#include "Screen.h"
#include <errno.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <unistd.h>

Result<Screen> Screen::open()
{
    int fd = ::open("/dev/fb0", O_RDWR | O_CLOEXEC);
    if (fd < 0) return err(errno);

    int width = ioctl(fd, FB_GET_WIDTH);
    int height = ioctl(fd, FB_GET_HEIGHT);

    void* p = mmap(nullptr, width * height * BYTES_PER_PIXEL, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (p == MAP_FAILED)
    {
        close(fd);
        return err(errno);
    }

    Screen screen;

    screen.m_canvas = ui::Canvas::create((u8*)p, width, height);
    screen.m_size = width * height * BYTES_PER_PIXEL;

    return screen;
}

void Screen::sync()
{
    msync(m_canvas.ptr, size(), MS_SYNC);
}