protograph-codegen 0.1.0

pub fn to_snake_case(s: &str) -> String {
    let mut result = String::new();
    for (i, c) in s.chars().enumerate() {
        if c.is_uppercase() {
            if i > 0 {
                result.push('_');
            }
            result.push(c.to_lowercase().next().unwrap());
        } else {
            result.push(c);
        }
    }
    result
}

pub fn to_pascal_case(s: &str) -> String {
    let mut result = String::new();
    let mut capitalize_next = true;
    for c in s.chars() {
        if c == '_' {
            capitalize_next = true;
        } else if capitalize_next {
            result.push(c.to_uppercase().next().unwrap());
            capitalize_next = false;
        } else {
            result.push(c);
        }
    }
    result
}

pub fn pluralize(s: &str) -> String {
    if s.ends_with('s') || s.ends_with('x') || s.ends_with("ch") || s.ends_with("sh") {
        format!("{}es", s)
    } else if s.ends_with('y') && !s.ends_with("ay") && !s.ends_with("ey") && !s.ends_with("oy") && !s.ends_with("uy") {
        format!("{}ies", &s[..s.len()-1])
    } else {
        format!("{}s", s)
    }
}

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

    #[test]
    fn test_to_snake_case() {
        assert_eq!(to_snake_case("UserId"), "user_id");
        assert_eq!(to_snake_case("authorId"), "author_id");
        assert_eq!(to_snake_case("ID"), "i_d");
    }

    #[test]
    fn test_to_pascal_case() {
        assert_eq!(to_pascal_case("user_id"), "UserId");
        assert_eq!(to_pascal_case("author_id"), "AuthorId");
    }

    #[test]
    fn test_pluralize() {
        assert_eq!(pluralize("User"), "Users");
        assert_eq!(pluralize("Post"), "Posts");
        assert_eq!(pluralize("Category"), "Categories");
    }
}