localharness 0.38.0

//! Pure subdomain-name validation — the single source of truth for the browser
//! create tools, kept in sync with the on-chain
//! `LocalharnessRegistryFacet._isValidName` rule. Native-tested (this is why it
//! lives at the crate root, not inside the wasm-only `app` module).
//!
//! The bug this closes (GitHub #66/#60): the create path used to `sanitize()` a
//! requested name by silently DROPPING any char outside `[a-z0-9-]`, so asking
//! to register `café-shop` quietly minted `caf-shop` — a DIFFERENT name than
//! requested — and a leading/trailing hyphen sailed past the client only to
//! revert on-chain. `validate` instead REJECTS a name that isn't already a
//! valid DNS-safe label, returning a human-readable reason the caller (the
//! AGENT, via a tool error) can act on, rather than guessing.

/// Validate + normalize a requested subdomain label.
///
/// Lowercases and trims (unsurprising normalization), then requires the result
/// to be a valid label: 3–32 chars, `[a-z0-9-]` only, no leading/trailing
/// hyphen, ASCII only. Returns the normalized name, or `Err(reason)` describing
/// the first violation (surfaced to the agent as a tool error — NOT painted as
/// form text). The 3–32 bound matches the app's existing create range; the
/// character/hyphen rule matches the contract's `_isValidName`.
pub fn validate(input: &str) -> Result<String, String> {
    let name = input.trim().to_ascii_lowercase();
    if !name.bytes().all(|b| b.is_ascii_lowercase() || b.is_ascii_digit() || b == b'-') {
        return Err(
            "use only lowercase letters, digits, and hyphens — no spaces, dots, or accented/unicode characters"
                .to_string(),
        );
    }
    // char count == byte count here (all-ASCII past the check above), but count
    // chars for a correct message regardless.
    let len = name.chars().count();
    if !(3..=32).contains(&len) {
        return Err(format!("name must be 3–32 characters (got {len})"));
    }
    if name.starts_with('-') || name.ends_with('-') {
        return Err("name can't start or end with a hyphen".to_string());
    }
    Ok(name)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn accepts_valid_labels() {
        assert_eq!(validate("alice").unwrap(), "alice");
        assert_eq!(validate("foo-bar").unwrap(), "foo-bar");
        assert_eq!(validate("a1b2c3").unwrap(), "a1b2c3");
        assert_eq!(validate(&"a".repeat(32)).unwrap(), "a".repeat(32));
    }

    #[test]
    fn normalizes_case_and_whitespace_unsurprisingly() {
        assert_eq!(validate("  Alice  ").unwrap(), "alice");
        assert_eq!(validate("MyAgent2").unwrap(), "myagent2");
    }

    #[test]
    fn rejects_unicode_instead_of_silently_mangling() {
        // The #66 repro: this used to mint "caf-shop"; now it's a clear error.
        assert!(validate("café-shop").is_err());
        assert!(validate("日本").is_err());
        assert!(validate("über").is_err());
    }

    #[test]
    fn rejects_spaces_and_dots() {
        assert!(validate("my cool app").is_err());
        assert!(validate("a.b.c").is_err());
        assert!(validate("under_score").is_err());
    }

    #[test]
    fn rejects_bad_length() {
        assert!(validate("ab").is_err()); // too short
        assert!(validate(&"a".repeat(33)).is_err()); // too long
        assert!(validate("").is_err());
    }

    #[test]
    fn rejects_edge_hyphens() {
        assert!(validate("-alice").is_err());
        assert!(validate("alice-").is_err());
        assert!(validate("--").is_err());
    }
}