#include <stdio.h>
#include <string.h>
#include "pico/stdlib.h"
#include "hardware/i2c.h"
#include "pico/binary_info.h"

const int PICO_I2C_SDA_PIN = 20;
const int PICO_I2C_SCL_PIN = 21;

// commands
const int LCD_CLEARDISPLAY = 0x01;
const int LCD_RETURNHOME = 0x02;
const int LCD_ENTRYMODESET = 0x04;
const int LCD_DISPLAYCONTROL = 0x08;
const int LCD_CURSORSHIFT = 0x10;
const int LCD_FUNCTIONSET = 0x20;
const int LCD_SETCGRAMADDR = 0x40;
const int LCD_SETDDRAMADDR = 0x80;

const int LCD_ENTRYSHIFTINCREMENT = 0x01;
const int LCD_ENTRYLEFT = 0x02;

const int LCD_BLINKON = 0x01;
const int LCD_CURSORON = 0x02;
const int LCD_DISPLAYON = 0x04;

const int LCD_MOVELEFT = 0x04;
const int LCD_DISPLAYMOVE = 0x08;

const int LCD_5x10DOTS = 0x04;
const int LCD_2LINE = 0x08;
const int LCD_8BITMODE = 0x10;

const int LCD_BACKLIGHT = 0x08;
const int LCD_ENABLE_BIT = 0x04;

static int addr = 0x27;

#define LCD_CHARACTER 1
#define LCD_COMMAND 0

#define MAX_LINES 2
#define MAX_CHARS 16
#define DELAY_US 600

void i2c_write_byte(uint8_t val);
void lcd_toggle_enable(uint8_t val);
void lcd_send_byte(uint8_t val, int mode);
void lcd_clear(void);
void lcd_set_cursor(int line, int position);
static inline void lcd_char(char val);
void lcd_string(const char *s);
void lcd_init();

int main() {
    i2c_init(i2c_default, 100 * 1000);
    gpio_set_function(PICO_I2C_SDA_PIN, GPIO_FUNC_I2C);
    gpio_set_function(PICO_I2C_SCL_PIN, GPIO_FUNC_I2C);
    gpio_pull_up(PICO_I2C_SDA_PIN);
    gpio_pull_up(PICO_I2C_SCL_PIN);
    lcd_init();

    static char message1[16] = "FATEC , ";
    static char message2[16] = "Kaue e lindo";
    static char valor[16];

    while (true) {
        lcd_set_cursor(0, 0);
        lcd_string(message1);
        lcd_set_cursor(1, 0);
        lcd_string(message2);
        lcd_set_cursor(0, 20);
        sprintf(valor, "%d", 24);
        lcd_string(valor);
        sleep_ms(1000);
        lcd_clear();
    }
}

void i2c_write_byte(uint8_t val) {
    i2c_write_blocking(i2c_default, addr, &val, 1, false);
}

void lcd_toggle_enable(uint8_t val) {

    sleep_us(DELAY_US);
    i2c_write_byte(val | LCD_ENABLE_BIT);
    sleep_us(DELAY_US);
    i2c_write_byte(val & ~LCD_ENABLE_BIT);
    sleep_us(DELAY_US);
}

void lcd_send_byte(uint8_t val, int mode) {
    uint8_t high = mode | (val & 0xF0) | LCD_BACKLIGHT;
    uint8_t low = mode | ((val << 4) & 0xF0) | LCD_BACKLIGHT;
    i2c_write_byte(high);
    lcd_toggle_enable(high);
    i2c_write_byte(low);
    lcd_toggle_enable(low);
}

void lcd_clear(void) {
    lcd_send_byte(LCD_CLEARDISPLAY, LCD_COMMAND);
}

void lcd_set_cursor(int line, int position) {
    int val = (line == 0) ? 0x80 + position : 0xC0 + position;
    lcd_send_byte(val, LCD_COMMAND);
}

static inline void lcd_char(char val) {
    lcd_send_byte(val, LCD_CHARACTER);
}

void lcd_string(const char *s) {
    while (*s) {
        lcd_char(*s++);
    }
}

void lcd_init() {
    lcd_send_byte(0x03, LCD_COMMAND);
    lcd_send_byte(0x03, LCD_COMMAND);
    lcd_send_byte(0x03, LCD_COMMAND);
    lcd_send_byte(0x02, LCD_COMMAND);
    lcd_send_byte(LCD_ENTRYMODESET | LCD_ENTRYLEFT, LCD_COMMAND);
    lcd_send_byte(LCD_FUNCTIONSET | LCD_2LINE, LCD_COMMAND);
    lcd_send_byte(LCD_DISPLAYCONTROL | LCD_DISPLAYON, LCD_COMMAND);
    lcd_clear();
}