use std::{
    env,
    ffi::{OsStr, OsString},
    fs,
    path::{Path, PathBuf},
    process::{Command, Output},
    sync::atomic::{AtomicUsize, Ordering},
};

static NEXT_TEMP_ID: AtomicUsize = AtomicUsize::new(0);

const EXPECTED_OUTPUT: &str =
    "test \"standard library path list discovery\" ... ok\n1 test(s) passed\n";

#[test]
fn slovo_std_path_accepts_os_path_list() {
    let root = temp_root();
    let first_std = root.join("first-empty-std");
    let second_std = root.join("second-std");
    let project = root.join("project");
    let source_dir = project.join("src");

    create_dir(&first_std);
    create_dir(&second_std);
    create_dir(&source_dir);

    write(
        &second_std.join("path_list_probe.slo"),
        "(module path_list_probe (export value))\n\n(fn value () -> i32\n  51)\n",
    );
    write(
        &project.join("slovo.toml"),
        concat!(
            "[project]\n",
            "name = \"standard-library-path-list-alpha\"\n",
            "source_root = \"src\"\n",
            "entry = \"main\"\n",
        ),
    );
    write(
        &source_dir.join("main.slo"),
        concat!(
            "(module main)\n\n",
            "(import std.path_list_probe (value))\n\n",
            "(fn main () -> i32\n",
            "  (value))\n\n",
            "(test \"standard library path list discovery\"\n",
            "  (= (value) 51))\n",
        ),
    );

    let std_path = env::join_paths([first_std.as_os_str(), second_std.as_os_str()])
        .expect("join std path list");

    let check = run_glagol([OsStr::new("check"), project.as_os_str()], &root, &std_path);
    assert_success_stdout(check, "", "standard library path list check");

    let test = run_glagol([OsStr::new("test"), project.as_os_str()], &root, &std_path);
    assert_success_stdout(test, EXPECTED_OUTPUT, "standard library path list test");
}

fn run_glagol<I, S>(args: I, cwd: &Path, std_path: &OsString) -> Output
where
    I: IntoIterator<Item = S>,
    S: AsRef<std::ffi::OsStr>,
{
    Command::new(env!("CARGO_BIN_EXE_glagol"))
        .args(args)
        .current_dir(cwd)
        .env("SLOVO_STD_PATH", std_path)
        .output()
        .expect("run glagol")
}

fn write(path: &Path, content: &str) {
    fs::write(path, content).unwrap_or_else(|err| panic!("write `{}`: {}", path.display(), err));
}

fn create_dir(path: &Path) {
    fs::create_dir_all(path).unwrap_or_else(|err| panic!("create `{}`: {}", path.display(), err));
}

fn temp_root() -> PathBuf {
    let path = env::temp_dir().join(format!(
        "glagol-standard-library-path-list-alpha-{}-{}",
        std::process::id(),
        NEXT_TEMP_ID.fetch_add(1, Ordering::Relaxed)
    ));
    let _ = fs::remove_dir_all(&path);
    fs::create_dir_all(&path).unwrap_or_else(|err| panic!("create `{}`: {}", path.display(), err));
    path
}

fn assert_success_stdout(output: Output, expected: &str, context: &str) {
    let stdout = String::from_utf8_lossy(&output.stdout);
    let stderr = String::from_utf8_lossy(&output.stderr);

    assert!(
        output.status.success(),
        "{} failed\nstatus: {:?}\nstdout:\n{}\nstderr:\n{}",
        context,
        output.status.code(),
        stdout,
        stderr
    );
    assert_eq!(stdout, expected, "{}", context);
    assert!(stderr.is_empty(), "{} wrote stderr:\n{}", context, stderr);
}