// Test-only workload: sustained dirty writes plus a child that ignores TERM.
use clap::{Parser, ValueEnum};
use std::{
    fs::{self, File},
    io::{Seek, SeekFrom, Write},
    process::Command,
};
unsafe extern "C" {
    fn signal(number: i32, handler: usize) -> usize;
}
#[derive(Parser)]
#[command(about = "Write disposable DATA stress output")]
struct Cli {
    role: Option<Role>,
}
#[derive(Clone, ValueEnum)]
enum Role {
    Child,
}
fn main() {
    let cli = Cli::parse();
    unsafe {
        signal(15, 1);
    }
    if matches!(cli.role, Some(Role::Child)) {
        loop {
            std::thread::park();
        }
    }
    fs::write(
        "/data/process-status",
        fs::read("/proc/self/status").unwrap(),
    )
    .unwrap();
    let child = Command::new(std::env::current_exe().unwrap())
        .arg("child")
        .spawn()
        .unwrap();
    fs::write("/data/child-pid", child.id().to_string()).unwrap();
    let mut file = File::create("/data/stress.bin").unwrap();
    let buffer: Vec<u8> = (0..1024 * 1024).map(|i| (i % 256) as u8).collect();
    let mut blocks = 0_u64;
    loop {
        if blocks % 64 == 0 {
            file.seek(SeekFrom::Start(0)).unwrap();
        }
        if let Err(error) = file.write_all(&buffer) {
            eprintln!("write fault: {error}");
            return;
        }
        blocks += 1;
        fs::write("/data/progress.next", blocks.to_string()).unwrap();
        fs::rename("/data/progress.next", "/data/progress").unwrap();
    }
}