// Copyright 2021 The etcd Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package etcdserver

import (
	"context"

	"github.com/coreos/go-semver/semver"
	"go.etcd.io/etcd/server/v3/storage/backend"
	"go.etcd.io/etcd/server/v3/storage/schema"
	"go.uber.org/zap"

	"go.etcd.io/etcd/api/v3/version"
	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
	serverversion "go.etcd.io/etcd/server/v3/etcdserver/version"
)

// serverVersionAdapter implements Server interface needed by serverversion.Monitor
type serverVersionAdapter struct {
	*EtcdServer
	tx backend.BatchTx
}

func newServerVersionAdapter(s *EtcdServer) *serverVersionAdapter {
	return &serverVersionAdapter{
		EtcdServer: s,
		tx:         nil,
	}
}

var _ serverversion.Server = (*serverVersionAdapter)(nil)

func (s *serverVersionAdapter) UpdateClusterVersion(version string) {
	// TODO switch to updateClusterVersionV3 in 3.6
	s.GoAttach(func() { s.updateClusterVersionV2(version) })
}

func (s *serverVersionAdapter) DowngradeCancel() {
	ctx, cancel := context.WithTimeout(context.Background(), s.Cfg.ReqTimeout())
	if _, err := s.downgradeCancel(ctx); err != nil {
		s.lg.Warn("failed to cancel downgrade", zap.Error(err))
	}
	cancel()
}

func (s *serverVersionAdapter) GetClusterVersion() *semver.Version {
	return s.cluster.Version()
}

func (s *serverVersionAdapter) GetDowngradeInfo() *membership.DowngradeInfo {
	return s.cluster.DowngradeInfo()
}

func (s *serverVersionAdapter) GetVersions() map[string]*version.Versions {
	return getVersions(s.lg, s.cluster, s.id, s.peerRt)
}

func (s *serverVersionAdapter) GetStorageVersion() *semver.Version {
	if s.tx == nil {
		s.Lock()
		defer s.Unlock()
	}
	v, err := schema.UnsafeDetectSchemaVersion(s.lg, s.tx)
	if err != nil {
		return nil
	}
	return &v
}

func (s *serverVersionAdapter) UpdateStorageVersion(target semver.Version) {
	if s.tx == nil {
		s.Lock()
		defer s.Unlock()
	}
	err := schema.UnsafeMigrate(s.lg, s.tx, target)
	if err != nil {
		s.lg.Error("failed migrating storage schema", zap.String("storage-version", target.String()), zap.Error(err))
	}
}

func (s *serverVersionAdapter) Lock() {
	s.tx = s.be.BatchTx()
	s.tx.Lock()
}

func (s *serverVersionAdapter) Unlock() {
	s.tx.Unlock()
	s.tx = nil
}