#include "lcd.h"
#include "i2c.h"           /* Ihr I²C-Master-Treiber */
#include <msp430fr2355.h>  /* für __delay_cycles() */
#include <stdint.h>

/* --- Interne Helfer: sendet eine 4-Bit-Halbnibble plus Control-Bits --- */
static void lcd_write_nibble(uint8_t nibble, uint8_t control)
{
    char buf[1];

    /* High-Nibble in die oberen 4 Bits */
    buf[0] = (nibble << 4) | control | LCD_BACKLIGHT;
    /* EN=1 */
    I2C_write(LCD_I2C_ADDR, buf, 1);
    buf[0] |= LCD_ENABLE;
    I2C_write(LCD_I2C_ADDR, buf, 1);
    __delay_cycles(500);        /* ca. 50 µs @ 1 MHz */
    /* EN=0 */
    buf[0] &= ~LCD_ENABLE;
    I2C_write(LCD_I2C_ADDR, buf, 1);
    __delay_cycles(500);
}

/* Sendet ein volles Byte (2×4-Bit) als Befehl (RS=0) */
static void lcd_send_cmd(uint8_t cmd)
{
    lcd_write_nibble(cmd >> 4, 0x00);
    lcd_write_nibble(cmd & 0x0F, 0x00);
}

/* Sendet ein volles Byte als Daten (RS=1) */
static void lcd_send_data(uint8_t data)
{
    lcd_write_nibble(data >> 4, LCD_RS);
    lcd_write_nibble(data & 0x0F, LCD_RS);
}

void lcd_init(void)
{
    /* Wartezeit nach Power-Up */
    __delay_cycles(50000);      /* ca. 50 ms */

    /* Initial­sequenz 8-Bit-Befehle (3×) */
    lcd_write_nibble(0x03, 0x00);
    __delay_cycles(20000);
    lcd_write_nibble(0x03, 0x00);
    __delay_cycles(5000);
    lcd_write_nibble(0x03, 0x00);
    __delay_cycles(2000);

    /* In 4-Bit-Modus schalten */
    lcd_write_nibble(0x02, 0x00);
    __delay_cycles(2000);

    /* Funktion: 4-Bit, 2 Zeilen, 5×8 Punkte */
    lcd_send_cmd(0x28);
    /* Display off */
    lcd_send_cmd(0x08);
    /* Clear */
    lcd_send_cmd(0x01);
    __delay_cycles(2000);
    /* Entry mode: Cursor++ */
    lcd_send_cmd(0x06);
    /* Display on, Cursor off, Blink off */
    lcd_send_cmd(0x0C);
}

void lcd_clear(void)
{
    lcd_send_cmd(0x01);
    __delay_cycles(2000);
}

void lcd_set_cursor(uint8_t row, uint8_t col)
{
    uint8_t addr = (row == 0 ? 0x00 : 0x40) + (col & 0x0F);
    lcd_send_cmd(0x80 | addr);
}

void lcd_print(const char *str)
{
    while (*str)
    {
        lcd_send_data((uint8_t)*str++);
    }
}