use std::collections::HashMap;
use std::iter::FromIterator;
use async_trait::async_trait;
use destream::en;
use futures::stream::{self, StreamExt, TryStreamExt};
use futures::TryFutureExt;
use tc_error::*;
use tc_transact::IntoView;
use tcgeneric::Id;
use crate::chain::ChainView;
use crate::fs;
use crate::object::ObjectView;
use crate::scalar::Scalar;
use crate::txn::Txn;
use super::State;
pub enum StateView {
Chain(ChainView),
Map(HashMap<Id, StateView>),
Object(Box<ObjectView>),
Scalar(Scalar),
Tuple(Vec<StateView>),
}
#[async_trait]
impl<'en> IntoView<'en, fs::Dir> for State {
type Txn = Txn;
type View = StateView;
async fn into_view(self, txn: Self::Txn) -> TCResult<Self::View> {
match self {
Self::Chain(chain) => chain.into_view(txn).map_ok(StateView::Chain).await,
Self::Map(map) => {
let map_view = stream::iter(map.into_iter())
.then(|(key, state)| state.into_view(txn.clone()).map_ok(|view| (key, view)))
.try_collect::<Vec<(Id, StateView)>>()
.await?;
Ok(StateView::Map(HashMap::from_iter(map_view)))
}
Self::Object(object) => {
object
.into_view(txn)
.map_ok(Box::new)
.map_ok(StateView::Object)
.await
}
Self::Scalar(scalar) => Ok(StateView::Scalar(scalar)),
Self::Tuple(tuple) => {
let tuple_view = stream::iter(tuple.into_iter())
.then(|state| state.into_view(txn.clone()))
.try_collect::<Vec<StateView>>()
.await?;
Ok(StateView::Tuple(tuple_view.into()))
}
}
}
}
impl<'en> en::IntoStream<'en> for StateView {
fn into_stream<E: en::Encoder<'en>>(self, encoder: E) -> Result<E::Ok, E::Error> {
match self {
StateView::Chain(chain) => chain.into_stream(encoder),
StateView::Map(map) => map.into_stream(encoder),
StateView::Object(object) => object.into_stream(encoder),
StateView::Scalar(scalar) => scalar.into_stream(encoder),
StateView::Tuple(tuple) => tuple.into_stream(encoder),
}
}
}