// This file is part of Substrate.

// Copyright (C) 2017-2022 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

//! Configuration of the networking layer.

use libp2p::{multiaddr, Multiaddr, PeerId};
use std::{fmt, str, str::FromStr};

/// Protocol name prefix, transmitted on the wire for legacy protocol names.
/// I.e., `dot` in `/dot/sync/2`. Should be unique for each chain. Always UTF-8.
/// Deprecated in favour of genesis hash & fork ID based protocol names.
#[derive(Clone, PartialEq, Eq, Hash)]
pub struct ProtocolId(smallvec::SmallVec<[u8; 6]>);

impl<'a> From<&'a str> for ProtocolId {
	fn from(bytes: &'a str) -> ProtocolId {
		Self(bytes.as_bytes().into())
	}
}

impl AsRef<str> for ProtocolId {
	fn as_ref(&self) -> &str {
		str::from_utf8(&self.0[..])
			.expect("the only way to build a ProtocolId is through a UTF-8 String; qed")
	}
}

impl fmt::Debug for ProtocolId {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		fmt::Debug::fmt(self.as_ref(), f)
	}
}

/// Parses a string address and splits it into Multiaddress and PeerId, if
/// valid.
///
/// # Example
///
/// ```
/// # use libp2p::{Multiaddr, PeerId};
/// # use sc_network_common::config::parse_str_addr;
/// let (peer_id, addr) = parse_str_addr(
/// 	"/ip4/198.51.100.19/tcp/30333/p2p/QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV"
/// ).unwrap();
/// assert_eq!(peer_id, "QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV".parse::<PeerId>().unwrap());
/// assert_eq!(addr, "/ip4/198.51.100.19/tcp/30333".parse::<Multiaddr>().unwrap());
/// ```
pub fn parse_str_addr(addr_str: &str) -> Result<(PeerId, Multiaddr), ParseErr> {
	let addr: Multiaddr = addr_str.parse()?;
	parse_addr(addr)
}

/// Splits a Multiaddress into a Multiaddress and PeerId.
pub fn parse_addr(mut addr: Multiaddr) -> Result<(PeerId, Multiaddr), ParseErr> {
	let who = match addr.pop() {
		Some(multiaddr::Protocol::P2p(key)) =>
			PeerId::from_multihash(key).map_err(|_| ParseErr::InvalidPeerId)?,
		_ => return Err(ParseErr::PeerIdMissing),
	};

	Ok((who, addr))
}

/// Address of a node, including its identity.
///
/// This struct represents a decoded version of a multiaddress that ends with `/p2p/<peerid>`.
///
/// # Example
///
/// ```
/// # use libp2p::{Multiaddr, PeerId};
/// # use sc_network_common::config::MultiaddrWithPeerId;
/// let addr: MultiaddrWithPeerId =
/// 	"/ip4/198.51.100.19/tcp/30333/p2p/QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV".parse().unwrap();
/// assert_eq!(addr.peer_id.to_base58(), "QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV");
/// assert_eq!(addr.multiaddr.to_string(), "/ip4/198.51.100.19/tcp/30333");
/// ```
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize, PartialEq)]
#[serde(try_from = "String", into = "String")]
pub struct MultiaddrWithPeerId {
	/// Address of the node.
	pub multiaddr: Multiaddr,
	/// Its identity.
	pub peer_id: PeerId,
}

impl MultiaddrWithPeerId {
	/// Concatenates the multiaddress and peer ID into one multiaddress containing both.
	pub fn concat(&self) -> Multiaddr {
		let proto = multiaddr::Protocol::P2p(From::from(self.peer_id));
		self.multiaddr.clone().with(proto)
	}
}

impl fmt::Display for MultiaddrWithPeerId {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		fmt::Display::fmt(&self.concat(), f)
	}
}

impl FromStr for MultiaddrWithPeerId {
	type Err = ParseErr;

	fn from_str(s: &str) -> Result<Self, Self::Err> {
		let (peer_id, multiaddr) = parse_str_addr(s)?;
		Ok(Self { peer_id, multiaddr })
	}
}

impl From<MultiaddrWithPeerId> for String {
	fn from(ma: MultiaddrWithPeerId) -> String {
		format!("{}", ma)
	}
}

impl TryFrom<String> for MultiaddrWithPeerId {
	type Error = ParseErr;
	fn try_from(string: String) -> Result<Self, Self::Error> {
		string.parse()
	}
}

/// Error that can be generated by `parse_str_addr`.
#[derive(Debug)]
pub enum ParseErr {
	/// Error while parsing the multiaddress.
	MultiaddrParse(multiaddr::Error),
	/// Multihash of the peer ID is invalid.
	InvalidPeerId,
	/// The peer ID is missing from the address.
	PeerIdMissing,
}

impl fmt::Display for ParseErr {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		match self {
			Self::MultiaddrParse(err) => write!(f, "{}", err),
			Self::InvalidPeerId => write!(f, "Peer id at the end of the address is invalid"),
			Self::PeerIdMissing => write!(f, "Peer id is missing from the address"),
		}
	}
}

impl std::error::Error for ParseErr {
	fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
		match self {
			Self::MultiaddrParse(err) => Some(err),
			Self::InvalidPeerId => None,
			Self::PeerIdMissing => None,
		}
	}
}

impl From<multiaddr::Error> for ParseErr {
	fn from(err: multiaddr::Error) -> ParseErr {
		Self::MultiaddrParse(err)
	}
}