#[derive(Debug, PartialEq, Eq, Clone)]
pub struct Timestamp(u64);

impl Timestamp {
    /// Returns none if the given unix timestamp doesn't fit in 5 bytes
    pub fn new(unix_time: u64) -> Option<Self> {
        // must fit in 5 bytes
        if unix_time > (1 << (5 * 8)) - 1 {
            return None;
        }

        Some(Self(unix_time))
    }

    pub fn unix_time(&self) -> u64 {
        self.0
    }

    /// Returns none if there is not enough space in the buffer
    pub fn encode<'a>(&self, buf: &'a mut [u8]) -> Option<&'a [u8]> {
        if buf.len() < 6 {
            return None;
        }

        buf[0] = 5;
        buf[1..6].copy_from_slice(&self.0.to_le_bytes()[0..5]);

        Some(&buf[0..6])
    }

    pub fn decode(data: &[u8]) -> Option<Self> {
        if data.len() < 6 {
            return None;
        }
        if data[0] != 5 {
            return None;
        }

        let mut extended_data = [0; 8];
        extended_data[0..5].copy_from_slice(&data[1..6]);

        Some(Self(u64::from_le_bytes(extended_data)))
    }
}