#![no_std] // 不链接 Rust 标准库
#![no_main] // 禁用 main 入口点，因为没有运行时
#![feature(custom_test_frameworks)]
#![test_runner(anos::test_runner)]
#![reexport_test_harness_main = "test_main"]

extern crate alloc;

use anos::println;
use bootloader::{entry_point, BootInfo};
use core::panic::PanicInfo;
use alloc::{boxed::Box, rc::Rc, vec, vec::Vec};

entry_point!(kernel_main);

fn kernel_main(boot_info: &'static BootInfo) -> ! {
    use anos::memory::{self, BootInfoFrameAllocator};
    use anos::allocator;
    use x86_64::{structures::paging::Page, VirtAddr};

    println!("Hello World{}", "!");
    anos::init();

    let phys_mem_offset = VirtAddr::new(boot_info.physical_memory_offset);
    let mut mapper = unsafe { memory::init(phys_mem_offset) };
    let mut frame_allocator = unsafe { BootInfoFrameAllocator::init(&boot_info.memory_map) };

    let page = Page::containing_address(VirtAddr::new(0xdeadbeaf000));
    memory::create_example_mapping(page, &mut mapper, &mut frame_allocator);

    let page_ptr: *mut u64 = page.start_address().as_mut_ptr();
    unsafe { page_ptr.offset(400).write_volatile(0x_f021_f077_f065_f04e) };

    allocator::init_heap(&mut mapper, &mut frame_allocator).expect("heap initialization failed");

    let heap_value = Box::new(41);
    println!("heap_value at {:p}", heap_value);

    let mut vec = Vec::new();
    for i in 0..500 {
        vec.push(i);
    }
    println!("vec at {:p}", vec.as_slice());

    let reference_counted = Rc::new(vec![1, 2, 3]);
    let cloned_reference = reference_counted.clone();
    println!(
        "current reference count is {}",
        Rc::strong_count(&cloned_reference)
    );
    core::mem::drop(reference_counted);
    println!(
        "reference count is {} now",
        Rc::strong_count(&cloned_reference)
    );

    // 触发一个中断
    x86_64::instructions::interrupts::int3();
    println!("It didn't crash!");

    #[cfg(test)]
    test_main();

    anos::hlt_loop();
}

// 在非测试模式下，将 panic 信息打印到 VGA 缓冲区
#[cfg(not(test))]
#[panic_handler]
// panic! 时将会进行栈展开，执行各种 drop 函数来回收垃圾
// 禁用标准库之后，这些东西就都没有了，我们需要把它重写一遍
fn panic(info: &PanicInfo) -> ! {
    println!("{}", info);
    anos::hlt_loop();
}

#[cfg(test)]
#[panic_handler]
fn panic(info: &PanicInfo) -> ! {
    anos::test_panic_handler(info)
}