// This file is part of Substrate.

// Copyright (C) 2017-2020 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/>.

//! Network packet message types. These get serialized and put into the lower level protocol payload.

use bitflags::bitflags;
use sp_runtime::{ConsensusEngineId, traits::{Block as BlockT, Header as HeaderT}};
use codec::{Encode, Decode, Input, Output, Error};
pub use self::generic::{
	BlockAnnounce, RemoteCallRequest, RemoteReadRequest,
	RemoteHeaderRequest, RemoteHeaderResponse,
	RemoteChangesRequest, RemoteChangesResponse,
	FinalityProofRequest, FinalityProofResponse,
	FromBlock, RemoteReadChildRequest, Roles,
};
use sc_client_api::StorageProof;

/// A unique ID of a request.
pub type RequestId = u64;

/// Type alias for using the message type using block type parameters.
pub type Message<B> = generic::Message<
	<B as BlockT>::Header,
	<B as BlockT>::Hash,
	<<B as BlockT>::Header as HeaderT>::Number,
	<B as BlockT>::Extrinsic,
>;

/// Type alias for using the status type using block type parameters.
pub type Status<B> = generic::Status<
	<B as BlockT>::Hash,
	<<B as BlockT>::Header as HeaderT>::Number,
>;

/// Type alias for using the block request type using block type parameters.
pub type BlockRequest<B> = generic::BlockRequest<
	<B as BlockT>::Hash,
	<<B as BlockT>::Header as HeaderT>::Number,
>;

/// Type alias for using the BlockData type using block type parameters.
pub type BlockData<B> = generic::BlockData<
	<B as BlockT>::Header,
	<B as BlockT>::Hash,
	<B as BlockT>::Extrinsic,
>;

/// Type alias for using the BlockResponse type using block type parameters.
pub type BlockResponse<B> = generic::BlockResponse<
	<B as BlockT>::Header,
	<B as BlockT>::Hash,
	<B as BlockT>::Extrinsic,
>;

/// A set of transactions.
pub type Transactions<E> = Vec<E>;

// Bits of block data and associated artifacts to request.
bitflags! {
	/// Node roles bitmask.
	pub struct BlockAttributes: u8 {
		/// Include block header.
		const HEADER = 0b00000001;
		/// Include block body.
		const BODY = 0b00000010;
		/// Include block receipt.
		const RECEIPT = 0b00000100;
		/// Include block message queue.
		const MESSAGE_QUEUE = 0b00001000;
		/// Include a justification for the block.
		const JUSTIFICATION = 0b00010000;
	}
}

impl BlockAttributes {
	/// Encodes attributes as big endian u32, compatible with SCALE-encoding (i.e the
	/// significant byte has zero index).
	pub fn to_be_u32(&self) -> u32 {
		u32::from_be_bytes([self.bits(), 0, 0, 0])
	}

	/// Decodes attributes, encoded with the `encode_to_be_u32()` call.
	pub fn from_be_u32(encoded: u32) -> Result<Self, Error> {
		BlockAttributes::from_bits(encoded.to_be_bytes()[0])
			.ok_or_else(|| Error::from("Invalid BlockAttributes"))
	}
}

impl Encode for BlockAttributes {
	fn encode_to<T: Output>(&self, dest: &mut T) {
		dest.push_byte(self.bits())
	}
}

impl codec::EncodeLike for BlockAttributes {}

impl Decode for BlockAttributes {
	fn decode<I: Input>(input: &mut I) -> Result<Self, Error> {
		Self::from_bits(input.read_byte()?).ok_or_else(|| Error::from("Invalid bytes"))
	}
}

#[derive(Debug, PartialEq, Eq, Clone, Copy, Encode, Decode)]
/// Block enumeration direction.
pub enum Direction {
	/// Enumerate in ascending order (from child to parent).
	Ascending = 0,
	/// Enumerate in descending order (from parent to canonical child).
	Descending = 1,
}

/// Block state in the chain.
#[derive(Debug, PartialEq, Eq, Clone, Copy, Encode, Decode)]
pub enum BlockState {
	/// Block is not part of the best chain.
	Normal,
	/// Latest best block.
	Best,
}

/// Remote call response.
#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
pub struct RemoteCallResponse {
	/// Id of a request this response was made for.
	pub id: RequestId,
	/// Execution proof.
	pub proof: StorageProof,
}

#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
/// Remote read response.
pub struct RemoteReadResponse {
	/// Id of a request this response was made for.
	pub id: RequestId,
	/// Read proof.
	pub proof: StorageProof,
}

/// Generic types.
pub mod generic {
	use bitflags::bitflags;
	use codec::{Encode, Decode, Input, Output};
	use sp_runtime::Justification;
	use super::{
		RemoteReadResponse, Transactions, Direction,
		RequestId, BlockAttributes, RemoteCallResponse, ConsensusEngineId,
		BlockState, StorageProof,
	};

	bitflags! {
		/// Bitmask of the roles that a node fulfills.
		pub struct Roles: u8 {
			/// No network.
			const NONE = 0b00000000;
			/// Full node, does not participate in consensus.
			const FULL = 0b00000001;
			/// Light client node.
			const LIGHT = 0b00000010;
			/// Act as an authority
			const AUTHORITY = 0b00000100;
		}
	}

	impl Roles {
		/// Does this role represents a client that holds full chain data locally?
		pub fn is_full(&self) -> bool {
			self.intersects(Roles::FULL | Roles::AUTHORITY)
		}

		/// Does this role represents a client that does not participates in the consensus?
		pub fn is_authority(&self) -> bool {
			*self == Roles::AUTHORITY
		}

		/// Does this role represents a client that does not hold full chain data locally?
		pub fn is_light(&self) -> bool {
			!self.is_full()
		}
	}

	impl<'a> From<&'a crate::config::Role> for Roles {
		fn from(roles: &'a crate::config::Role) -> Self {
			match roles {
				crate::config::Role::Full => Roles::FULL,
				crate::config::Role::Light => Roles::LIGHT,
				crate::config::Role::Sentry { .. } => Roles::AUTHORITY,
				crate::config::Role::Authority { .. } => Roles::AUTHORITY,
			}
		}
	}

	impl codec::Encode for Roles {
		fn encode_to<T: codec::Output>(&self, dest: &mut T) {
			dest.push_byte(self.bits())
		}
	}

	impl codec::EncodeLike for Roles {}

	impl codec::Decode for Roles {
		fn decode<I: codec::Input>(input: &mut I) -> Result<Self, codec::Error> {
			Self::from_bits(input.read_byte()?).ok_or_else(|| codec::Error::from("Invalid bytes"))
		}
	}

	/// Consensus is mostly opaque to us
	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	pub struct ConsensusMessage {
		/// Identifies consensus engine.
		pub engine_id: ConsensusEngineId,
		/// Message payload.
		pub data: Vec<u8>,
	}

	/// Block data sent in the response.
	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	pub struct BlockData<Header, Hash, Extrinsic> {
		/// Block header hash.
		pub hash: Hash,
		/// Block header if requested.
		pub header: Option<Header>,
		/// Block body if requested.
		pub body: Option<Vec<Extrinsic>>,
		/// Block receipt if requested.
		pub receipt: Option<Vec<u8>>,
		/// Block message queue if requested.
		pub message_queue: Option<Vec<u8>>,
		/// Justification if requested.
		pub justification: Option<Justification>,
	}

	/// Identifies starting point of a block sequence.
	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	pub enum FromBlock<Hash, Number> {
		/// Start with given hash.
		Hash(Hash),
		/// Start with given block number.
		Number(Number),
	}

	/// A network message.
	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	pub enum Message<Header, Hash, Number, Extrinsic> {
		/// Status packet.
		Status(Status<Hash, Number>),
		/// Block request.
		BlockRequest(BlockRequest<Hash, Number>),
		/// Block response.
		BlockResponse(BlockResponse<Header, Hash, Extrinsic>),
		/// Block announce.
		BlockAnnounce(BlockAnnounce<Header>),
		/// Transactions.
		Transactions(Transactions<Extrinsic>),
		/// Consensus protocol message.
		Consensus(ConsensusMessage),
		/// Remote method call request.
		RemoteCallRequest(RemoteCallRequest<Hash>),
		/// Remote method call response.
		RemoteCallResponse(RemoteCallResponse),
		/// Remote storage read request.
		RemoteReadRequest(RemoteReadRequest<Hash>),
		/// Remote storage read response.
		RemoteReadResponse(RemoteReadResponse),
		/// Remote header request.
		RemoteHeaderRequest(RemoteHeaderRequest<Number>),
		/// Remote header response.
		RemoteHeaderResponse(RemoteHeaderResponse<Header>),
		/// Remote changes request.
		RemoteChangesRequest(RemoteChangesRequest<Hash>),
		/// Remote changes response.
		RemoteChangesResponse(RemoteChangesResponse<Number, Hash>),
		/// Remote child storage read request.
		RemoteReadChildRequest(RemoteReadChildRequest<Hash>),
		/// Finality proof request.
		FinalityProofRequest(FinalityProofRequest<Hash>),
		/// Finality proof response.
		FinalityProofResponse(FinalityProofResponse<Hash>),
		/// Batch of consensus protocol messages.
		ConsensusBatch(Vec<ConsensusMessage>),
	}

	impl<Header, Hash, Number, Extrinsic> Message<Header, Hash, Number, Extrinsic> {
		/// Message id useful for logging.
		pub fn id(&self) -> &'static str {
			match self {
				Message::Status(_) => "Status",
				Message::BlockRequest(_) => "BlockRequest",
				Message::BlockResponse(_) => "BlockResponse",
				Message::BlockAnnounce(_) => "BlockAnnounce",
				Message::Transactions(_) => "Transactions",
				Message::Consensus(_) => "Consensus",
				Message::RemoteCallRequest(_) => "RemoteCallRequest",
				Message::RemoteCallResponse(_) => "RemoteCallResponse",
				Message::RemoteReadRequest(_) => "RemoteReadRequest",
				Message::RemoteReadResponse(_) => "RemoteReadResponse",
				Message::RemoteHeaderRequest(_) => "RemoteHeaderRequest",
				Message::RemoteHeaderResponse(_) => "RemoteHeaderResponse",
				Message::RemoteChangesRequest(_) => "RemoteChangesRequest",
				Message::RemoteChangesResponse(_) => "RemoteChangesResponse",
				Message::RemoteReadChildRequest(_) => "RemoteReadChildRequest",
				Message::FinalityProofRequest(_) => "FinalityProofRequest",
				Message::FinalityProofResponse(_) => "FinalityProofResponse",
				Message::ConsensusBatch(_) => "ConsensusBatch",
			}
		}
	}

	/// Status sent on connection.
	// TODO https://github.com/paritytech/substrate/issues/4674: replace the `Status`
	// struct with this one, after waiting a few releases beyond `NetworkSpecialization`'s
	// removal (https://github.com/paritytech/substrate/pull/4665)
	//
	// and set MIN_VERSION to 6.
	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	pub struct CompactStatus<Hash, Number> {
		/// Protocol version.
		pub version: u32,
		/// Minimum supported version.
		pub min_supported_version: u32,
		/// Supported roles.
		pub roles: Roles,
		/// Best block number.
		pub best_number: Number,
		/// Best block hash.
		pub best_hash: Hash,
		/// Genesis block hash.
		pub genesis_hash: Hash,
	}

	/// Status sent on connection.
	#[derive(Debug, PartialEq, Eq, Clone, Encode)]
	pub struct Status<Hash, Number> {
		/// Protocol version.
		pub version: u32,
		/// Minimum supported version.
		pub min_supported_version: u32,
		/// Supported roles.
		pub roles: Roles,
		/// Best block number.
		pub best_number: Number,
		/// Best block hash.
		pub best_hash: Hash,
		/// Genesis block hash.
		pub genesis_hash: Hash,
		/// DEPRECATED. Chain-specific status.
		pub chain_status: Vec<u8>,
	}

	impl<Hash: Decode, Number: Decode> Decode for Status<Hash, Number> {
		fn decode<I: Input>(value: &mut I) -> Result<Self, codec::Error> {
			const LAST_CHAIN_STATUS_VERSION: u32 = 5;
			let compact = CompactStatus::decode(value)?;
			let chain_status = match <Vec<u8>>::decode(value) {
				Ok(v) => v,
				Err(e) => if compact.version <= LAST_CHAIN_STATUS_VERSION {
					return Err(e)
				} else {
					Vec::new()
				}
			};

			let CompactStatus {
				version,
				min_supported_version,
				roles,
				best_number,
				best_hash,
				genesis_hash,
			} = compact;

			Ok(Status {
				version,
				min_supported_version,
				roles,
				best_number,
				best_hash,
				genesis_hash,
				chain_status,
			})
		}
	}

	/// Request block data from a peer.
	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	pub struct BlockRequest<Hash, Number> {
		/// Unique request id.
		pub id: RequestId,
		/// Bits of block data to request.
		pub fields: BlockAttributes,
		/// Start from this block.
		pub from: FromBlock<Hash, Number>,
		/// End at this block. An implementation defined maximum is used when unspecified.
		pub to: Option<Hash>,
		/// Sequence direction.
		pub direction: Direction,
		/// Maximum number of blocks to return. An implementation defined maximum is used when unspecified.
		pub max: Option<u32>,
	}

	/// Response to `BlockRequest`
	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	pub struct BlockResponse<Header, Hash, Extrinsic> {
		/// Id of a request this response was made for.
		pub id: RequestId,
		/// Block data for the requested sequence.
		pub blocks: Vec<BlockData<Header, Hash, Extrinsic>>,
	}

	/// Announce a new complete relay chain block on the network.
	#[derive(Debug, PartialEq, Eq, Clone)]
	pub struct BlockAnnounce<H> {
		/// New block header.
		pub header: H,
		/// Block state. TODO: Remove `Option` and custom encoding when v4 becomes common.
		pub state: Option<BlockState>,
		/// Data associated with this block announcement, e.g. a candidate message.
		pub data: Option<Vec<u8>>,
	}

	// Custom Encode/Decode impl to maintain backwards compatibility with v3.
	// This assumes that the packet contains nothing but the announcement message.
	// TODO: Get rid of it once protocol v4 is common.
	impl<H: Encode> Encode for BlockAnnounce<H> {
		fn encode_to<T: Output>(&self, dest: &mut T) {
			self.header.encode_to(dest);
			if let Some(state) = &self.state {
				state.encode_to(dest);
			}
			if let Some(data) = &self.data {
				data.encode_to(dest)
			}
		}
	}

	impl<H: Decode> Decode for BlockAnnounce<H> {
		fn decode<I: Input>(input: &mut I) -> Result<Self, codec::Error> {
			let header = H::decode(input)?;
			let state = BlockState::decode(input).ok();
			let data = Vec::decode(input).ok();
			Ok(BlockAnnounce {
				header,
				state,
				data,
			})
		}
	}

	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	/// Remote call request.
	pub struct RemoteCallRequest<H> {
		/// Unique request id.
		pub id: RequestId,
		/// Block at which to perform call.
		pub block: H,
		/// Method name.
		pub method: String,
		/// Call data.
		pub data: Vec<u8>,
	}

	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	/// Remote storage read request.
	pub struct RemoteReadRequest<H> {
		/// Unique request id.
		pub id: RequestId,
		/// Block at which to perform call.
		pub block: H,
		/// Storage key.
		pub keys: Vec<Vec<u8>>,
	}

	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	/// Remote storage read child request.
	pub struct RemoteReadChildRequest<H> {
		/// Unique request id.
		pub id: RequestId,
		/// Block at which to perform call.
		pub block: H,
		/// Child Storage key.
		pub storage_key: Vec<u8>,
		/// Storage key.
		pub keys: Vec<Vec<u8>>,
	}

	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	/// Remote header request.
	pub struct RemoteHeaderRequest<N> {
		/// Unique request id.
		pub id: RequestId,
		/// Block number to request header for.
		pub block: N,
	}

	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	/// Remote header response.
	pub struct RemoteHeaderResponse<Header> {
		/// Id of a request this response was made for.
		pub id: RequestId,
		/// Header. None if proof generation has failed (e.g. header is unknown).
		pub header: Option<Header>,
		/// Header proof.
		pub proof: StorageProof,
	}

	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	/// Remote changes request.
	pub struct RemoteChangesRequest<H> {
		/// Unique request id.
		pub id: RequestId,
		/// Hash of the first block of the range (including first) where changes are requested.
		pub first: H,
		/// Hash of the last block of the range (including last) where changes are requested.
		pub last: H,
		/// Hash of the first block for which the requester has the changes trie root. All other
		/// affected roots must be proved.
		pub min: H,
		/// Hash of the last block that we can use when querying changes.
		pub max: H,
		/// Storage child node key which changes are requested.
		pub storage_key: Option<Vec<u8>>,
		/// Storage key which changes are requested.
		pub key: Vec<u8>,
	}

	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	/// Remote changes response.
	pub struct RemoteChangesResponse<N, H> {
		/// Id of a request this response was made for.
		pub id: RequestId,
		/// Proof has been generated using block with this number as a max block. Should be
		/// less than or equal to the RemoteChangesRequest::max block number.
		pub max: N,
		/// Changes proof.
		pub proof: Vec<Vec<u8>>,
		/// Changes tries roots missing on the requester' node.
		pub roots: Vec<(N, H)>,
		/// Missing changes tries roots proof.
		pub roots_proof: StorageProof,
	}

	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	/// Finality proof request.
	pub struct FinalityProofRequest<H> {
		/// Unique request id.
		pub id: RequestId,
		/// Hash of the block to request proof for.
		pub block: H,
		/// Additional data blob (that both requester and provider understood) required for proving finality.
		pub request: Vec<u8>,
	}

	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
	/// Finality proof response.
	pub struct FinalityProofResponse<H> {
		/// Id of a request this response was made for.
		pub id: RequestId,
		/// Hash of the block (the same as in the FinalityProofRequest).
		pub block: H,
		/// Finality proof (if available).
		pub proof: Option<Vec<u8>>,
	}
}