//! Platform-specific extensions to `std` for UEFI platforms.
//!
//! Provides access to platform-level information on UEFI platforms, and
//! exposes UEFI-specific functions that would otherwise be inappropriate as
//! part of the core `std` library.
//!
//! It exposes more ways to deal with platform-specific strings ([`OsStr`],
//! [`OsString`]), allows to set permissions more granularly, extract low-level
//! file descriptors from files and sockets, and has platform-specific helpers
//! for spawning processes.
//!
//! [`OsStr`]: crate::ffi::OsStr
//! [`OsString`]: crate::ffi::OsString

pub mod alloc;
pub mod args;
#[path = "../unix/cmath.rs"]
pub mod cmath;
pub mod env;
#[path = "../unsupported/fs.rs"]
pub mod fs;
#[path = "../unsupported/io.rs"]
pub mod io;
#[path = "../unsupported/locks/mod.rs"]
pub mod locks;
#[path = "../unsupported/net.rs"]
pub mod net;
#[path = "../unsupported/once.rs"]
pub mod once;
pub mod os;
#[path = "../windows/os_str.rs"]
pub mod os_str;
pub mod path;
#[path = "../unsupported/pipe.rs"]
pub mod pipe;
#[path = "../unsupported/process.rs"]
pub mod process;
pub mod stdio;
#[path = "../unsupported/thread.rs"]
pub mod thread;
#[path = "../unsupported/thread_local_key.rs"]
pub mod thread_local_key;
#[path = "../unsupported/thread_parking.rs"]
pub mod thread_parking;
#[path = "../unsupported/time.rs"]
pub mod time;

mod helpers;

#[cfg(test)]
mod tests;

pub type RawOsError = usize;

use crate::io as std_io;
use crate::os::uefi;
use crate::ptr::NonNull;
use crate::sync::atomic::{AtomicPtr, Ordering};

pub mod memchr {
    pub use core::slice::memchr::{memchr, memrchr};
}

static EXIT_BOOT_SERVICE_EVENT: AtomicPtr<crate::ffi::c_void> =
    AtomicPtr::new(crate::ptr::null_mut());

/// # SAFETY
/// - must be called only once during runtime initialization.
/// - argc must be 2.
/// - argv must be &[Handle, *mut SystemTable].
pub(crate) unsafe fn init(argc: isize, argv: *const *const u8, _sigpipe: u8) {
    assert_eq!(argc, 2);
    let image_handle = unsafe { NonNull::new(*argv as *mut crate::ffi::c_void).unwrap() };
    let system_table = unsafe { NonNull::new(*argv.add(1) as *mut crate::ffi::c_void).unwrap() };
    unsafe { uefi::env::init_globals(image_handle, system_table) };

    // Register exit boot services handler
    match helpers::create_event(
        r_efi::efi::EVT_SIGNAL_EXIT_BOOT_SERVICES,
        r_efi::efi::TPL_NOTIFY,
        Some(exit_boot_service_handler),
        crate::ptr::null_mut(),
    ) {
        Ok(x) => {
            if EXIT_BOOT_SERVICE_EVENT
                .compare_exchange(
                    crate::ptr::null_mut(),
                    x.as_ptr(),
                    Ordering::Release,
                    Ordering::Acquire,
                )
                .is_err()
            {
                abort_internal();
            };
        }
        Err(_) => abort_internal(),
    }
}

/// # SAFETY
/// this is not guaranteed to run, for example when the program aborts.
/// - must be called only once during runtime cleanup.
pub unsafe fn cleanup() {
    if let Some(exit_boot_service_event) =
        NonNull::new(EXIT_BOOT_SERVICE_EVENT.swap(crate::ptr::null_mut(), Ordering::Acquire))
    {
        let _ = unsafe { helpers::close_event(exit_boot_service_event) };
    }
}

#[inline]
pub const fn unsupported<T>() -> std_io::Result<T> {
    Err(unsupported_err())
}

#[inline]
pub const fn unsupported_err() -> std_io::Error {
    std_io::const_io_error!(std_io::ErrorKind::Unsupported, "operation not supported on UEFI",)
}

pub fn decode_error_kind(code: RawOsError) -> crate::io::ErrorKind {
    use crate::io::ErrorKind;
    use r_efi::efi::Status;

    match r_efi::efi::Status::from_usize(code) {
        Status::ALREADY_STARTED
        | Status::COMPROMISED_DATA
        | Status::CONNECTION_FIN
        | Status::CRC_ERROR
        | Status::DEVICE_ERROR
        | Status::END_OF_MEDIA
        | Status::HTTP_ERROR
        | Status::ICMP_ERROR
        | Status::INCOMPATIBLE_VERSION
        | Status::LOAD_ERROR
        | Status::MEDIA_CHANGED
        | Status::NO_MAPPING
        | Status::NO_MEDIA
        | Status::NOT_STARTED
        | Status::PROTOCOL_ERROR
        | Status::PROTOCOL_UNREACHABLE
        | Status::TFTP_ERROR
        | Status::VOLUME_CORRUPTED => ErrorKind::Other,
        Status::BAD_BUFFER_SIZE | Status::INVALID_LANGUAGE => ErrorKind::InvalidData,
        Status::ABORTED => ErrorKind::ConnectionAborted,
        Status::ACCESS_DENIED => ErrorKind::PermissionDenied,
        Status::BUFFER_TOO_SMALL => ErrorKind::FileTooLarge,
        Status::CONNECTION_REFUSED => ErrorKind::ConnectionRefused,
        Status::CONNECTION_RESET => ErrorKind::ConnectionReset,
        Status::END_OF_FILE => ErrorKind::UnexpectedEof,
        Status::HOST_UNREACHABLE => ErrorKind::HostUnreachable,
        Status::INVALID_PARAMETER => ErrorKind::InvalidInput,
        Status::IP_ADDRESS_CONFLICT => ErrorKind::AddrInUse,
        Status::NETWORK_UNREACHABLE => ErrorKind::NetworkUnreachable,
        Status::NO_RESPONSE => ErrorKind::HostUnreachable,
        Status::NOT_FOUND => ErrorKind::NotFound,
        Status::NOT_READY => ErrorKind::ResourceBusy,
        Status::OUT_OF_RESOURCES => ErrorKind::OutOfMemory,
        Status::SECURITY_VIOLATION => ErrorKind::PermissionDenied,
        Status::TIMEOUT => ErrorKind::TimedOut,
        Status::UNSUPPORTED => ErrorKind::Unsupported,
        Status::VOLUME_FULL => ErrorKind::StorageFull,
        Status::WRITE_PROTECTED => ErrorKind::ReadOnlyFilesystem,
        _ => ErrorKind::Uncategorized,
    }
}

pub fn abort_internal() -> ! {
    if let Some(exit_boot_service_event) =
        NonNull::new(EXIT_BOOT_SERVICE_EVENT.load(Ordering::Acquire))
    {
        let _ = unsafe { helpers::close_event(exit_boot_service_event) };
    }

    if let (Some(boot_services), Some(handle)) =
        (uefi::env::boot_services(), uefi::env::try_image_handle())
    {
        let boot_services: NonNull<r_efi::efi::BootServices> = boot_services.cast();
        let _ = unsafe {
            ((*boot_services.as_ptr()).exit)(
                handle.as_ptr(),
                r_efi::efi::Status::ABORTED,
                0,
                crate::ptr::null_mut(),
            )
        };
    }

    // In case SystemTable and ImageHandle cannot be reached, use `core::intrinsics::abort`
    core::intrinsics::abort();
}

// This function is needed by the panic runtime. The symbol is named in
// pre-link args for the target specification, so keep that in sync.
#[cfg(not(test))]
#[no_mangle]
pub extern "C" fn __rust_abort() {
    abort_internal();
}

#[inline]
pub fn hashmap_random_keys() -> (u64, u64) {
    get_random().unwrap()
}

fn get_random() -> Option<(u64, u64)> {
    use r_efi::protocols::rng;

    let mut buf = [0u8; 16];
    let handles = helpers::locate_handles(rng::PROTOCOL_GUID).ok()?;
    for handle in handles {
        if let Ok(protocol) = helpers::open_protocol::<rng::Protocol>(handle, rng::PROTOCOL_GUID) {
            let r = unsafe {
                ((*protocol.as_ptr()).get_rng)(
                    protocol.as_ptr(),
                    crate::ptr::null_mut(),
                    buf.len(),
                    buf.as_mut_ptr(),
                )
            };
            if r.is_error() {
                continue;
            } else {
                return Some((
                    u64::from_le_bytes(buf[..8].try_into().ok()?),
                    u64::from_le_bytes(buf[8..].try_into().ok()?),
                ));
            }
        }
    }
    None
}

/// Disable access to BootServices if `EVT_SIGNAL_EXIT_BOOT_SERVICES` is signaled
extern "efiapi" fn exit_boot_service_handler(_e: r_efi::efi::Event, _ctx: *mut crate::ffi::c_void) {
    uefi::env::disable_boot_services();
}

pub fn is_interrupted(_code: RawOsError) -> bool {
    false
}
