#include <Keypad.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <WiFi.h>
#include <WebServer.h>

// ==============================
// WIFI CHO PHÒNG ĐIỂM DANH
// ==============================
const char* ssid = "Wokwi-GUEST";
const char* password = "";

WebServer server(80);

// Thông báo từ phòng bơm
String pumpMessage = "";

// ==============================
// LCD
// ==============================
LiquidCrystal_I2C lcd(0x27, 16, 2);

// ==============================
// KEYPAD
// ==============================
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] = {32, 33, 25, 26};
byte colPins[COLS] = {27, 14, 12, 13};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// ==============================
// PINS
// ==============================
const int LDR_PIN = 34;    
const int LED_PIN = 2;     

// ==============================
// LOGIC BIẾN
// ==============================
bool autoMode = true;
int lightThreshold = 300;
String currentEntry = "";

unsigned long lastLCDupdate = 0;
const unsigned long LCD_INTERVAL = 500;

// ATTENDANCE
struct Attendee {
  String code;
  String name;
};
Attendee attendees[] = {
  {"1234", "Nguyen A"},
  {"2345", "Tran B"},
  {"3456", "Le C"}
};
const int NUM_KNOWN = sizeof(attendees) / sizeof(attendees[0]);

#define MAX_CHECKIN 50
String checkedInCodes[MAX_CHECKIN];
int checkedInCount = 0;

// ==============================
// SERVER HANDLER NHẬN THÔNG BÁO
// ==============================
void handleNotify() {
  if (server.hasArg("n")) {
    pumpMessage = server.arg("n");

    Serial.print("==> THONG BAO TU PHONG BOM: ");
    Serial.println(pumpMessage);

    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Thong bao tu");
    lcd.setCursor(0,1);

    if (pumpMessage == "full") {
      lcd.print("Nuoc: FULL  !!!");
    } else if (pumpMessage == "low") {
      lcd.print("Nuoc: THAP !!! ");
    } else {
      lcd.print("Msg: " + pumpMessage);
    }

    delay(2000);  // Hiển thị cảnh báo 2 giây
    lcd.clear();
  }

  server.send(200, "text/plain", "OK");
}

// ==============================
// SETUP
// ==============================
void setup() {
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);

  // LCD
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Diem danh ESP32");
  delay(700);
  lcd.clear();

  // WIFI
  WiFi.begin(ssid, password);
  Serial.print("Dang ket noi WiFi...");
  while (WiFi.status() != WL_CONNECTED) delay(100);
  Serial.println("OK!");

  Serial.print("IP phong diem danh: ");
  Serial.println(WiFi.localIP());

  server.on("/notify", handleNotify);
  server.begin();
}

// ==============================
// LOOP
// ==============================
void loop() {
  server.handleClient();

  // Lấy keypad
  char k = keypad.getKey();
  if (k) handleKey(k);

  // Auto Light
  int raw = analogRead(LDR_PIN);
  static bool ledState = false;

  if (autoMode) {
    ledState = (raw < lightThreshold);
    digitalWrite(LED_PIN, ledState ? HIGH : LOW);
  }

  // Update LCD
  if (millis() - lastLCDupdate > LCD_INTERVAL) {
    updateLCD(raw);
    lastLCDupdate = millis();
  }
}

// ==============================
// KEYPAD XỬ LÝ
// ==============================
void handleKey(char k) {
  if (k == '#') {
    if (currentEntry.length() == 4) {
      processCode(currentEntry);
    }
    currentEntry = "";
  }
  else if (k == '*') {
    currentEntry = "";
    lcd.setCursor(0,1);
    lcd.print("Cleared        ");
  }
  else {
    if (currentEntry.length() < 4) {
      currentEntry += k;
      lcd.setCursor(0,1);
      lcd.print("Code: " + currentEntry);
    }
  }
}

// ==============================
// CHECK CODE
// ==============================
void processCode(String code) {
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Checking...");

  int idx = -1;
  for (int i=0;i<NUM_KNOWN;i++) {
    if (attendees[i].code == code) idx = i;
  }

  if (idx >= 0) {
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Welcome:");

    lcd.setCursor(0,1);
    lcd.print(attendees[idx].name);

    checkedInCodes[checkedInCount++] = code;
  } else {
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Invalid code");
  }

  delay(1500);
  lcd.clear();
}

// ==============================
// LCD UPDATE
// ==============================
void updateLCD(int raw) {
  lcd.setCursor(0,0);
  lcd.print("L:");
  lcd.print(raw);
  lcd.print(" LED:");
  lcd.print(digitalRead(LED_PIN) ? "ON " : "OFF");

  lcd.setCursor(0,1);
  lcd.print("Mode:");
  lcd.print(autoMode ? "AUTO" : "MAN");
  lcd.print(" C:");
  lcd.print(checkedInCount);
}