#include <SD.h>
#include <ezButton.h>
#include <LiquidCrystal_I2C.h>
#include "lcd_custom_character.h"

File file;

int book_num = 0;
int book_state = 0; 
ezButton next(2);
ezButton prev(3);
ezButton select_book(4);
ezButton open_book(5);

LiquidCrystal_I2C lcd(0x27,20,4);

int prev_book_num=-1;
int page_num=0,prev_page_num=-1;
String display_text="";



void check_book(){
  if(prev_book_num != book_num){
    prev_book_num= book_num;
    lcd.clear();

  if(book_num){
    lcd_print(0,0,"THINK AND GROW RICH");

    Serial.println("THINK AND GROW RICH");
  }
  else {
    lcd_print(0,0,"HARRY PORTER");
    Serial.println("HARRY PORTER");
  }
  }
}


void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);

  if (!SD.begin())Serial.println("SD Card is not detected");
  else Serial.println("SD card detected");


  /*file = SD.open("harry.txt",FILE_READ);
  Serial.print("Total chracters :");
  Serial.println(file.size());
  if (file){
    Serial.println("Harry porter: ");
    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);

}

void display_char(int x,int y,int id){
  lcd.setCursor(x,y);
  lcd.write(id);

}

void animate(){
  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++){
    display_char(11,3,1);
    display_char(9,3,3);
    display_char(7,3,0);
    if (i%2==0){
      display_char(8,3,2);
      display_char(10,3,2);
      delay(1100);
    }
    else{
      display_char(8,3,4);
      display_char(10,3,4);
      delay(100);
    }
  }
  lcd.clear();

}

void welcome(){
  lcd_print(1,0,"WELCOME");
  delay(1000);
  lcd_print(8,1,"TO");
  delay(1000);
  lcd_print(10,2,"DIGI BOOK");
  delay(1000);
}

void loop() {
  book_num= constrain(book_num,0,1);
  // put your main code here, to run repeatedly:
  next.loop();
  prev.loop();
  select_book.loop();
  open_book.loop();
  
  if (book_state==0){
    check_book();
  }

  if (next.isPressed()){
    if(book_state)page_num++;
    else book_num++;
    

  }
  else if(prev.isPressed()){
    if(book_state)page_num--;
    else book_num--;
    

  }
  else if (select_book.isPressed()){
    book_state=0;
    page_num=0;
    prev_book_num=-1;
    prev_page_num=-1;

    check_book();
  }
  else if (open_book.isPressed()){
    book_state=1;
    read_book();
  }
book_num=constrain(book_num,0,1);
if(page_num<0)page_num=0;
check_book();
read_book();
delay(10);

}

void read_book(){
  if(book_state){
    if(book_num){
      file= SD.open("think.txt",FILE_READ);
      Serial.println("total characters: ");
      Serial.println(file.size());
    }
    else {
      file= SD.open("harry.txt",FILE_READ);
      Serial.println("total characters: ");
      Serial.println(file.size());
      }
      int total_pages=file.size()/80;
      page_num= constrain(page_num,0,total_pages);
      int pointer= page_num*80;

      display_text= "";
      if (file){
        if(prev_page_num  !=page_num){
          prev_page_num=page_num;
          display_text="";
          file.seek(pointer);
          while (display_text.length()!= 80){
            char data= file.read();
            display_text.concat(data);

          }
          page_print();

        }
      }
  }
  file.close();
}

void page_print(){
  for (int i =0;i<4;i++){
    lcd_print(0,i,display_text.substring(i*20,(i+1)*20));

  }
}