use std::fs;
use std::process::Command;

// test disk read speeds by reading for /dev/zero and writing it to /dev/null
pub fn disk_read_test(size: &u8) {
    // convert size in Gigabytes down to Megabytes
    let size_gigs: u32 = (*size as u32 * 1024 * 8).into();

    // run sync to clear out any disk caches prior to running
    Command::new("sync");

    // run the dd command
    let output = Command::new("dd")
        .arg("bs=128k")
        .arg(format!("count={}", size_gigs))
        .arg("if=/dev/zero")
        .arg("of=/dev/null")
        .output()
        .expect("Failed to execute command");

    // check that the command succeeded
    assert!(output.status.success());

    // dd's output ends up in stderr
    println!("{}", String::from_utf8_lossy(&output.stderr));

    // run another sync to clear out the disk's cache
    Command::new("sync");
}

// test disk write speeds by continually writing zeroes to it
pub fn disk_write_test(tempfile: &str, size: &u8) {
    // convert size in Gigabytes down to Megabytes
    let size_gigs: u32 = (*size as u32 * 1024).into();

    // run the dd command with a block size of 1 MB
    let output = Command::new("dd")
        .arg("bs=1M")
        .arg(format!("count={}", size_gigs))
        .arg("if=/dev/zero")
        .arg(format!("of={}", tempfile))
        .output()
        .expect("Failed to execute command");

    // check that the command succeeded
    assert!(output.status.success());

    // for whatever reason, `dd` output ends up in stderr
    println!("{}", String::from_utf8_lossy(&output.stderr));

    // remove the test file
    match fs::remove_file(tempfile) {
        Ok(()) => println!("Cleaning up..."),
        Err(e) => println!("There was a problem during cleanup - {}", e),
    }
}