// Licensed to Elasticsearch B.V. under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Elasticsearch B.V. licenses this file to you 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 beater

import (
	"github.com/elastic/beats/filebeat/input/file"
	"github.com/elastic/beats/libbeat/logp"
)

// eventAcker handles publisher pipeline ACKs and forwards
// them to the registrar or directly to the stateless logger.
type eventACKer struct {
	stateful  statefulLogger
	stateless statelessLogger
	log       *logp.Logger
}

type statefulLogger interface {
	Published(states []file.State)
}

type statelessLogger interface {
	Published(c int) bool
}

func newEventACKer(stateless statelessLogger, stateful statefulLogger) *eventACKer {
	return &eventACKer{stateless: stateless, stateful: stateful, log: logp.NewLogger("acker")}
}

func (a *eventACKer) ackEvents(data []interface{}) {
	stateless := 0
	states := make([]file.State, 0, len(data))
	for _, datum := range data {
		if datum == nil {
			stateless++
			continue
		}

		st, ok := datum.(file.State)
		if !ok {
			stateless++
			continue
		}

		states = append(states, st)
	}

	if len(states) > 0 {
		a.log.Debugw("stateful ack", "count", len(states))
		a.stateful.Published(states)
	}

	if stateless > 0 {
		a.log.Debugw("stateless ack", "count", stateless)
		a.stateless.Published(stateless)
	}
}