#include <SD.h>
#include <ezButton.h>
#include <LiquidCrystal_I2C.h>
#include "lcd_custom_character.h"
int book_num = 0;
int book_state = 0;
int prev_book_num = -1;
int page_num = 0;
int prev_page_num = -1;

String display_text = "";


ezButton next(2);
ezButton previous(3);
ezButton selectBook(4);
ezButton openBook(5);

File file;
LiquidCrystal_I2C lcd(0x27,20,4);
void setup() {
  SD.begin();
  // put your setup code here, to run once:
  Serial.begin(9600);
  /*if(!SD.begin()){
    Serial.println("SD card not detected");
  }
  else{
    Serial.println("SD card detected");
  }*/
  next.setDebounceTime(50);
  previous.setDebounceTime(50);
  selectBook.setDebounceTime(50);
  openBook.setDebounceTime(50);
  lcd.init();
  lcd.backlight();
  lcd.clear();
  welcome();
  delay(1000);
  animate();
  /*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.println();
    file.close();
  }
  Serial.println("File read successfully");*/
}

void loop() {
  // put your main code here, to run repeatedly:
  next.loop();
  previous.loop();
  selectBook.loop();
  openBook.loop();

  if(next.isPressed()){
    if(book_state){
      page_num ++;
    }
    else{
      book_num++;
    }
  }
  else if(previous.isPressed()){
    if(book_state){
      page_num --;
    }
    else{
      book_num --;
    }
  }
  else if(selectBook.isPressed()){
    book_state = 0;
    prev_book_num = -1;
    prev_page_num = -1;
    page_num = 0;
  }
  else if(openBook.isPressed()){
    book_state = 1;
  }
  book_num = constrain(book_num,0,1);
  if(page_num < 0){
    page_num = 0;
  }
  check_book();
  read_book();
}

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");
    }
    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);
    }
    int total_pages = file.size()/80;
    page_num = constrain(page_num,0,total_pages);
    int pointer = page_num * 80;
    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 lcd_print(int x, int y, String msg){
  lcd.setCursor(x,y);
  lcd.print(msg);
}

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,"DigiBook");
  delay(1000);
}

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