use percent_encoding::{utf8_percent_encode, NON_ALPHANUMERIC};

/// Build an inline `Content-Disposition` header value for a given filename.
pub fn inline_content_disposition(filename: &str) -> Option<String> {
    if filename.is_empty() {
        return None;
    }

    let sanitized: String = filename
        .chars()
        .map(|ch| match ch {
            '"' | '\\' => '_',
            _ => ch,
        })
        .collect();
    let encoded = utf8_percent_encode(&sanitized, NON_ALPHANUMERIC);

    Some(format!(
        "inline; filename=\"{}\"; filename*=UTF-8''{}",
        sanitized, encoded
    ))
}