#include "SPI.h"
#include "Adafruit_GFX.h"
#include "Adafruit_ILI9341.h"

#define TFT_DC 2
#define TFT_CS 3
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);
#define IR_PIN A0
uint32_t lastCode;

#define CODE_0     2540240640
#define CODE_1     3476094720
#define CODE_2     3877175040
#define CODE_3     2239430400
#define CODE_4     4010868480
#define CODE_5     3342401280
#define CODE_6     2774204160
#define CODE_7     3175284480
#define CODE_8     3041591040
#define CODE_9     2907897600
#define CODE_ADD   4244832000
#define CODE_SUB   1738080000
#define CODE_C     1336999680
#define CODE_POWER 1570963200
#define CODE_MUL   534839040
#define CODE_EQUAL 1470693120
#define CODE_DIV   1871773440
#define CODE_MENU  501415680
#define CODE_BS    1036189440

long num1=0,num2=0;
char op=0;
String inputStr;
String history[5];
uint8_t histIdx=0,histCount=0,pageFlag=0;

// 水平居中打印
void printCenter(const char *txt,int y,uint16_t color,uint8_t size)
{
  int16_t x1,y1;uint16_t w,h;
  tft.setTextSize(size);
  tft.getTextBounds(txt,0,y,&x1,&y1,&w,&h);
  int x=(tft.width()-w)/2;
  tft.setTextColor(color);
  tft.setCursor(x,y);
  tft.println(txt);
}

// 右对齐打印，不换行避免纵向截断
void printRA(const char *txt,int y,uint16_t c)
{
  int16_t x1,y1;uint16_t w,h;
  tft.setTextSize(2);
  tft.getTextBounds(txt,0,y,&x1,&y1,&w,&h);
  tft.setTextColor(c);
  tft.setCursor(tft.width()-w-1,y);
  tft.print(txt);
}

// 右下角签名，预留安全底边不截断
void printSign()
{
  tft.setTextSize(2);
  printRA("  ",240,ILI9341_GREEN);
  printRA("  ",265,ILI9341_GREEN);
}

uint32_t readIR()
{
  if(digitalRead(IR_PIN))return 0;
  uint32_t t=micros();
  while(!digitalRead(IR_PIN));
  uint32_t low=micros()-t;
  if(low<5000){
    while(digitalRead(IR_PIN));
    while(!digitalRead(IR_PIN));
    return lastCode;
  }
  while(digitalRead(IR_PIN));
  uint32_t code=0;
  for(uint8_t i=0;i<32;i++){
    while(!digitalRead(IR_PIN));
    uint32_t s=micros();
    while(digitalRead(IR_PIN));
    if(micros()-s>1000)code|=1UL<<i;
  }
  lastCode=code;
  return code;
}

// 主计算器界面
void refreshScreen()
{
  tft.fillScreen(ILI9341_BLACK);
  tft.setTextSize(2);
  tft.setTextColor(ILI9341_WHITE);
  tft.setCursor(10,20);
  tft.print("CALC");
  tft.drawFastHLine(10,45,tft.width()-20,ILI9341_DARKGREY);
  tft.setTextSize(3);
  tft.setTextColor(ILI9341_YELLOW);
  tft.setCursor(10,55);
  tft.print(inputStr);
  if(op!=0){
    tft.setTextSize(2);
    tft.setTextColor(ILI9341_CYAN);
    tft.setCursor(10,120);
    tft.print(num1);
    tft.print(op);
    tft.print(" ?");
  }
  printSign();
  pageFlag=0;
}

// 开机欢迎页（文字全部居中）
void showWelcome()
{
  tft.fillScreen(ILI9341_BLACK);
  printCenter("CALC",60,ILI9341_YELLOW,3);
  printCenter("IR Remote",120,ILI9341_CYAN,2);
  printCenter("Press any key",160,ILI9341_CYAN,2);
  printSign();
  pageFlag=1;
}

void calcReset()
{
  num1=0;op=0;inputStr="";histIdx=0;histCount=0;
  showWelcome();
}

// 等于运算弹窗
void calcEqual()
{
  if(inputStr.length()==0||op==0)return;
  num2=inputStr.toInt();
  long res=0;
  if(op=='+')res=num1+num2;
  if(op=='-')res=num1-num2;
  if(op=='*')res=num1*num2;
  if(op=='/'){if(num2==0)return;res=num1/num2;}
  String rec=String(num1)+String(op)+String(num2)+"="+String(res);
  if(histCount<5)history[histCount++]=rec;
  else{for(int i=0;i<4;i++)history[i]=history[i+1];history[4]=rec;}
  histIdx=histCount-1;
  tft.fillScreen(ILI9341_BLACK);
  tft.setTextSize(3);
  tft.setTextColor(ILI9341_YELLOW);
  tft.setCursor(10,40);
  tft.print(num1);tft.print(op);tft.print(num2);tft.print("=");tft.print(res);
  printSign();
  pageFlag=1;
  num1=res;inputStr="";op=0;
}

// 单条历史翻阅
void showHistory(int dir)
{
  if(histCount==0)return;
  histIdx+=dir;
  if(histIdx<0)histIdx=histCount-1;
  if(histIdx>=histCount)histIdx=0;
  tft.fillScreen(ILI9341_BLACK);
  tft.setTextSize(2);
  tft.setTextColor(ILI9341_CYAN);
  tft.setCursor(10,40);
  tft.print("H ");tft.print(histIdx+1);tft.print("/");tft.print(histCount);
  tft.setCursor(10,90);tft.print(history[histIdx]);
  printSign();
  pageFlag=1;
}

// MENU全部历史弹窗（修复自动换行）
void showAllHistory()
{
  tft.fillScreen(ILI9341_BLACK);
  tft.setTextSize(2);
  tft.setTextColor(ILI9341_CYAN);
  tft.setCursor(10,10);
  tft.println("HIST");
  if(histCount==0)
  {
    tft.println("Empty");
  }
  else
  {
    for(uint8_t i=0;i<histCount;i++)
    {
      tft.print(i+1);
      tft.print(". ");
      tft.println(history[i]);
    }
  }
  printSign();
  pageFlag=1;
}

void setup()
{
  Serial.begin(115200); // 新增UART初始化
  tft.begin();
  calcReset();
}

void loop()
{
  uint32_t code=readIR();
  if(code==0){
    delay(5);
    return;
  }

  // 完全复刻稳定原版弹窗逻辑
  if(pageFlag == 1)
  {
    refreshScreen();
    delay(100);
    return;
  }

  // 数字输入
  if(code==CODE_0)inputStr+="0";
  else if(code==CODE_1)inputStr+="1";
  else if(code==CODE_2)inputStr+="2";
  else if(code==CODE_3)inputStr+="3";
  else if(code==CODE_4)inputStr+="4";
  else if(code==CODE_5)inputStr+="5";
  else if(code==CODE_6)inputStr+="6";
  else if(code==CODE_7)inputStr+="7";
  else if(code==CODE_8)inputStr+="8";
  else if(code==CODE_9)inputStr+="9";

  // 四则运算符
  else if(code==CODE_ADD){if(inputStr.length()>0)num1=inputStr.toInt();op='+';inputStr="";}
  else if(code==CODE_SUB){if(inputStr.length()>0)num1=inputStr.toInt();op='-';inputStr="";}
  else if(code==CODE_MUL){if(inputStr.length()>0)num1=inputStr.toInt();op='*';inputStr="";}
  else if(code==CODE_DIV){if(inputStr.length()>0)num1=inputStr.toInt();op='/';inputStr="";}

  // 清除输入
  else if(code==CODE_C)inputStr="";
  // 电源重置
  else if(code==CODE_POWER){calcReset();return;}
  // 等于弹窗
  else if(code==CODE_EQUAL){calcEqual();return;}
  // 上一条历史
  else if(code==CODE_MUL){showHistory(-1);return;}
  // 下一条历史
  else if(code==CODE_DIV){showHistory(1);return;}
  // MENU全部历史
  else if(code==CODE_MENU){showAllHistory();return;}
  // 退格删除
  else if(code==CODE_BS){if(inputStr.length()>0)inputStr.remove(inputStr.length()-1);}

  // ============ 新增UART双向通信代码 ============
  // 接收电脑串口指令
  if(Serial.available() > 0)
  {
    char cmd = Serial.read();
    if(cmd == 'C') inputStr = "";
    if(cmd == 'R') calcReset();
  }
  // 实时打印计算器状态到电脑串口
  Serial.print(F("输入:"));
  Serial.print(inputStr);
  Serial.print(F(" 运算符:"));
  Serial.print(op);
  Serial.print(F(" 数字1:"));
  Serial.println(num1);
  // ==============================================

  refreshScreen();
  delay(100);
}