#include <LoRa.h>

// -------------------- Pins --------------------
const int trigPin = 6;
const int echoPin = 5;
const int waterLevelSensorPin = A0;
const int waterSensorPower = 3;
const int switchPin = 8;
const int motorPin1 = A1;
const int motorPin2 = A2;
const int enaPin = 5; 

// -------------------- Variables --------------------
float duration;
float distance;

int SyncWord = 0x26;

unsigned long previousMillis = 0;
const long interval = 10000;

int sensorValue = 0;
float waterLevelCM = 0.0;
float WaterLevel = 0.0;  // from sonar when used

// Calibration / geometry constants — you must measure for your setup
const int sensorMin = 0;     // analog reading when sensor is “dry” (adjust)
const int sensorMax = 600;     // analog reading when sensor is “fully immersed” (adjust)
const float probeLength = 4.0; // “length” in cm that sensor maps over
const float sensorToBottom = 30;  // distance from ultrasonic sensor to bottom (cm), adjust

void setup() {
  Serial.begin(9600);
  while (!Serial);

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(waterSensorPower, OUTPUT);
  digitalWrite(waterSensorPower, LOW);

  pinMode(switchPin, INPUT_PULLUP);


  Serial.println("LoRa Sender");
  if (!LoRa.begin(433E6)) {
    Serial.println("Starting LoRa failed!");
    while (1);
  }
  LoRa.setSpreadingFactor(12);
  LoRa.setSignalBandwidth(62.5E3);
  LoRa.setCodingRate4(8);
  LoRa.setSyncWord(SyncWord);
}

void loop() {
  unsigned long currentMillis = millis();

  // 1) Read the water sensor (analog) — power it just for the reading
  if (sensorValue <= 400) {
  digitalWrite(waterSensorPower, HIGH);
  delay(3000);  // brief stabilization
  sensorValue = analogRead(waterLevelSensorPin);
  Serial.println(sensorValue);
  }

  waterLevelCM = (float)(sensorValue - sensorMin) * probeLength / (sensorMax - sensorMin);
  // Map analog value to “cm” scale

  if (waterLevelCM >= 3) {

    // Trigger ultrasonic
    digitalWrite(trigPin, LOW);
    delayMicroseconds(5);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    duration = pulseIn(echoPin, HIGH, 30);  // timeout of 30 ms
    distance = duration * 0.034 / 2.0;
    WaterLevel = sensorToBottom - distance;
    Serial.println(distance);

  // 3) Send via LoRa at intervals
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;

    LoRa.beginPacket();
    if (sensorValue >= 3) {
      LoRa.print("11,");
      LoRa.print(WaterLevel);
    } 
    if (WaterLevel >= 15){
      LoRa.print("22");
    }
    if (WaterLevelCM >= 0.50) {
      LoRa.print(waterLevelCM);
    }
    LoRa.endPacket();

    // (Optional) also print to Serial for debugging
  }

  

}