use std::io;

use super::Reader;
use super::Writer;

pub trait Domain<'de>: std::fmt::Debug + Eq + std::hash::Hash + Ord + Clone {
    type Decode: DomainDecode<'de, Self> + Default;
    type Encode: DomainEncode<'de, Self> + Default;
}

pub trait DomainDecode<'de, D: Domain<'de>> {
    fn decode_embedded<R: Reader<'de> + ?Sized>(
        &mut self,
        r: &mut R,
        read_annotations: bool,
    ) -> io::Result<D>;
}

pub trait DomainEncode<'de, D: Domain<'de>> {
    fn encode_embedded(
        &mut self,
        w: &mut dyn Writer,
        d: &D,
    ) -> io::Result<()>;
}

impl<'a, 'de, D: Domain<'de>, T: DomainDecode<'de, D>> DomainDecode<'de, D> for &'a mut T {
    fn decode_embedded<R: Reader<'de> + ?Sized>(
        &mut self,
        r: &mut R,
        read_annotations: bool,
    ) -> io::Result<D> {
        (**self).decode_embedded(r, read_annotations)
    }
}

impl<'a, 'de, D: Domain<'de>, T: DomainEncode<'de, D>> DomainEncode<'de, D> for &'a mut T {
    fn encode_embedded(
        &mut self,
        w: &mut dyn Writer,
        d: &D,
    ) -> io::Result<()> {
        (**self).encode_embedded(w, d)
    }
}

#[derive(Default)]
pub struct DefaultDomainCodec;

impl<'de, D: Domain<'de>> DomainDecode<'de, D> for DefaultDomainCodec {
    fn decode_embedded<R: Reader<'de> + ?Sized>(
        &mut self,
        r: &mut R,
        read_annotations: bool,
    ) -> io::Result<D> {
        D::Decode::default().decode_embedded(r, read_annotations)
    }
}

impl<'de, D: Domain<'de>> DomainEncode<'de, D> for DefaultDomainCodec {
    fn encode_embedded(
        &mut self,
        w: &mut dyn Writer,
        d: &D,
    ) -> io::Result<()> {
        D::Encode::default().encode_embedded(w, d)
    }
}

#[derive(Default)]
pub struct DebugDomainCodec;

impl<'de, Err: Into<io::Error>, D: Domain<'de> + std::str::FromStr<Err = Err>> DomainDecode<'de, D> for DebugDomainCodec {
    fn decode_embedded<R: Reader<'de> + ?Sized>(
        &mut self,
        r: &mut R,
        _read_annotations: bool,
    ) -> io::Result<D> {
        r.next_str()?.parse().map_err(|e: Err| e.into())
    }
}

impl<'de, D: Domain<'de>> DomainEncode<'de, D> for DebugDomainCodec {
    fn encode_embedded(
        &mut self,
        w: &mut dyn Writer,
        d: &D,
    ) -> io::Result<()> {
        w.write_string(&format!("{:?}", d))
    }
}

#[derive(Default)]
pub struct NoEmbeddedDomainCodec;

impl<'de, D: Domain<'de>> DomainDecode<'de, D> for NoEmbeddedDomainCodec {
    fn decode_embedded<R: Reader<'de> + ?Sized>(
        &mut self,
        _r: &mut R,
        _read_annotations: bool,
    ) -> io::Result<D> {
        Err(io::Error::new(io::ErrorKind::Unsupported, "Embedded values not supported here"))
    }
}

impl<'de, D: Domain<'de>> DomainEncode<'de, D> for NoEmbeddedDomainCodec {
    fn encode_embedded(
        &mut self,
        _w: &mut dyn Writer,
        _d: &D,
    ) -> io::Result<()> {
        Err(io::Error::new(io::ErrorKind::Unsupported, "Embedded values not supported here"))
    }
}