use std::io;

use super::IOValue;
use super::Reader;
use super::Writer;
use super::Value;

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

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

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

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

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

impl<D: Domain> DomainEncode<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<Err: Into<io::Error>, D: Domain + std::str::FromStr<Err = Err>> DomainDecode<D> for DebugDomainCodec {
    fn decode_embedded<'de, 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<D: Domain> DomainEncode<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<D: Domain> DomainDecode<D> for NoEmbeddedDomainCodec {
    fn decode_embedded<'de, 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<D: Domain> DomainEncode<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"))
    }
}

#[derive(Default)]
pub struct IOValueDomainCodec;

impl Domain for IOValue {
    type Decode = IOValueDomainCodec;
    type Encode = IOValueDomainCodec;
}

impl DomainDecode<IOValue> for IOValueDomainCodec {
    fn decode_embedded<'de, R: Reader<'de> + ?Sized>(
        &mut self,
        r: &mut R,
        read_annotations: bool,
    ) -> io::Result<IOValue> {
        Ok(r.next_iovalue(read_annotations)?)
    }
}

impl DomainEncode<IOValue> for IOValueDomainCodec {
    fn encode_embedded(
        &mut self,
        w: &mut dyn Writer,
        d: &IOValue,
    ) -> io::Result<()> {
        d.write(w, self)
    }
}