#include <LiquidCrystal.h>
#include <Keypad.h>

// LCD引脚配置
LiquidCrystal lcd(19, 20, 11, 12, 13, 14); // 根据实际接线调整

// 4x4矩阵键盘配置
const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {42, 41, 40, 39}; // 连接键盘行引脚
byte colPins[COLS] = {38, 37, 36, 35};  // 修正了之前的错误引脚号(363改为36)
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// 光敏电阻引脚
const int photoResistorPin = 1;

// LED指示灯引脚
const int redLedPin = 4;    // 红灯引脚
const int greenLedPin = 5;   // 绿灯引脚

// 系统变量
bool submitted[8] = {false}; // 学号1-8的提交状态
int baselineLight = 0;       // 环境光基准值
bool detecting = true;       // 是否在检测作业状态
unsigned long lastDisplayTime = 0;
const int displayInterval = 1000; // 状态显示间隔(毫秒)
int currentID = -1;          // 当前输入的学生ID

void setup() {
  Serial.begin(115200);
  
  // 初始化LCD
  lcd.begin(16, 2);
  lcd.print("Automatic HW");
  lcd.setCursor(0, 1);
  lcd.print("Collector v1.0");
  
  // 初始化光敏电阻
  pinMode(photoResistorPin, INPUT);
  
  // 初始化LED指示灯
  pinMode(redLedPin, OUTPUT);
  pinMode(greenLedPin, OUTPUT);
  
  // 初始状态：红灯亮，绿灯灭
  digitalWrite(redLedPin, HIGH);
  digitalWrite(greenLedPin, LOW);
  
  delay(1000);
  baselineLight = analogRead(photoResistorPin); // 获取环境光基准
  
  delay(2000);
  lcd.clear();
}

void loop() {
  // 更新指示灯状态
  updateLEDs();
  
  if (detecting) {
    detectHomework();
    displayStatusCycle();
  } else {
    getStudentID();
  }
}

// 更新LED指示灯状态
void updateLEDs() {
  if (detecting) {
    // 检测模式：红灯亮，绿灯灭
    digitalWrite(redLedPin, HIGH);
    digitalWrite(greenLedPin, LOW);
  } else {
    // 输入模式：红灯灭，绿灯亮
    digitalWrite(redLedPin, LOW);
    digitalWrite(greenLedPin, HIGH);
  }
}

// 检测作业下落
void detectHomework() {
  static int lastLight = baselineLight;
  static bool wasDark = false;
  
  int currentLight = analogRead(photoResistorPin);
  
  // 检测到光线变暗
  if (currentLight > baselineLight + 1000 && !wasDark) {
    wasDark = true;
    Serial.println("Dark detected");
  }
  
  // 检测到光线恢复
  if (wasDark && currentLight > baselineLight - 50) {
    wasDark = false;
    Serial.println("Light restored - homework detected");
    homeworkDetected();
  }
  
  lastLight = currentLight;
  delay(50);
}

// 检测到作业后的处理
void homeworkDetected() {
  detecting = false;
  lcd.clear();
  lcd.print("Homework Detected");
  lcd.setCursor(0, 1);
  lcd.print("Enter ID(1-8):");
  
  // 更新LED状态
  updateLEDs();
}

void getStudentID() {
  char key = keypad.getKey();
  
  if (key) {
    Serial.print("Key pressed: ");
    Serial.println(key);
    
    if (key >= '1' && key <= '8') {
      currentID = key - '1'; // 保存当前输入
      lcd.clear();
      lcd.print("ID:");
      lcd.print(key);
      lcd.print(" Press D to confirm");
      lcd.setCursor(0, 1);
      lcd.print("or * to cancel");
    }
    else if (key == 'D' && currentID != -1) {  // 添加currentID有效性检查
      submitted[currentID] = true;
      lcd.clear();
      lcd.print("ID:");
      lcd.print(currentID + 1);
      lcd.print(" SUBMITTED");
      delay(2000);
      detecting = true;
      currentID = -1;
      lcd.clear();
      
      // 更新LED状态
      updateLEDs();
    }
    else if (key == '*') {
      detecting = true;
      currentID = -1;
      lcd.clear();
      
      // 更新LED状态
      updateLEDs();
    }
  }
}

// 循环显示提交状态
void displayStatusCycle() {
  static int displayID = 0;
  
  if (millis() - lastDisplayTime > displayInterval) {
    lastDisplayTime = millis();
    
    lcd.clear();
    lcd.print("ID:");
    lcd.print(displayID + 1);
    lcd.print(" Status:");
    lcd.setCursor(0, 1);
    lcd.print(submitted[displayID] ? "Y Submitted" : "N Not Submitted");
    
    displayID = (displayID + 1) % 8;
  }
}