/*!
 * Hako-like source detection and minimal normalization helpers.
 *
 * - looks_like_hako_code: heuristics to detect Hako surface in Nyash path
 * - strip_local_decl: drop leading `local ` at line head for Nyash parser compatibility
 * - fail_fast_on_hako: env-gated policy (default ON) to fail fast on Hako-like source in Nyash VM path
 */

/// Heuristic detection of Hako-like source (development-only convenience)
pub fn looks_like_hako_code(s: &str) -> bool {
    s.contains("using selfhost.")
        || s.contains("using hakorune.")
        || s.lines().any(|l| l.trim_start().starts_with("local "))
}

/// Remove leading `local ` declarations at line head to keep Nyash parser stable
pub fn strip_local_decl(s: &str) -> String {
    let mut out = String::with_capacity(s.len());
    for line in s.lines() {
        let leading = line.len() - line.trim_start().len();
        let (indent, rest) = line.split_at(leading);
        if rest.starts_with("local ") || rest.starts_with("local\t") {
            let bytes = rest.as_bytes();
            let mut i = 5; // after 'local'
            while i < bytes.len() && (bytes[i] == b' ' || bytes[i] == b'\t') {
                i += 1;
                break;
            }
            out.push_str(indent);
            out.push_str(&rest[i..]);
            out.push('\n');
        } else {
            out.push_str(line);
            out.push('\n');
        }
    }
    out
}

/// Policy toggle: fail fast when Hako-like code enters Nyash VM path
/// Default: ON (true)
pub fn fail_fast_on_hako() -> bool {
    match std::env::var("HAKO_FAIL_FAST_ON_HAKO_IN_NYASH_VM").ok().as_deref() {
        Some("0") | Some("false") | Some("off") => false,
        _ => true,
    }
}