/*
  Session 1 — Simple irrigation pump simulation (Arduino Uno — works in Tinkercad Circuits)
  Parts : green LED (pump running) on D9 (PWM) + 220Ω, red LED (tank empty) on D12 + 220Ω,
          push button on D2 (INPUT_PULLUP, other leg to GND), potentiometer on A0 (pump speed)
  Concepts: GPIO (digitalRead / digitalWrite), PWM (analogWrite 0-255), Serial Communication
*/
const int PUMP_LED = 9;      // PWM pin (~)
const int ALARM_LED = 12;
const int BUTTON = 2;
const int SPEED_POT = A0;

bool pumpOn = false;
bool lastButton = HIGH;
unsigned long startedAt = 0;
const unsigned long MAX_RUN_MS = 10000;   // safety: stop the pump after 10 s in the simulation

void setup() {
  pinMode(PUMP_LED, OUTPUT);
  pinMode(ALARM_LED, OUTPUT);
  pinMode(BUTTON, INPUT_PULLUP);           // pressed = LOW
  Serial.begin(9600);
  Serial.println(F("KFS farm pump simulator ready. Press the button to start/stop irrigation."));
}

void loop() {
  bool now = digitalRead(BUTTON);
  if (lastButton == HIGH && now == LOW) {   // falling edge = one press
    pumpOn = !pumpOn;
    startedAt = millis();
    Serial.println(pumpOn ? F("Pump ON") : F("Pump OFF"));
    delay(30);                              // debounce
  }
  lastButton = now;

  if (pumpOn && millis() - startedAt > MAX_RUN_MS) {
    pumpOn = false;
    digitalWrite(ALARM_LED, HIGH);          // timeout -> alarm LED (e.g. tank empty / pipe blocked)
    Serial.println(F("Safety timeout! Pump stopped."));
  }

  int pot = analogRead(SPEED_POT);          // 0..1023
  int duty = map(pot, 0, 1023, 0, 255);     // 0..255  (PWM duty cycle)
  analogWrite(PUMP_LED, pumpOn ? duty : 0);
  if (!pumpOn && digitalRead(BUTTON) == LOW) digitalWrite(ALARM_LED, LOW);

  static unsigned long lastPrint = 0;
  if (millis() - lastPrint > 1000) {
    lastPrint = millis();
    Serial.print(F("pump=")); Serial.print(pumpOn);
    Serial.print(F(" speed%=")); Serial.println(duty * 100 / 255);
  }
}