#![no_main]
#![feature(compiler_builtins_lib)]
#![feature(custom_test_frameworks)]
#![feature(abi_x86_interrupt)]
#![test_runner(crate::test_runner)]
#![reexport_test_harness_main = "test_main"]
#![no_std]

mod interrupts;
mod io;

use core::fmt::Write;
use io::vga_text::OStream;
use io::{qemu, serial, vga_text};

#[cfg(test)]
pub fn test_runner(tests: &[&dyn Fn(&mut OStream)]) {
    let mut stdout = OStream::new();
    stdout.clear();
    write!(&mut stdout, "running {} tests\n", tests.len()).unwrap();
    for test in tests {
        test(&mut stdout)
    }
}

#[no_mangle]
pub extern "C" fn _start() -> ! {
    interrupts::table::init();
    if cfg!(test) {
        #[cfg(test)]
        test_main();
        qemu::exit_qemu(qemu::QemuExitCode::Success);
    }

    let mut stdout = OStream::new();
    stdout.clear();
    panic!("panic!");

    core::iter::successors(Some(0), |n| Some(n + 1))
        .for_each(|n| write!(&mut stdout, "hello world {}!", n).unwrap());

    x86_64::instructions::interrupts::int3();
    loop {}
}

#[panic_handler]
#[no_mangle]
pub extern "C" fn panic_handler(_info: &core::panic::PanicInfo) -> ! {
    let mut stderr = OStream::new();
    stderr.set_state(vga_text::CharState::from_colors(
        vga_text::Color::LightRed,
        vga_text::Color::Red,
    ));
    stderr.clear();
    stderr.print(b"uff-os");
    stderr.set_row(10);
    stderr.set_state(vga_text::CharState::from_colors(
        vga_text::Color::White,
        vga_text::Color::Red,
    ));
    stderr.print_centered(b"<kernel panic>");
    stderr.set_row(14);
    let text = _info
        .payload()
        .downcast_ref::<&str>()
        .unwrap_or(&"no panic information is obtainable");
    stderr.set_state(vga_text::CharState::from_colors(
        vga_text::Color::Cyan,
        vga_text::Color::Red,
    ));
    stderr.print_centered(text.as_bytes());
    if cfg!(test) {
        write!(serial::SerialStream::new(), "Testing failed\n").unwrap();
        qemu::exit_qemu(qemu::QemuExitCode::Failed);
    }
    loop {}
}