// Copyright 2022 TiKV Project Authors. Licensed under Apache-2.0.
// Modifications Copyright 2022 PingCAP, Inc.
//! TiKV uses raft under the hook to provide consistency between replicas.
//! Though technically, `Engine` trait should hide the details of raft, but in
//! some cases it's unavoidable to access raft interface somehow. This module
//! supports the access pattern via extension.

use kvproto::raft_serverpb::RaftMessage;

/// An interface to provide direct access to raftstore layer.
pub trait RaftExtension: Clone + Send {
    /// Feed the message to the raft group.
    ///
    /// If it's a `key_message` is true, it will log a warning if the message
    /// failed to send.
    fn feed(&self, _msg: RaftMessage, _key_message: bool) {}

    /// Retport the message is rejected by the remote peer.
    fn report_reject_message(&self, _region_id: u64, _from_peer_id: u64) {}

    /// Report the target peer is unreachable.
    fn report_peer_unreachable(&self, _region_id: u64, _to_peer_id: u64) {}

    /// Report the target store is unreachable.
    fn report_store_unreachable(&self, _store_id: u64) {}

    /// Report the address of a store is resolved.
    fn report_resolved(&self, _store_id: u64, _group_id: u64) {}
}

/// An extension that does nothing or panic on all operations.
#[derive(Clone)]
pub struct FakeExtension;

impl RaftExtension for FakeExtension {}