extern crate base64;
extern crate uuid;
use uuid::ParseError;
use base64::DecodeError;


use uuid::Uuid;

#[derive(Debug)]
pub enum ConvertError{
    ParseError(ParseError),
    FromBase64Error(DecodeError)
}

///Convert uuid to a 22 character string blob
///```rust
///extern crate blob_uuid;
///fn main(){
///   let uuid = Uuid::parse_str("557c8018-5e21-4b74-8bb0-9040e2e8ead1").unwrap();
///   assert_eq!("VXyAGF4hS3SLsJBA4ujq0Q", blob_uuid::to_blob(uuid));
///}
///
///```
pub fn to_blob(uuid: &Uuid) -> String{
        base64::encode_config(uuid.as_bytes(), base64::URL_SAFE_NO_PAD)
}

/// Convert a string blob back to uuid 
/// ```rust
///extern crate blob_uuid;
///fn main(){
/// let uuid = Uuid::parse_str("557c8018-5e21-4b74-8bb0-9040e2e8ead1").unwrap();
/// assert_eq!(uuid, blob_uuid::to_uuid("VXyAGF4hS3SLsJBA4ujq0Q").unwrap());
///}
/// ```
pub fn to_uuid(blob: &str) -> Result<Uuid, ConvertError>{
        match base64::decode_config(blob, base64::URL_SAFE_NO_PAD){
            Ok(bytes) => {
                match Uuid::from_bytes(&bytes){
                    Ok(uuid) => Ok(uuid),
                    Err(e) => Err(ConvertError::ParseError(e))
                }
            },
            Err(e) => {
                Err(ConvertError::FromBase64Error(e))
            }
        }
}


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

    #[test]
    fn test_blobs() {
        let uuid_str = "557c8018-5e21-4b74-8bb0-9040e2e8ead1";
        println!("uuid_str: {}", uuid_str);
        let blob = "VXyAGF4hS3SLsJBA4ujq0Q";
        println!("blob: {}", blob);
        let uuid = Uuid::parse_str(uuid_str).unwrap();
        assert_eq!(uuid, to_uuid(blob).unwrap());
        assert_eq!(blob, to_blob(&uuid));
    }


    #[test]
    fn test_more_blobs(){
        for _ in 0..10{
            let uuid = Uuid::new_v4();
            let blob = to_blob(&uuid);
            assert_eq!(blob.chars().count(), 22);
            println!("{}   |   {}",uuid,blob);
        }
    }
}