#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>

// Pin Definitions
#define DHTPIN PA8
#define DHTTYPE DHT22
#define SWITCH_PIN PA0
#define SOIL_PIN PA7
#define BUZ PB14
#define LED PB13

// Libraries & Objects
DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Struct to store sensor data
struct SensorData {
  float temp;
  float humid;
  int soilRaw;
  char soilLevel[10]; // "Wet", "Moist", "Dry"
};

// Soil reading history buffer
const int historySize = 5;
int soilHistory[historySize];
int historyIndex = 0;

// Function Prototypes
void readDHT(SensorData *data);
void readSoil(SensorData *data);
void updateDisplayDHT(const SensorData *data);
void updateDisplaySoil(const SensorData *data);
void updateBuzzerAndLED(const SensorData *data);

void setup() {
  pinMode(LED, OUTPUT);
  pinMode(BUZ, OUTPUT);
  pinMode(SWITCH_PIN, INPUT);

  dht.begin();
  lcd.init();
  lcd.backlight();

  lcd.setCursor(0, 0);
  lcd.print("Sensor System");
  delay(2000);
  lcd.clear();
}

void loop() {
  int switchState = digitalRead(SWITCH_PIN);

  SensorData sensor;
  lcd.clear();

  if (switchState == LOW) {
    readDHT(&sensor);
    updateDisplayDHT(&sensor);
    digitalWrite(LED, LOW);
    digitalWrite(BUZ, LOW);
  } else {
    readSoil(&sensor);
    updateDisplaySoil(&sensor);
    updateBuzzerAndLED(&sensor);
  }

  delay(2000);
}

// === Function Definitions ===

void readDHT(SensorData *data) {
  data->temp = dht.readTemperature();
  data->humid = dht.readHumidity();
}

void readSoil(SensorData *data) {
  data->soilRaw = analogRead(SOIL_PIN);

  // Add to history buffer (circular)
  soilHistory[historyIndex++] = data->soilRaw;
  if (historyIndex >= historySize) historyIndex = 0;

  if (data->soilRaw < 1000) {
    strcpy(data->soilLevel, "Wet");
  } else if (data->soilRaw < 2500) {
    strcpy(data->soilLevel, "Moist");
  } else {
    strcpy(data->soilLevel, "Dry");
  }
}

void updateDisplayDHT(const SensorData *data) {
  if (isnan(data->temp) || isnan(data->humid)) {
    lcd.setCursor(0, 0);
    lcd.print("DHT Read Error");
  } else {
    lcd.setCursor(0, 0);
    lcd.print("Temp: ");
    lcd.print(data->temp, 1);
    lcd.print(" C");

    lcd.setCursor(0, 1);
    lcd.print("Humid: ");
    lcd.print(data->humid, 1);
    lcd.print(" %");
  }
}

void updateDisplaySoil(const SensorData *data) {
  lcd.setCursor(0, 0);
  lcd.print("Soil Moisture:");

  lcd.setCursor(0, 1);
  lcd.print("Raw:");
  lcd.print(data->soilRaw);
  lcd.print(" ");
  lcd.print(data->soilLevel);
}

void updateBuzzerAndLED(const SensorData *data) {
  if (strcmp(data->soilLevel, "Moist") == 0) {
    digitalWrite(LED, LOW);
    digitalWrite(BUZ, LOW);
  } else {
    digitalWrite(LED, HIGH);
    digitalWrite(BUZ, HIGH);
  }
}