extern crate base64;
extern crate mime_sniffer;

use self::base64::encode;
use self::mime_sniffer::MimeTypeSniffer;

pub fn data_to_dataurl(mime: &str, data: &[u8]) -> String {
    let mimetype: String;

    if mime == "" {
        mimetype = detect_mimetype(data);
    } else {
        mimetype = mime.to_string();
    }

    format!("data:{};base64,{}", mimetype, encode(data))
}

fn detect_mimetype(data: &[u8]) -> String {
    let detected_mimetype = data.sniff_mime_type();
    if detected_mimetype != None {
        detected_mimetype.unwrap().to_string()
    } else {
        "".to_string()
    }
}

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

    #[test]
    fn test_data_to_dataurl() {
        let mime = "application/javascript";
        let data = "var word = 'hello';\nalert(word);\n";
        let datauri = data_to_dataurl(mime, data.as_bytes());
        assert_eq!(&datauri, "data:application/javascript;base64,dmFyIHdvcmQgPSAnaGVsbG8nOwphbGVydCh3b3JkKTsK");
    }
}