// Copyright 2021 Centrifuge GmbH (centrifuge.io).
// This file is part of Centrifuge chain project.

// Centrifuge 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 (see http://www.gnu.org/licenses).

// Centrifuge 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.

use frame_support::{dispatch::DispatchResult, weights::Weight};
use sp_runtime::{app_crypto::sp_core::H160, DispatchError};
use sp_std::vec::Vec;

/// Type that represents the hash of an LP message.
pub type MessageHash = [u8; 32];

/// An encoding & decoding trait for the purpose of meeting the
/// LiquidityPools General Message Passing Format
pub trait LpMessageSerializer: Sized {
	/// Serialize the message
	fn serialize(&self) -> Vec<u8>;

	/// Deserialize the message
	fn deserialize(input: &[u8]) -> Result<Self, DispatchError>;
}

/// Behavior or a message that can be batched
pub trait LpMessageBatch: Sized {
	/// Extend this message with a new one
	fn pack_with(&mut self, other: Self) -> DispatchResult;

	/// Decompose the message into a list of messages
	/// If the message is not decomposable, it returns the own message.
	fn submessages(&self) -> Vec<Self>;

	/// Creates an empty message.
	/// It's the identity message for composing messages with pack_with
	fn empty() -> Self;
}

/// Support for hashing
pub trait LpMessageHash {
	/// Retrieves the message hash, if the message is a proof type.
	fn get_message_hash(&self) -> MessageHash;
}

/// Behavior of a message that can support proofs
pub trait LpMessageProof: LpMessageHash {
	/// Returns whether the message is a proof or not.
	fn is_proof_message(&self) -> bool;

	/// Converts the message into a message proof type.
	fn to_proof_message(&self) -> Self;
}

//Behavior of a message that support recovery
pub trait LpMessageRecovery: LpMessageHash {
	/// Creates a message used for initiating message recovery.
	///
	/// Hash - hash of the message that should be recovered.
	/// Router - the address of the recovery router.
	fn initiate_recovery_message(hash: MessageHash, router: [u8; 32]) -> Self;

	/// Creates a message used for disputing message recovery.
	///
	/// Hash - hash of the message that should be disputed.
	/// Router - the address of the recovery router.
	fn dispute_recovery_message(hash: MessageHash, router: [u8; 32]) -> Self;
}

/// Behavior of a message that can be forwarded
pub trait LpMessageForwarded: Sized {
	type Domain;

	/// Checks whether a message is a forwarded one.
	fn is_forwarded(&self) -> bool;

	/// Unwraps a forwarded message.
	fn unwrap_forwarded(self) -> Option<(Self::Domain, H160, Self)>;

	/// Attempts to wrap into a forwarded message.
	fn try_wrap_forward(
		domain: Self::Domain,
		forwarding_contract: H160,
		message: Self,
	) -> Result<Self, DispatchError>;
}

pub trait RouterProvider<Domain>: Sized {
	/// The router identifier.
	type RouterId;

	/// Returns a list of routers supported for the given domain.
	fn routers_for_domain(domain: Domain) -> Vec<Self::RouterId>;
}

/// The behavior of an entity that can send messages
pub trait MessageSender {
	/// The middleware by where this message is sent
	type Middleware;

	/// The originator of the message to be sent
	type Origin;

	/// The type of the message
	type Message;

	/// Sends a message for origin to destination
	fn send(
		middleware: Self::Middleware,
		origin: Self::Origin,
		message: Self::Message,
	) -> DispatchResult;
}

/// The behavior of an entity that can receive messages
pub trait MessageReceiver {
	/// The middleware by where this message is received
	type Middleware;

	/// The originator of the received message
	type Origin;

	type Message;

	/// Sends a message for origin to destination
	fn receive(
		middleware: Self::Middleware,
		origin: Self::Origin,
		message: Self::Message,
	) -> DispatchResult;
}

/// The trait required for queueing messages.
pub trait MessageQueue {
	/// The message type.
	type Message;

	/// Submit a message to the queue.
	fn queue(msg: Self::Message) -> DispatchResult;
}

/// The trait required for processing dequeued messages.
pub trait MessageProcessor {
	/// The message type.
	type Message;

	/// Process a message.
	fn process(msg: Self::Message) -> (DispatchResult, Weight);

	/// Max weight that processing a message can take
	fn max_processing_weight(msg: &Self::Message) -> Weight;
}

/// The trait required for handling outbound LP messages.
pub trait OutboundMessageHandler {
	/// The sender type of the outbound message.
	type Sender;

	/// The destination type of the outbound message.
	type Destination;

	/// The message type.
	type Message;

	/// Handle an outbound message.
	fn handle(
		sender: Self::Sender,
		destination: Self::Destination,
		msg: Self::Message,
	) -> DispatchResult;
}

/// The trait required for handling inbound LP messages.
pub trait InboundMessageHandler {
	/// The sender type of the inbound message.
	type Sender;

	/// The message type.
	type Message;

	/// Handle an inbound message.
	fn handle(sender: Self::Sender, msg: Self::Message) -> DispatchResult;
}