rusteal-codegen 0.8.0

pub fn to_snake_case(name: &str) -> String {
    let mut result = String::with_capacity(name.len() + 8);
    let chars: Vec<char> = name.chars().collect();

    for (i, &ch) in chars.iter().enumerate() {
        if ch.is_ascii_uppercase() {
            if i > 0 {
                let prev = chars[i - 1];

                let new_word = prev.is_ascii_lowercase()
                    || prev.is_ascii_digit()
                    || (prev.is_ascii_uppercase()
                        && i + 1 < chars.len()
                        && chars[i + 1].is_ascii_lowercase());

                if new_word {
                    result.push('_');
                }
            }

            result.push(ch.to_ascii_lowercase());
        } else {
            result.push(ch);
        }
    }

    result
}

pub fn strip_bool_prefix(name: &str) -> String {
    if name.starts_with('b') && name.len() > 1 && name.as_bytes()[1].is_ascii_uppercase() {
        to_snake_case(&name[1..])
    } else {
        to_snake_case(name)
    }
}

const RESERVED_WORDS: &[&str] = &[
    "as", "break", "const", "continue", "crate", "else", "enum", "extern", "false", "fn", "for",
    "if", "impl", "in", "let", "loop", "match", "mod", "move", "mut", "pub", "ref", "return",
    "self", "Self", "static", "struct", "super", "trait", "true", "type", "unsafe", "use", "where",
    "while", "async", "await", "dyn", "abstract", "become", "box", "do", "final", "macro",
    "override", "priv", "typeof", "unsized", "virtual", "yield", "try",
];

pub fn is_reserved(name: &str) -> bool {
    RESERVED_WORDS.contains(&name)
}

pub fn escape_reserved(name: &str) -> String {
    match name {
        "Self" | "self" | "super" | "crate" => format!("{name}_"),
        _ if is_reserved(name) => format!("r#{name}"),
        _ => name.to_string(),
    }
}

#[allow(dead_code)]
pub fn strip_ue_prefix(cpp_name: &str) -> &str {
    if cpp_name.len() > 1 {
        let first = cpp_name.as_bytes()[0];
        let second = cpp_name.as_bytes()[1];

        if (first == b'A' || first == b'U') && second.is_ascii_uppercase() {
            return &cpp_name[1..];
        }
    }

    cpp_name
}

#[allow(dead_code)]
pub fn strip_struct_prefix(cpp_name: &str) -> &str {
    if cpp_name.len() > 1
        && cpp_name.as_bytes()[0] == b'F'
        && cpp_name.as_bytes()[1].is_ascii_uppercase()
    {
        &cpp_name[1..]
    } else {
        cpp_name
    }
}

#[allow(dead_code)]
pub fn to_module_name(name: &str) -> String {
    let snake = to_snake_case(name);
    escape_reserved(&snake)
}

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

    #[test]
    fn test_to_snake_case() {
        assert_eq!(to_snake_case("AActor"), "a_actor");
        assert_eq!(to_snake_case("GetObjectCount"), "get_object_count");
        assert_eq!(to_snake_case("bNetTemporary"), "b_net_temporary");
        assert_eq!(to_snake_case("HTTPServer"), "http_server");
        assert_eq!(to_snake_case("FVector"), "f_vector");
        assert_eq!(to_snake_case("ECollisionChannel"), "e_collision_channel");
        assert_eq!(to_snake_case("URL"), "url");

        assert_eq!(
            to_snake_case("K2_GetActorLocation"),
            "k2_get_actor_location"
        );
    }

    #[test]
    fn test_strip_bool_prefix() {
        assert_eq!(strip_bool_prefix("bNetTemporary"), "net_temporary");
        assert_eq!(strip_bool_prefix("bHidden"), "hidden");
        assert_eq!(strip_bool_prefix("boolean"), "boolean");
    }

    #[test]
    fn test_escape_reserved() {
        assert_eq!(escape_reserved("Self"), "Self_");
        assert_eq!(escape_reserved("crate"), "crate_");
        assert_eq!(escape_reserved("type"), "r#type");
        assert_eq!(escape_reserved("r#move"), "r#move");
        assert_eq!(escape_reserved("move"), "r#move");
        assert_eq!(escape_reserved("actor"), "actor");
    }

    #[test]
    fn test_strip_ue_prefix() {
        assert_eq!(strip_ue_prefix("AActor"), "Actor");
        assert_eq!(strip_ue_prefix("UObject"), "Object");
        assert_eq!(strip_ue_prefix("FVector"), "FVector");
    }
}