// Copyright 2016-2018, Pulumi Corporation.
//
// 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 filestate

import (
	"os"

	"github.com/pulumi/pulumi/pkg/resource/deploy"
	"github.com/pulumi/pulumi/pkg/tokens"
)

// localSnapshotManager is a simple SnapshotManager implementation that persists snapshots
// to disk on the local machine.
type localSnapshotPersister struct {
	name    tokens.QName
	backend *localBackend
}

func (sm *localSnapshotPersister) Invalidate() error {
	return nil
}

func (sm *localSnapshotPersister) Save(snapshot *deploy.Snapshot) error {
	config, _, _, err := sm.backend.getStack(sm.name)
	if err != nil && !os.IsNotExist(err) {
		return err
	}

	_, err = sm.backend.saveStack(sm.name, config, snapshot)
	return err

}

func (b *localBackend) newSnapshotPersister(stackName tokens.QName) *localSnapshotPersister {
	return &localSnapshotPersister{name: stackName, backend: b}
}