// spi.c
#include "spi.h"
#include <avr/io.h>

// Define pin macros for CS, MOSI, MISO, SCK
#define SPI_DDR   DDRB
#define SPI_PORT  PORTB
#define SPI_PIN   PINB
#define SPI_CS    PB4  // Chip Select pin
#define SPI_MOSI  PB2
#define SPI_MISO  PB3
#define SPI_SCK   PB1
#define SPI_SS    PB0

void spi_init(void) {
    // Set MOSI, SCK, SS, CS as output; MISO input
    SPI_DDR |= (1 << SPI_MOSI) | (1 << SPI_SCK) | (1 << SPI_SS) | (1 << SPI_CS);
    SPI_DDR &= ~(1 << SPI_MISO);

    // Pull CS high initially
    SPI_PORT |= (1 << SPI_CS);

    // Enable SPI, Master mode, fosc/4
    SPCR = (1 << SPE) | (1 << MSTR);
    SPSR = 0;
}

void spi_cs_low(void) {
    SPI_PORT &= ~(1 << SPI_CS);
}

void spi_cs_high(void) {
    SPI_PORT |= (1 << SPI_CS);
}

uint8_t spi_transfer(uint8_t data) {
    SPDR = data;
    while (!(SPSR & (1 << SPIF)));
    return SPDR;
}

void spi_write_buffer(const uint8_t *buf, uint16_t len) {
    for (uint16_t i = 0; i < len; i++) {
        spi_transfer(buf[i]);
    }
}

uint8_t spi_read(void) {
    return spi_transfer(0xFF);
}

// UART support

#define UART_BAUD 9600
#define UBRR_VALUE ((F_CPU / (16UL * UART_BAUD)) - 1)

void uart_init(void) {
    UBRR0H = (uint8_t)(UBRR_VALUE >> 8);
    UBRR0L = (uint8_t)(UBRR_VALUE);
    UCSR0B = (1 << RXEN0) | (1 << TXEN0);
    UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);
}

void uart_putc(char c) {
    while (!(UCSR0A & (1 << UDRE0)));
    UDR0 = c;
}

char uart_getc(void) {
    while (!(UCSR0A & (1 << RXC0)));
    return UDR0;
}

void uart_puts(const char *s) {
    while (*s) {
        uart_putc(*s++);
    }
}