#include <WiFi.h>
#include <ThingSpeak.h>
#include <Adafruit_SSD1306.h>
#include <DHT.h>

// Sensor Pins (from your diagram.json)
#define SOIL_MOISTURE_PIN 34  // chip1:SIG -> esp:34
#define DHT_PIN 32            // dht1:SDA -> esp:32
#define PH_PIN 26             // chip3:OUT0 -> esp:26
#define TDS_PIN 27            // chip3:OUT1 -> esp:27
#define LED_PIN 19            // led1:A -> esp:19
#define NPK_RX 16             // chip2:TX -> esp:16 (RX1)
#define NPK_TX 17             // chip2:RX -> esp:17 (TX1)

// OLED Display
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// WiFi Credentials
char* WIFI_NAME = "Wokwi-GUEST";
char* WIFI_PASSWORD = "";

// ThingSpeak Settings
unsigned long myChannelNumber = 2564339;
const char* myApiKey = "3PDPDDF1RA32WIER";
WiFiClient client;

// Sensor Objects
DHT dht(DHT_PIN, DHT22);

// NPK Sensor Protocol
#define NPK_REQUEST_NITROGEN 1
#define NPK_REQUEST_PHOSPHORUS 3
#define NPK_REQUEST_POTASSIUM 5

// Variables
float temperature, humidity;
int soilMoisture;
int tdsValue = 0;
float phValue = 0;
int nitrogen = 0, phosphorus = 0, potassium = 0;

// Soil Health Thresholds
const int MOISTURE_THRESHOLD_LOW = 15;
const int MOISTURE_THRESHOLD_HIGH = 85;
const int N_THRESHOLD = 50;
const int P_THRESHOLD = 30;
const int K_THRESHOLD = 40;
const float PH_THRESHOLD_LOW = 5.5;
const float PH_THRESHOLD_HIGH = 7.5;
const int TDS_THRESHOLD = 500; // ppm

void setup() {
  Serial.begin(115200);
  Serial1.begin(15200, SERIAL_8N1, NPK_RX, NPK_TX); // Initialize Serial1 for NPK sensor
  
  // Initialize OLED
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.display();
  delay(2000);
  display.clearDisplay();
  
  // Initialize DHT
  dht.begin();
  
  // Initialize LED
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);
  
  // Connect to WiFi
  WiFi.begin(WIFI_NAME, WIFI_PASSWORD);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println();
  Serial.println("Connected to WiFi");
  
  // Initialize ThingSpeak
  ThingSpeak.begin(client);

  // Configure analog pins for TDS/pH
  pinMode(PH_PIN, INPUT);
  pinMode(TDS_PIN, INPUT);
}

void loop() {
  // Read all sensors
  readSensors();
  
  // Check soil health
  bool isSoilHealthy = checkSoilHealth();
  
  // Control LED based on soil health
  digitalWrite(LED_PIN, isSoilHealthy ? LOW : HIGH);
  
  // Display data on OLED
  displayData();
  
  // Send data to ThingSpeak
  sendToThingSpeak();
  
  delay(8000); // Wait 15 seconds between updates
}

void readSensors() {
  // Read DHT22 (Temperature and Humidity)
  humidity = dht.readHumidity();
  temperature = dht.readTemperature();
  
  // Read Soil Moisture (0-100%)
  int soilValue = analogRead(SOIL_MOISTURE_PIN);
  soilMoisture = map(soilValue, 0, 4095, 0, 100);
  
  // Read TDS
  int16_t tdsRaw = analogRead(TDS_PIN);
  float tdsVoltage = tdsRaw * (3.3 / 4095.0);  // Changed 5.0 to 3.3
  tdsValue = (tdsVoltage / 2.3) * 1000;  // TDS in ppm
  
  // Read pH
  int16_t phRaw = analogRead(PH_PIN);
  float phVoltage = phRaw * (3.3 / 4095.0);  // Changed 5.0 to 3.3
  phValue = (phVoltage / 2.3) * 14.0;    // pH value
  
  // Debugging
  Serial.println("------ Sensor Readings ------");
  Serial.print("Temperature: "); Serial.print(temperature); Serial.println("°C");
  Serial.print("Humidity: "); Serial.print(humidity); Serial.println("%");
  Serial.print("Soil Moisture: "); Serial.print(soilMoisture); Serial.println("%");
  
  // Debug Raw Values
  Serial.print("Raw pH: "); Serial.print(phRaw); Serial.print(" | Voltage: "); Serial.println(phVoltage, 2);
  Serial.print("Raw TDS: "); Serial.print(tdsRaw); Serial.print(" | Voltage: "); Serial.println(tdsVoltage, 2);
  
  Serial.print("pH Value: "); Serial.println(phValue, 2); // 2 decimal places
  Serial.print("TDS Value: "); Serial.print(tdsValue); Serial.println(" ppm");
  
  // Read NPK sensor through custom protocol
  readNPKSensor();
}


void readNPKSensor() {
  // Request nitrogen
  Serial1.write(NPK_REQUEST_NITROGEN);
  delay(10);
  if (Serial1.available()) {
    nitrogen = Serial1.read();
  }
  
  // Request phosphorus
  Serial1.write(NPK_REQUEST_PHOSPHORUS);
  delay(10);
  if (Serial1.available()) {
    phosphorus = Serial1.read();
  }
  
  // Request potassium
  Serial1.write(NPK_REQUEST_POTASSIUM);
  delay(10);
  if (Serial1.available()) {
    potassium = Serial1.read();
  }
}

bool checkSoilHealth() {
  // Check if any parameter is outside healthy range
  if (soilMoisture < MOISTURE_THRESHOLD_LOW || soilMoisture > MOISTURE_THRESHOLD_HIGH ||
      phValue < PH_THRESHOLD_LOW || phValue > PH_THRESHOLD_HIGH ||
      tdsValue > TDS_THRESHOLD ||
      nitrogen < N_THRESHOLD || phosphorus < P_THRESHOLD || potassium < K_THRESHOLD) {
    return false; // Soil health is bad
  }
  return true; // Soil health is good
}

void displayData() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  
  display.println("Soil Monitoring System");
  display.println("---------------------");
  display.print("Temp: "); display.print(temperature); display.println(" C");
  display.print("Hum:  "); display.print(humidity); display.println(" %");
  display.print("Moist:"); display.print(soilMoisture); display.println(" %");
  display.print("pH:   "); display.println(phValue, 1); // 1 decimal place
  display.print("TDS:  "); display.print(tdsValue); display.println(" ppm");
  display.print("NPK: N"); display.print(nitrogen);
  display.print(" P"); display.print(phosphorus);
  display.print(" K"); display.println(potassium);
  
  // Add soil health status
  display.setCursor(0, 56);
  display.print("Soil: ");
  display.print(checkSoilHealth() ? "HEALTHY" : "UNHEALTHY");
  
  display.display();
}

void sendToThingSpeak() {
  ThingSpeak.setField(1, temperature);
  ThingSpeak.setField(2, humidity);
  ThingSpeak.setField(3, soilMoisture);
  ThingSpeak.setField(4, phValue);
  ThingSpeak.setField(5, tdsValue);
  ThingSpeak.setField(6, nitrogen);
  ThingSpeak.setField(7, phosphorus);
  ThingSpeak.setField(8, potassium);
  
  int statusCode = ThingSpeak.writeFields(myChannelNumber, myApiKey);
  
  if (statusCode == 200) {
    Serial.println("Data sent to ThingSpeak successfully");
  } else {
    Serial.println("Problem sending data to ThingSpeak");
  }
}