#include "U8glib.h"
#include <SPI.h>
#include <SD.h>
#include <Wire.h>
#include <RTClib.h>
#include <NewPing.h>

#define TRIG_PIN 6 // Define the trigger pin for the ultrasonic sensor
#define ECHO_PIN 7 // Define the echo pin for the ultrasonic sensor
#define MAX_DISTANCE 200 // Define maximum distance for the ultrasonic sensor

#define BUTTON_UP_PIN 12 // Pin for UP button
#define BUTTON_DOWN_PIN 4 // Pin for DOWN button
#define BUTTON_LEFT_PIN 8 // Pin for LEFT button
#define BUTTON_SELECT_PIN 2 // Pin for SELECT button

#define CHIP_SELECT_PIN 10 // Pin for SD card chip select
#define RTC_SDA_PIN A4 // Pin for RTC SDA
#define RTC_SCL_PIN A5 // Pin for RTC SCL

RTC_DS1307 rtc; // Create an RTC object
NewPing sonar(TRIG_PIN, ECHO_PIN, MAX_DISTANCE); // Create a NewPing object

U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_DEV_0 | U8G_I2C_OPT_NO_ACK | U8G_I2C_OPT_FAST); // Fast I2C / TWI

const int NUM_ITEMS = 10; // Number of items in the menu including the ultrasonic sensor option
const int MAX_ITEM_LENGTH = 20; // Maximum characters for the item name
const int ITEMS_DISPLAYED = 5; // Number of menu items displayed on the screen at a time
const int DATA_DISPLAYED = 2; // Number of lines displayed for saved data

char menu_items[NUM_ITEMS][MAX_ITEM_LENGTH] = {
  { "3D Cube" },
  { "Battery" },
  { "Dashboard" },
  { "Fireworks" },
  { "GPS Speed" },
  { "Big Knob" },
  { "Park Sensor" },
  { "Turbo Gauge" },
  { "View Saved Data" }, // New menu item to view saved data
  { "Ultrasonic Sensor" } // New menu item for the ultrasonic sensor
};

int current_item = 0; // Variable to track the current selected menu item
bool ultrasonic_selected = false; // Flag to indicate if ultrasonic sensor option is selected
bool view_data_selected = false; // Flag to indicate if view saved data option is selected

File dataFile; // File object for SD card data

int current_line_index = 0; // Variable to track the current line index for viewing saved data

void setup() {
  Serial.begin(9600); // Initialize serial communication
  Wire.begin(); // Initialize I2C communication for RTC
  rtc.begin(); // Initialize RTC
  
  if (!rtc.isrunning()) {
    Serial.println("RTC is not running!");
  }
  
  if (!SD.begin(CHIP_SELECT_PIN)) { // Initialize SD card
    Serial.println("SD card initialization failed!");
    return;
  }
  Serial.println("SD card initialized.");
  
  // Configure button pins as inputs with pull-up resistors
  pinMode(BUTTON_UP_PIN, INPUT_PULLUP);
  pinMode(BUTTON_DOWN_PIN, INPUT_PULLUP);
  pinMode(BUTTON_LEFT_PIN, INPUT_PULLUP);
  pinMode(BUTTON_SELECT_PIN, INPUT_PULLUP);
}

void loop() {
  if (!ultrasonic_selected && !view_data_selected) {
    // Read button states and update current item accordingly
    if (digitalRead(BUTTON_UP_PIN) == LOW) {
      current_item = (current_item + NUM_ITEMS - 1) % NUM_ITEMS; // Move to previous item
      delay(250); // Debounce delay
    }
    if (digitalRead(BUTTON_DOWN_PIN) == LOW) {
      current_item = (current_item + 1) % NUM_ITEMS; // Move to next item
      delay(250); // Debounce delay
    }

    // Display menu options on the LCD screen
    u8g.firstPage();
    do {
      u8g.setFont(u8g_font_7x14);
      for (int i = 0; i < ITEMS_DISPLAYED; ++i) {
        int index = (current_item + i - ITEMS_DISPLAYED / 2 + NUM_ITEMS) % NUM_ITEMS;
        if (i == ITEMS_DISPLAYED / 2) {
          u8g.drawStr(0, (i + 1) * 10, "-> "); // Indicator for current selected item
        }
        u8g.drawStr(20, (i + 1) * 10, menu_items[index]);
      }
    } while (u8g.nextPage());

    // Check if SELECT button is pressed to select the item
    if (digitalRead(BUTTON_SELECT_PIN) == LOW) {
      if (current_item == NUM_ITEMS - 1) { // If "Ultrasonic Sensor" option is selected
        ultrasonic_selected = true; // Enable ultrasonic sensor mode
      } else if (current_item == NUM_ITEMS - 2) { // If "View Saved Data" option is selected
        view_data_selected = true; // Enable view saved data mode
        current_line_index = 0; // Reset the line index when entering view saved data mode
      }
      delay(250); // Debounce delay
    }
  } else if (view_data_selected) { // View saved data mode
    viewSavedData(); // View saved data from SD card
  } else { // Ultrasonic sensor mode
    // Read distance from ultrasonic sensor
    unsigned int duration = sonar.ping_median(5); // Measure distance in microseconds
    unsigned int distance = duration / US_ROUNDTRIP_CM; // Convert to centimeters

    // Print distance to serial monitor
    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");

    // Save data to SD card
    saveDataToSDCard(distance);

    // Display distance on the OLED screen
    displayUltrasonicDistance(distance);

    // Check if LEFT button is pressed to exit ultrasonic sensor mode
    if (digitalRead(BUTTON_LEFT_PIN) == LOW) {
      ultrasonic_selected = false; // Disable ultrasonic sensor mode
      delay(250); // Debounce delay
    }
  }
}

void viewSavedData() {
  u8g.firstPage();
  do {
    u8g.setFont(u8g_font_7x14);
    dataFile = SD.open("data.txt");
    if (dataFile) {
      int lineIndex = 0;
      while (dataFile.available()) {
        if (lineIndex >= current_line_index && lineIndex < current_line_index + DATA_DISPLAYED) {
          String line = dataFile.readStringUntil('\n');
          // Parse the line to extract date/time and distance
          int commaIndex = line.indexOf(',');
          if (commaIndex != -1) {
            String dateTime = line.substring(0, commaIndex);
            String distanceStr = line.substring(commaIndex + 1);
            // Display date/time and distance
            u8g.drawStr(0, (lineIndex - current_line_index + 1) * 20, dateTime.c_str());
            u8g.drawStr(0, (lineIndex - current_line_index + 2) * 20, distanceStr.c_str());
          }
        } else {
          dataFile.readStringUntil('\n'); // Read and discard lines outside the current view
        }
        lineIndex++;
      }
      dataFile.close();
    } else {
      Serial.println("Error opening data file!");
    }
  } while (u8g.nextPage());

  // Read button states for scrolling through data
  if (digitalRead(BUTTON_UP_PIN) == LOW && current_line_index > 0) {
    current_line_index--; // Scroll up if not at the beginning
    delay(250); // Debounce delay
  }
  if (digitalRead(BUTTON_DOWN_PIN) == LOW) {
    current_line_index++; // Scroll down
    delay(250); // Debounce delay
  }

  // Check if LEFT button is pressed to exit view saved data mode
  if (digitalRead(BUTTON_LEFT_PIN) == LOW) {
    view_data_selected = false; // Disable view saved data mode
    delay(250); // Debounce delay
  }
}

void saveDataToSDCard(unsigned int distance) {
  dataFile = SD.open("data.txt", FILE_WRITE);
  if (dataFile) {
    DateTime now = rtc.now();
    dataFile.print(now.year(), DEC);
    dataFile.print('/');
    dataFile.print(now.month(), DEC);
    dataFile.print('/');
    dataFile.print(now.day(), DEC);
    dataFile.print(" ");
    dataFile.print(now.hour(), DEC);
    dataFile.print(':');
    dataFile.print(now.minute(), DEC);
    dataFile.print(':');
    dataFile.print(now.second(), DEC);
    dataFile.print(',');
    dataFile.println(distance);
    dataFile.close();
    Serial.println("Data saved to SD card.");
  } else {
    Serial.println("Error opening data file!");
  }
}

void displayUltrasonicDistance(unsigned int distance) {
  u8g.firstPage();
  do {
    u8g.setFont(u8g_font_7x14);
    u8g.drawStr(0, 20, "Ultrasonic Sensor:");
    u8g.drawStr(0, 40, String(distance).c_str()); // Convert distance to string and draw on the screen
  } while (u8g.nextPage());
}