ilo 0.11.3

// Regression: `ilo file.ilo` with no func name used to dump raw AST JSON,
// which was a long-running first-touch surprise documented repeatedly in
// the assessment log (entries at lines 527, 623, 816, 839, 936, 1045).
//
// New behaviour:
//   * `ilo file.ilo`           with exactly one fn → runs that fn
//   * `ilo file.ilo`           with multiple fns   → prints a friendly
//                                                    listing and exits 1
//   * `ilo file.ilo func args` keeps working unchanged
//   * `ilo --ast file.ilo`     dumps the AST as JSON (explicit flag,
//                              works before or after the source)
//   * `ilo '<code>'`           inline with no func arg still AST-dumps
//                              (legacy contract from PR #178 preserved)

use std::process::Command;

fn ilo() -> Command {
    Command::new(env!("CARGO_BIN_EXE_ilo"))
}

fn run(args: &[&str]) -> (bool, String, String) {
    let out = ilo()
        .args(args)
        .output()
        .unwrap_or_else(|e| panic!("failed to spawn ilo: {e}"));
    (
        out.status.success(),
        String::from_utf8_lossy(&out.stdout).to_string(),
        String::from_utf8_lossy(&out.stderr).to_string(),
    )
}

fn write_temp(content: &str) -> (tempfile::TempDir, std::path::PathBuf) {
    let dir = tempfile::tempdir().expect("tempdir");
    let path = dir.path().join("prog.ilo");
    std::fs::write(&path, content).expect("write temp ilo");
    (dir, path)
}

// ── single-fn file: auto-run ───────────────────────────────────────────────────

#[test]
fn single_fn_file_runs_with_no_func_arg() {
    let (_dir, path) = write_temp("f>n;42\n");
    let (ok, stdout, stderr) = run(&[path.to_str().unwrap()]);
    assert!(ok, "expected success; stderr: {stderr}");
    assert_eq!(stdout.trim(), "42");
    assert!(
        !stdout.contains("\"declarations\""),
        "no AST dump expected; got: {stdout}"
    );
}

#[test]
fn single_fn_file_runs_with_positional_args() {
    let (_dir, path) = write_temp("double x:n>n;*x 2\n");
    let (ok, stdout, stderr) = run(&[path.to_str().unwrap(), "7"]);
    assert!(ok, "stderr: {stderr}");
    assert_eq!(stdout.trim(), "14");
}

// ── multi-fn file: friendly listing, non-zero exit ────────────────────────────

#[test]
fn multi_fn_file_with_no_func_arg_lists_and_exits_nonzero() {
    let (_dir, path) = write_temp("foo>n;1\nbar>n;2\nbaz>n;3\n");
    let (ok, stdout, stderr) = run(&[path.to_str().unwrap()]);
    assert!(!ok, "expected non-zero exit; stdout: {stdout}");
    assert!(
        stderr.contains("defines multiple functions"),
        "expected listing header; stderr: {stderr}"
    );
    assert!(
        stderr.contains("foo"),
        "expected foo listed; stderr: {stderr}"
    );
    assert!(
        stderr.contains("bar"),
        "expected bar listed; stderr: {stderr}"
    );
    assert!(
        stderr.contains("baz"),
        "expected baz listed; stderr: {stderr}"
    );
    assert!(
        stderr.contains("--ast"),
        "expected --ast hint; stderr: {stderr}"
    );
    assert!(
        !stdout.contains("\"declarations\""),
        "no AST dump expected; got: {stdout}"
    );
}

#[test]
fn multi_fn_file_with_func_name_runs_unchanged() {
    let (_dir, path) = write_temp("foo>n;1\nbar>n;2\nbaz>n;3\n");
    let (ok, stdout, stderr) = run(&[path.to_str().unwrap(), "bar"]);
    assert!(ok, "expected success; stderr: {stderr}");
    assert_eq!(stdout.trim(), "2");
}

#[test]
fn multi_fn_file_with_func_name_and_args() {
    let (_dir, path) = write_temp("add a:n b:n>n;+a b\nmul a:n b:n>n;*a b\n");
    let (ok, stdout, stderr) = run(&[path.to_str().unwrap(), "mul", "6", "7"]);
    assert!(ok, "stderr: {stderr}");
    assert_eq!(stdout.trim(), "42");
}

// ── --ast flag: explicit AST dump ─────────────────────────────────────────────

#[test]
fn ast_flag_dumps_single_fn_file() {
    let (_dir, path) = write_temp("f>n;42\n");
    let (ok, stdout, _stderr) = run(&["--ast", path.to_str().unwrap()]);
    assert!(ok);
    assert!(
        stdout.contains("\"declarations\""),
        "expected JSON AST; got: {stdout}"
    );
    // Crucially does NOT execute the fn.
    assert!(
        !stdout.trim().starts_with("42"),
        "AST dump must not execute; got: {stdout}"
    );
}

#[test]
fn ast_flag_dumps_multi_fn_file() {
    let (_dir, path) = write_temp("foo>n;1\nbar>n;2\n");
    let (ok, stdout, stderr) = run(&["--ast", path.to_str().unwrap()]);
    assert!(ok, "stderr: {stderr}");
    assert!(
        stdout.contains("\"declarations\""),
        "expected JSON AST; got: {stdout}"
    );
    assert!(
        !stderr.contains("defines multiple functions"),
        "no listing should fire when --ast is explicit; stderr: {stderr}"
    );
}

#[test]
fn ast_flag_trailing_position() {
    let (_dir, path) = write_temp("foo>n;1\nbar>n;2\n");
    let (ok, stdout, _stderr) = run(&[path.to_str().unwrap(), "--ast"]);
    assert!(ok);
    assert!(stdout.contains("\"declarations\""));
}

#[test]
fn ast_flag_on_inline_code() {
    let (ok, stdout, _stderr) = run(&["--ast", "f>n;5"]);
    assert!(ok);
    assert!(stdout.contains("\"declarations\""));
}

// ── legacy inline-no-func AST dump preserved ──────────────────────────────────

#[test]
fn inline_no_func_still_dumps_ast() {
    let (ok, stdout, _stderr) = run(&["f>n;5"]);
    assert!(ok);
    assert!(
        stdout.contains("\"declarations\""),
        "inline-no-func default AST dump should be preserved; got: {stdout}"
    );
}

// ── no-fn file: AST dump (nothing to run) ─────────────────────────────────────

#[test]
fn empty_file_dumps_ast() {
    // A file with zero functions has nothing to run, so the AST-dump
    // path is still the right fallback. Empty file is the cleanest
    // example we can write portably.
    let (_dir, path) = write_temp("");
    let (ok, stdout, stderr) = run(&[path.to_str().unwrap()]);
    assert!(ok, "stderr: {stderr}");
    assert!(stdout.contains("\"declarations\""));
}