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

// LCD display settings
#define I2C_ADDR    0x27
#define LCD_COLS    16
#define LCD_ROWS    2

// Keypad settings
const byte ROWS = 4; // Four rows
const byte COLS = 4; // Four columns
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {9, 8, 7, 6}; // Connect to the row pinouts of the keypad
byte colPins[COLS] = {5, 4, 3, 2}; // Connect to the column pinouts of the keypad

// Initialize the Keypad and LCD
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLS, LCD_ROWS);

int threshold = 0; // Threshold for soil moisture
bool thresholdEntered = false; // Flag to check if threshold is entered

// Pins for relay and moisture sensor
int relayPin = 10;
int moistureSensorPin = A0;

// State definitions for the state machine
enum State {
  WELCOME, // Initial welcome state
  MAIN_MENU, // Main menu state
  ENTER_THRESHOLD, // State for entering threshold
  VIEW_STATUS, // State for viewing status
  RESET_SYSTEM // State for resetting the system
};

State currentState = WELCOME; // Start with the welcome state

void setup() {
  lcd.init(); // Initialize the LCD
  lcd.backlight(); // Turn on the backlight
  pinMode(relayPin, OUTPUT); // Set relay pin as output
  displayWelcomeMessage(); // Display the welcome message
}

void loop() {
  char key = keypad.getKey(); // Read the key pressed on the keypad

  switch (currentState) {
    case WELCOME:
      if (millis() > 4000) {  // Display welcome message for 4 seconds
        lcd.clear();
        currentState = MAIN_MENU;
        displayMainMenu(); // Show main menu after welcome message
      }
      break;

    case MAIN_MENU:
      if (key) handleMainMenuInput(key); // Handle input in main menu
      break;

    case ENTER_THRESHOLD:
      if (key) handleThresholdInput(key); // Handle threshold input
      break;

    case VIEW_STATUS:
      displayStatus(); // Display the current status
      if (key == 'C') { // Go back to main menu if 'C' is pressed
        currentState = MAIN_MENU;
        lcd.clear();
        displayMainMenu();
      }
      break;

    case RESET_SYSTEM:
      resetSystem(); // Reset the system
      currentState = MAIN_MENU;
      displayMainMenu(); // Go back to main menu after resetting
      break;
  }
}

void displayWelcomeMessage() {
  lcd.setCursor(0, 0);
  lcd.print("Welcome to Smart");
  lcd.setCursor(3, 1);
  lcd.print("Irrigation");
}

void displayMainMenu() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("1:Set Threshold");
  lcd.setCursor(0, 1);
  lcd.print("2:View Status");
}

void handleMainMenuInput(char key) {
  if (key == '1') { // If '1' is pressed, enter threshold input state
    currentState = ENTER_THRESHOLD;
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Enter threshold:");
    lcd.setCursor(7, 1);
    lcd.print("__%");
  } else if (key == '2') { // If '2' is pressed, enter view status state
    currentState = VIEW_STATUS;
    lcd.clear();
  }
}

void handleThresholdInput(char key) {
  if (key >= '0' && key <= '9') { // If a number key is pressed
    if (threshold < 10) {
      threshold = threshold * 10 + (key - '0');
    } else {
      threshold = (threshold % 10) * 10 + (key - '0');
    }
    lcd.setCursor(7, 1);
    lcd.print("__%   "); // Clear previous threshold
    lcd.setCursor(7, 1);
    lcd.print(threshold); // Display currently entered threshold
  } else if (key == 'C') { // Clear the threshold if 'C' is pressed
    threshold = 0;
    lcd.setCursor(7, 1);
    lcd.print("__%");
  } else if (key == 'D') { // Confirm the threshold if 'D' is pressed
    thresholdEntered = true;
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Threshold set:");
    lcd.setCursor(6, 1);
    lcd.print(threshold);
    lcd.print("%");
    delay(2000);
    currentState = MAIN_MENU;
    lcd.clear();
    displayMainMenu(); // Go back to main menu after setting threshold
  }
}

void displayStatus() {
  if (thresholdEntered) {
    int moisture = analogRead(moistureSensorPin); // Read moisture level
    int moisturePercentage = map(moisture, 0, 1023, 0, 100); // Convert to percentage

    lcd.setCursor(0, 0);
    lcd.print("Moisture:");
    lcd.print(moisturePercentage);
    lcd.print("%  ");

    lcd.setCursor(0, 1);
    lcd.print("Th:");
    lcd.print(threshold);
    lcd.print("% ");

    if (moisturePercentage < threshold) {
      digitalWrite(relayPin, HIGH); // Turn on the pump if moisture is below threshold
      lcd.print("Pump: ON ");
    } else {
      digitalWrite(relayPin, LOW); // Turn off the pump if moisture is above threshold
      lcd.print("Pump: OFF");
    }
  } else {
    lcd.setCursor(0, 0);
    lcd.print("Threshold not set");
    lcd.setCursor(0, 1);
    lcd.print("Press 'C' to go back");
  }
}

void resetSystem() {
  threshold = 0;
  thresholdEntered = false;
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("System reset");
  delay(2000);
  lcd.clear();
}