// 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"
	"os"
	"testing"
	"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"
)

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, err := NewHead(nil, nil, 10000)
		if err != nil {
			require.NoError(b, err)
		}

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

// 	hb, close := openTestDB(t, nil)
// 	defer close()

// 	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 := createTestHead(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 := createTestHead(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.EqualError(t, err, ErrOutOfBounds.Error())
// 			}

// 			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)
		}
	}
}