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//! `bitwisetools` allows you to encode and decode bitwise fields easily
#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn decode_encode() {

        let reference = vec!["thing1", "thing2", "thing3"];
        assert_eq!(5, encode_bitwise(reference.clone(), decode_bitwise(reference, 5)));
    }
    #[test]
    fn encode() {
        let reference = vec!["thing1", "thing2", "thing3"];
        let actual = vec!["thing1", "thing3"];
        assert_eq!(5, encode_bitwise(reference, actual))
    }
}
/// Decodes a bitwise field of type `u32`
///
/// # Examples
/// ```
/// let reference = vec!["thing1", "thing2", "thing3"];
/// let array = bitwisetools::decode_bitwise(reference, 5);
/// assert_eq!(vec!["thing1", "thing3"], array);
/// ```  
pub fn decode_bitwise<T>(i: T, n: u32) -> T
where
    T: IntoIterator + std::iter::FromIterator<<T as std::iter::IntoIterator>::Item> + std::fmt::Debug,
{
    i.into_iter().enumerate().filter(|(i, _x)| (1 << i) == (n & (1 << i))).map(|(_i, x)| x).collect::<T>()
}

/// Encodes an array (of any iterable type) to a bitwise field
///
/// # Panics
/// There are no guarantees around arguments with duplicate items
/// 
/// # Examples
/// ```
/// let reference = vec!["thing1", "thing2", "thing3"];
/// let actual = vec!["thing1", "thing3"];
/// let field = bitwisetools::encode_bitwise(reference, actual); 
/// assert_eq!(5, field)
/// ```
 
pub fn encode_bitwise<T>(r: T, w: T) -> u32
where
    T: IntoIterator,
    <T as std::iter::IntoIterator>::IntoIter: std::clone::Clone,
    <T as std::iter::IntoIterator>::Item: std::cmp::PartialEq,
    <T as std::iter::IntoIterator>::Item: std::fmt::Debug
{
    let ri = r.into_iter();
    let mut n = 0;
    w.into_iter().for_each(|x| n += 1 << ri.clone().position(|v| v == x).ok_or(format!("item \"{:?}\" not found in reference collection", x)).unwrap());
    n as u32
}