#include <SD.h>
#include <ezButton.h>
#include <LiquidCrystal_I2C.h>
#include "lcd_custom_character.h"
File file;

ezButton next(2);
ezButton prev(3);
ezButton select_book(4); 
ezButton open_book(5);

// keeps track of which book is to be read 
int book_num = 0;

//checks if the book should be opened or not.
int book_state = 0;

// flag to avoid reptation of the currently selected book
int prev_book = -1;

LiquidCrystal_I2C lcd(0x27 , 20 , 4);

void setup() 
{
    Serial.begin(9600);
    if (!SD.begin())
        Serial.println("SD card not detected");
    else 
        Serial.println("SD card detected");
    
    // file = SD.open("harry.txt" , FILE_READ);
    // Serial.print("Total Characters: ");
    // Serial.println(file.size());

    // if(file)
    // {
    //     Serial.println("Harry Potter");
    //     delay(2000);
    //     while (file.available())
    //     {
    //         char data = file.read();
    //         Serial.print(data);
    //     }
    //     Serial.println();
    //     file.close();
    // }
    // Serial.println("File read successfully");

    next.setDebounceTime(50);
    prev.setDebounceTime(50);
    select_book.setDebounceTime(50);
    open_book.setDebounceTime(50); 

    lcd.init();
    lcd.backlight();
    lcd.clear();

    welcome();
    animate();

    delay(1000);
}

void lcd_print(int x , int y , String message)
{
    lcd.setCursor(x,y);
    lcd.print(message);
}

//created to draw customised charcter
void display_char(int x, int y, int id) 
{
  lcd.setCursor(x, y);

  //draw customised charcter with it's id
  lcd.write(id);
}

void animate() 
{
  // createChar() method to assign an id to the customized characters
  lcd.createChar(0, left_stick);
  lcd.createChar(1, right_stick);
  lcd.createChar(2, open_eye);
  lcd.createChar(3, middle_stick);
  lcd.createChar(4, closed_eye);

  for (int i = 0; i < 5; i++) 
  {
    //         col, row, id (left stick)
    display_char(11, 3, 1); // right stick
    display_char(9, 3, 3);  // middle stick
    display_char(7, 3, 0);  // left stick
    if (i % 2 == 0) 
    {
      display_char(8, 3, 2);  //open eye
      display_char(10, 3, 2); //open eye
      delay(1100);
    }
    else 
    {
      display_char(8, 3, 4);  //closed eye
      display_char(10, 3, 4); //closed eye
      delay(100);
    }
  }
  lcd.clear();
}


void welcome()
{
  lcd_print(2,0, "Welcome");
  delay(1000);
  lcd_print(8,1, "To");
  delay(1000);
  lcd_print(10,2, "Digi Book");
  delay(1000);
}
void loop() 
{
    next.loop();
    prev.loop();
    select_book.loop();
    open_book.loop();

    if (next.isPressed())
          book_num++;
    else if (prev.isPressed())
          book_num--;
    else if (select_book.isPressed())
    {
          // changes values to restart after opening a book
          book_state = 0;
          prev_book = -1;
    }
    else if(open_book.isPressed()) 
    {
          // changes value of the variable to enable book opening in the read_book() 
          book_state = 1;
    } 
    // makes sure doesn't go past 0 or 1 as only 2 books present.
    book_num = constrain(book_num,0,1);

    //checks which book is selected
    check_book();

    // reads book content 
    read_book();
}

void check_book()
{
  // to avoid repeative printing of book name
  if (prev_book != book_num)
  {
      lcd.clear();
      prev_book = book_num;
      if (book_num)
        lcd_print(0,0,"Think and Grow Rich!");
      else
         lcd_print(0,0,"Harry Potter!");
  }
}

void read_book()
{
   if(book_state)
   {
      if(book_num)
      {
         file= SD.open("think.txt",FILE_READ);
      }
      else
      {
         file= SD.open("harry.txt",FILE_READ);
      }

      String display_text="";
      if(file)
      {
          while(file.available())
          {
              char data=file.read();
              Serial.print(data);
          }
      }
   } 
   file.close();
}