use {
    crate::{Error, File, Special},
    std::io::{Read, Write},
};

#[repr(u8)]
#[derive(Debug)]
pub enum FileType {
    Normal(File),
    HardLink(String),
    SoftLink(String),
    Directory,
    Character(Special),
    Block(Special),
    Fifo,
}

impl FileType {
    pub fn read<T: Read>(reader: &mut T) -> Result<Self, Error> {
        let mut buf = [0; 1];
        reader.read_exact(&mut buf)?;
        match buf[0] {
            0 => {
                let file = File::read(reader)?;
                Ok(Self::Normal(file))
            }
            1 => {
                let mut len = [0; 8];
                reader.read_exact(&mut len)?;
                let len = u64::from_le_bytes(len);
                let mut buf = Vec::with_capacity(len.try_into()?);
                let mut handle = reader.take(len);
                handle.read_exact(&mut buf)?;
                let s = String::from_utf8(buf)?;
                Ok(Self::HardLink(s))
            }
            2 => {
                let mut len = [0; 8];
                reader.read_exact(&mut len)?;
                let len = u64::from_le_bytes(len);
                let mut buf = Vec::with_capacity(len.try_into()?);
                let mut handle = reader.take(len);
                handle.read_exact(&mut buf)?;
                let s = String::from_utf8(buf)?;
                Ok(Self::SoftLink(s))
            }
            3 => Ok(Self::Directory),
            4 => {
                let sp = Special::read(reader)?;
                Ok(Self::Character(sp))
            }
            5 => {
                let sp = Special::read(reader)?;
                Ok(Self::Block(sp))
            }
            6 => Ok(Self::Fifo),
            _ => Err(Error::UnknownFileType),
        }
    }

    pub fn write<T: Write>(&self, writer: &mut T) -> Result<(), Error> {
        match self {
            Self::Normal(f) => {
                writer.write_all(&[0])?;
                f.write(writer)?;
            }
            Self::HardLink(s) => {
                writer.write_all(&[1])?;
                let len = s.len() as u64;
                writer.write_all(&len.to_le_bytes())?;
                writer.write_all(s.as_bytes())?;
            }
            Self::SoftLink(s) => {
                writer.write_all(&[2])?;
                let len = s.len() as u64;
                writer.write_all(&len.to_le_bytes())?;
                writer.write_all(s.as_bytes())?;
            }
            Self::Directory => writer.write_all(&[3])?,
            Self::Character(s) => {
                writer.write_all(&[4])?;
                s.write(writer)?;
            }
            Self::Block(s) => {
                writer.write_all(&[5])?;
                s.write(writer)?;
            }
            Self::Fifo => writer.write_all(&[6])?,
        }
        Ok(())
    }
}