#include <DallasTemperature.h>
#include <OneWire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Wire.h>

const int PH_PIN = 32, 
          TEMP_PIN = 22;
          
#define ncom 3 // number of commands

char commar[ncom] = {0x1, 0x3, 0x5}; // Actual commands
const char* respar[ncom] = {"Phosphorous value is: ", "Potassium value is: ", "Nitrogen value is: "};
uint8_t rtValue[ncom]; // Store the return values from the custom chip in here

float phVal = 0, tempVal = 0;
int readVal = 0;

OneWire oneWire(TEMP_PIN);  // creates the OneWire object using a specific pin
DallasTemperature sensor(&oneWire);

// OLED display setup
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  
  // Initialize OLED display
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3C for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Infinite loop if display initialization fails
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  
  Serial2.begin(15200, SERIAL_8N1, 16, 17); // Initialize the custom chip communication line
  pinMode(PH_PIN, INPUT);
  sensor.begin();
}

void loop() {
  // Read and display pH value
  readVal = analogRead(PH_PIN);
  phVal = ((float) readVal / 4095.0) * 14;
  Serial.print("Current PH: ");
  Serial.println(phVal);

  // Read and display temperature value
  sensor.requestTemperatures();
  tempVal = sensor.getTempCByIndex(0);
  if (tempVal == -127) {
    Serial.println("Temperature Sensor Not Found.");
    delay(1000);
    return;
  }
  Serial.print("Temperature: ");
  Serial.print(tempVal);
  Serial.println("ºC");
  
  // Display values on OLED
  displayValues(phVal, tempVal);

  delay(1000);
  
  // Read and display NPK values
  readNPKSensor();
}

void readNPKSensor() {
  for (uint8_t i = 0; i < ncom; i++) {
    Serial2.print((char)commar[i]); // Send the command stored in ncom array through serial2
    if (Serial2.available()) {
      rtValue[i] = Serial2.read();
      Serial2.flush();
      Serial.print(respar[i]);
      Serial.println(rtValue[i]);
    }
  }
  
  // Display NPK values on OLED
  displayNPKValues(rtValue[0], rtValue[1], rtValue[2]);
}

void displayValues(float pH, float temperature) {
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Current PH: ");
  display.println(pH);
  
  display.setCursor(0, 10);
  display.print("Temperature: ");
  display.print(temperature);
  display.println(" C");
  
  display.display(); 
}

void displayNPKValues(uint8_t nitrogen, uint8_t phosphorous, uint8_t potassium) {
  display.setCursor(0, 30);
  display.print("N: ");
  display.print(nitrogen);

  display.setCursor(0, 40);
  display.print("P: ");
  display.print(phosphorous);

  display.setCursor(0, 50);
  display.print("K: ");
  display.print(potassium);

  display.display();
}