#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#include <EEPROM.h>
#include <etl/vector.h> 


const int MAX_NUMS = 10;
etl::vector<int, MAX_NUMS> storedNumbers;

// ---------- Настройка матричной клавиатуры 4x4 ----------
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] = {5, 4, 3, 2};  // строки (входы с pull-up)
byte colPins[COLS] = {A3, A2, A1, A0};  // столбцы (выходы)
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);


LiquidCrystal_I2C lcd(0x27, 16, 2);

String inputStr = "";
bool isStoring = true;
String currentInput = "";

const int EEPROM_ADDR= 0;
void setup() {
  Serial.begin(115200);
  lcd.init();
  lcd.backlight();
  lcd.print("Borders");
  delay(1500);
  lcd.clear();
  loadFromEEPROM();
  
  updateDisplay();
}

void loop() {
  char key = keypad.getKey();
  if (key) {
    handleKey(key);
  }
}

void handleKey(char key) {
  if (isStoring) {  
    if (isdigit(key)) {
      if (inputStr.length() < 4) inputStr += key;
      updateInputLine();
    } 
    else if (key == 'B') {
      if (inputStr.length() > 0) inputStr.remove(inputStr.length()-1);
      updateInputLine();
    } 
    else if (key == '#') {
      storedNumbers.clear();
      inputStr = "";
      saveToEEPROM();
      lcd.clear();
      lcd.print("Full reset");
      delay(1000);
      showMainScreen();
    } 
    else if (key == '*') { 
      if (!inputStr.isEmpty() && storedNumbers.size() < MAX_NUMS) {
        storedNumbers.push_back(inputStr.toInt());
        inputStr = "";
        saveToEEPROM();
      }
      if (storedNumbers.size() > 0) {
        sortStored();
        isStoring = false;
        lcd.clear();
        lcd.print("Stage 2 switch");
        delay(1200);
      }
      showMainScreen();
    }
  } 
  else {  // === ЭТАП 2: Поиск интервала ===
    if (isdigit(key)) {
      if (inputStr.length() < 4) inputStr += key;
      updateInputLine();
    } 
    else if (key == 'B') {
      if (inputStr.length() > 0) inputStr.remove(inputStr.length()-1);
      updateInputLine();
    } 
    else if (key == '#') {  // Возврат в Этап 1
      isStoring = true;
      inputStr = "";
      lcd.clear();
      lcd.print("Back to Stage 1");
      delay(1000);
      showMainScreen();
    } 
    else if (key == '*' || key == 'A' || key == 'C' || key == 'D') {  // Подтверждение ввода
      if (!inputStr.isEmpty()) {
        int num = inputStr.toInt();
        inputStr = "";
        findAndShowInterval(num);
      }
    }
  }
}
void sortStored() {
  for (size_t i = 0; i < storedNumbers.size(); ++i) {
    for (size_t j = i + 1; j < storedNumbers.size(); ++j) {
      if (storedNumbers[i] > storedNumbers[j]) {
        int temp = storedNumbers[i];
        storedNumbers[i] = storedNumbers[j];
        storedNumbers[j] = temp;
      }
    }
  }
}


void updateInputLine() {
  lcd.setCursor(0, 1);
  lcd.print("Enter: ");
  lcd.print(inputStr);
  lcd.print("    "); //cleaning
}

void showMainScreen() {
  lcd.clear();
  if (isStoring) {
    lcd.print("Stage 1: Bounds");
    lcd.setCursor(0,1);
    lcd.print("Numbers: ");
    lcd.print(storedNumbers.size());
    lcd.print("/10");
  } else {
    lcd.print("Stage 2: Search");
    lcd.setCursor(0,1);
    lcd.print("Enter a number:");
  }
}


void findAndShowInterval(int num) {
  lcd.clear();
  lcd.print("Number: ");
  lcd.print(num);
  
  if (storedNumbers.empty()) {
    lcd.setCursor(0,1);
    lcd.print("No bounds!");
    delay(2000);
    return;
  }
  lcd.setCursor(0,1);
  // Крайние случаи
  if (num < storedNumbers[0]) {
    lcd.print("Less than [");
    lcd.print(storedNumbers[0]);
    lcd.print("]");
    delay(2500);
    return;
  }
  if (num > storedNumbers.back()) {
    lcd.print("More than [");
    lcd.print(storedNumbers.back());
    lcd.print("]");
    delay(2500);
    return;
  }
  // Поиск интервала
  for (size_t i = 0; i < storedNumbers.size() - 1; ++i) {
    if (num >= storedNumbers[i] && num <= storedNumbers[i+1]) {
      lcd.print("[");
      lcd.print(storedNumbers[i]);
      lcd.print(",");
      lcd.print(storedNumbers[i+1]);
      lcd.print("]");
      delay(3000);
      return;
    }
  }
  lcd.print("Not found");
  delay(2000);
}


// Работа с EEPROM
void saveToEEPROM() {
  int count = storedNumbers.size();
  EEPROM.put(EEPROM_ADDR, count);
  for (int i = 0; i < count; ++i) {
    EEPROM.put(EEPROM_ADDR + 4 + i * sizeof(int), storedNumbers[i]);
  }
}
void loadFromEEPROM() {
  int count = 0;
  EEPROM.get(EEPROM_ADDR, count);
  if (count > 0 && count <= MAX_NUMS) {
    storedNumbers.clear();
    for (int i = 0; i < count; ++i) {
      int val = 0;
      EEPROM.get(EEPROM_ADDR + 4 + i * sizeof(int), val);
      storedNumbers.push_back(val);
    }
  }
}