/*
 * Smart Irrigation System with Soil Moisture Sensor
 * ESP32 based automatic plant watering system
 * 
 * Components:
 * - ESP32 DevKit
 * - Soil Moisture Sensor (Analog)
 * - Relay Module
 * - Water Pump
 * - LED indicators
 */

// Pin Definitions
#define SOIL_MOISTURE_PIN 34  // Analog pin for soil moisture sensor
#define RELAY_PIN 25          // Digital pin to control relay/pump
#define LED_DRY 26            // LED indicator for dry soil (Red)
#define LED_WET 27            // LED indicator for wet soil (Green)
#define LED_PUMP 33           // LED indicator for pump status (Blue)

// Threshold values (adjust based on your sensor)
#define DRY_THRESHOLD 40      // Below this value, soil is dry (0-100 scale)
#define WET_THRESHOLD 70      // Above this value, soil is wet enough

// Timing constants
#define PUMP_ON_TIME 5000     // Pump runs for 5 seconds
#define READ_INTERVAL 2000    // Read sensor every 2 seconds

// Variables
int soilMoistureValue = 0;
int soilMoisturePercent = 0;
bool pumpActive = false;
unsigned long lastReadTime = 0;
unsigned long pumpStartTime = 0;

void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);
  Serial.println("Smart Irrigation System Starting...");
  
  // Configure pins
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(LED_DRY, OUTPUT);
  pinMode(LED_WET, OUTPUT);
  pinMode(LED_PUMP, OUTPUT);
  
  // Initialize outputs to OFF
  digitalWrite(RELAY_PIN, LOW);
  digitalWrite(LED_DRY, LOW);
  digitalWrite(LED_WET, LOW);
  digitalWrite(LED_PUMP, LOW);
  
  Serial.println("System Ready!");
  Serial.println("Monitoring soil moisture...");
  Serial.println("-------------------------------");
}

void loop() {
  unsigned long currentTime = millis();
  
  // Read soil moisture at regular intervals
  if (currentTime - lastReadTime >= READ_INTERVAL) {
    readSoilMoisture();
    lastReadTime = currentTime;
  }
  
  // Control irrigation based on moisture level
  if (!pumpActive && soilMoisturePercent < DRY_THRESHOLD) {
    // Soil is dry, start watering
    startPump();
  }
  
  // Stop pump after designated time
  if (pumpActive && (currentTime - pumpStartTime >= PUMP_ON_TIME)) {
    stopPump();
  }
  
  // Update LED indicators
  updateLEDIndicators();
}

void readSoilMoisture() {
  // Read analog value from sensor
  soilMoistureValue = analogRead(SOIL_MOISTURE_PIN);
  
  // Convert to percentage (0-100%)
  // ESP32 ADC: 0-4095 (12-bit)
  // Higher value = more moisture
  soilMoisturePercent = map(soilMoistureValue, 0, 4095, 0, 100);
  
  // Display readings
  Serial.print("Soil Moisture: ");
  Serial.print(soilMoisturePercent);
  Serial.print("%  (Raw: ");
  Serial.print(soilMoistureValue);
  Serial.print(")  Status: ");
  
  if (soilMoisturePercent < DRY_THRESHOLD) {
    Serial.println("DRY - Needs watering!");
  } else if (soilMoisturePercent > WET_THRESHOLD) {
    Serial.println("WET - No watering needed");
  } else {
    Serial.println("MODERATE - Monitoring");
  }
}

void startPump() {
  if (!pumpActive) {
    pumpActive = true;
    pumpStartTime = millis();
    digitalWrite(RELAY_PIN, HIGH);
    digitalWrite(LED_PUMP, HIGH);
    
    Serial.println(">>> PUMP STARTED - Watering plants...");
  }
}

void stopPump() {
  if (pumpActive) {
    pumpActive = false;
    digitalWrite(RELAY_PIN, LOW);
    digitalWrite(LED_PUMP, LOW);
    
    Serial.println(">>> PUMP STOPPED - Watering complete");
    Serial.println("-------------------------------");
  }
}

void updateLEDIndicators() {
  // Update soil moisture indicator LEDs
  if (soilMoisturePercent < DRY_THRESHOLD) {
    digitalWrite(LED_DRY, HIGH);
    digitalWrite(LED_WET, LOW);
  } else if (soilMoisturePercent > WET_THRESHOLD) {
    digitalWrite(LED_DRY, LOW);
    digitalWrite(LED_WET, HIGH);
  } else {
    // Moderate moisture - both LEDs dim or off
    digitalWrite(LED_DRY, LOW);
    digitalWrite(LED_WET, LOW);
  }
}