#![no_std]
#![no_main]

use limine::BaseRevision;
use xv1_kernel::drawing::framebuffer::set_fb_data;
use core::fmt::Write;
use xv1_kernel::serial;
use core::panic::PanicInfo;
use limine::request::{FramebufferRequest, HhdmRequest};
use limine::{RequestsEndMarker, RequestsStartMarker};

#[used]
#[unsafe(link_section = ".requests")]
pub static BASE_REVISION: BaseRevision = BaseRevision::new();
#[used]
#[unsafe(link_section = ".requests")]
pub static FRAMEBUFFER_REQUEST: FramebufferRequest = FramebufferRequest::new();
#[used]
#[unsafe(link_section = ".requests")]
pub static HHDM_REQUEST: HhdmRequest = HhdmRequest::new();

/// Define the start and end markers for Limine requests.
#[used]
#[unsafe(link_section = ".requests_start_marker")]
static _START_MARKER: RequestsStartMarker = RequestsStartMarker::new();
#[used]
#[unsafe(link_section = ".requests_end_marker")]
static _END_MARKER: RequestsEndMarker = RequestsEndMarker::new();

#[unsafe(no_mangle)]
unsafe extern "C" fn kmain() -> ! {
    assert!(BASE_REVISION.is_supported());

    serial!("Hello from xv1!");
    let fb = set_fb_data(&FRAMEBUFFER_REQUEST);

    let white = (255u32 << fb.red_mask_shift)
        | (255u32 << fb.green_mask_shift)
        | (255u32 << fb.blue_mask_shift);

    unsafe {
        (fb.base as *mut u32).write_volatile(white);
    }

    loop {
        x86_64::instructions::hlt();
    }
}

#[panic_handler]
fn panic(info: &PanicInfo) -> ! {
    let mut serial =
        unsafe { uart_16550::Uart16550Tty::new_port(0x3F8, uart_16550::Config::default()) };
    if let Ok(s) = serial.as_mut() {
        let _ = writeln!(s, "PANIC: {info}");
    }
    loop {
        x86_64::instructions::hlt();
    }
}

pub fn hhdm_offset() -> u64 { HHDM_REQUEST.response().expect("No HHDM response :(").offset }