//! The stub guard (review 010 action 3): no `*:not_implemented` path
//! may exist in `src/`. A handler that registers successfully and
//! returns an error of this form on every invocation is a bug, not a
//! documented limitation — shipping one is a hard failure per the
//! repo ruling (reviews 010/011; four stubs shipped across nine
//! published versions before this guard existed).

#[test]
fn source_tree_has_no_not_implemented_path() {
    let manifest = env!("CARGO_MANIFEST_DIR");
    let src = std::path::Path::new(manifest).join("src");
    let mut offenders = Vec::new();
    walk(&src, &mut offenders);
    assert!(
        offenders.is_empty(),
        "no `not_implemented` string may appear in src/ — a registered surface \
         that always fails is the stub class (review 010 S-01..S-04); offended \
         by: {offenders:?}"
    );
}

fn walk(dir: &std::path::Path, offenders: &mut Vec<String>) {
    let entries = match std::fs::read_dir(dir) {
        Ok(entries) => entries,
        Err(_) => return,
    };
    for entry in entries.flatten() {
        let path = entry.path();
        if path.is_dir() {
            walk(&path, offenders);
        } else if path.extension().is_some_and(|e| e == "rs") {
            let contents = match std::fs::read_to_string(&path) {
                Ok(c) => c,
                Err(_) => continue,
            };
            for (line_no, line) in contents.lines().enumerate() {
                if line.contains("not_implemented") {
                    offenders.push(format!(
                        "{}:{}",
                        path.strip_prefix(env!("CARGO_MANIFEST_DIR"))
                            .unwrap_or(&path)
                            .display(),
                        line_no + 1
                    ));
                }
            }
        }
    }
}