// Copyright 2014 Google Inc. All Rights Reserved.
//
// 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 utils

import (
	"testing"
	"time"

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

func createTime(id int) time.Time {
	var zero time.Time
	return zero.Add(time.Duration(id+1) * time.Second)
}

func expectSize(t *testing.T, sb *TimedStore, expectedSize int) {
	if sb.Size() != expectedSize {
		t.Errorf("Expected size %v, got %v", expectedSize, sb.Size())
	}
}

func expectAllElements(t *testing.T, sb *TimedStore, expected []int) {
	size := sb.Size()
	els := make([]interface{}, size)
	for i := 0; i < size; i++ {
		els[i] = sb.Get(size - i - 1)
	}
	expectElements(t, []interface{}(els), expected)
}

func expectElements(t *testing.T, actual []interface{}, expected []int) {
	if len(actual) != len(expected) {
		t.Errorf("Expected elements %v, got %v", expected, actual)
		return
	}
	for i, el := range actual {
		if el.(int) != expected[i] {
			t.Errorf("Expected elements %v, got %v", expected, actual)
			return
		}
	}
}

func TestAdd(t *testing.T) {
	sb := NewTimedStore(5*time.Second, 100)

	// Add 1.
	sb.Add(createTime(0), 0)
	expectSize(t, sb, 1)
	expectAllElements(t, sb, []int{0})

	// Fill the buffer.
	for i := 1; i <= 5; i++ {
		expectSize(t, sb, i)
		sb.Add(createTime(i), i)
	}
	expectSize(t, sb, 5)
	expectAllElements(t, sb, []int{1, 2, 3, 4, 5})

	// Add more than is available in the buffer
	sb.Add(createTime(6), 6)
	expectSize(t, sb, 5)
	expectAllElements(t, sb, []int{2, 3, 4, 5, 6})

	// Replace all elements.
	for i := 7; i <= 10; i++ {
		sb.Add(createTime(i), i)
	}
	expectSize(t, sb, 5)
	expectAllElements(t, sb, []int{6, 7, 8, 9, 10})
}

func TestGet(t *testing.T) {
	sb := NewTimedStore(5*time.Second, -1)
	sb.Add(createTime(1), 1)
	sb.Add(createTime(2), 2)
	sb.Add(createTime(3), 3)
	expectSize(t, sb, 3)

	assert := assert.New(t)
	assert.Equal(sb.Get(0).(int), 3)
	assert.Equal(sb.Get(1).(int), 2)
	assert.Equal(sb.Get(2).(int), 1)
}

func TestInTimeRange(t *testing.T) {
	sb := NewTimedStore(5*time.Second, -1)
	assert := assert.New(t)

	var empty time.Time

	// No elements.
	assert.Empty(sb.InTimeRange(createTime(0), createTime(5), 10))
	assert.Empty(sb.InTimeRange(createTime(0), empty, 10))
	assert.Empty(sb.InTimeRange(empty, createTime(5), 10))
	assert.Empty(sb.InTimeRange(empty, empty, 10))

	// One element.
	sb.Add(createTime(1), 1)
	expectSize(t, sb, 1)
	expectElements(t, sb.InTimeRange(createTime(0), createTime(5), 10), []int{1})
	expectElements(t, sb.InTimeRange(createTime(1), createTime(5), 10), []int{1})
	expectElements(t, sb.InTimeRange(createTime(0), createTime(1), 10), []int{1})
	expectElements(t, sb.InTimeRange(createTime(1), createTime(1), 10), []int{1})
	assert.Empty(sb.InTimeRange(createTime(2), createTime(5), 10))

	// Two element.
	sb.Add(createTime(2), 2)
	expectSize(t, sb, 2)
	expectElements(t, sb.InTimeRange(createTime(0), createTime(5), 10), []int{1, 2})
	expectElements(t, sb.InTimeRange(createTime(1), createTime(5), 10), []int{1, 2})
	expectElements(t, sb.InTimeRange(createTime(0), createTime(2), 10), []int{1, 2})
	expectElements(t, sb.InTimeRange(createTime(1), createTime(2), 10), []int{1, 2})
	expectElements(t, sb.InTimeRange(createTime(1), createTime(1), 10), []int{1})
	expectElements(t, sb.InTimeRange(createTime(2), createTime(2), 10), []int{2})
	assert.Empty(sb.InTimeRange(createTime(3), createTime(5), 10))

	// Many elements.
	sb.Add(createTime(3), 3)
	sb.Add(createTime(4), 4)
	expectSize(t, sb, 4)
	expectElements(t, sb.InTimeRange(createTime(0), createTime(5), 10), []int{1, 2, 3, 4})
	expectElements(t, sb.InTimeRange(createTime(0), createTime(5), 10), []int{1, 2, 3, 4})
	expectElements(t, sb.InTimeRange(createTime(1), createTime(5), 10), []int{1, 2, 3, 4})
	expectElements(t, sb.InTimeRange(createTime(0), createTime(4), 10), []int{1, 2, 3, 4})
	expectElements(t, sb.InTimeRange(createTime(1), createTime(4), 10), []int{1, 2, 3, 4})
	expectElements(t, sb.InTimeRange(createTime(0), createTime(2), 10), []int{1, 2})
	expectElements(t, sb.InTimeRange(createTime(1), createTime(2), 10), []int{1, 2})
	expectElements(t, sb.InTimeRange(createTime(2), createTime(3), 10), []int{2, 3})
	expectElements(t, sb.InTimeRange(createTime(3), createTime(4), 10), []int{3, 4})
	expectElements(t, sb.InTimeRange(createTime(3), createTime(5), 10), []int{3, 4})
	assert.Empty(sb.InTimeRange(createTime(5), createTime(5), 10))

	// Start and end time ignores maxResults.
	expectElements(t, sb.InTimeRange(createTime(1), createTime(5), 1), []int{1, 2, 3, 4})

	// No start time.
	expectElements(t, sb.InTimeRange(empty, createTime(5), 10), []int{1, 2, 3, 4})
	expectElements(t, sb.InTimeRange(empty, createTime(4), 10), []int{1, 2, 3, 4})
	expectElements(t, sb.InTimeRange(empty, createTime(3), 10), []int{1, 2, 3})
	expectElements(t, sb.InTimeRange(empty, createTime(2), 10), []int{1, 2})
	expectElements(t, sb.InTimeRange(empty, createTime(1), 10), []int{1})

	// No end time.
	expectElements(t, sb.InTimeRange(createTime(0), empty, 10), []int{1, 2, 3, 4})
	expectElements(t, sb.InTimeRange(createTime(1), empty, 10), []int{1, 2, 3, 4})
	expectElements(t, sb.InTimeRange(createTime(2), empty, 10), []int{2, 3, 4})
	expectElements(t, sb.InTimeRange(createTime(3), empty, 10), []int{3, 4})
	expectElements(t, sb.InTimeRange(createTime(4), empty, 10), []int{4})

	// No start or end time.
	expectElements(t, sb.InTimeRange(empty, empty, 10), []int{1, 2, 3, 4})

	// Start after data.
	assert.Empty(sb.InTimeRange(createTime(5), createTime(5), 10))
	assert.Empty(sb.InTimeRange(createTime(5), empty, 10))

	// End before data.
	assert.Empty(sb.InTimeRange(createTime(0), createTime(0), 10))
	assert.Empty(sb.InTimeRange(empty, createTime(0), 10))
}

func TestInTimeRangeWithLimit(t *testing.T) {
	sb := NewTimedStore(5*time.Second, -1)
	sb.Add(createTime(1), 1)
	sb.Add(createTime(2), 2)
	sb.Add(createTime(3), 3)
	sb.Add(createTime(4), 4)
	expectSize(t, sb, 4)

	var empty time.Time

	// Limit cuts off from latest timestamp.
	expectElements(t, sb.InTimeRange(empty, empty, 4), []int{1, 2, 3, 4})
	expectElements(t, sb.InTimeRange(empty, empty, 3), []int{2, 3, 4})
	expectElements(t, sb.InTimeRange(empty, empty, 2), []int{3, 4})
	expectElements(t, sb.InTimeRange(empty, empty, 1), []int{4})
	assert.Empty(t, sb.InTimeRange(empty, empty, 0))
}

func TestLimitedSize(t *testing.T) {
	sb := NewTimedStore(time.Hour, 5)

	// Add 1.
	sb.Add(createTime(0), 0)
	expectSize(t, sb, 1)
	expectAllElements(t, sb, []int{0})

	// Fill the buffer.
	for i := 1; i <= 5; i++ {
		expectSize(t, sb, i)
		sb.Add(createTime(i), i)
	}
	expectSize(t, sb, 5)
	expectAllElements(t, sb, []int{1, 2, 3, 4, 5})

	// Add more than is available in the buffer
	sb.Add(createTime(6), 6)
	expectSize(t, sb, 5)
	expectAllElements(t, sb, []int{2, 3, 4, 5, 6})

	// Replace all elements.
	for i := 7; i <= 10; i++ {
		sb.Add(createTime(i), i)
	}
	expectSize(t, sb, 5)
	expectAllElements(t, sb, []int{6, 7, 8, 9, 10})
}