// Pin assignments
const int r1 = 3;
const int r2 = 4;
const int r3 = 5;
const int r4 = 6;
const int r5 = 7;
const int pcs = 8;

int sv = 0;  // System state
int bi = 0;  // Battery indicator
const int threshold = 200;

unsigned long r1OnTime = 0;
unsigned long r4OnTime = 0;
unsigned long r3OnTime = 0;
const unsigned long delayDuration = 2000; // 2 seconds

void setup() {
    pinMode(r1, OUTPUT);
    pinMode(r2, OUTPUT);
    pinMode(r3, OUTPUT);
    pinMode(r4, OUTPUT);
    pinMode(r5, OUTPUT);
    pinMode(pcs, INPUT);

    Serial.begin(9600);
}

void loop() {
    // Read sensor values
    int pcsState = digitalRead(pcs);
    int batteryVoltage = analogRead(A0);
    int bs = analogRead(A1);
    int bcs = analogRead(A2);

    if (pcsState == LOW) {
        sv = 1;
    } else {
        sv = 0;
    }

    // Relay 1 control with non-blocking delay
    if (sv == 1 || batteryVoltage < threshold) {
        if (millis() - r1OnTime >= delayDuration) {
            digitalWrite(r1, HIGH);
            r1OnTime = millis();
        }
    } else if (pcsState == HIGH) {
        digitalWrite(r1, LOW);
    }

    // Relay 4 control with non-blocking delay
    if (sv == 1 || bs < threshold) {     //ac mains is on or 3s battery is at critically low
        if (millis() - r4OnTime >= delayDuration) {  //2sec delay 
            digitalWrite(r4, HIGH);                  // r4 turn off
            r4OnTime = millis();
        }
    } else {
        digitalWrite(r4, LOW);
    }

    // Relay 3 control with non-blocking delay
    if (batteryVoltage < threshold && bs >= threshold) {
        digitalWrite(r3, LOW);
    } else if (batteryVoltage > threshold || bs < threshold) {
        if (millis() - r3OnTime >= delayDuration) {
            digitalWrite(r3, HIGH);
            r3OnTime = millis();
        }
    }

  if(bs <680){
    digitalWrite(r2, LOW);
  }
  if(bs > 1000 && bcs > 1000 ){
    digitalWrite(r2, HIGH);
  }
}