/*
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 statechange

import (
	"encoding/json"
	"fmt"
	"strings"

	"k8s.io/apimachinery/pkg/util/sets"

	"github.com/aws/karpenter/pkg/controllers/interruption/messages"
)

var acceptedStates = sets.NewString("stopping", "stopped", "shutting-down", "terminated")

type Parser struct{}

func (p Parser) Parse(raw string) (messages.Message, error) {
	msg := Message{}
	if err := json.Unmarshal([]byte(raw), &msg); err != nil {
		return nil, fmt.Errorf("unmarhsalling the message as EC2InstanceStateChangeNotification, %w", err)
	}

	// We ignore states that are not in the set of states we can react to
	if !acceptedStates.Has(strings.ToLower(msg.Detail.State)) {
		return nil, nil
	}
	return msg, nil
}

func (p Parser) Version() string {
	return "0"
}

func (p Parser) Source() string {
	return "aws.ec2"
}

func (p Parser) DetailType() string {
	return "EC2 Instance State-change Notification"
}