//! Implementations of serialization for structures found in liballoc

use std::hash::{Hash, BuildHasher};

use crate::{Decodable, Encodable, Decoder, Encoder};
use std::collections::{LinkedList, VecDeque, BTreeMap, BTreeSet, HashMap, HashSet};
use std::rc::Rc;
use std::sync::Arc;

use smallvec::{Array, SmallVec};

impl<A> Encodable for SmallVec<A>
    where A: Array,
          A::Item: Encodable
{
    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
        s.emit_seq(self.len(), |s| {
            for (i, e) in self.iter().enumerate() {
                s.emit_seq_elt(i, |s| e.encode(s))?;
            }
            Ok(())
        })
    }
}

impl<A> Decodable for SmallVec<A>
    where A: Array,
          A::Item: Decodable
{
    fn decode<D: Decoder>(d: &mut D) -> Result<SmallVec<A>, D::Error> {
        d.read_seq(|d, len| {
            let mut vec = SmallVec::with_capacity(len);
            // FIXME(#48994) - could just be collected into a Result<SmallVec, D::Error>
            for i in 0..len {
                vec.push(d.read_seq_elt(i, |d| Decodable::decode(d))?);
            }
            Ok(vec)
        })
    }
}

impl<T: Encodable> Encodable for LinkedList<T> {
    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
        s.emit_seq(self.len(), |s| {
            for (i, e) in self.iter().enumerate() {
                s.emit_seq_elt(i, |s| e.encode(s))?;
            }
            Ok(())
        })
    }
}

impl<T:Decodable> Decodable for LinkedList<T> {
    fn decode<D: Decoder>(d: &mut D) -> Result<LinkedList<T>, D::Error> {
        d.read_seq(|d, len| {
            let mut list = LinkedList::new();
            for i in 0..len {
                list.push_back(d.read_seq_elt(i, |d| Decodable::decode(d))?);
            }
            Ok(list)
        })
    }
}

impl<T: Encodable> Encodable for VecDeque<T> {
    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
        s.emit_seq(self.len(), |s| {
            for (i, e) in self.iter().enumerate() {
                s.emit_seq_elt(i, |s| e.encode(s))?;
            }
            Ok(())
        })
    }
}

impl<T:Decodable> Decodable for VecDeque<T> {
    fn decode<D: Decoder>(d: &mut D) -> Result<VecDeque<T>, D::Error> {
        d.read_seq(|d, len| {
            let mut deque: VecDeque<T> = VecDeque::with_capacity(len);
            for i in 0..len {
                deque.push_back(d.read_seq_elt(i, |d| Decodable::decode(d))?);
            }
            Ok(deque)
        })
    }
}

impl<K, V> Encodable for BTreeMap<K, V>
    where K: Encodable + PartialEq + Ord,
          V: Encodable
{
    fn encode<S: Encoder>(&self, e: &mut S) -> Result<(), S::Error> {
        e.emit_map(self.len(), |e| {
            let mut i = 0;
            for (key, val) in self {
                e.emit_map_elt_key(i, |e| key.encode(e))?;
                e.emit_map_elt_val(i, |e| val.encode(e))?;
                i += 1;
            }
            Ok(())
        })
    }
}

impl<K, V> Decodable for BTreeMap<K, V>
    where K: Decodable + PartialEq + Ord,
          V: Decodable
{
    fn decode<D: Decoder>(d: &mut D) -> Result<BTreeMap<K, V>, D::Error> {
        d.read_map(|d, len| {
            let mut map = BTreeMap::new();
            for i in 0..len {
                let key = d.read_map_elt_key(i, |d| Decodable::decode(d))?;
                let val = d.read_map_elt_val(i, |d| Decodable::decode(d))?;
                map.insert(key, val);
            }
            Ok(map)
        })
    }
}

impl<T> Encodable for BTreeSet<T>
    where T: Encodable + PartialEq + Ord
{
    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
        s.emit_seq(self.len(), |s| {
            let mut i = 0;
            for e in self {
                s.emit_seq_elt(i, |s| e.encode(s))?;
                i += 1;
            }
            Ok(())
        })
    }
}

impl<T> Decodable for BTreeSet<T>
    where T: Decodable + PartialEq + Ord
{
    fn decode<D: Decoder>(d: &mut D) -> Result<BTreeSet<T>, D::Error> {
        d.read_seq(|d, len| {
            let mut set = BTreeSet::new();
            for i in 0..len {
                set.insert(d.read_seq_elt(i, |d| Decodable::decode(d))?);
            }
            Ok(set)
        })
    }
}

impl<K, V, S> Encodable for HashMap<K, V, S>
    where K: Encodable + Hash + Eq,
          V: Encodable,
          S: BuildHasher,
{
    fn encode<E: Encoder>(&self, e: &mut E) -> Result<(), E::Error> {
        e.emit_map(self.len(), |e| {
            let mut i = 0;
            for (key, val) in self {
                e.emit_map_elt_key(i, |e| key.encode(e))?;
                e.emit_map_elt_val(i, |e| val.encode(e))?;
                i += 1;
            }
            Ok(())
        })
    }
}

impl<K, V, S> Decodable for HashMap<K, V, S>
    where K: Decodable + Hash + Eq,
          V: Decodable,
          S: BuildHasher + Default,
{
    fn decode<D: Decoder>(d: &mut D) -> Result<HashMap<K, V, S>, D::Error> {
        d.read_map(|d, len| {
            let state = Default::default();
            let mut map = HashMap::with_capacity_and_hasher(len, state);
            for i in 0..len {
                let key = d.read_map_elt_key(i, |d| Decodable::decode(d))?;
                let val = d.read_map_elt_val(i, |d| Decodable::decode(d))?;
                map.insert(key, val);
            }
            Ok(map)
        })
    }
}

impl<T, S> Encodable for HashSet<T, S>
    where T: Encodable + Hash + Eq,
          S: BuildHasher,
{
    fn encode<E: Encoder>(&self, s: &mut E) -> Result<(), E::Error> {
        s.emit_seq(self.len(), |s| {
            let mut i = 0;
            for e in self {
                s.emit_seq_elt(i, |s| e.encode(s))?;
                i += 1;
            }
            Ok(())
        })
    }
}

impl<T, S> Decodable for HashSet<T, S>
    where T: Decodable + Hash + Eq,
          S: BuildHasher + Default,
{
    fn decode<D: Decoder>(d: &mut D) -> Result<HashSet<T, S>, D::Error> {
        d.read_seq(|d, len| {
            let state = Default::default();
            let mut set = HashSet::with_capacity_and_hasher(len, state);
            for i in 0..len {
                set.insert(d.read_seq_elt(i, |d| Decodable::decode(d))?);
            }
            Ok(set)
        })
    }
}

impl<T: Encodable> Encodable for Rc<[T]> {
    fn encode<E: Encoder>(&self, s: &mut E) -> Result<(), E::Error> {
        s.emit_seq(self.len(), |s| {
            for (index, e) in self.iter().enumerate() {
                s.emit_seq_elt(index, |s| e.encode(s))?;
            }
            Ok(())
        })
    }
}

impl<T: Decodable> Decodable for Rc<[T]> {
    fn decode<D: Decoder>(d: &mut D) -> Result<Rc<[T]>, D::Error> {
        d.read_seq(|d, len| {
            let mut vec = Vec::with_capacity(len);
            for index in 0..len {
                vec.push(d.read_seq_elt(index, |d| Decodable::decode(d))?);
            }
            Ok(vec.into())
        })
    }
}

impl<T: Encodable> Encodable for Arc<[T]> {
    fn encode<E: Encoder>(&self, s: &mut E) -> Result<(), E::Error> {
        s.emit_seq(self.len(), |s| {
            for (index, e) in self.iter().enumerate() {
                s.emit_seq_elt(index, |s| e.encode(s))?;
            }
            Ok(())
        })
    }
}

impl<T: Decodable> Decodable for Arc<[T]> {
    fn decode<D: Decoder>(d: &mut D) -> Result<Arc<[T]>, D::Error> {
        d.read_seq(|d, len| {
            let mut vec = Vec::with_capacity(len);
            for index in 0..len {
                vec.push(d.read_seq_elt(index, |d| Decodable::decode(d))?);
            }
            Ok(vec.into())
        })
    }
}