// Copyright 2017 The Prometheus Authors
// 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 tsdb

import (
	"io/ioutil"
	"math"
	"math/rand"
	"os"
	"sort"
	"testing"
	"time"
	"unsafe"

	"github.com/pkg/errors"
	"github.com/prometheus/tsdb/labels"

	promlabels "github.com/prometheus/prometheus/pkg/labels"
	"github.com/prometheus/prometheus/pkg/textparse"
	"github.com/stretchr/testify/require"
)

// createTestHeadBlock creates a new head block with a SegmentWAL.
func createTestHeadBlock(t testing.TB, dir string, mint, maxt int64) *HeadBlock {
	dir, err := TouchHeadBlock(dir, mint, maxt)
	require.NoError(t, err)

	return openTestHeadBlock(t, dir)
}

func openTestHeadBlock(t testing.TB, dir string) *HeadBlock {
	wal, err := OpenSegmentWAL(dir, nil, 5*time.Second)
	require.NoError(t, err)

	h, err := OpenHeadBlock(dir, nil, wal)
	require.NoError(t, err)
	return h
}

func BenchmarkCreateSeries(b *testing.B) {
	lbls, err := readPrometheusLabels("cmd/tsdb/testdata.1m", 1e6)
	require.NoError(b, err)

	b.Run("", func(b *testing.B) {
		dir, err := ioutil.TempDir("", "create_series_bench")
		require.NoError(b, err)
		defer os.RemoveAll(dir)

		h := createTestHeadBlock(b, dir, 0, 1)

		b.ReportAllocs()
		b.ResetTimer()

		for _, l := range lbls[:b.N] {
			h.create(l.Hash(), l)
		}
	})
}

func readPrometheusLabels(fn string, n int) ([]labels.Labels, error) {
	f, err := os.Open(fn)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	b, err := ioutil.ReadAll(f)
	if err != nil {
		return nil, err
	}

	p := textparse.New(b)
	i := 0
	var mets []labels.Labels
	hashes := map[uint64]struct{}{}

	for p.Next() && i < n {
		m := make(labels.Labels, 0, 10)
		p.Metric((*promlabels.Labels)(unsafe.Pointer(&m)))

		h := m.Hash()
		if _, ok := hashes[h]; ok {
			continue
		}
		mets = append(mets, m)
		hashes[h] = struct{}{}
		i++
	}
	if err := p.Err(); err != nil {
		return nil, err
	}
	if i != n {
		return mets, errors.Errorf("requested %d metrics but found %d", n, i)
	}
	return mets, nil
}

func TestAmendDatapointCausesError(t *testing.T) {
	dir, _ := ioutil.TempDir("", "test")
	defer os.RemoveAll(dir)

	hb := createTestHeadBlock(t, dir, 0, 1000)

	app := hb.Appender()
	_, err := app.Add(labels.Labels{}, 0, 0)
	require.NoError(t, err, "Failed to add sample")
	require.NoError(t, app.Commit(), "Unexpected error committing appender")

	app = hb.Appender()
	_, err = app.Add(labels.Labels{}, 0, 1)
	require.Equal(t, ErrAmendSample, err)
}

func TestDuplicateNaNDatapointNoAmendError(t *testing.T) {
	dir, _ := ioutil.TempDir("", "test")
	defer os.RemoveAll(dir)

	hb := createTestHeadBlock(t, dir, 0, 1000)

	app := hb.Appender()
	_, err := app.Add(labels.Labels{}, 0, math.NaN())
	require.NoError(t, err, "Failed to add sample")
	require.NoError(t, app.Commit(), "Unexpected error committing appender")

	app = hb.Appender()
	_, err = app.Add(labels.Labels{}, 0, math.NaN())
	require.NoError(t, err)
}

func TestNonDuplicateNaNDatapointsCausesAmendError(t *testing.T) {
	dir, _ := ioutil.TempDir("", "test")
	defer os.RemoveAll(dir)

	hb := createTestHeadBlock(t, dir, 0, 1000)

	app := hb.Appender()
	_, err := app.Add(labels.Labels{}, 0, math.Float64frombits(0x7ff0000000000001))
	require.NoError(t, err, "Failed to add sample")
	require.NoError(t, app.Commit(), "Unexpected error committing appender")

	app = hb.Appender()
	_, err = app.Add(labels.Labels{}, 0, math.Float64frombits(0x7ff0000000000002))
	require.Equal(t, ErrAmendSample, err)
}

func TestSkippingInvalidValuesInSameTxn(t *testing.T) {
	dir, _ := ioutil.TempDir("", "test")
	defer os.RemoveAll(dir)

	hb := createTestHeadBlock(t, dir, 0, 1000)

	// Append AmendedValue.
	app := hb.Appender()
	_, err := app.Add(labels.Labels{{"a", "b"}}, 0, 1)
	require.NoError(t, err)
	_, err = app.Add(labels.Labels{{"a", "b"}}, 0, 2)
	require.NoError(t, err)
	require.NoError(t, app.Commit())
	require.Equal(t, uint64(1), hb.Meta().Stats.NumSamples)

	// Make sure the right value is stored.
	q := hb.Querier(0, 10)
	ss := q.Select(labels.NewEqualMatcher("a", "b"))
	ssMap, err := readSeriesSet(ss)
	require.NoError(t, err)

	require.Equal(t, map[string][]sample{
		labels.New(labels.Label{"a", "b"}).String(): []sample{{0, 1}},
	}, ssMap)

	require.NoError(t, q.Close())

	// Append Out of Order Value.
	app = hb.Appender()
	_, err = app.Add(labels.Labels{{"a", "b"}}, 10, 3)
	require.NoError(t, err)
	_, err = app.Add(labels.Labels{{"a", "b"}}, 7, 5)
	require.NoError(t, err)
	require.NoError(t, app.Commit())
	require.Equal(t, uint64(2), hb.Meta().Stats.NumSamples)

	q = hb.Querier(0, 10)
	ss = q.Select(labels.NewEqualMatcher("a", "b"))
	ssMap, err = readSeriesSet(ss)
	require.NoError(t, err)

	require.Equal(t, map[string][]sample{
		labels.New(labels.Label{"a", "b"}).String(): []sample{{0, 1}, {10, 3}},
	}, ssMap)
	require.NoError(t, q.Close())
}

func TestHeadBlock_e2e(t *testing.T) {
	numDatapoints := 1000
	numRanges := 1000
	timeInterval := int64(3)
	maxTime := int64(2 * 1000)
	minTime := int64(200)
	// Create 8 series with 1000 data-points of different ranges and run queries.
	lbls := [][]labels.Label{
		{
			{"a", "b"},
			{"instance", "localhost:9090"},
			{"job", "prometheus"},
		},
		{
			{"a", "b"},
			{"instance", "127.0.0.1:9090"},
			{"job", "prometheus"},
		},
		{
			{"a", "b"},
			{"instance", "127.0.0.1:9090"},
			{"job", "prom-k8s"},
		},
		{
			{"a", "b"},
			{"instance", "localhost:9090"},
			{"job", "prom-k8s"},
		},
		{
			{"a", "c"},
			{"instance", "localhost:9090"},
			{"job", "prometheus"},
		},
		{
			{"a", "c"},
			{"instance", "127.0.0.1:9090"},
			{"job", "prometheus"},
		},
		{
			{"a", "c"},
			{"instance", "127.0.0.1:9090"},
			{"job", "prom-k8s"},
		},
		{
			{"a", "c"},
			{"instance", "localhost:9090"},
			{"job", "prom-k8s"},
		},
	}

	seriesMap := map[string][]sample{}
	for _, l := range lbls {
		seriesMap[labels.New(l...).String()] = []sample{}
	}

	dir, _ := ioutil.TempDir("", "test")
	defer os.RemoveAll(dir)

	hb := createTestHeadBlock(t, dir, minTime, maxTime)
	app := hb.Appender()

	for _, l := range lbls {
		ls := labels.New(l...)
		series := []sample{}

		ts := rand.Int63n(300)
		for i := 0; i < numDatapoints; i++ {
			v := rand.Float64()
			if ts >= minTime && ts <= maxTime {
				series = append(series, sample{ts, v})
			}

			_, err := app.Add(ls, ts, v)
			if ts >= minTime && ts <= maxTime {
				require.NoError(t, err)
			} else {
				require.Error(t, ErrOutOfBounds, err)
			}

			ts += rand.Int63n(timeInterval) + 1
		}

		seriesMap[labels.New(l...).String()] = series
	}

	require.NoError(t, app.Commit())

	// Query each selector on 1000 random time-ranges.
	queries := []struct {
		ms []labels.Matcher
	}{
		{
			ms: []labels.Matcher{labels.NewEqualMatcher("a", "b")},
		},
		{
			ms: []labels.Matcher{
				labels.NewEqualMatcher("a", "b"),
				labels.NewEqualMatcher("job", "prom-k8s"),
			},
		},
		{
			ms: []labels.Matcher{
				labels.NewEqualMatcher("a", "c"),
				labels.NewEqualMatcher("instance", "localhost:9090"),
				labels.NewEqualMatcher("job", "prometheus"),
			},
		},
		// TODO: Add Regexp Matchers.
	}

	for _, qry := range queries {
		matched := labels.Slice{}
		for _, ls := range lbls {
			s := labels.Selector(qry.ms)
			if s.Matches(ls) {
				matched = append(matched, ls)
			}
		}

		sort.Sort(matched)

		for i := 0; i < numRanges; i++ {
			mint := rand.Int63n(300)
			maxt := mint + rand.Int63n(timeInterval*int64(numDatapoints))

			q := hb.Querier(mint, maxt)
			ss := q.Select(qry.ms...)

			// Build the mockSeriesSet.
			matchedSeries := make([]Series, 0, len(matched))
			for _, m := range matched {
				smpls := boundedSamples(seriesMap[m.String()], mint, maxt)

				// Only append those series for which samples exist as mockSeriesSet
				// doesn't skip series with no samples.
				// TODO: But sometimes SeriesSet returns an empty SeriesIterator
				if len(smpls) > 0 {
					matchedSeries = append(matchedSeries, newSeries(
						m.Map(),
						smpls,
					))
				}
			}
			expSs := newListSeriesSet(matchedSeries)

			// Compare both SeriesSets.
			for {
				eok, rok := expSs.Next(), ss.Next()

				// Skip a series if iterator is empty.
				if rok {
					for !ss.At().Iterator().Next() {
						rok = ss.Next()
						if !rok {
							break
						}
					}
				}

				require.Equal(t, eok, rok, "next")

				if !eok {
					break
				}
				sexp := expSs.At()
				sres := ss.At()

				require.Equal(t, sexp.Labels(), sres.Labels(), "labels")

				smplExp, errExp := expandSeriesIterator(sexp.Iterator())
				smplRes, errRes := expandSeriesIterator(sres.Iterator())

				require.Equal(t, errExp, errRes, "samples error")
				require.Equal(t, smplExp, smplRes, "samples")
			}
		}
	}

	return
}

func TestHBDeleteSimple(t *testing.T) {
	numSamples := int64(10)

	dir, _ := ioutil.TempDir("", "test")
	defer os.RemoveAll(dir)

	hb := createTestHeadBlock(t, dir, 0, numSamples)
	app := hb.Appender()

	smpls := make([]float64, numSamples)
	for i := int64(0); i < numSamples; i++ {
		smpls[i] = rand.Float64()
		app.Add(labels.Labels{{"a", "b"}}, i, smpls[i])
	}

	require.NoError(t, app.Commit())
	cases := []struct {
		intervals intervals
		remaint   []int64
	}{
		{
			intervals: intervals{{0, 3}},
			remaint:   []int64{4, 5, 6, 7, 8, 9},
		},
		{
			intervals: intervals{{1, 3}},
			remaint:   []int64{0, 4, 5, 6, 7, 8, 9},
		},
		{
			intervals: intervals{{1, 3}, {4, 7}},
			remaint:   []int64{0, 8, 9},
		},
		{
			intervals: intervals{{1, 3}, {4, 700}},
			remaint:   []int64{0},
		},
		{
			intervals: intervals{{0, 9}},
			remaint:   []int64{},
		},
	}

Outer:
	for _, c := range cases {
		// Reset the tombstones.
		hb.tombstones = newEmptyTombstoneReader()

		// Delete the ranges.
		for _, r := range c.intervals {
			require.NoError(t, hb.Delete(r.mint, r.maxt, labels.NewEqualMatcher("a", "b")))
		}

		// Compare the result.
		q := hb.Querier(0, numSamples)
		res := q.Select(labels.NewEqualMatcher("a", "b"))

		expSamples := make([]sample, 0, len(c.remaint))
		for _, ts := range c.remaint {
			expSamples = append(expSamples, sample{ts, smpls[ts]})
		}

		expss := newListSeriesSet([]Series{
			newSeries(map[string]string{"a": "b"}, expSamples),
		})

		if len(expSamples) == 0 {
			require.False(t, res.Next())
			continue
		}

		for {
			eok, rok := expss.Next(), res.Next()
			require.Equal(t, eok, rok, "next")

			if !eok {
				continue Outer
			}
			sexp := expss.At()
			sres := res.At()

			require.Equal(t, sexp.Labels(), sres.Labels(), "labels")

			smplExp, errExp := expandSeriesIterator(sexp.Iterator())
			smplRes, errRes := expandSeriesIterator(sres.Iterator())

			require.Equal(t, errExp, errRes, "samples error")
			require.Equal(t, smplExp, smplRes, "samples")
		}
	}
}

func TestDeleteUntilCurMax(t *testing.T) {
	numSamples := int64(10)

	dir, _ := ioutil.TempDir("", "test")
	defer os.RemoveAll(dir)

	hb := createTestHeadBlock(t, dir, 0, 2*numSamples)
	app := hb.Appender()

	smpls := make([]float64, numSamples)
	for i := int64(0); i < numSamples; i++ {
		smpls[i] = rand.Float64()
		app.Add(labels.Labels{{"a", "b"}}, i, smpls[i])
	}

	require.NoError(t, app.Commit())
	require.NoError(t, hb.Delete(0, 10000, labels.NewEqualMatcher("a", "b")))
	app = hb.Appender()
	_, err := app.Add(labels.Labels{{"a", "b"}}, 11, 1)
	require.NoError(t, err)
	require.NoError(t, app.Commit())

	q := hb.Querier(0, 100000)
	res := q.Select(labels.NewEqualMatcher("a", "b"))

	require.True(t, res.Next())
	exps := res.At()
	it := exps.Iterator()
	ressmpls, err := expandSeriesIterator(it)
	require.NoError(t, err)
	require.Equal(t, []sample{{11, 1}}, ressmpls)
}

func TestDelete_e2e(t *testing.T) {
	numDatapoints := 1000
	numRanges := 1000
	timeInterval := int64(2)
	maxTime := int64(2 * 1000)
	minTime := int64(200)
	// Create 8 series with 1000 data-points of different ranges, delete and run queries.
	lbls := [][]labels.Label{
		{
			{"a", "b"},
			{"instance", "localhost:9090"},
			{"job", "prometheus"},
		},
		{
			{"a", "b"},
			{"instance", "127.0.0.1:9090"},
			{"job", "prometheus"},
		},
		{
			{"a", "b"},
			{"instance", "127.0.0.1:9090"},
			{"job", "prom-k8s"},
		},
		{
			{"a", "b"},
			{"instance", "localhost:9090"},
			{"job", "prom-k8s"},
		},
		{
			{"a", "c"},
			{"instance", "localhost:9090"},
			{"job", "prometheus"},
		},
		{
			{"a", "c"},
			{"instance", "127.0.0.1:9090"},
			{"job", "prometheus"},
		},
		{
			{"a", "c"},
			{"instance", "127.0.0.1:9090"},
			{"job", "prom-k8s"},
		},
		{
			{"a", "c"},
			{"instance", "localhost:9090"},
			{"job", "prom-k8s"},
		},
	}

	seriesMap := map[string][]sample{}
	for _, l := range lbls {
		seriesMap[labels.New(l...).String()] = []sample{}
	}

	dir, _ := ioutil.TempDir("", "test")
	defer os.RemoveAll(dir)

	hb := createTestHeadBlock(t, dir, minTime, maxTime)
	app := hb.Appender()

	for _, l := range lbls {
		ls := labels.New(l...)
		series := []sample{}

		ts := rand.Int63n(300)
		for i := 0; i < numDatapoints; i++ {
			v := rand.Float64()
			if ts >= minTime && ts <= maxTime {
				series = append(series, sample{ts, v})
			}

			_, err := app.Add(ls, ts, v)
			if ts >= minTime && ts <= maxTime {
				require.NoError(t, err)
			} else {
				require.Error(t, ErrOutOfBounds, err)
			}

			ts += rand.Int63n(timeInterval) + 1
		}

		seriesMap[labels.New(l...).String()] = series
	}

	require.NoError(t, app.Commit())

	// Delete a time-range from each-selector.
	dels := []struct {
		ms     []labels.Matcher
		drange intervals
	}{
		{
			ms:     []labels.Matcher{labels.NewEqualMatcher("a", "b")},
			drange: intervals{{300, 500}, {600, 670}},
		},
		{
			ms: []labels.Matcher{
				labels.NewEqualMatcher("a", "b"),
				labels.NewEqualMatcher("job", "prom-k8s"),
			},
			drange: intervals{{300, 500}, {100, 670}},
		},
		{
			ms: []labels.Matcher{
				labels.NewEqualMatcher("a", "c"),
				labels.NewEqualMatcher("instance", "localhost:9090"),
				labels.NewEqualMatcher("job", "prometheus"),
			},
			drange: intervals{{300, 400}, {100, 6700}},
		},
		// TODO: Add Regexp Matchers.
	}

	for _, del := range dels {
		// Reset the deletes everytime.
		writeTombstoneFile(hb.dir, newEmptyTombstoneReader())
		hb.tombstones = newEmptyTombstoneReader()

		for _, r := range del.drange {
			require.NoError(t, hb.Delete(r.mint, r.maxt, del.ms...))
		}

		matched := labels.Slice{}
		for _, ls := range lbls {
			s := labels.Selector(del.ms)
			if s.Matches(ls) {
				matched = append(matched, ls)
			}
		}

		sort.Sort(matched)

		for i := 0; i < numRanges; i++ {
			mint := rand.Int63n(200)
			maxt := mint + rand.Int63n(timeInterval*int64(numDatapoints))

			q := hb.Querier(mint, maxt)
			ss := q.Select(del.ms...)

			// Build the mockSeriesSet.
			matchedSeries := make([]Series, 0, len(matched))
			for _, m := range matched {
				smpls := boundedSamples(seriesMap[m.String()], mint, maxt)
				smpls = deletedSamples(smpls, del.drange)

				// Only append those series for which samples exist as mockSeriesSet
				// doesn't skip series with no samples.
				// TODO: But sometimes SeriesSet returns an empty SeriesIterator
				if len(smpls) > 0 {
					matchedSeries = append(matchedSeries, newSeries(
						m.Map(),
						smpls,
					))
				}
			}
			expSs := newListSeriesSet(matchedSeries)

			// Compare both SeriesSets.
			for {
				eok, rok := expSs.Next(), ss.Next()

				// Skip a series if iterator is empty.
				if rok {
					for !ss.At().Iterator().Next() {
						rok = ss.Next()
						if !rok {
							break
						}
					}
				}
				require.Equal(t, eok, rok, "next")

				if !eok {
					break
				}
				sexp := expSs.At()
				sres := ss.At()

				require.Equal(t, sexp.Labels(), sres.Labels(), "labels")

				smplExp, errExp := expandSeriesIterator(sexp.Iterator())
				smplRes, errRes := expandSeriesIterator(sres.Iterator())

				require.Equal(t, errExp, errRes, "samples error")
				require.Equal(t, smplExp, smplRes, "samples")
			}
		}
	}

	return
}

func boundedSamples(full []sample, mint, maxt int64) []sample {
	for len(full) > 0 {
		if full[0].t >= mint {
			break
		}
		full = full[1:]
	}
	for i, s := range full {
		// Terminate on the first sample larger than maxt.
		if s.t > maxt {
			return full[:i]
		}
	}
	// maxt is after highest sample.
	return full
}

func deletedSamples(full []sample, dranges intervals) []sample {
	ds := make([]sample, 0, len(full))
Outer:
	for _, s := range full {
		for _, r := range dranges {
			if r.inBounds(s.t) {
				continue Outer
			}
		}

		ds = append(ds, s)
	}

	return ds
}

func TestComputeChunkEndTime(t *testing.T) {
	cases := []struct {
		start, cur, max int64
		res             int64
	}{
		{
			start: 0,
			cur:   250,
			max:   1000,
			res:   1000,
		},
		{
			start: 100,
			cur:   200,
			max:   1000,
			res:   550,
		},
		// Case where we fit floored 0 chunks. Must catch division by 0
		// and default to maximum time.
		{
			start: 0,
			cur:   500,
			max:   1000,
			res:   1000,
		},
		// Catch divison by zero for cur == start. Strictly not a possible case.
		{
			start: 100,
			cur:   100,
			max:   1000,
			res:   104,
		},
	}

	for _, c := range cases {
		got := computeChunkEndTime(c.start, c.cur, c.max)
		if got != c.res {
			t.Errorf("expected %d for (start: %d, cur: %d, max: %d), got %d", c.res, c.start, c.cur, c.max, got)
		}
	}
}