/**
   Arduino Electronic Safe

   Copyright (C) 2020, Uri Shaked.
   Released under the MIT License.
*/


#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
 
const int greenLEDPin =2;  //绿LED亮，表示结果正确
const int redLEDPin =3;    //红LED亮，表示结果错误
 
 
int firstNum ;   //加法或减法操作的第一个数
int secondNum ;  //加法或减法操作的第二个数
int result ;     //两个数的运算结果
int myResult;   //我计算的运算结果
 
char operatr = ' ';  //存放‘+’或‘-’的字符
 
int start_flag = 0 ;   //开始运算标志位
 
int rightNum= 0; //记录正确数
int errorNum= 0; //记录错误数
 
int counts = 0;    //记录答题次数
 
 
long startTime;  //开始记录答题时间
long endTime;    //结束记录答题时间
 
/*
 * 下面的配置是对4*4键盘的配置
 */
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] = {5, 6, 7, 8}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {9, 10, 11, 12}; //connect to the column pinouts of the keypad
 
Keypad myKeypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS); 
 
//液晶屏的配置
LiquidCrystal_I2C lcd(0x27,16,2);   //创建对象，并配置LCD地址及行列
 
void startDisplay(){
  lcd.clear(); //清屏
  lcd.setCursor(0, 0) ;   //设置光标位置为第1行第1个位置
  lcd.print("Welcome!");  //使屏幕显示Welcome!
  lcd.setCursor(0, 1) ;   //设置光标位置为第2行第1个位置
  lcd.print("Press A to start"); 
  delay(500);  
}
 
void setup() {
  pinMode(greenLEDPin,OUTPUT);
  pinMode(redLEDPin,OUTPUT);
  lcd.init();    //初始化LCD
  lcd.backlight();  //打开背光
  delay(500); //延时500ms
  startDisplay(); 
  randomSeed(analogRead(A0));  
}
 
void loop() {                
  char newKey = myKeypad.getKey();
  if(newKey != NO_KEY && newKey == 'A'){
    start_flag=1;
    startTime=millis();
  }
  if(start_flag==1 && counts <= 10){   //开始运算
    counts++;
    gennerator();       //生成数据并赋值给相关变量
    lcd.clear();         //清屏
    lcd.setCursor(0, 0);   //设置光标位置为第1行第1个位置
    lcd.print(firstNum);   //显示第一个数字
    lcd.print(operatr);   //显示运算符
    lcd.print(secondNum); //显示第二个数字
    lcd.print("=");       //显示 =
    while(1){
      char newKey = myKeypad.getKey();
      //把输入的数值显示出来，并把最后的输入结果赋给myResult
      for(int i=0;i<=9;i++){    
        if(newKey != NO_KEY && newKey ==('0'+i)){
          int num=newKey-48;   //把字符数字变为数学中的数字
          lcd.print(num); //使屏幕显示文字
          delay(100);
          myResult=myResult*10+num;
        }
      }
      if(newKey != NO_KEY && newKey == 'D'){
          break;
      }
    }
    lcd.setCursor(0, 1);
    if(result==myResult){
      rightNum++; 
      digitalWrite(greenLEDPin,HIGH);    
      lcd.print("    great^-^");  
    }else{
      errorNum++;
      digitalWrite(redLEDPin,HIGH);   
      lcd.print("   losing-_-");
    }
    delay(2000);
    digitalWrite(greenLEDPin,LOW);
    digitalWrite(redLEDPin,LOW);     
  }
  //结束本轮答题
  endToHandle();  
}
 
void endToHandle(){
  if(start_flag==1&& counts == 10){
    lcd.clear();         //清屏
    lcd.setCursor(0, 0);
    lcd.print("right:"); 
    lcd.print(rightNum);
    lcd.setCursor(0, 1);
    lcd.print("error:"); 
    lcd.print(errorNum); 
    delay(3000); 
  
    
    lcd.clear();         //清屏
    lcd.setCursor(0, 0);
    if(rightNum==10){
      lcd.print("  best!!"); 
    }else if(rightNum>=8){
      lcd.print("  great!!");
    }else if(rightNum>=6){
      lcd.print("  passed!!");
    }else{
      lcd.print("need work hard!");
    }
    delay(3000);
 
    endTime=millis();
    int fen=(endTime-startTime)/1000/60;
    int miao=(endTime-startTime)/1000%60;
    lcd.clear();         //清屏
    lcd.setCursor(0, 0);
    lcd.print("Time:");
    lcd.print(fen);
    lcd.print("\'");
    lcd.print(miao);
    lcd.print("\"");
    delay(5000);
    
    start_flag=0;
    counts=0;
    lcd.clear();         //清屏
    lcd.setCursor(0, 0);
    lcd.print("Press A to start");    
  }
}
 
/*
 * 通过生成的随机数给firstNum、secondNum、result、operatr赋值，myResult重新赋值为0
 */
 
void gennerator(){
  int x=random(99)+1;  //生成一个1-99的数字
  int y=random(99)+1;
  int z=random(2);      //生成一个0或1的数字，0代表加法，1代表减法
  if(z==0){
    operatr = '+';
    if(x>y){
      result=x;    //最大的数存放结果
      firstNum=y ;
      secondNum=x-y ;
    }else{
      result=y;
      firstNum=x;
      secondNum=y-x ;
    }
  }else {
    operatr = '-';
    if(x>y){
      result=x-y;
      firstNum=x;
      secondNum=y;
    }else{
      result=y-x;
      firstNum=y;
      secondNum=x ;
    }
  }
  myResult=0;   
}