use std::fmt::{Display, Formatter, LowerHex};
use rand::random;

/// Helper struct for the identifiers used in `dest`, `src`, `packet_id` and `reply_to`.
#[derive(Debug, Eq, PartialEq, Copy, Clone, Hash)]
pub struct Identifier {
    pub bytes: [u8; 4],
}

impl Identifier {
    pub fn random() -> Identifier {
        Identifier::from(random::<u32>())
    }
}

impl Default for Identifier {
    fn default() -> Self {
        Identifier::from(0x00000000)
    }
}

impl Display for Identifier {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "0x{:x}{:x}{:x}{:x}",
            self.bytes[0], self.bytes[1], self.bytes[2], self.bytes[3]
        )
    }
}

impl LowerHex for Identifier {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "{:x}{:x}{:x}{:x}",
            self.bytes[0], self.bytes[1], self.bytes[2], self.bytes[3]
        )
    }
}

impl From<&[u8]> for Identifier {
    fn from(value: &[u8]) -> Self {
        let mut bytes = [0_u8; 4];
        bytes[..4].copy_from_slice(value[..4].as_ref());
        Identifier {
            bytes
        }
    }
}

impl From<Vec<u8>> for Identifier {
    fn from(value: Vec<u8>) -> Self {
        Identifier::from(value.as_slice())
    }
}

impl From<u32> for Identifier {
    fn from(value: u32) -> Self {
        Identifier {
            bytes: [
                (value >> 24) as u8,
                (value >> 16) as u8,
                (value >> 8) as u8,
                (value >> 0) as u8,
            ],
        }
    }
}

impl Into<u32> for Identifier {
    fn into(self) -> u32 {
        u32::from_be_bytes(self.bytes)
    }
}