use x86_64::{VirtAddr, registers::rflags::RFlags, structures::idt::InterruptStackFrameValue};

use crate::{
    arch::{
        asm::ltr,
        x86_64::{
            gdt::{SELECTORS, dump_gdt},
            interrupts::IDT,
        },
    },
    log::{LOGGER, LogLevel},
    log_info,
    memory::alloc::format,
};

pub fn init() -> Result<(), ()> {
    // Ensure GDT exists
    SELECTORS.gdt.load();
    log_info!("GDT loaded!");
    // Load IDT
    IDT.load();
    log_info!("IDT loaded!");
    x86_64::registers::model_specific::Star::write(
        SELECTORS.sel_user_code,
        SELECTORS.sel_user_stack,
        SELECTORS.sel_kernel_code,
        SELECTORS.sel_kernel_stack,
    )
    .expect("Segment order in GDT is bad");
    dump_gdt();
    ltr(SELECTORS.sel_tss.index());
    Ok(())
}

pub fn jump_to_usermode(sp: VirtAddr, ip: VirtAddr) -> ! {
    unsafe {
        InterruptStackFrameValue::new(
            ip,
            SELECTORS.sel_user_code,
            RFlags::INTERRUPT_FLAG,
            sp,
            SELECTORS.sel_user_stack,
        )
        .iretq();
    }
}