#include<stdio.h>
//#include"ReadKeyPad.h"

//#define I2C_ADDR 0x27 << 1 // LCD I2C address (shifted for STM32)

volatile uint32_t button_press_count = 0;
volatile uint32_t last_button_time = 0;
char display_buffer[21] = {0};
uint8_t buffer_index = 0;
uint8_t display_on = 1;

void delay_ms(uint32_t ms) {
    for (uint32_t i = 0; i < ms * 800; i++) {
        __NOP();
    }
}

void process_key(char key) 
{
    display_buffer[buffer_index++] = key;
    if (buffer_index >= 20) buffer_index = 0;
   // lcd_update_display();
}
const char keypad_map[4][4] = {
    {'1', '2', '3', 'A'},
    {'4', '5', '6', 'B'},
    {'7', '8', '9', 'C'},
    {'*', '0', '#', 'D'}
};

void Keypad_Init(void) 
{
    // Enable GPIOA clock
   RCC->IOPENR |= (1 << 0);

    // PA0–PA3 as output (rows)
    GPIOA->MODER &= ~(0xFFF << 0); // Clear MODER[7:0]
    GPIOA->MODER |=  (0x555 << 0); // Set MODER0-3 to output (01)

    GPIOA->OTYPER &= ~(0x0F);     // Push-pull for PA0–PA3
    GPIOA->PUPDR  &= ~(0xFF << 0);// No pull-up/down for PA0–PA3

    // PA4–PA7 as input (columns)
    GPIOA->MODER &= ~(0xFF << 8); // Set MODER4-7 to input (00)
    GPIOA->PUPDR &= ~(0xFF << 8); // Clear PUPDR
    GPIOA->PUPDR |=  (0xAA << 8); // Pull-down for PA4–PA7
}
char Keypad_Read(void)
{
    for (int row = 0; row < 4; row++) {
        GPIOA->ODR &= ~(0x0F);             // Clear all rows (PA0–PA3)
        GPIOA->ODR |= (1 << row);          // Set current row HIGH
        delay_ms(1);                       // Allow signals to settle

        uint8_t col_data = (GPIOA->IDR >> 4) & 0x0F; // Read PA4–PA7
         delay_ms(20); 
        if (col_data) {                    // If any column is HIGH
            delay_ms(20);                  // Debounce

            // Check which column is active manually (avoid second for-loop)
            int col = -1;
            if (col_data & 0x01) col = 0;
            else if (col_data & 0x02) col = 1;
            else if (col_data & 0x04) col = 2;
            else if (col_data & 0x08) col = 3;

            if (col != -1) {
                // Wait for key release
                while ((GPIOA->IDR >> (col + 4)) & 0x01);
                return keypad_map[row][col];
            }
        }
    }

    return '\0'; // No key pressed
}

void setup() {
  Keypad_Init();
  Serial.begin(9600);
   Serial.print("Hey stm32: \n");
}

void loop() {
  char key = Keypad_Read();
  if(key)
  {
  Serial.print("Key Pressed: \n");
  Serial.println(key);
  //delay(1000);
  }
}