use std::any::Any;
use std::convert::Infallible;
use std::error::Error;
use std::io;
use std::panic::UnwindSafe;
use std::path::{Path, PathBuf};
use std::{fs, panic};

const PAM_CONFIG: &str = "\
auth required pam_testharness.so
account required pam_testharness.so
password required pam_testharness.so
session required pam_testharness.so
";
const PAM_CONFIG_PATH: &str = "/etc/pam.d/testharness";
const PAM_MODULE_PATH: &str = "/lib/security/pam_testharness.so";

#[derive(Debug, thiserror::Error)]
enum TestError {
    #[error("error in test harness: {0}")]
    HarnessError(#[from] io::Error),
    #[error("panic in test: {0:?}")]
    Panic(Box<dyn Any + Send>),
    #[error(transparent)]
    TestError(anyhow::Error),
}

#[test]
fn test_auth_only() -> Result<(), TestError> {
    harness(|| Ok::<(), Infallible>(()))
}

fn harness<E: Error + Send + Sync + 'static>(
    test: impl Fn() -> Result<(), E> + UnwindSafe,
) -> Result<(), TestError> {
    let dylib_path = test_cdylib::build_current_project();
    let module_path = Path::new(PAM_MODULE_PATH);
    let config_path = Path::new(PAM_CONFIG_PATH);
    let parent = module_path.parent().unwrap();
    fs::create_dir_all(parent)?;
    fs::copy(dylib_path, module_path)?;
    fs::write(config_path, PAM_CONFIG)?;
    panic::catch_unwind(test)
        .map_err(TestError::Panic)?
        .map_err(|e| TestError::TestError(e.into()))?;
    fs::remove_file(module_path)?;
    fs::remove_file(config_path)?;
    // If the /lib/security directory can't be removed, that's OK.
    let _ = fs::remove_dir(parent);
    Ok(())
}