// Copyright 2012 Prometheus Team
// 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 leveldb

import (
	"github.com/matttproud/prometheus/model"
	"github.com/matttproud/prometheus/storage/metric"
	"github.com/matttproud/prometheus/utility/test"
	"io/ioutil"
	"os"
	"testing"
	"time"
)

var testGetValueAtTime = func(t test.Tester) {
	type value struct {
		year  int
		month time.Month
		day   int
		hour  int
		value float32
	}

	type input struct {
		year      int
		month     time.Month
		day       int
		hour      int
		staleness time.Duration
	}

	type output struct {
		value model.SampleValue
	}

	type behavior struct {
		name   string
		input  input
		output *output
	}

	var contexts = []struct {
		name      string
		values    []value
		behaviors []behavior
	}{
		{
			name:   "no values",
			values: []value{},
			behaviors: []behavior{
				{
					name: "random target",
					input: input{
						year:      1984,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(0),
					},
				},
			},
		},
		{
			name: "singleton",
			values: []value{
				{
					year:  1984,
					month: 3,
					day:   30,
					hour:  0,
					value: 0,
				},
			},
			behaviors: []behavior{
				{
					name: "exact without staleness policy",
					input: input{
						year:      1984,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(0),
					},
					output: &output{
						value: 0,
					},
				},
				{
					name: "exact with staleness policy",
					input: input{
						year:      1984,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: &output{
						value: 0,
					},
				},
				{
					name: "before without staleness policy",
					input: input{
						year:      1984,
						month:     3,
						day:       29,
						hour:      0,
						staleness: time.Duration(0),
					},
				},
				{
					name: "before with staleness policy",
					input: input{
						year:      1984,
						month:     3,
						day:       29,
						hour:      0,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
				{
					name: "after without staleness policy",
					input: input{
						year:      1984,
						month:     3,
						day:       31,
						hour:      0,
						staleness: time.Duration(0),
					},
				},
				{
					name: "after with staleness policy",
					input: input{
						year:      1984,
						month:     3,
						day:       31,
						hour:      0,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
			},
		},
		{
			name: "double",
			values: []value{
				{
					year:  1984,
					month: 3,
					day:   30,
					hour:  0,
					value: 0,
				},
				{
					year:  1985,
					month: 3,
					day:   30,
					hour:  0,
					value: 1,
				},
			},
			behaviors: []behavior{
				{
					name: "exact first without staleness policy",
					input: input{
						year:      1984,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(0),
					},
					output: &output{
						value: 0,
					},
				},
				{
					name: "exact first with staleness policy",
					input: input{
						year:      1984,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: &output{
						value: 0,
					},
				},
				{
					name: "exact second without staleness policy",
					input: input{
						year:      1985,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(0),
					},
					output: &output{
						value: 1,
					},
				},
				{
					name: "exact second with staleness policy",
					input: input{
						year:      1985,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: &output{
						value: 1,
					},
				},
				{
					name: "before first without staleness policy",
					input: input{
						year:      1983,
						month:     9,
						day:       29,
						hour:      12,
						staleness: time.Duration(0),
					},
				},
				{
					name: "before first with staleness policy",
					input: input{
						year:      1983,
						month:     9,
						day:       29,
						hour:      12,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
				{
					name: "after second with staleness policy",
					input: input{
						year:      1985,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
				{
					name: "middle without staleness policy",
					input: input{
						year:      1984,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(0),
					},
				},
				{
					name: "middle with insufficient staleness policy",
					input: input{
						year:      1984,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(364*24) * time.Hour,
					},
				},
				{
					name: "middle with sufficient staleness policy",
					input: input{
						year:      1984,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: &output{
						value: 0.5,
					},
				},
			},
		},
		{
			name: "triple",
			values: []value{
				{
					year:  1984,
					month: 3,
					day:   30,
					hour:  0,
					value: 0,
				},
				{
					year:  1985,
					month: 3,
					day:   30,
					hour:  0,
					value: 1,
				},
				{
					year:  1986,
					month: 3,
					day:   30,
					hour:  0,
					value: 2,
				},
			},
			behaviors: []behavior{
				{
					name: "exact first without staleness policy",
					input: input{
						year:      1984,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(0),
					},
					output: &output{
						value: 0,
					},
				},
				{
					name: "exact first with staleness policy",
					input: input{
						year:      1984,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: &output{
						value: 0,
					},
				},
				{
					name: "exact second without staleness policy",
					input: input{
						year:      1985,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(0),
					},
					output: &output{
						value: 1,
					},
				},
				{
					name: "exact second with staleness policy",
					input: input{
						year:      1985,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: &output{
						value: 1,
					},
				},
				{
					name: "exact third without staleness policy",
					input: input{
						year:      1986,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(0),
					},
					output: &output{
						value: 2,
					},
				},
				{
					name: "exact third with staleness policy",
					input: input{
						year:      1986,
						month:     3,
						day:       30,
						hour:      0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: &output{
						value: 2,
					},
				},
				{
					name: "before first without staleness policy",
					input: input{
						year:      1983,
						month:     9,
						day:       29,
						hour:      12,
						staleness: time.Duration(0),
					},
				},
				{
					name: "before first with staleness policy",
					input: input{
						year:      1983,
						month:     9,
						day:       29,
						hour:      12,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
				{
					name: "after third with staleness policy",
					input: input{
						year:      1986,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
				{
					name: "first middle without staleness policy",
					input: input{
						year:      1984,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(0),
					},
				},
				{
					name: "first middle with insufficient staleness policy",
					input: input{
						year:      1984,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(364*24) * time.Hour,
					},
				},
				{
					name: "first middle with sufficient staleness policy",
					input: input{
						year:      1984,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: &output{
						value: 0.5,
					},
				},
				{
					name: "second middle without staleness policy",
					input: input{
						year:      1985,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(0),
					},
				},
				{
					name: "second middle with insufficient staleness policy",
					input: input{
						year:      1985,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(364*24) * time.Hour,
					},
				},
				{
					name: "second middle with sufficient staleness policy",
					input: input{
						year:      1985,
						month:     9,
						day:       28,
						hour:      12,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: &output{
						value: 1.5,
					},
				},
			},
		},
	}

	for i, context := range contexts {
		// Wrapping in function to enable garbage collection of resources.
		func() {
			temporaryDirectory, _ := ioutil.TempDir("", "leveldb_metric_persistence_test")

			defer func() {
				if err := os.RemoveAll(temporaryDirectory); err != nil {
					t.Errorf("%d(%s). Could not remove temporary directory: %q\n", i, context.name, err)
				}
			}()

			persistence, _ := NewLevelDBMetricPersistence(temporaryDirectory)

			defer func() {
				persistence.Close()
			}()

			m := model.Metric{
				"name": "age_in_years",
			}

			for j, value := range context.values {
				err := persistence.AppendSample(&model.Sample{
					Value:     model.SampleValue(value.value),
					Timestamp: time.Date(value.year, value.month, value.day, value.hour, 0, 0, 0, time.UTC),
					Metric:    m,
				})

				if err != nil {
					t.Errorf("%d.%d(%s). Could not create sample: %q\n", i, j, context.name, err)
				}
			}

			for j, behavior := range context.behaviors {
				input := behavior.input
				time := time.Date(input.year, input.month, input.day, input.hour, 0, 0, 0, time.UTC)
				p := metric.StalenessPolicy{
					DeltaAllowance: input.staleness,
				}

				actual, err := persistence.GetValueAtTime(&m, &time, &p)
				if err != nil {
					t.Errorf("%d.%d(%s). Could not query for value: %q\n", i, j, behavior.name, err)
				}

				if behavior.output == nil {
					if actual != nil {
						t.Errorf("%d.%d(%s). Expected nil but got: %q\n", i, j, behavior.name, actual)
					}
				} else {
					if actual == nil {
						t.Errorf("%d.%d(%s). Expected %s but got nil\n", i, j, behavior.name, behavior.output)
					} else {
						if actual.Value != behavior.output.value {
							t.Errorf("%d.%d(%s). Expected %s but got %s\n", i, j, behavior.name, behavior.output, actual)

						}
					}
				}
			}
		}()
	}
}

func TestGetValueAtTime(t *testing.T) {
	testGetValueAtTime(t)
}

func BenchmarkGetValueAtTime(b *testing.B) {
	for i := 0; i < b.N; i++ {
		testGetValueAtTime(b)
	}
}

var testGetBoundaryValues = func(t test.Tester) {
	type value struct {
		year  int
		month time.Month
		day   int
		hour  int
		value float32
	}

	type input struct {
		openYear  int
		openMonth time.Month
		openDay   int
		openHour  int
		endYear   int
		endMonth  time.Month
		endDay    int
		endHour   int
		staleness time.Duration
	}

	type output struct {
		open model.SampleValue
		end  model.SampleValue
	}

	type behavior struct {
		name   string
		input  input
		output *output
	}

	var contexts = []struct {
		name      string
		values    []value
		behaviors []behavior
	}{
		{
			name:   "no values",
			values: []value{},
			behaviors: []behavior{
				{
					name: "non-existent interval without staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
				},
				{
					name: "non-existent interval with staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
			},
		},
		{
			name: "single value",
			values: []value{
				{
					year:  1984,
					month: 3,
					day:   30,
					hour:  0,
					value: 0,
				},
			},
			behaviors: []behavior{
				{
					name: "on start but missing end without staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
				},
				{
					name: "non-existent interval with staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
				{
					name: "on end but not start without staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1984,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
				},
				{
					name: "on end but not start without staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1984,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
				{
					name: "before point without staleness policy",
					input: input{
						openYear:  1982,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1983,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
				},
				{
					name: "before point with staleness policy",
					input: input{
						openYear:  1982,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1983,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
				{
					name: "after point without staleness policy",
					input: input{
						openYear:  1985,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1986,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
				},
				{
					name: "after point with staleness policy",
					input: input{
						openYear:  1985,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1986,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
				{
					name: "spanning point without staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 9,
						openDay:   29,
						openHour:  12,
						endYear:   1984,
						endMonth:  9,
						endDay:    28,
						endHour:   12,
						staleness: time.Duration(0),
					},
				},
				{
					name: "spanning point with staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 9,
						openDay:   29,
						openHour:  12,
						endYear:   1984,
						endMonth:  9,
						endDay:    28,
						endHour:   12,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
			},
		},
		{
			name: "double values",
			values: []value{
				{
					year:  1984,
					month: 3,
					day:   30,
					hour:  0,
					value: 0,
				},
				{
					year:  1985,
					month: 3,
					day:   30,
					hour:  0,
					value: 1,
				},
			},
			behaviors: []behavior{
				{
					name: "on points without staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
					output: &output{
						open: 0,
						end:  1,
					},
				},
				{
					name: "on points with staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: &output{
						open: 0,
						end:  1,
					},
				},
				{
					name: "on first before second outside of staleness",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1984,
						endMonth:  6,
						endDay:    29,
						endHour:   6,
						staleness: time.Duration(178*24) * time.Hour,
					},
				},
				{
					name: "on first before second within staleness",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1984,
						endMonth:  6,
						endDay:    29,
						endHour:   6,
						staleness: time.Duration(356*24) * time.Hour,
					},
				},
				{
					name: "on first after second outside of staleness",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  6,
						endDay:    29,
						endHour:   6,
						staleness: time.Duration(178*24) * time.Hour,
					},
				},
				{
					name: "on first after second within staleness",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  6,
						endDay:    29,
						endHour:   6,
						staleness: time.Duration(356*24) * time.Hour,
					},
				},
			},
		},
	}

	for i, context := range contexts {
		// Wrapping in function to enable garbage collection of resources.
		func() {
			temporaryDirectory, _ := ioutil.TempDir("", "leveldb_metric_persistence_test")

			defer func() {
				if err := os.RemoveAll(temporaryDirectory); err != nil {
					t.Errorf("%d(%s). Could not remove temporary directory: %q\n", i, context.name, err)
				}
			}()

			persistence, _ := NewLevelDBMetricPersistence(temporaryDirectory)

			defer func() {
				persistence.Close()
			}()

			m := model.Metric{
				"name": "age_in_years",
			}

			for j, value := range context.values {
				err := persistence.AppendSample(&model.Sample{
					Value:     model.SampleValue(value.value),
					Timestamp: time.Date(value.year, value.month, value.day, value.hour, 0, 0, 0, time.UTC),
					Metric:    m,
				})

				if err != nil {
					t.Errorf("%d.%d(%s). Could not create sample: %q\n", i, j, context.name, err)
				}
			}

			for j, behavior := range context.behaviors {
				input := behavior.input
				open := time.Date(input.openYear, input.openMonth, input.openDay, input.openHour, 0, 0, 0, time.UTC)
				end := time.Date(input.endYear, input.endMonth, input.endDay, input.endHour, 0, 0, 0, time.UTC)
				i := model.Interval{
					OldestInclusive: open,
					NewestInclusive: end,
				}
				p := metric.StalenessPolicy{
					DeltaAllowance: input.staleness,
				}

				openValue, endValue, err := persistence.GetBoundaryValues(&m, &i, &p)
				if err != nil {
					t.Errorf("%d.%d(%s). Could not query for value: %q\n", i, j, behavior.name, err)
				}

				if behavior.output == nil {
					if openValue != nil {
						t.Errorf("%d.%d(%s). Expected nil but got: %q\n", i, j, behavior.name, openValue)
					}
					if endValue != nil {
						t.Errorf("%d.%d(%s). Expected nil but got: %q\n", i, j, behavior.name, endValue)
					}
				} else {
					if openValue == nil {
						t.Errorf("%d.%d(%s). Expected %s but got nil\n", i, j, behavior.name, behavior.output)
					}
					if endValue == nil {
						t.Errorf("%d.%d(%s). Expected %s but got nil\n", i, j, behavior.name, behavior.output)
					}
					if openValue.Value != behavior.output.open {
						t.Errorf("%d.%d(%s). Expected %s but got %s\n", i, j, behavior.name, behavior.output.open, openValue.Value)
					}
					if endValue.Value != behavior.output.end {
						t.Errorf("%d.%d(%s). Expected %s but got %s\n", i, j, behavior.name, behavior.output.end, endValue.Value)
					}
				}
			}
		}()
	}
}

func TestGetBoundaryValues(t *testing.T) {
	testGetBoundaryValues(t)
}

func BenchmarkGetBoundaryValues(b *testing.B) {
	for i := 0; i < b.N; i++ {
		testGetBoundaryValues(b)
	}
}

var testGetRangeValues = func(t test.Tester) {
	type value struct {
		year  int
		month time.Month
		day   int
		hour  int
		value float32
	}

	type input struct {
		openYear  int
		openMonth time.Month
		openDay   int
		openHour  int
		endYear   int
		endMonth  time.Month
		endDay    int
		endHour   int
		staleness time.Duration
	}

	type output struct {
		year  int
		month time.Month
		day   int
		hour  int
		value float32
	}

	type behavior struct {
		name   string
		input  input
		output []output
	}

	var contexts = []struct {
		name      string
		values    []value
		behaviors []behavior
	}{
		{
			name:   "no values",
			values: []value{},
			behaviors: []behavior{
				{
					name: "non-existent interval without staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
				},
				{
					name: "non-existent interval with staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
				},
			},
		},
		{
			name: "singleton value",
			values: []value{
				{
					year:  1984,
					month: 3,
					day:   30,
					hour:  0,
					value: 0,
				},
			},
			behaviors: []behavior{
				{
					name: "start on first value without staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
					},
				},
				{
					name: "start on first value with staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
					},
				},
				{
					name: "end on first value without staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1984,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
					},
				},
				{
					name: "end on first value with staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1984,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
					},
				},
				{
					name: "overlap on first value without staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
					},
				},
				{
					name: "overlap on first value with staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
					},
				},
			},
		},
		{
			name: "two values",
			values: []value{
				{
					year:  1984,
					month: 3,
					day:   30,
					hour:  0,
					value: 0,
				},
				{
					year:  1985,
					month: 3,
					day:   30,
					hour:  0,
					value: 1,
				},
			},
			behaviors: []behavior{
				{
					name: "start on first value without staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
						{
							year:  1985,
							month: 3,
							day:   30,
							hour:  0,
							value: 1,
						},
					},
				},
				{
					name: "start on first value with staleness policy",
					input: input{
						openYear:  1984,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
						{
							year:  1985,
							month: 3,
							day:   30,
							hour:  0,
							value: 1,
						},
					},
				},
				{
					name: "start on second value without staleness policy",
					input: input{
						openYear:  1985,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1986,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
					output: []output{
						{
							year:  1985,
							month: 3,
							day:   30,
							hour:  0,
							value: 1,
						},
					},
				},
				{
					name: "start on second value with staleness policy",
					input: input{
						openYear:  1985,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1986,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: []output{
						{
							year:  1985,
							month: 3,
							day:   30,
							hour:  0,
							value: 1,
						},
					},
				},
				{
					name: "end on first value without staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1984,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
					},
				},
				{
					name: "end on first value with staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1984,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
					},
				},
				{
					name: "end on second value without staleness policy",
					input: input{
						openYear:  1985,
						openMonth: 1,
						openDay:   1,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
					output: []output{
						{
							year:  1985,
							month: 3,
							day:   30,
							hour:  0,
							value: 1,
						},
					},
				},
				{
					name: "end on second value with staleness policy",
					input: input{
						openYear:  1985,
						openMonth: 1,
						openDay:   1,
						openHour:  0,
						endYear:   1985,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: []output{
						{
							year:  1985,
							month: 3,
							day:   30,
							hour:  0,
							value: 1,
						},
					},
				},
				{
					name: "overlap on values without staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1986,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(0),
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
						{
							year:  1985,
							month: 3,
							day:   30,
							hour:  0,
							value: 1,
						},
					},
				},
				{
					name: "overlap on values with staleness policy",
					input: input{
						openYear:  1983,
						openMonth: 3,
						openDay:   30,
						openHour:  0,
						endYear:   1986,
						endMonth:  3,
						endDay:    30,
						endHour:   0,
						staleness: time.Duration(365*24) * time.Hour,
					},
					output: []output{
						{
							year:  1984,
							month: 3,
							day:   30,
							hour:  0,
							value: 0,
						},
						{
							year:  1985,
							month: 3,
							day:   30,
							hour:  0,
							value: 1,
						},
					},
				},
			},
		},
	}

	for i, context := range contexts {
		// Wrapping in function to enable garbage collection of resources.
		func() {
			temporaryDirectory, _ := ioutil.TempDir("", "leveldb_metric_persistence_test")

			defer func() {
				if err := os.RemoveAll(temporaryDirectory); err != nil {
					t.Errorf("%d(%s). Could not remove temporary directory: %q\n", i, context.name, err)
				}
			}()

			persistence, _ := NewLevelDBMetricPersistence(temporaryDirectory)

			defer func() {
				persistence.Close()
			}()

			m := model.Metric{
				"name": "age_in_years",
			}

			for j, value := range context.values {
				err := persistence.AppendSample(&model.Sample{
					Value:     model.SampleValue(value.value),
					Timestamp: time.Date(value.year, value.month, value.day, value.hour, 0, 0, 0, time.UTC),
					Metric:    m,
				})

				if err != nil {
					t.Errorf("%d.%d(%s). Could not create sample: %q\n", i, j, context.name, err)
				}
			}

			for j, behavior := range context.behaviors {
				input := behavior.input
				open := time.Date(input.openYear, input.openMonth, input.openDay, input.openHour, 0, 0, 0, time.UTC)
				end := time.Date(input.endYear, input.endMonth, input.endDay, input.endHour, 0, 0, 0, time.UTC)
				i := model.Interval{
					OldestInclusive: open,
					NewestInclusive: end,
				}
				p := metric.StalenessPolicy{
					DeltaAllowance: input.staleness,
				}

				values, err := persistence.GetRangeValues(&m, &i, &p)
				if err != nil {
					t.Errorf("%d.%d(%s). Could not query for value: %q\n", i, j, behavior.name, err)
				}

				if values == nil && len(behavior.output) != 0 {
					t.Fatalf("%d.%d(%s). Expected %s but got: %s\n", i, j, behavior.name, behavior.output, values)
				}

				if behavior.output == nil {
					if values != nil {
						t.Fatalf("%d.%d(%s). Expected nil values but got: %s\n", i, j, behavior.name, values)
					}
				} else {
					if len(behavior.output) != len(values.Values) {
						t.Errorf("%d.%d(%s). Expected length %d but got: %d\n", i, j, len(behavior.output), len(values.Values))
					}

					for k, actual := range values.Values {
						expected := behavior.output[k]
						if actual.Value != model.SampleValue(expected.value) {
							t.Errorf("%d.%d.%d(%s). Expected %d but got: %d\n", i, j, k, len(behavior.output), actual)
						}
					}
				}
			}
		}()
	}
}

func TestGetRangeValues(t *testing.T) {
	testGetRangeValues(t)
}

func BenchmarkGetRangeValues(b *testing.B) {
	for i := 0; i < b.N; i++ {
		testGetRangeValues(b)
	}
}