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

extern crate compiler_builtins;

mod vga_text;
use vga_text::OStream;

use core::fmt::Write;

#[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());
    for test in tests {
        test(&mut stdout)
    }
}

#[test_case]
fn test01(stdout: &mut OStream) {
    write!(stdout, "running test01 . . . OK");
}

#[no_mangle]
pub extern "C" fn _start() -> ! {

    if cfg!(test) {
        #[cfg(test)]
        test_main();
        loop {}
    }

    let mut stdout = vga_text::OStream::new();
    stdout.clear();

    write!(&mut stdout, "hello world!");

    // panic!("i has panicing");

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

    loop {}
}

#[panic_handler]
#[no_mangle]
pub extern "C" fn panic_handler(_info: &core::panic::PanicInfo) -> ! {
    let mut stderr = vga_text::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 informations are obtainable");
    stderr.set_state(vga_text::CharState::from_colors(
            vga_text::Color::Cyan, vga_text::Color::Red));
    stderr.print_centered(text.as_bytes());
    loop {}
}