// Copyright 2018 Parity Technologies (UK) Ltd.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

use futures::prelude::*;
use crate::upgrade::{InboundUpgrade, OutboundUpgrade, UpgradeInfo};

/// Wraps around an upgrade and applies a closure to the output.
#[derive(Debug, Clone)]
pub struct MapUpgrade<U, F> { upgrade: U, fun: F }

impl<U, F> MapUpgrade<U, F> {
    pub fn new(upgrade: U, fun: F) -> Self {
        MapUpgrade { upgrade, fun }
    }
}

impl<U, F> UpgradeInfo for MapUpgrade<U, F>
where
    U: UpgradeInfo
{
    type UpgradeId = U::UpgradeId;
    type NamesIter = U::NamesIter;

    fn protocol_names(&self) -> Self::NamesIter {
        self.upgrade.protocol_names()
    }
}

impl<C, U, F, T> InboundUpgrade<C> for MapUpgrade<U, F>
where
    U: InboundUpgrade<C>,
    F: FnOnce(U::Output) -> T
{
    type Output = T;
    type Error = U::Error;
    type Future = MapFuture<U::Future, F>;

    fn upgrade_inbound(self, sock: C, id: Self::UpgradeId) -> Self::Future {
        MapFuture {
            inner: self.upgrade.upgrade_inbound(sock, id),
            map: Some(self.fun)
        }
    }
}

impl<C, U, F, T> OutboundUpgrade<C> for MapUpgrade<U, F>
where
    U: OutboundUpgrade<C>,
    F: FnOnce(U::Output) -> T
{
    type Output = T;
    type Error = U::Error;
    type Future = MapFuture<U::Future, F>;

    fn upgrade_outbound(self, sock: C, id: Self::UpgradeId) -> Self::Future {
        MapFuture {
            inner: self.upgrade.upgrade_outbound(sock, id),
            map: Some(self.fun)
        }
    }
}

/// Wraps around an upgrade and applies a closure to the error.
#[derive(Debug, Clone)]
pub struct MapUpgradeErr<U, F> { upgrade: U, fun: F }

impl<U, F> MapUpgradeErr<U, F> {
    pub fn new(upgrade: U, fun: F) -> Self {
        MapUpgradeErr { upgrade, fun }
    }
}

impl<U, F> UpgradeInfo for MapUpgradeErr<U, F>
where
    U: UpgradeInfo
{
    type UpgradeId = U::UpgradeId;
    type NamesIter = U::NamesIter;

    fn protocol_names(&self) -> Self::NamesIter {
        self.upgrade.protocol_names()
    }
}

impl<C, U, F, T> InboundUpgrade<C> for MapUpgradeErr<U, F>
where
    U: InboundUpgrade<C>,
    F: FnOnce(U::Error) -> T
{
    type Output = U::Output;
    type Error = T;
    type Future = MapErrFuture<U::Future, F>;

    fn upgrade_inbound(self, sock: C, id: Self::UpgradeId) -> Self::Future {
        MapErrFuture {
            fut: self.upgrade.upgrade_inbound(sock, id),
            fun: Some(self.fun)
        }
    }
}

impl<C, U, F, T> OutboundUpgrade<C> for MapUpgradeErr<U, F>
where
    U: OutboundUpgrade<C>,
    F: FnOnce(U::Error) -> T,
{
    type Output = U::Output;
    type Error = T;
    type Future = MapErrFuture<U::Future, F>;

    fn upgrade_outbound(self, sock: C, id: Self::UpgradeId) -> Self::Future {
        MapErrFuture {
            fut: self.upgrade.upgrade_outbound(sock, id),
            fun: Some(self.fun)
        }
    }
}

pub struct MapFuture<TInnerFut, TMap> {
    inner: TInnerFut,
    map: Option<TMap>,
}

impl<TInnerFut, TIn, TMap, TOut> Future for MapFuture<TInnerFut, TMap>
where
    TInnerFut: Future<Item = TIn>,
    TMap: FnOnce(TIn) -> TOut,
{
    type Item = TOut;
    type Error = TInnerFut::Error;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        let item = try_ready!(self.inner.poll());
        let map = self.map.take().expect("Future has already finished");
        Ok(Async::Ready(map(item)))
    }
}

pub struct MapErrFuture<T, F> {
    fut: T,
    fun: Option<F>,
}

impl<T, E, F, A> Future for MapErrFuture<T, F>
where
    T: Future<Error = E>,
    F: FnOnce(E) -> A,
{
    type Item = T::Item;
    type Error = A;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        match self.fut.poll() {
            Ok(Async::NotReady) => Ok(Async::NotReady),
            Ok(Async::Ready(x)) => Ok(Async::Ready(x)),
            Err(e) => {
                let f = self.fun.take().expect("Future has not resolved yet");
                Err(f(e))
            }
        }
    }
}