use bytemuck::TransparentWrapper;

use std::any::Any;
use std::borrow::{Cow, Borrow};
use std::cmp::Ordering;
use std::fmt::Debug;
use std::hash::{Hash, Hasher};
use std::io;
use std::marker::PhantomData;
use std::str::FromStr;
use std::sync::Arc;
use std::vec::Vec;

pub use std::collections::BTreeSet as Set;
pub use std::collections::BTreeMap as Map;

use crate::{AtomClass, TextWriter, DefaultDomainCodec, write_value};
use crate::CompoundClass;
use crate::Domain;
use crate::SignedInteger;
use crate::ValueClass;
use crate::Writer;
use crate::boundary as B;
use crate::domain::{NoEmbeddedDomainCodec, DomainEncode, IOValueDomainCodec};

use super::float::{eq_f32, eq_f64, cmp_f32, cmp_f64};

pub type PlainValue<'a, D = IOValue> = Box<dyn Value<D> + 'a>;

/// Atomic values from the specification.
pub trait Value<D: Domain> {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> {
        write_value(w, self, enc)
    }

    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static;
    fn value_class(&self) -> ValueClass;

    fn as_boolean(&self) -> Option<bool> { None }
    fn as_float(&self) -> Option<f32> { None }
    fn as_double(&self) -> Option<f64> { None }

    fn is_signed_integer(&self) -> bool { false }
    fn as_signed_integer(&self) -> Option<SignedInteger> { None }

    fn as_string(&self) -> Option<Cow<'_, str>> { None }
    fn as_bytestring(&self) -> Option<Cow<'_, [u8]>> { None }
    fn as_symbol(&self) -> Option<Cow<'_, str>> { None }

    fn is_record(&self) -> bool { false }
    fn label(&self) -> &dyn Value<D> { panic!("Not a record") }

    fn is_sequence(&self) -> bool { false }
    fn len(&self) -> usize { panic!("Has no length") }
    fn index(&self, _i: usize) -> &dyn Value<D> { panic!("Not indexable") }
    fn iter(&self) -> Box<dyn Iterator<Item = &dyn Value<D>> + '_> { panic!("Not iterable") }

    fn is_set(&self) -> bool { false }
    fn has(&self, _v: &dyn Value<D>) -> bool { false }

    fn is_dictionary(&self) -> bool { false }
    fn get(&self, _k: &dyn Value<D>) -> Option<&dyn Value<D>> { None }
    fn entries(&self) -> Box<dyn Iterator<Item = (&dyn Value<D>, &dyn Value<D>)> + '_> { panic!("Not a dictionary") }

    fn is_embedded(&self) -> bool { false }
    fn embedded(&self) -> Cow<'_, D> { panic!("Not an embedded value") }

    fn annotations(&self) -> Option<&[IOValue]> { None }

    fn specialized(&self) -> Option<&dyn Any> { None }
}

pub fn value<D: Domain, V: Value<D>>(v: &V) -> &dyn Value<D> {
    v
}

pub fn owned<D: Domain, V: Value<D> + 'static>(v: V) -> PlainValue<'static, D> {
    Box::new(v)
}

pub fn arcvalue<D: Domain, V: Value<D> + 'static>(v: V) -> ArcValue<D> {
    ArcValue(Arc::new(v))
}

pub fn iovalue<V: Value<IOValue> + 'static>(v: V) -> IOValue {
    IOValue(arcvalue(v))
}

pub fn copy_via<D: Domain, E: Domain + 'static, F, Err>(
    v: &dyn Value<D>,
    f: &mut F,
) -> Result<PlainValue<'static, E>, Err>
where
    F: FnMut(&D) -> Result<PlainValue<'static, E>, Err>
{
    match v.value_class() {
        ValueClass::Atomic(a) => Ok(match a {
            AtomClass::Boolean => owned(v.as_boolean().unwrap()),
            AtomClass::Float => owned(v.as_float().unwrap()),
            AtomClass::Double => owned(v.as_double().unwrap()),
            AtomClass::SignedInteger => owned(v.as_signed_integer().unwrap()),
            AtomClass::String => owned(v.as_string().unwrap().into_owned()),
            AtomClass::ByteString => owned(Bytes(v.as_bytestring().unwrap().into_owned())),
            AtomClass::Symbol => owned(Symbol(v.as_symbol().unwrap().into_owned())),
        }),
        ValueClass::Compound(c) => Ok(match c {
            CompoundClass::Sequence =>
                owned(v.iter().map(|w| copy_via(w, f)).collect::<Result<Vec<_>, _>>()?),
            CompoundClass::Set =>
                owned(v.iter().map(|w| copy_via(w, f)).collect::<Result<Set<_>, _>>()?),
            CompoundClass::Record =>
                owned(Record::new(
                    copy_via(v.label(), f)?,
                    v.iter().map(|w| copy_via(w, f)).collect::<Result<Vec<_>, _>>()?)),
            CompoundClass::Dictionary =>
                owned(v.entries().map(|(k, w)| Ok((copy_via(k, f)?, copy_via(w, f)?)))
                      .collect::<Result<Map<_, _>, _>>()?),
        }),
        ValueClass::Embedded => f(&v.embedded()),
    }
}

impl<'a, D: Domain + 'static> From<&'a dyn Value<D>> for PlainValue<'static, D> {
    fn from(v: &'a dyn Value<D>) -> Self {
        v.value_clone()
    }
}

impl<'a, D: Domain, V: Value<D> + ?Sized> Value<D> for &'a V {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> { (*self).write(w, enc) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { (*self).value_clone() }
    fn value_class(&self) -> ValueClass { (*self).value_class() }
    fn as_boolean(&self) -> Option<bool> { (*self).as_boolean() }
    fn as_float(&self) -> Option<f32> { (*self).as_float() }
    fn as_double(&self) -> Option<f64> { (*self).as_double() }
    fn is_signed_integer(&self) -> bool { (*self).is_signed_integer() }
    fn as_signed_integer(&self) -> Option<SignedInteger> { (*self).as_signed_integer() }
    fn as_string(&self) -> Option<Cow<'_, str>> { (*self).as_string() }
    fn as_bytestring(&self) -> Option<Cow<'_, [u8]>> { (*self).as_bytestring() }
    fn as_symbol(&self) -> Option<Cow<'_, str>> { (*self).as_symbol() }
    fn is_record(&self) -> bool { (*self).is_record() }
    fn label(&self) -> &dyn Value<D> { (*self).label() }
    fn is_sequence(&self) -> bool { (*self).is_sequence() }
    fn len(&self) -> usize { (*self).len() }
    fn index(&self, i: usize) -> &dyn Value<D> { (*self).index(i) }
    fn iter(&self) -> Box<dyn Iterator<Item = &dyn Value<D>> + '_> { (*self).iter() }
    fn is_set(&self) -> bool { (*self).is_set() }
    fn has(&self, v: &dyn Value<D>) -> bool { (*self).has(v) }
    fn is_dictionary(&self) -> bool { (*self).is_dictionary() }
    fn get<'value>(&'value self, k: &dyn Value<D>) -> Option<&'value dyn Value<D>> { (*self).get(k) }
    fn entries(&self) -> Box<dyn Iterator<Item = (&dyn Value<D>, &dyn Value<D>)> + '_> { (*self).entries() }
    fn is_embedded(&self) -> bool { (*self).is_embedded() }
    fn embedded(&self) -> Cow<'_, D> { (*self).embedded() }
    fn annotations(&self) -> Option<&[IOValue]> { (*self).annotations() }
}

impl<'a, D: Domain> Value<D> for PlainValue<'a, D> {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> { self.as_ref().write(w, enc) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { self.as_ref().value_clone() }
    fn value_class(&self) -> ValueClass { self.as_ref().value_class() }
    fn as_boolean(&self) -> Option<bool> { self.as_ref().as_boolean() }
    fn as_float(&self) -> Option<f32> { self.as_ref().as_float() }
    fn as_double(&self) -> Option<f64> { self.as_ref().as_double() }
    fn is_signed_integer(&self) -> bool { self.as_ref().is_signed_integer() }
    fn as_signed_integer(&self) -> Option<SignedInteger> { self.as_ref().as_signed_integer() }
    fn as_string(&self) -> Option<Cow<'_, str>> { self.as_ref().as_string() }
    fn as_bytestring(&self) -> Option<Cow<'_, [u8]>> { self.as_ref().as_bytestring() }
    fn as_symbol(&self) -> Option<Cow<'_, str>> { self.as_ref().as_symbol() }
    fn is_record(&self) -> bool { self.as_ref().is_record() }
    fn label(&self) -> &dyn Value<D> { self.as_ref().label() }
    fn is_sequence(&self) -> bool { self.as_ref().is_sequence() }
    fn len(&self) -> usize { self.as_ref().len() }
    fn index(&self, i: usize) -> &dyn Value<D> { self.as_ref().index(i) }
    fn iter(&self) -> Box<dyn Iterator<Item = &dyn Value<D>> + '_> { self.as_ref().iter() }
    fn is_set(&self) -> bool { self.as_ref().is_set() }
    fn has(&self, v: &dyn Value<D>) -> bool { self.as_ref().has(v) }
    fn is_dictionary(&self) -> bool { self.as_ref().is_dictionary() }
    fn get<'value>(&'value self, k: &dyn Value<D>) -> Option<&'value dyn Value<D>> { self.as_ref().get(k) }
    fn entries(&self) -> Box<dyn Iterator<Item = (&dyn Value<D>, &dyn Value<D>)> + '_> { self.as_ref().entries() }
    fn is_embedded(&self) -> bool { self.as_ref().is_embedded() }
    fn embedded(&self) -> Cow<'_, D> { self.as_ref().embedded() }
    fn annotations(&self) -> Option<&[IOValue]> { self.as_ref().annotations() }
}

impl<'a, D: Domain> Debug for dyn Value<D> + 'a {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        TextWriter::fmt_value(f, &mut DefaultDomainCodec, self).map_err(|_| std::fmt::Error)
    }
}

impl<'a, Err: Into<io::Error>, D: Domain + FromStr<Err = Err> + 'static> FromStr for PlainValue<'a, D> {
    type Err = io::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        crate::annotated_from_str(s, &mut DefaultDomainCodec)
    }
}

impl<'a, D: Domain> Hash for dyn Value<D> + 'a {
    fn hash<H: Hasher>(&self, state: &mut H) {
        match self.value_class() {
            ValueClass::Atomic(a) => match a {
                AtomClass::Boolean => self.as_boolean().unwrap().hash(state),
                AtomClass::Float => self.as_float().unwrap().to_bits().hash(state),
                AtomClass::Double => self.as_double().unwrap().to_bits().hash(state),
                AtomClass::SignedInteger => self.as_signed_integer().unwrap().hash(state),
                AtomClass::String => self.as_string().unwrap().hash(state),
                AtomClass::ByteString => self.as_bytestring().unwrap().hash(state),
                AtomClass::Symbol => self.as_symbol().unwrap().hash(state),
            }
            ValueClass::Compound(c) => match c {
                CompoundClass::Sequence |
                CompoundClass::Set => {
                    state.write_usize(self.len());
                    for v in self.iter() { v.hash(state) }
                }
                CompoundClass::Record => {
                    self.label().hash(state);
                    state.write_usize(self.len());
                    for v in self.iter() { v.hash(state) }
                }
                CompoundClass::Dictionary => {
                    state.write_usize(self.len());
                    for (k, v) in self.entries() {
                        k.hash(state);
                        v.hash(state);
                    }
                }
            }
            ValueClass::Embedded => self.embedded().hash(state),
        }
    }
}

fn iters_eq<'a, D: Domain>(
    mut i1: Box<dyn Iterator<Item = &dyn Value<D>> + 'a>,
    mut i2: Box<dyn Iterator<Item = &dyn Value<D>> + 'a>,
) -> bool {
    loop {
        match i1.next() {
            None => return i2.next().is_none(),
            Some(v1) => match i2.next() {
                None => return false,
                Some(v2) => if v1 != v2 { return false; },
            }
        }
    }
}

impl<'a, D: Domain> PartialEq for dyn Value<D> + 'a {
    fn eq(&self, other: &Self) -> bool {
        let cls = self.value_class();
        if cls != other.value_class() { return false; }
        match cls {
            ValueClass::Atomic(a) => match a {
                AtomClass::Boolean =>
                    self.as_boolean().unwrap() == other.as_boolean().unwrap(),
                AtomClass::Float =>
                    eq_f32(self.as_float().unwrap(), other.as_float().unwrap()),
                AtomClass::Double =>
                    eq_f64(self.as_double().unwrap(), other.as_double().unwrap()),
                AtomClass::SignedInteger =>
                    self.as_signed_integer().unwrap() == other.as_signed_integer().unwrap(),
                AtomClass::String =>
                    self.as_string().unwrap() == other.as_string().unwrap(),
                AtomClass::ByteString =>
                    self.as_bytestring().unwrap() == other.as_bytestring().unwrap(),
                AtomClass::Symbol =>
                    self.as_symbol().unwrap() == other.as_symbol().unwrap(),
            }
            ValueClass::Compound(c) => match c {
                CompoundClass::Record => {
                    if self.label() != other.label() { return false; }
                    iters_eq(self.iter(), other.iter())
                }
                CompoundClass::Sequence => {
                    iters_eq(self.iter(), other.iter())
                }
                CompoundClass::Set => {
                    let s1 = self.iter().collect::<Set<_>>();
                    let s2 = other.iter().collect::<Set<_>>();
                    s1 == s2
                }
                CompoundClass::Dictionary => {
                    let d1 = self.entries().collect::<Map<_, _>>();
                    let d2 = other.entries().collect::<Map<_, _>>();
                    d1 == d2
                }
            }
            ValueClass::Embedded => self.embedded() == other.embedded(),
        }
    }
}

fn iters_cmp<'a, D: Domain>(
    mut i1: Box<dyn Iterator<Item = &dyn Value<D>> + 'a>,
    mut i2: Box<dyn Iterator<Item = &dyn Value<D>> + 'a>,
) -> Ordering {
    loop {
        match i1.next() {
            None => match i2.next() {
                None => return Ordering::Equal,
                Some(_) => return Ordering::Less,
            }
            Some(v1) => match i2.next() {
                None => return Ordering::Greater,
                Some(v2) => match v1.cmp(v2) {
                    Ordering::Equal => (),
                    other => return other,
                }
            }
        }
    }
}

impl<'a, D: Domain> Ord for dyn Value<D> + 'a {
    fn cmp(&self, other: &Self) -> Ordering {
        let cls = self.value_class();
        cls.cmp(&other.value_class()).then_with(|| match cls {
            ValueClass::Atomic(a) => match a {
                AtomClass::Boolean =>
                    self.as_boolean().cmp(&other.as_boolean()),
                AtomClass::Float =>
                    cmp_f32(self.as_float().unwrap(), other.as_float().unwrap()),
                AtomClass::Double =>
                    cmp_f64(self.as_double().unwrap(), other.as_double().unwrap()),
                AtomClass::SignedInteger =>
                    self.as_signed_integer().cmp(&other.as_signed_integer()),
                AtomClass::String =>
                    self.as_string().cmp(&other.as_string()),
                AtomClass::ByteString =>
                    self.as_bytestring().cmp(&other.as_bytestring()),
                AtomClass::Symbol =>
                    self.as_symbol().cmp(&other.as_symbol()),
            },
            ValueClass::Compound(c) => match c {
                CompoundClass::Record =>
                    self.label().cmp(other.label()).then_with(
                        || iters_cmp(self.iter(), other.iter())),
                CompoundClass::Sequence => iters_cmp(self.iter(), other.iter()),
                CompoundClass::Set => {
                    let s1 = self.iter().collect::<Set<_>>();
                    let s2 = other.iter().collect::<Set<_>>();
                    s1.cmp(&s2)
                }
                CompoundClass::Dictionary => {
                    let d1 = self.entries().collect::<Map<_, _>>();
                    let d2 = other.entries().collect::<Map<_, _>>();
                    d1.cmp(&d2)
                }
            },
            ValueClass::Embedded => self.embedded().cmp(&other.embedded()),
        })
    }
}

impl<'a, D: Domain> Eq for dyn Value<D> + 'a {}

impl<'a, D: Domain> PartialOrd for dyn Value<D> + 'a {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

#[derive(Debug, Clone)]
pub enum Atom<'a> {
    Boolean(bool),
    Float(f32),
    Double(f64),
    SignedInteger(SignedInteger),
    String(Cow<'a, str>),
    ByteString(Cow<'a, [u8]>),
    Symbol(Cow<'a, str>),
}

impl<'a> Atom<'a> {
    pub fn into_value<D: Domain>(self) -> PlainValue<'static, D> {
        match self {
            Atom::Boolean(b) => Box::new(b),
            Atom::Float(f) => Box::new(f),
            Atom::Double(d) => Box::new(d),
            Atom::SignedInteger(i) => Box::new(i),
            Atom::String(s) => Box::new(s.into_owned()),
            Atom::ByteString(bs) => Box::new(Bytes(bs.into_owned())),
            Atom::Symbol(s) => Box::new(Symbol(s.into_owned())),
        }
    }
}

impl<'r, 'a> From<&'r Atom<'a>> for AtomClass {
    fn from(a: &'r Atom<'a>) -> Self {
        match a {
            Atom::Boolean(_) => AtomClass::Boolean,
            Atom::Float(_) => AtomClass::Float,
            Atom::Double(_) => AtomClass::Double,
            Atom::SignedInteger(_) => AtomClass::SignedInteger,
            Atom::String(_) => AtomClass::String,
            Atom::ByteString(_) => AtomClass::ByteString,
            Atom::Symbol(_) => AtomClass::Symbol,
        }
    }
}

impl<'a, D: Domain> Value<D> for Atom<'a> {
    fn write(&self, w: &mut dyn Writer, _enc: &mut dyn DomainEncode<D>) -> io::Result<()> {
        match self {
            Atom::Boolean(b) => w.write_bool(*b),
            Atom::Float(f) => w.write_f32(*f),
            Atom::Double(d) => w.write_f64(*d),
            Atom::SignedInteger(i) => w.write_signed_integer(i),
            Atom::String(s) => w.write_string(s),
            Atom::ByteString(bs) => w.write_bytes(bs),
            Atom::Symbol(s) => w.write_symbol(s),
        }
    }

    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static {
        self.clone().into_value()
    }

    fn value_class(&self) -> ValueClass {
        ValueClass::Atomic(self.into())
    }

    fn as_boolean(&self) -> Option<bool> {
        if let Atom::Boolean(b) = self { Some(*b) } else { None }
    }

    fn as_float(&self) -> Option<f32> {
        if let Atom::Float(f) = self { Some(*f) } else { None }
    }

    fn as_double(&self) -> Option<f64> {
        if let Atom::Double(d) = self { Some(*d) } else { None }
    }

    fn is_signed_integer(&self) -> bool { matches!(self, Atom::SignedInteger(_)) }
    fn as_signed_integer(&self) -> Option<SignedInteger> {
        if let Atom::SignedInteger(i) = self { Some(i.clone()) } else { None }
    }

    fn as_string(&self) -> Option<Cow<'_, str>> {
        if let Atom::String(s) = self { Some(Cow::Borrowed(s)) } else { None }
    }

    fn as_bytestring(&self) -> Option<Cow<'_, [u8]>> {
        if let Atom::ByteString(s) = self { Some(Cow::Borrowed(s)) } else { None }
    }

    fn as_symbol(&self) -> Option<Cow<'_, str>> {
        if let Atom::Symbol(s) = self { Some(Cow::Borrowed(s)) } else { None }
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub enum NoValue {}

impl Domain for NoValue {
    type Decode = NoEmbeddedDomainCodec;
    type Encode = NoEmbeddedDomainCodec;
}

impl FromStr for NoValue {
    type Err = io::Error;

    fn from_str(_s: &str) -> Result<Self, Self::Err> {
        Err(io::Error::new(io::ErrorKind::Unsupported, "Embedded values not supported here"))
    }
}

impl<D: Domain> Value<D> for NoValue {
    fn write(&self, _w: &mut dyn Writer, _enc: &mut dyn DomainEncode<D>) -> io::Result<()> { unreachable!() }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { unreachable!() }
    fn value_class(&self) -> ValueClass { unreachable!() }
}

impl<D: Domain> Value<D> for bool {
    fn write(&self, w: &mut dyn Writer, __enc: &mut dyn DomainEncode<D>) -> io::Result<()> { w.write_bool(*self) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { Box::new(*self) }
    fn value_class(&self) -> ValueClass { ValueClass::Atomic(AtomClass::Boolean) }
    fn as_boolean(&self) -> Option<bool> { Some(*self) }
}

impl<D: Domain> Value<D> for u64 {
    fn write(&self, w: &mut dyn Writer, _enc: &mut dyn DomainEncode<D>) -> io::Result<()> { w.write_u64(*self) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { Box::new(*self) }
    fn value_class(&self) -> ValueClass { ValueClass::Atomic(AtomClass::SignedInteger) }
    fn as_signed_integer(&self) -> Option<SignedInteger> {
        Some((*self).into())
    }
}

impl<D: Domain> Value<D> for SignedInteger {
    fn write(&self, w: &mut dyn Writer, _enc: &mut dyn DomainEncode<D>) -> io::Result<()> { w.write_signed_integer(self) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { Box::new(self.clone()) }
    fn value_class(&self) -> ValueClass { ValueClass::Atomic(AtomClass::SignedInteger) }
    fn as_signed_integer(&self) -> Option<SignedInteger> {
        Some(self.clone())
    }
}

impl<D: Domain> Value<D> for f32 {
    fn write(&self, w: &mut dyn Writer, _enc: &mut dyn DomainEncode<D>) -> io::Result<()> { w.write_f32(*self) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { Box::new(*self) }
    fn value_class(&self) -> ValueClass { ValueClass::Atomic(AtomClass::Float) }
    fn as_float(&self) -> Option<f32> { Some(*self) }
    fn as_double(&self) -> Option<f64> { Some(*self as f64) }
}

impl<D: Domain> Value<D> for f64 {
    fn write(&self, w: &mut dyn Writer, _enc: &mut dyn DomainEncode<D>) -> io::Result<()> { w.write_f64(*self) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { Box::new(*self) }
    fn value_class(&self) -> ValueClass { ValueClass::Atomic(AtomClass::Float) }
    fn as_float(&self) -> Option<f32> { Some(*self as f32) }
    fn as_double(&self) -> Option<f64> { Some(*self) }
}

impl<D: Domain> Value<D> for str {
    fn write(&self, w: &mut dyn Writer, _enc: &mut dyn DomainEncode<D>) -> io::Result<()> { w.write_string(self) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { Box::new(self.to_owned()) }
    fn value_class(&self) -> ValueClass { ValueClass::Atomic(AtomClass::String) }
    fn as_string(&self) -> Option<Cow<'_, str>> { Some(Cow::Borrowed(self)) }
}

impl<D: Domain> Value<D> for String {
    fn write(&self, w: &mut dyn Writer, _enc: &mut dyn DomainEncode<D>) -> io::Result<()> { w.write_string(self) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { Box::new(self.clone()) }
    fn value_class(&self) -> ValueClass { ValueClass::Atomic(AtomClass::String) }
    fn as_string(&self) -> Option<Cow<'_, str>> { Some(Cow::Borrowed(self)) }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
#[repr(transparent)]
pub struct Bytes<T: AsRef<[u8]> + Debug = Vec<u8>>(T);

impl<T: AsRef<[u8]> + Debug> Bytes<T> {
    pub fn new(t: T) -> Self {
        Bytes(t)
    }
}

impl<T: AsRef<[u8]> + Debug, D: Domain> Value<D> for Bytes<T> {
    fn write(&self, w: &mut dyn Writer, _enc: &mut dyn DomainEncode<D>) -> io::Result<()> { w.write_bytes(self.0.as_ref()) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { Box::new(Bytes(self.0.as_ref().to_owned())) }
    fn value_class(&self) -> ValueClass { ValueClass::Atomic(AtomClass::ByteString) }
    fn as_bytestring(&self) -> Option<Cow<'_, [u8]>> { Some(Cow::Borrowed(self.0.as_ref())) }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
#[repr(transparent)]
pub struct Symbol<T: AsRef<str> + Debug = String>(T);

impl<T: AsRef<str> + Debug> Symbol<T> {
    pub fn new(t: T) -> Self {
        Symbol(t)
    }
}

impl<T: AsRef<str> + Debug, D: Domain> Value<D> for Symbol<T> {
    fn write(&self, w: &mut dyn Writer, _enc: &mut dyn DomainEncode<D>) -> io::Result<()> { w.write_symbol(self.0.as_ref()) }
    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { Box::new(Symbol(self.0.as_ref().to_owned())) }
    fn value_class(&self) -> ValueClass { ValueClass::Atomic(AtomClass::Symbol) }
    fn as_symbol(&self) -> Option<Cow<'_, str>> { Some(Cow::Borrowed(self.0.as_ref())) }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
#[repr(transparent)]
pub struct Record<V>(Vec<V> /* at least one element, for the label */);

impl<V> Record<V> {
    pub fn new(label: V, mut fields: Vec<V>) -> Self {
        fields.insert(0, label);
        Record(fields)
    }

    pub fn _from_vec(v: Vec<V>) -> Self {
        if v.is_empty() { panic!("Internal error: empty vec supplied to Record::_from_vec") }
        Record(v)
    }

    pub fn _vec(&self) -> &Vec<V> {
        &self.0
    }
}

impl<D: Domain, V: Value<D>> Value<D> for Record<V> {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> {
        w.start_record()?;
        let mut b = B::start(B::Item::RecordLabel);
        w.boundary(&b)?;
        self.0[0].write(w, enc)?;
        for e in &self.0[1..] {
            b.shift(Some(B::Item::RecordField));
            w.boundary(&b)?;
            e.write(w, enc)?;
        }
        b.shift(None);
        w.boundary(&b)?;
        w.end_record()
    }

    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static {
        Box::new(Record(self.0.iter().map(|v| v.value_clone()).collect()))
    }

    fn value_class(&self) -> ValueClass { ValueClass::Compound(CompoundClass::Record) }
    fn is_record(&self) -> bool { true }
    fn label(&self) -> &dyn Value<D> { &self.0[0] }
    fn len(&self) -> usize { self.0.len() - 1 }
    fn index(&self, i: usize) -> &dyn Value<D> { &self.0[i + 1] }
    fn iter(&self) -> Box<dyn Iterator<Item = &dyn Value<D>> + '_> {
        Box::new(self.0[1..].iter().map(value))
    }
}

impl<D: Domain, V: Value<D>> Value<D> for Vec<V> {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> {
        (&self[..]).write(w, enc)
    }

    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static {
        (&self[..]).value_clone()
    }

    fn value_class(&self) -> ValueClass { ValueClass::Compound(CompoundClass::Sequence) }
    fn is_sequence(&self) -> bool { true }
    fn len(&self) -> usize { self.len() }
    fn index(&self, i: usize) -> &dyn Value<D> { &self[i] }
    fn iter(&self) -> Box<dyn Iterator<Item = &dyn Value<D>> + '_> {
        Box::new(self[..].iter().map(value))
    }
}

impl<D: Domain, V: Value<D>> Value<D> for [V] {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> {
        w.start_sequence()?;
        let mut b = B::Type::default();
        for e in self {
            b.shift(Some(B::Item::SequenceValue));
            w.boundary(&b)?;
            e.write(w, enc)?;
        }
        b.shift(None);
        w.boundary(&b)?;
        w.end_sequence()
    }

    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static {
        Box::new(self.iter().map(|v| v.value_clone()).collect::<Vec<_>>())
    }

    fn value_class(&self) -> ValueClass { ValueClass::Compound(CompoundClass::Sequence) }
    fn is_sequence(&self) -> bool { true }
    fn len(&self) -> usize { self.len() }
    fn index(&self, i: usize) -> &dyn Value<D> { &self[i] }
    fn iter(&self) -> Box<dyn Iterator<Item = &dyn Value<D>> + '_> {
        Box::new(self[..].iter().map(value))
    }
}

impl<'e, D: Domain, E: for<'a> Borrow<Key<'a, D>> + Ord + 'e> Value<D> for Set<E> {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> {
        w.start_set()?;
        let mut b = B::Type::default();
        for e in self {
            b.shift(Some(B::Item::SetValue));
            w.boundary(&b)?;
            Key::peel_ref(e.borrow()).write(w, enc)?;
        }
        b.shift(None);
        w.boundary(&b)?;
        w.end_set()
    }

    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static {
        Box::new(self.iter().map(|v| Key::peel_ref(&v.borrow()).value_clone()).collect::<Set<_>>())
    }

    fn value_class(&self) -> ValueClass { ValueClass::Compound(CompoundClass::Set) }
    fn is_set(&self) -> bool { true }
    fn len(&self) -> usize { self.len() }
    fn has(&self, v: &dyn Value<D>) -> bool { self.contains(&Key::wrap_ref(v)) }
    fn iter(&self) -> Box<dyn Iterator<Item = &dyn Value<D>> + '_> {
        Box::new(self.iter().map(|e| Key::peel_ref(&e.borrow())))
    }
}

// Many thanks to SkiFire13 and the other participants in
// https://users.rust-lang.org/t/is-the-lifetime-of-a-btreemap-get-result-attached-to-the-key-as-well-as-the-map/83568/7
// for the idea of using TransparentWrapper here.
//
#[derive(PartialEq, Eq, PartialOrd, Ord)]
#[repr(transparent)]
pub struct Key<'a, D: Domain>(pub dyn Value<D> + 'a);
unsafe impl<'a, D: Domain> TransparentWrapper<dyn Value<D> + 'a> for Key<'a, D> {}

impl<'a, 'b: 'a, D: Domain> Borrow<Key<'a, D>> for PlainValue<'b, D> {
    fn borrow(&self) -> &Key<'a, D> {
        Key::wrap_ref(&**self)
    }
}

impl<'a, 'b: 'a, D: Domain> Borrow<Key<'a, D>> for &'b (dyn Value<D> + 'b) {
    fn borrow(&self) -> &Key<'a, D> {
        Key::wrap_ref(self)
    }
}

impl<'k, D: Domain, V: Value<D>, K: for<'a> Borrow<Key<'a, D>> + Ord + 'k> Value<D>
    for Map<K, V>
{
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> {
        w.start_dictionary()?;
        let mut b = B::Type::default();
        for (k, v) in self {
            b.shift(Some(B::Item::DictionaryKey));
            w.boundary(&b)?;
            Key::peel_ref(k.borrow()).write(w, enc)?;
            b.shift(Some(B::Item::DictionaryValue));
            w.boundary(&b)?;
            v.write(w, enc)?;
        }
        b.shift(None);
        w.boundary(&b)?;
        w.end_dictionary()
    }

    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static {
        Box::new(Value::entries(self).map(|(k, v)| (k.value_clone(), v.value_clone())).collect::<Map<_, _>>())
    }

    fn value_class(&self) -> ValueClass { ValueClass::Compound(CompoundClass::Dictionary) }
    fn is_dictionary(&self) -> bool { true }
    fn len(&self) -> usize { self.len() }
    fn has(&self, v: &dyn Value<D>) -> bool { self.contains_key(&Key::wrap_ref(v)) }
    fn get(&self, k: &dyn Value<D>) -> Option<&dyn Value<D>> {
        match Map::get(self, &Key::wrap_ref(k)) {
            Some(v) => Some(v),
            None => None,
        }
    }
    fn entries(&self) -> Box<dyn Iterator<Item = (&dyn Value<D>, &dyn Value<D>)> + '_> {
        Box::new(self.iter().map(|(k,v)| (Key::peel_ref(&k.borrow()), value(v))))
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
#[repr(transparent)]
pub struct Embedded<D: Domain>(D);

impl<D: Domain> Embedded<D> {
    pub fn new(d: D) -> Self {
        Embedded(d)
    }

    pub fn embedded_value(&self) -> &D {
        &self.0
    }

    pub fn into_embedded_value(self) -> D {
        self.0
    }
}

impl<D: Domain> Value<D> for Embedded<D> {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> {
        w.start_embedded()?;
        enc.encode_embedded(w, &self.0)?;
        w.end_embedded()
    }

    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static { Box::new(self.clone()) }
    fn value_class(&self) -> ValueClass { ValueClass::Embedded }
    fn is_embedded(&self) -> bool { true }
    fn embedded(&self) -> Cow<'_, D> { Cow::Borrowed(&self.0) }
}

#[derive(Debug)]
pub struct Annotations<D: Domain, V: Value<D>>(V, Vec<IOValue>, PhantomData<D>);

impl<D: Domain, V: Value<D>> Annotations<D, V> {
    pub fn new(value: V, anns: Vec<IOValue>) -> Self {
        Annotations(value, anns, PhantomData)
    }

    pub fn value(&self) -> &dyn Value<D> {
        &self.0
    }
}

impl<D: Domain, V: Value<D>> Value<D> for Annotations<D, V> {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> {
        if !self.1.is_empty() {
            w.start_annotations()?;
            let mut b = B::Type::default();
            for ann in &self.1 {
                b.shift(Some(B::Item::Annotation));
                w.boundary(&b)?;
                ann.write(w, &mut IOValueDomainCodec)?;
            }
            b.shift(Some(B::Item::AnnotatedValue));
            w.boundary(&b)?;
            self.0.write(w, enc)?;
            b.shift(None);
            w.boundary(&b)?;
            w.end_annotations()
        } else {
            self.0.write(w, enc)
        }
    }

    fn value_clone(&self) -> PlainValue<'static, D> where D: 'static {
        Box::new(Annotations(self.0.value_clone(),
                             self.1.iter().map(|v| v.value_clone().into()).collect(),
                             PhantomData))
    }

    fn value_class(&self) -> ValueClass { self.value().value_class() }
    fn as_boolean(&self) -> Option<bool> { self.value().as_boolean() }
    fn as_float(&self) -> Option<f32> { self.value().as_float() }
    fn as_double(&self) -> Option<f64> { self.value().as_double() }
    fn is_signed_integer(&self) -> bool { self.value().is_signed_integer() }
    fn as_signed_integer(&self) -> Option<SignedInteger> { self.value().as_signed_integer() }
    fn as_string(&self) -> Option<Cow<'_, str>> { self.value().as_string() }
    fn as_bytestring(&self) -> Option<Cow<'_, [u8]>> { self.value().as_bytestring() }
    fn as_symbol(&self) -> Option<Cow<'_, str>> { self.value().as_symbol() }
    fn is_record(&self) -> bool { self.value().is_record() }
    fn label(&self) -> &dyn Value<D> { self.value().label() }
    fn is_sequence(&self) -> bool { self.value().is_sequence() }
    fn len(&self) -> usize { self.value().len() }
    fn index(&self, i: usize) -> &dyn Value<D> { self.value().index(i) }
    fn iter(&self) -> Box<dyn Iterator<Item = &dyn Value<D>> + '_> { self.value().iter() }
    fn is_set(&self) -> bool { self.value().is_set() }
    fn has(&self, v: &dyn Value<D>) -> bool { self.value().has(v) }
    fn is_dictionary(&self) -> bool { self.value().is_dictionary() }
    fn get(&self, k: &dyn Value<D>) -> Option<&dyn Value<D>> { self.value().get(k) }
    fn entries(&self) -> Box<dyn Iterator<Item = (&dyn Value<D>, &dyn Value<D>)> + '_> { self.value().entries() }
    fn is_embedded(&self) -> bool { self.value().is_embedded() }
    fn embedded(&self) -> Cow<'_, D> { self.value().embedded() }
    fn annotations(&self) -> Option<&[IOValue]> { Some(&self.1) }
}

impl<D: Domain, V: Value<D>> PartialEq for Annotations<D, V> {
    fn eq(&self, other: &Self) -> bool {
        self.value().eq(&other.value())
    }
}

impl<D: Domain, V: Value<D>> Eq for Annotations<D, V> {}

impl<D: Domain, V: Value<D>> Hash for Annotations<D, V> {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.value().hash(state);
    }
}

impl<D: Domain, V: Value<D>> PartialOrd for Annotations<D, V> {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

impl<D: Domain, V: Value<D>> Ord for Annotations<D, V> {
    fn cmp(&self, other: &Self) -> Ordering {
        self.value().cmp(&other.value())
    }
}

#[derive(Clone, Eq, Hash, PartialOrd, Ord)]
#[repr(transparent)]
pub struct ArcValue<D: Domain + 'static = IOValue>(Arc<dyn Value<D>>);

#[derive(Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
#[repr(transparent)]
pub struct IOValue(ArcValue);

impl<D: Domain> Debug for ArcValue<D> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        value(self).fmt(f)
    }
}

impl Debug for IOValue {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        value(self).fmt(f)
    }
}

impl<D: Domain> PartialEq for ArcValue<D> {
    fn eq(&self, other: &Self) -> bool {
        &self.0 == &other.0
    }
}

impl<Err: Into<io::Error>, D: Domain + FromStr<Err = Err> + 'static> FromStr for ArcValue<D> {
    type Err = io::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        Ok(arcvalue(crate::annotated_from_str(s, &mut DefaultDomainCodec)?))
    }
}

impl FromStr for IOValue {
    type Err = io::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        crate::annotated_iovalue_from_str(s)
    }
}

impl<D: Domain> From<PlainValue<'static, D>> for ArcValue<D> {
    fn from(b: PlainValue<'static, D>) -> Self {
        ArcValue(Arc::from(b))
    }
}

impl From<PlainValue<'static, IOValue>> for IOValue {
    fn from(b: PlainValue<'static, IOValue>) -> Self {
        IOValue(b.into())
    }
}

impl From<ArcValue<IOValue>> for IOValue {
    fn from(b: ArcValue<IOValue>) -> Self {
        IOValue(b)
    }
}

impl<'a> Borrow<Key<'a, IOValue>> for IOValue {
    fn borrow(&self) -> &Key<'a, IOValue> {
        Key::wrap_ref(&*self.0.0)
    }
}

impl<'a, D: Domain> Borrow<Key<'a, D>> for ArcValue<D> {
    fn borrow(&self) -> &Key<'a, D> {
        Key::wrap_ref(&*self.0)
    }
}

impl<D: Domain> Value<D> for ArcValue<D> {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<D>) -> io::Result<()> { self.0.write(w, enc) }
    fn value_clone(&self) -> PlainValue<'static, D> { Box::new(self.clone()) }
    fn value_class(&self) -> ValueClass { self.0.value_class() }
    fn as_boolean(&self) -> Option<bool> { self.0.as_boolean() }
    fn as_float(&self) -> Option<f32> { self.0.as_float() }
    fn as_double(&self) -> Option<f64> { self.0.as_double() }
    fn is_signed_integer(&self) -> bool { self.0.is_signed_integer() }
    fn as_signed_integer(&self) -> Option<SignedInteger> { self.0.as_signed_integer() }
    fn as_string(&self) -> Option<Cow<'_, str>> { self.0.as_string() }
    fn as_bytestring(&self) -> Option<Cow<'_, [u8]>> { self.0.as_bytestring() }
    fn as_symbol(&self) -> Option<Cow<'_, str>> { self.0.as_symbol() }
    fn is_record(&self) -> bool { self.0.is_record() }
    fn label(&self) -> &dyn Value<D> { self.0.label() }
    fn is_sequence(&self) -> bool { self.0.is_sequence() }
    fn len(&self) -> usize { self.0.len() }
    fn index(&self, i: usize) -> &dyn Value<D> { self.0.index(i) }
    fn iter(&self) -> Box<dyn Iterator<Item = &dyn Value<D>> + '_> { self.0.iter() }
    fn is_set(&self) -> bool { self.0.is_set() }
    fn has(&self, v: &dyn Value<D>) -> bool { self.0.has(v) }
    fn is_dictionary(&self) -> bool { self.0.is_dictionary() }
    fn get<'value>(&'value self, k: &dyn Value<D>) -> Option<&'value dyn Value<D>> { self.0.get(k) }
    fn entries(&self) -> Box<dyn Iterator<Item = (&dyn Value<D>, &dyn Value<D>)> + '_> { self.0.entries() }
    fn is_embedded(&self) -> bool { self.0.is_embedded() }
    fn embedded(&self) -> Cow<'_, D> { self.0.embedded() }
    fn annotations(&self) -> Option<&[IOValue]> { self.0.annotations() }
}

impl Value<IOValue> for IOValue {
    fn write(&self, w: &mut dyn Writer, enc: &mut dyn DomainEncode<IOValue>) -> io::Result<()> { self.0.write(w, enc) }
    fn value_clone(&self) -> PlainValue<'static, IOValue> { Box::new(self.clone()) }
    fn value_class(&self) -> ValueClass { self.0.value_class() }
    fn as_boolean(&self) -> Option<bool> { self.0.as_boolean() }
    fn as_float(&self) -> Option<f32> { self.0.as_float() }
    fn as_double(&self) -> Option<f64> { self.0.as_double() }
    fn is_signed_integer(&self) -> bool { self.0.is_signed_integer() }
    fn as_signed_integer(&self) -> Option<SignedInteger> { self.0.as_signed_integer() }
    fn as_string(&self) -> Option<Cow<'_, str>> { self.0.as_string() }
    fn as_bytestring(&self) -> Option<Cow<'_, [u8]>> { self.0.as_bytestring() }
    fn as_symbol(&self) -> Option<Cow<'_, str>> { self.0.as_symbol() }
    fn is_record(&self) -> bool { self.0.is_record() }
    fn label(&self) -> &dyn Value<IOValue> { self.0.label() }
    fn is_sequence(&self) -> bool { self.0.is_sequence() }
    fn len(&self) -> usize { self.0.len() }
    fn index(&self, i: usize) -> &dyn Value<IOValue> { self.0.index(i) }
    fn iter(&self) -> Box<dyn Iterator<Item = &dyn Value<IOValue>> + '_> { self.0.iter() }
    fn is_set(&self) -> bool { self.0.is_set() }
    fn has(&self, v: &dyn Value<IOValue>) -> bool { self.0.has(v) }
    fn is_dictionary(&self) -> bool { self.0.is_dictionary() }
    fn get<'value>(&'value self, k: &dyn Value<IOValue>) -> Option<&'value dyn Value<IOValue>> { self.0.get(k) }
    fn entries(&self) -> Box<dyn Iterator<Item = (&dyn Value<IOValue>, &dyn Value<IOValue>)> + '_> { self.0.entries() }
    fn is_embedded(&self) -> bool { self.0.is_embedded() }
    fn embedded(&self) -> Cow<'_, IOValue> { self.0.embedded() }
    fn annotations(&self) -> Option<&[IOValue]> { self.0.annotations() }
}