// Copyright 2024, Linaro Limited
// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
// SPDX-License-Identifier: GPL-2.0-or-later

//! Definitions required by QEMU when registering a device.

use ::core::ffi::{c_void, CStr};

use crate::bindings::{Object, ObjectClass, TypeInfo};

/// Trait a type must implement to be registered with QEMU.
pub trait ObjectImpl {
    type Class;
    const TYPE_INFO: TypeInfo;
    const TYPE_NAME: &'static CStr;
    const PARENT_TYPE_NAME: Option<&'static CStr>;
    const ABSTRACT: bool;
    const INSTANCE_INIT: Option<unsafe extern "C" fn(obj: *mut Object)>;
    const INSTANCE_POST_INIT: Option<unsafe extern "C" fn(obj: *mut Object)>;
    const INSTANCE_FINALIZE: Option<unsafe extern "C" fn(obj: *mut Object)>;
}

pub trait Class {
    const CLASS_INIT: Option<unsafe extern "C" fn(klass: *mut ObjectClass, data: *mut c_void)>;
    const CLASS_BASE_INIT: Option<
        unsafe extern "C" fn(klass: *mut ObjectClass, data: *mut c_void),
    >;
}

#[macro_export]
macro_rules! module_init {
    ($func:expr, $type:expr) => {
        #[used]
        #[cfg_attr(target_os = "linux", link_section = ".ctors")]
        #[cfg_attr(target_os = "macos", link_section = "__DATA,__mod_init_func")]
        #[cfg_attr(target_os = "windows", link_section = ".CRT$XCU")]
        pub static LOAD_MODULE: extern "C" fn() = {
            extern "C" fn __load() {
                unsafe {
                    $crate::bindings::register_module_init(Some($func), $type);
                }
            }

            __load
        };
    };
    (qom: $func:ident => $body:block) => {
        // NOTE: To have custom identifiers for the ctor func we need to either supply
        // them directly as a macro argument or create them with a proc macro.
        #[used]
        #[cfg_attr(target_os = "linux", link_section = ".ctors")]
        #[cfg_attr(target_os = "macos", link_section = "__DATA,__mod_init_func")]
        #[cfg_attr(target_os = "windows", link_section = ".CRT$XCU")]
        pub static LOAD_MODULE: extern "C" fn() = {
            extern "C" fn __load() {
                #[no_mangle]
                unsafe extern "C" fn $func() {
                    $body
                }

                unsafe {
                    $crate::bindings::register_module_init(
                        Some($func),
                        $crate::bindings::module_init_type::MODULE_INIT_QOM,
                    );
                }
            }

            __load
        };
    };
}

#[macro_export]
macro_rules! type_info {
    ($t:ty) => {
        $crate::bindings::TypeInfo {
            name: <$t as $crate::definitions::ObjectImpl>::TYPE_NAME.as_ptr(),
            parent: if let Some(pname) = <$t as $crate::definitions::ObjectImpl>::PARENT_TYPE_NAME {
                pname.as_ptr()
            } else {
                ::core::ptr::null_mut()
            },
            instance_size: ::core::mem::size_of::<$t>() as $crate::bindings::size_t,
            instance_align: ::core::mem::align_of::<$t>() as $crate::bindings::size_t,
            instance_init: <$t as $crate::definitions::ObjectImpl>::INSTANCE_INIT,
            instance_post_init: <$t as $crate::definitions::ObjectImpl>::INSTANCE_POST_INIT,
            instance_finalize: <$t as $crate::definitions::ObjectImpl>::INSTANCE_FINALIZE,
            abstract_: <$t as $crate::definitions::ObjectImpl>::ABSTRACT,
            class_size:  ::core::mem::size_of::<<$t as $crate::definitions::ObjectImpl>::Class>() as $crate::bindings::size_t,
            class_init: <<$t as $crate::definitions::ObjectImpl>::Class as $crate::definitions::Class>::CLASS_INIT,
            class_base_init: <<$t as $crate::definitions::ObjectImpl>::Class as $crate::definitions::Class>::CLASS_BASE_INIT,
            class_data: ::core::ptr::null_mut(),
            interfaces: ::core::ptr::null_mut(),
        };
    }
}