use crate::proc::context::CpuContext;
use crate::syscall::SyscallResult;

pub const KEY_COM1_GSI: u64 = 0;
pub const KEY_KBD_GSI: u64 = 1;
pub const KEY_VIRTIO_NET_GSI: u64 = 2;
pub const KEY_HAS_FRAMEBUFFER: u64 = 3;
pub const KEY_HAS_IOMMU: u64 = 4;

struct BootPlatformInfo {
    com1_gsi: i64,
    kbd_gsi: i64,
    virtio_net_gsi: i64,
}

static mut PLATFORM_INFO: BootPlatformInfo = BootPlatformInfo {
    com1_gsi: -1,
    kbd_gsi: -1,
    virtio_net_gsi: -1,
};

static PLATFORM_INITIALIZED: core::sync::atomic::AtomicBool =
    core::sync::atomic::AtomicBool::new(false);

#[allow(clippy::deref_addrof)]
pub fn store_platform_info(
    com1_gsi: Option<crate::arch::ioapic::Gsi>,
    kbd_gsi: Option<crate::arch::ioapic::Gsi>,
    virtio_net_gsi: Option<crate::arch::ioapic::Gsi>,
) {
    unsafe {
        let info = &mut *(&raw mut PLATFORM_INFO);
        info.com1_gsi = com1_gsi.map_or(-1, |g| g.raw() as i64);
        info.kbd_gsi = kbd_gsi.map_or(-1, |g| g.raw() as i64);
        info.virtio_net_gsi = virtio_net_gsi.map_or(-1, |g| g.raw() as i64);
    }
    PLATFORM_INITIALIZED.store(true, core::sync::atomic::Ordering::Release);
}

#[allow(clippy::deref_addrof)]
pub fn sys_platform_info(ctx: &mut CpuContext) {
    let pid = crate::arch::syscall::current_pid();
    if pid != crate::types::Pid::new(0) {
        ctx.rax = SyscallResult::error(crate::error::KernelError::PermissionDenied).raw();
        return;
    }

    let key = ctx.rdi;

    ctx.rax = match key {
        KEY_COM1_GSI => unsafe { (&*(&raw const PLATFORM_INFO)).com1_gsi as u64 },
        KEY_KBD_GSI => unsafe { (&*(&raw const PLATFORM_INFO)).kbd_gsi as u64 },
        KEY_VIRTIO_NET_GSI => unsafe { (&*(&raw const PLATFORM_INFO)).virtio_net_gsi as u64 },
        KEY_HAS_FRAMEBUFFER => match crate::arch::boot::framebuffer().is_some() {
            true => 1,
            false => 0,
        },
        KEY_HAS_IOMMU => match crate::iommu::is_available() {
            true => 1,
            false => 0,
        },
        _ => SyscallResult::error(crate::error::KernelError::InvalidParameter).raw(),
    };
}