#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/i2c.h"
#include "rom/ets_sys.h"

#define LCD_20X04   1
#define I2C_ACK_CHECK_EN      1
#define I2C_ADDRESS_LCD       0x27
#define I2C_SCL_LCD           21
#define I2C_SDA_LCD           22

#define CLEAR_DISPLAY               0x01
#define RETURN_HOME_UNSHIFT         0x02
#define CURSOR_RIGHT_SHIFT          0x05
#define CURSOR_RIGHT_NO_SHIFT_LEFT  0x06
#define CURSOR_RIGHT_SHIFT_LEFT     0x07
#define DISPLAY_OFF                 0x08
#define DISPLAY_ON_CURSOR_OFF       0x0C
#define DISPLAY_ON_CURSOR_ON_STEADY 0x0E
#define DISPLAY_ON_CURSOR_ON_BLINK  0x0F
#define SHIFT_CURSOR_LEFT           0x10
#define SHIFT_CURSOR_RIGHT          0x14
#define SHIFT_DISPLAY_LEFT          0x18
#define SHIFT_DISPLAY_RIGHT         0x1C
#define SET_4BIT_MODE               0x28
#define RETURN_HOME                 0x80

#define PCF8574_RS    0
#define PCF8574_RW    1
#define PCF8574_EN    2
#define PCF8574_BL    3
#define LCD_RS_CMD    0
#define LCD_RS_DATA   1

typedef struct {
  uint8_t i2c_address;
  uint8_t i2c_port;
  uint8_t screen_size;
  uint8_t screen_backlight;
} lcd_i2c_device_t;

void i2c_init(void);
void lcd_init(lcd_i2c_device_t * lcd);
void lcd_i2c_write_byte(lcd_i2c_device_t * lcd, uint8_t data);
void lcd_i2c_write_command(lcd_i2c_device_t * lcd, uint8_t register_select, uint8_t cmd);
void lcd_set_cursor(lcd_i2c_device_t * lcd, uint8_t column, uint8_t row);
void lcd_i2c_write_custom_char(lcd_i2c_device_t * lcd, uint8_t char_address, const uint8_t * pixels);

void i2c_init(void) 
{
  i2c_config_t i2c_config = {
      .mode = I2C_MODE_MASTER,
      .sda_io_num = I2C_SDA_LCD,
      .sda_pullup_en = GPIO_PULLUP_ENABLE,
      .scl_io_num = I2C_SCL_LCD,
      .scl_pullup_en = GPIO_PULLUP_ENABLE,
      .master.clk_speed = 400000,
  };

  esp_err_t error = i2c_param_config(I2C_NUM_1, &i2c_config);
  if (error != ESP_OK) {
        while(1);
    }
  i2c_driver_install(I2C_NUM_1, I2C_MODE_MASTER, 0, 0, 0);
}

void lcd_init(lcd_i2c_device_t * lcd)
{
  lcd_i2c_write_command(lcd, LCD_RS_CMD, RETURN_HOME_UNSHIFT);
  lcd_i2c_write_command(lcd, LCD_RS_CMD, SET_4BIT_MODE);
  lcd_i2c_write_command(lcd, LCD_RS_CMD, CLEAR_DISPLAY);
  lcd_i2c_write_command(lcd, LCD_RS_CMD, DISPLAY_ON_CURSOR_OFF);
  lcd_i2c_write_command(lcd, LCD_RS_CMD, CURSOR_RIGHT_NO_SHIFT_LEFT);
  vTaskDelay(20 / portTICK_PERIOD_MS);
}

void lcd_i2c_write_byte(lcd_i2c_device_t * lcd, uint8_t data)
{
  i2c_cmd_handle_t cmd_handle = i2c_cmd_link_create(); 
  i2c_master_start(cmd_handle);
  i2c_master_write_byte(cmd_handle, (lcd->i2c_address << 1) | I2C_MASTER_WRITE, I2C_ACK_CHECK_EN);
  i2c_master_write_byte(cmd_handle, data, 1);
  i2c_master_stop(cmd_handle);
  i2c_master_cmd_begin(lcd->i2c_port, cmd_handle, 100 / portTICK_PERIOD_MS);
  i2c_cmd_link_delete(cmd_handle);
}

void lcd_i2c_write_command(lcd_i2c_device_t * lcd, uint8_t register_select, uint8_t cmd)
{
  uint8_t config = (register_select)? (1 << PCF8574_RS) : 0;
  config |= (lcd->screen_backlight)? (1 << PCF8574_BL) : 0;
  config |= (config & 0x0F) | (0xF0 & cmd);
  config |= (1 << PCF8574_EN);

  lcd_i2c_write_byte(lcd, config);
  ets_delay_us(10);

  config &= ~(1 << PCF8574_EN);
  lcd_i2c_write_byte(lcd, config);
  ets_delay_us(50); 
  config = (config & 0x0F) | (cmd << 4);
  config |= (1 << PCF8574_EN);

  lcd_i2c_write_byte(lcd, config);
  ets_delay_us(10); 
  config &= ~(1 << PCF8574_EN);
  
  lcd_i2c_write_byte(lcd, config);
  ets_delay_us(50);

  if (cmd == CLEAR_DISPLAY)
  {
    vTaskDelay(20 / portTICK_PERIOD_MS);
  }
}

void lcd_set_cursor(lcd_i2c_device_t * lcd, uint8_t column, uint8_t row)
{
  switch (row) {
    case 0:
      lcd_i2c_write_command(lcd, LCD_RS_CMD, 0x80 + column);
      break;
    case 1:
      lcd_i2c_write_command(lcd, LCD_RS_CMD, 0xC0 + column);
      break;
    case 2:
      lcd_i2c_write_command(lcd, LCD_RS_CMD, 0x94 + column);
      break;
    case 3:
      lcd_i2c_write_command(lcd, LCD_RS_CMD, 0xD4 + column);
      break;
    default:
      break;
  }
}

void lcd_i2c_write_custom_char(lcd_i2c_device_t * lcd, uint8_t address, const uint8_t * pixels)
{
  lcd_i2c_write_command(lcd, LCD_RS_CMD, 0x40 | (address << 3)); 

  for (uint8_t i = 0; i < 8; i++)
  {
    lcd_i2c_write_command(lcd, LCD_RS_DATA, pixels[i]);
  }

  lcd_i2c_write_command(lcd, LCD_RS_CMD, RETURN_HOME);
}

void lcd_i2c_print_msg(lcd_i2c_device_t * lcd, char * msg)
{
  uint8_t i = 0;

  while (msg[i] != '\0')
  {
    lcd_i2c_write_command(lcd, LCD_RS_DATA, msg[i++]);
  }
}

// Función para calcular opciones de cambio
int contarOpcionesCambio(int N, int B[], int tam) {
    int opciones[N + 1];
    for (int i = 0; i <= N; i++) {
        opciones[i] = 0;
    }
    opciones[0] = 1;
    for (int i = 0; i < tam; i++) {
        for (int j = B[i]; j <= N; j++) {
            opciones[j] += opciones[j - B[i]];
        }
    }
    return opciones[N];
}


#define SMILE        5
#define DROP         2

void app_main() {
    // Inicialización del LCD
    i2c_init();
    lcd_i2c_device_t my_lcd = {
        .i2c_port = I2C_NUM_1,
        .i2c_address = I2C_ADDRESS_LCD,
        .screen_size = LCD_20X04,
        .screen_backlight = 1,
    };
    vTaskDelay(20 / portTICK_PERIOD_MS);
    lcd_init(&my_lcd);

    // Valores para el cálculo
    /*
    int N = 10;  // Cantidad de cambio deseado
    int B[] = {6, 5, 3, 2};  // Denominaciones
    int tam = sizeof(B) / sizeof(B[0]);
    */


    int N = 4;  // Cantidad de cambio deseado
    int B[] = {2, 3, 1};  // Denominaciones
    int tam = sizeof(B) / sizeof(B[0]);

    /*
    int N = 3;  // Cantidad de cambio deseado
    int B[] = {8, 3, 1, 2};  // Denominaciones
    int tam = sizeof(B) / sizeof(B[0]);
    */
    
    // Cálculo del número de opciones de cambio
    int resultado = contarOpcionesCambio(N, B, tam);
    
    // Mostrar resultado en la LCD
    char message[20];
    sprintf(message, "Opciones: %d", resultado);
    lcd_i2c_print_msg(&my_lcd, message);
}