use std::{
    io::{BufRead, Read, Result, Write},
    net::Ipv4Addr,
};

pub fn write<W: Write>(mut writer: W, v: &[u8]) -> Result<()> {
    writer.write_all(v)
}

pub fn write_u8<W: Write>(mut writer: W, v: u8) -> Result<()> {
    writer.write_all(&[v])
}

pub fn write_u16<W: Write>(mut writer: W, v: u16) -> Result<()> {
    writer.write_all(&u16::to_be_bytes(v))
}

pub fn write_u32<W: Write>(mut writer: W, v: u32) -> Result<()> {
    writer.write_all(&u32::to_be_bytes(v))
}

pub fn write_ipv4<W: Write>(mut writer: W, v: Ipv4Addr) -> Result<()> {
    writer.write_all(&v.octets())
}

pub fn write_null_terminated_string<W: Write>(mut writer: W, v: &str) -> Result<()> {
    writer.write_all(v.as_bytes())?;
    writer.write_all(&[0u8])
}

pub fn read_u8<R: Read>(mut reader: R) -> Result<u8> {
    let mut buf = [0u8; 1];
    reader.read_exact(&mut buf)?;
    Ok(buf[0])
}

pub fn read_u16<R: Read>(mut reader: R) -> Result<u16> {
    let mut buf = [0u8; 2];
    reader.read_exact(&mut buf)?;
    Ok(u16::from_be_bytes(buf))
}

pub fn read_u32<R: Read>(mut reader: R) -> Result<u32> {
    let mut buf = [0u8; 4];
    reader.read_exact(&mut buf)?;
    Ok(u32::from_be_bytes(buf))
}

pub fn read_arr<const N: usize, R: Read>(mut reader: R) -> Result<[u8; N]> {
    let mut buf = [0u8; N];
    reader.read_exact(&mut buf)?;
    Ok(buf)
}

pub fn read_null_terminated_vec<R: BufRead>(mut reader: R) -> Result<Vec<u8>> {
    let mut buf = Vec::default();
    reader.read_until(0, &mut buf)?;
    buf.pop();
    Ok(buf)
}

pub fn read_null_terminated_string<R: BufRead>(reader: R) -> Result<String> {
    let buf = read_null_terminated_vec(reader)?;
    Ok(String::from_utf8(buf).unwrap())
}

pub fn read_len8_prefixed_vec<R: BufRead>(mut reader: R) -> Result<Vec<u8>> {
    let len = read_u8(&mut reader)?;
    let mut buf = vec![0u8; len as usize];
    reader.read_exact(&mut buf)?;
    Ok(buf)
}

pub fn read_len8_prefixed_string<R: BufRead>(reader: R) -> Result<String> {
    let buf = read_len8_prefixed_vec(reader)?;
    Ok(String::from_utf8(buf).unwrap())
}

pub fn read_ipv4<R: BufRead>(reader: R) -> Result<Ipv4Addr> {
    Ok(Ipv4Addr::from_octets(read_arr(reader)?))
}