use axum::http::{HeaderMap, header};

/// Return the inbound media type without parameters, defaulting to binary.
pub(super) fn content_type(headers: &HeaderMap) -> String {
    headers
        .get(header::CONTENT_TYPE)
        .and_then(|value| value.to_str().ok())
        .and_then(|value| value.split(';').next())
        .map(str::trim)
        .filter(|value| !value.is_empty())
        .unwrap_or("application/octet-stream")
        .to_string()
}

#[cfg(test)]
mod tests {
    use super::content_type;
    use axum::http::{HeaderMap, HeaderValue, header};

    #[test]
    fn content_type_from_headers_defaults_to_octet_stream() {
        let headers = HeaderMap::new();

        assert_eq!(content_type(&headers), "application/octet-stream");
    }

    #[test]
    fn content_type_from_headers_preserves_parameters() {
        let mut headers = HeaderMap::new();
        headers.insert(
            header::CONTENT_TYPE,
            HeaderValue::from_static("text/plain; charset=utf-8"),
        );

        assert_eq!(content_type(&headers), "text/plain");
    }

    #[test]
    fn content_type_from_headers_discards_empty_values() {
        let mut headers = HeaderMap::new();
        headers.insert(
            header::CONTENT_TYPE,
            HeaderValue::from_static(" ; charset=utf-8"),
        );

        assert_eq!(content_type(&headers), "application/octet-stream");
    }
}