// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF 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 pulsar

import (
	"sort"
	"sync"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
)

const testNackDelay = 300 * time.Millisecond

type nackMockedConsumer struct {
	ch     chan messageID
	closed bool
	lock   sync.Mutex
}

func newNackMockedConsumer() *nackMockedConsumer {
	t := &nackMockedConsumer{
		ch: make(chan messageID, 10),
	}
	go func() {
		// since the client ticks at an interval of delay / 3
		// wait another interval to ensure we get all messages
		time.Sleep(testNackDelay + 101*time.Millisecond)
		t.lock.Lock()
		defer t.lock.Unlock()
		t.closed = true
		close(t.ch)
	}()
	return t
}

func (nmc *nackMockedConsumer) Redeliver(msgIds []messageID) {
	nmc.lock.Lock()
	defer nmc.lock.Unlock()
	if nmc.closed {
		return
	}
	for _, id := range msgIds {
		nmc.ch <- id
	}
}

func sortMessageIds(msgIds []messageID) []messageID {
	sort.Slice(msgIds, func(i, j int) bool {
		return msgIds[i].ledgerID < msgIds[j].entryID
	})
	return msgIds
}

func (nmc *nackMockedConsumer) Wait() <-chan messageID {
	return nmc.ch
}

func TestNacksTracker(t *testing.T) {
	nmc := newNackMockedConsumer()
	nacks := newNegativeAcksTracker(nmc, testNackDelay)

	nacks.Add(messageID{
		ledgerID: 1,
		entryID:  1,
		batchIdx: 1,
	})

	nacks.Add(messageID{
		ledgerID: 2,
		entryID:  2,
		batchIdx: 1,
	})

	msgIds := make([]messageID, 0)
	for id := range nmc.Wait() {
		msgIds = append(msgIds, id)
	}
	msgIds = sortMessageIds(msgIds)

	assert.Equal(t, 2, len(msgIds))
	assert.Equal(t, int64(1), msgIds[0].ledgerID)
	assert.Equal(t, int64(1), msgIds[0].entryID)
	assert.Equal(t, int64(2), msgIds[1].ledgerID)
	assert.Equal(t, int64(2), msgIds[1].entryID)

	nacks.Close()
}

func TestNacksWithBatchesTracker(t *testing.T) {
	nmc := newNackMockedConsumer()
	nacks := newNegativeAcksTracker(nmc, testNackDelay)

	nacks.Add(messageID{
		ledgerID: 1,
		entryID:  1,
		batchIdx: 1,
	})

	nacks.Add(messageID{
		ledgerID: 1,
		entryID:  1,
		batchIdx: 2,
	})

	nacks.Add(messageID{
		ledgerID: 1,
		entryID:  1,
		batchIdx: 3,
	})

	nacks.Add(messageID{
		ledgerID: 2,
		entryID:  2,
		batchIdx: 1,
	})

	msgIds := make([]messageID, 0)
	for id := range nmc.Wait() {
		msgIds = append(msgIds, id)
	}
	msgIds = sortMessageIds(msgIds)

	assert.Equal(t, 2, len(msgIds))
	assert.Equal(t, int64(1), msgIds[0].ledgerID)
	assert.Equal(t, int64(1), msgIds[0].entryID)
	assert.Equal(t, int64(2), msgIds[1].ledgerID)
	assert.Equal(t, int64(2), msgIds[1].entryID)

	nacks.Close()
}