay[2], LOW);
        relayStatus[2] = false;
      }
      if(!relayStatus[3]){
        digitalWrite(relay[3], HIGH);
        relayStatus[3] = true;
      }
      if(!relayStatus[0]){
        digitalWrite(relay[0], HIGH);
        relayStatus[0] = true;
      }
    }
  }
  else {
    ifPrint("Cycle B");
    long runTime = getRunningTime(currentCycle);
    Serial.println(runTime);
    // relay A stays off in each condition.
    if(relayStatus[0]){
      digitalWrite(relay[0], LOW);
      relayStatus[0] = false;
    }
    // Relay B ON for 2 minutes. B can be turned ON with either 1,2,3 or 4 hours interval
    if (runTime < 120){
      if(relayStatus[2]){
        digitalWrite(relay[2], LOW);
        relayStatus[2] = false;
      }
      if(relayStatus[3]){
        digitalWrite(relay[3], LOW);
        relayStatus[3] = false;
      }
      if(!relayStatus[1]){
        digitalWrite(relay[1], HIGH);
        relayStatus[1] = true;
      }
    }
    else if (runTime >= 120 && runTime < 240){  // checks from 2 to 4 minutes
      if(isC_present){  // if C is present then turn on it and turn off B
        if(relayStatus[1]){
          digitalWrite(relay[1], LOW);
          relayStatus[1] = false;
        }
        if(relayStatus[3]){
          digitalWrite(relay[3], LOW);
          relayStatus[3] = false;
        }
        if(!relayStatus[2]){
          digitalWrite(relay[2], HIGH);
          relayStatus[2] = true;
        }
      }
      else{
        if(relayStatus[1]){   // if C is not present turn off B and turn on A and Fan
          digitalWrite(relay[1], LOW);
          relayStatus[1] = false;
        }
        if(relayStatus[2]){
          digitalWrite(relay[2], LOW);
          relayStatus[2] = false;
        }
        if(!relayStatus[3]){ 
          digitalWrite(relay[3], HIGH);
          relayStatus[3] = true;
        }
      }
    }
    else if(runTime >= (B_variation * 3600) - 120) {   //last 2 minutes of subcycle Fan turns off
      if(relayStatus[3]){
        digitalWrite(relay[3], LOW);
        relayStatus[3] = false;
      }
    }
    else{  // Fan remains on when nothing is on or last 2 minutes of subcycle
      if(relayStatus[1]){  
        digitalWrite(relay[1], LOW);
        relayStatus[1] = false;
      }
      if(relayStatus[2]){
        digitalWrite(relay[2], LOW);
        relayStatus[2] = false;
      }
      if(!relayStatus[3]){
        digitalWrite(relay[3], HIGH);
        relayStatus[3] = true;
      }
    }
  }
}

char getCycle() {
  int currentHour = now.hour();
  if (currentHour >= 6 && currentHour < 18) {
    return 'A';
  } else {
    return 'B';
  }
}

long getRunningTime(char cycle){
  int startHour = 18;
  if(cycle == 'A'){
    startHour = 6;
  }
  int cycleHour = (now.hour() - startHour < 0) ? now.hour() - startHour + 24 : now.hour() - startHour;
  int runningTimeHour = cycleHour;
  while(runningTimeHour >= B_variation){
    runningTimeHour -= B_variation;
  }
  long runningTime = runningTimeHour * 3600 + now.minute() * 60 + now.second();
  return runningTime;
}

void displayTime(){
  if(now.second() != lastSecond){
    lcd.setCursor(4,0);
    if(now.hour() < 10){
      lcd.print("0");
    }
    lcd.print(now.hour());
    lcd.print(":");
    if(now.minute() < 10){
      lcd.print("0");
    }
    lcd.print(now.minute());
    lcd.print(":");
    if(now.second() < 10){
      lcd.print("0");
    }
    lcd.println(now.second());
    if(now.year() < 10){
      lcd.print("0");
    }
    lcd.setCursor(1,1);
    lcd.print(now.year());
    lcd.print('/');
    if(now.month() < 10){
      lcd.print("0");
    }
    lcd.print(now.month());
    lcd.print('/');
    if(now.day() < 10){
      lcd.print("0");
    }
    lcd.print(now.day());
    lcd.print(" ");
    lcd.println(daysOfTheWeek[now.dayOfTheWeek()]);
    lastSecond = now.second();
  }
}

void ifPrint(const char* message) {
  if (debug) {
    Serial.println(message);
  }
}