package chunk

import (
	"bytes"
	"encoding/base64"
	"fmt"
	"reflect"
	"sort"
	"testing"

	jsoniter "github.com/json-iterator/go"
	"github.com/prometheus/common/model"
	"github.com/prometheus/prometheus/model/labels"
	"github.com/prometheus/prometheus/promql/parser"
	"github.com/stretchr/testify/require"
	"github.com/weaveworks/common/test"

	"github.com/cortexproject/cortex/pkg/querier/astmapper"
)

type ByHashRangeKey []IndexEntry

func (a ByHashRangeKey) Len() int      { return len(a) }
func (a ByHashRangeKey) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a ByHashRangeKey) Less(i, j int) bool {
	if a[i].HashValue != a[j].HashValue {
		return a[i].HashValue < a[j].HashValue
	}
	return bytes.Compare(a[i].RangeValue, a[j].RangeValue) < 0
}

func mergeResults(rss ...[]IndexEntry) []IndexEntry {
	results := []IndexEntry{}
	for _, rs := range rss {
		results = append(results, rs...)
	}
	return results
}

const table = "table"

func mustMakeSchema(schemaName string) BaseSchema {
	s, err := PeriodConfig{
		Schema:      schemaName,
		IndexTables: PeriodicTableConfig{Prefix: table},
	}.CreateSchema()
	if err != nil {
		panic(err)
	}
	return s
}

func makeSeriesStoreSchema(schemaName string) SeriesStoreSchema {
	return mustMakeSchema(schemaName).(SeriesStoreSchema)
}

func makeStoreSchema(schemaName string) StoreSchema {
	return mustMakeSchema(schemaName).(StoreSchema)
}

func TestSchemaHashKeys(t *testing.T) {
	mkResult := func(tableName, fmtStr string, from, through int) []IndexEntry {
		want := []IndexEntry{}
		for i := from; i < through; i++ {
			want = append(want, IndexEntry{
				TableName: tableName,
				HashValue: fmt.Sprintf(fmtStr, i),
			})
		}
		return want
	}

	const (
		userID         = "userid"
		periodicPrefix = "periodicPrefix"
	)

	hourlyBuckets := makeStoreSchema("v1")
	dailyBuckets := makeStoreSchema("v3")
	labelBuckets := makeStoreSchema("v4")
	metric := labels.Labels{
		{Name: model.MetricNameLabel, Value: "foo"},
		{Name: "bar", Value: "baz"},
	}
	chunkID := "chunkID"

	for i, tc := range []struct {
		StoreSchema
		from, through int64
		metricName    string
		want          []IndexEntry
	}{
		// Basic test case for the various bucketing schemes
		{
			hourlyBuckets,
			0, (30 * 60) - 1, "foo", // chunk is smaller than bucket
			mkResult(table, "userid:%d:foo", 0, 1),
		},
		{
			hourlyBuckets,
			0, (3 * 24 * 60 * 60) - 1, "foo",
			mkResult(table, "userid:%d:foo", 0, 3*24),
		},
		{
			hourlyBuckets,
			0, 30 * 60, "foo", // chunk is smaller than bucket
			mkResult(table, "userid:%d:foo", 0, 1),
		},
		{
			dailyBuckets,
			0, (3 * 24 * 60 * 60) - 1, "foo",
			mkResult(table, "userid:d%d:foo", 0, 3),
		},
		{
			labelBuckets,
			0, (3 * 24 * 60 * 60) - 1, "foo",
			mergeResults(
				mkResult(table, "userid:d%d:foo", 0, 3),
				mkResult(table, "userid:d%d:foo:bar", 0, 3),
			),
		},
	} {
		t.Run(fmt.Sprintf("TestSchemaHashKeys[%d]", i), func(t *testing.T) {
			have, err := tc.StoreSchema.GetWriteEntries(
				model.TimeFromUnix(tc.from), model.TimeFromUnix(tc.through),
				userID, tc.metricName,
				metric, chunkID,
			)
			if err != nil {
				t.Fatal(err)
			}
			for i := range have {
				have[i].RangeValue = nil
			}
			sort.Sort(ByHashRangeKey(have))
			sort.Sort(ByHashRangeKey(tc.want))
			if !reflect.DeepEqual(tc.want, have) {
				t.Fatalf("wrong hash buckets - %s", test.Diff(tc.want, have))
			}
		})
	}
}

// range value types
const (
	_ = iota
	MetricNameRangeValue
	ChunkTimeRangeValue
	SeriesRangeValue
)

// parseRangeValueType returns the type of rangeValue
func parseRangeValueType(rangeValue []byte) (int, error) {
	components := decodeRangeKey(rangeValue, make([][]byte, 0, 5))
	switch {
	case len(components) < 3:
		return 0, fmt.Errorf("invalid range value: %x", rangeValue)

	// v1 & v2 chunk time range values
	case len(components) == 3:
		return ChunkTimeRangeValue, nil

	// chunk time range values
	case len(components[3]) == 1:
		switch components[3][0] {
		case chunkTimeRangeKeyV1:
			return ChunkTimeRangeValue, nil

		case chunkTimeRangeKeyV2:
			return ChunkTimeRangeValue, nil

		case chunkTimeRangeKeyV3:
			return ChunkTimeRangeValue, nil

		case chunkTimeRangeKeyV4:
			return ChunkTimeRangeValue, nil

		case chunkTimeRangeKeyV5:
			return ChunkTimeRangeValue, nil

		// metric name range values
		case metricNameRangeKeyV1:
			return MetricNameRangeValue, nil

		// series range values
		case seriesRangeKeyV1:
			return SeriesRangeValue, nil
		}
	}
	return 0, fmt.Errorf("unrecognised range value type. version: %q", string(components[3]))
}

func TestSchemaRangeKey(t *testing.T) {
	const (
		userID     = "userid"
		metricName = "foo"
		chunkID    = "chunkID"
	)

	var (
		hourlyBuckets = makeStoreSchema("v1")
		dailyBuckets  = makeStoreSchema("v2")
		base64Keys    = makeStoreSchema("v3")
		labelBuckets  = makeStoreSchema("v4")
		tsRangeKeys   = makeStoreSchema("v5")
		v6RangeKeys   = makeStoreSchema("v6")
		metric        = labels.Labels{
			{Name: model.MetricNameLabel, Value: metricName},
			{Name: "bar", Value: "bary"},
			{Name: "baz", Value: "bazy"},
		}
	)

	mkEntries := func(hashKey string, callback func(labelName, labelValue string) ([]byte, []byte)) []IndexEntry {
		result := []IndexEntry{}
		for _, label := range metric {
			if label.Name == model.MetricNameLabel {
				continue
			}
			rangeValue, value := callback(label.Name, label.Value)
			result = append(result, IndexEntry{
				TableName:  table,
				HashValue:  hashKey,
				RangeValue: rangeValue,
				Value:      value,
			})
		}
		return result
	}

	for i, tc := range []struct {
		StoreSchema
		want []IndexEntry
	}{
		// Basic test case for the various bucketing schemes
		{
			hourlyBuckets,
			mkEntries("userid:0:foo", func(labelName, labelValue string) ([]byte, []byte) {
				return []byte(fmt.Sprintf("%s\x00%s\x00%s\x00", labelName, labelValue, chunkID)), nil
			}),
		},
		{
			dailyBuckets,
			mkEntries("userid:d0:foo", func(labelName, labelValue string) ([]byte, []byte) {
				return []byte(fmt.Sprintf("%s\x00%s\x00%s\x00", labelName, labelValue, chunkID)), nil
			}),
		},
		{
			base64Keys,
			mkEntries("userid:d0:foo", func(labelName, labelValue string) ([]byte, []byte) {
				encodedValue := base64.RawStdEncoding.EncodeToString([]byte(labelValue))
				return []byte(fmt.Sprintf("%s\x00%s\x00%s\x001\x00", labelName, encodedValue, chunkID)), nil
			}),
		},
		{
			labelBuckets,
			[]IndexEntry{
				{
					TableName:  table,
					HashValue:  "userid:d0:foo",
					RangeValue: []byte("\x00\x00chunkID\x002\x00"),
				},
				{
					TableName:  table,
					HashValue:  "userid:d0:foo:bar",
					RangeValue: []byte("\x00YmFyeQ\x00chunkID\x001\x00"),
				},
				{
					TableName:  table,
					HashValue:  "userid:d0:foo:baz",
					RangeValue: []byte("\x00YmF6eQ\x00chunkID\x001\x00"),
				},
			},
		},
		{
			tsRangeKeys,
			[]IndexEntry{
				{
					TableName:  table,
					HashValue:  "userid:d0:foo",
					RangeValue: []byte("0036ee7f\x00\x00chunkID\x003\x00"),
				},
				{
					TableName:  table,
					HashValue:  "userid:d0:foo:bar",
					RangeValue: []byte("0036ee7f\x00YmFyeQ\x00chunkID\x004\x00"),
				},
				{
					TableName:  table,
					HashValue:  "userid:d0:foo:baz",
					RangeValue: []byte("0036ee7f\x00YmF6eQ\x00chunkID\x004\x00"),
				},
			},
		},
		{
			v6RangeKeys,
			[]IndexEntry{
				{
					TableName:  table,
					HashValue:  "userid:d0:foo",
					RangeValue: []byte("0036ee7f\x00\x00chunkID\x003\x00"),
				},
				{
					TableName:  table,
					HashValue:  "userid:d0:foo:bar",
					RangeValue: []byte("0036ee7f\x00\x00chunkID\x005\x00"),
					Value:      []byte("bary"),
				},
				{
					TableName:  table,
					HashValue:  "userid:d0:foo:baz",
					RangeValue: []byte("0036ee7f\x00\x00chunkID\x005\x00"),
					Value:      []byte("bazy"),
				},
			},
		},
	} {
		t.Run(fmt.Sprintf("TestSchameRangeKey[%d]", i), func(t *testing.T) {
			have, err := tc.StoreSchema.GetWriteEntries(
				model.TimeFromUnix(0), model.TimeFromUnix(60*60)-1,
				userID, metricName,
				metric, chunkID,
			)
			if err != nil {
				t.Fatal(err)
			}
			sort.Sort(ByHashRangeKey(have))
			sort.Sort(ByHashRangeKey(tc.want))
			if !reflect.DeepEqual(tc.want, have) {
				t.Fatalf("wrong hash buckets - %s", test.Diff(tc.want, have))
			}

			// Test we can parse the resulting range keys
			for _, entry := range have {
				rangeValueType, err := parseRangeValueType(entry.RangeValue)
				require.NoError(t, err)

				switch rangeValueType {
				case MetricNameRangeValue:
					_, err := parseMetricNameRangeValue(entry.RangeValue, entry.Value)
					require.NoError(t, err)
				case ChunkTimeRangeValue:
					_, _, err := parseChunkTimeRangeValue(entry.RangeValue, entry.Value)
					require.NoError(t, err)
				case SeriesRangeValue:
					_, err := parseSeriesRangeValue(entry.RangeValue, entry.Value)
					require.NoError(t, err)
				}
			}
		})
	}
}

func BenchmarkEncodeLabelsJson(b *testing.B) {
	decoded := &labels.Labels{}
	lbs := labels.FromMap(map[string]string{
		"foo":      "bar",
		"fuzz":     "buzz",
		"cluster":  "test",
		"test":     "test1",
		"instance": "cortex-01",
		"bar":      "foo",
		"version":  "0.1",
	})
	json := jsoniter.ConfigFastest
	var data []byte
	var err error
	for n := 0; n < b.N; n++ {
		data, err = json.Marshal(lbs)
		if err != nil {
			panic(err)
		}
		err = json.Unmarshal(data, decoded)
		if err != nil {
			panic(err)
		}
	}
	b.Log("data size", len(data))
	b.Log("decode", decoded)
}

func BenchmarkEncodeLabelsString(b *testing.B) {
	var decoded labels.Labels
	lbs := labels.FromMap(map[string]string{
		"foo":      "bar",
		"fuzz":     "buzz",
		"cluster":  "test",
		"test":     "test1",
		"instance": "cortex-01",
		"bar":      "foo",
		"version":  "0.1",
	})
	var data []byte
	var err error
	for n := 0; n < b.N; n++ {
		data = []byte(lbs.String())
		decoded, err = parser.ParseMetric(string(data))
		if err != nil {
			panic(err)
		}
	}
	b.Log("data size", len(data))
	b.Log("decode", decoded)
}

func TestV10IndexQueries(t *testing.T) {
	fromShards := func(n int) (res []IndexQuery) {
		for i := 0; i < n; i++ {
			res = append(res, IndexQuery{
				TableName:       "tbl",
				HashValue:       fmt.Sprintf("%02d:%s:%s:%s", i, "hash", "metric", "label"),
				RangeValueStart: []byte(fmt.Sprint(i)),
				ValueEqual:      []byte(fmt.Sprint(i)),
			})
		}
		return res
	}

	var testExprs = []struct {
		name     string
		queries  []IndexQuery
		shard    *astmapper.ShardAnnotation
		expected []IndexQuery
	}{
		{
			name:     "passthrough when no shard specified",
			queries:  fromShards(2),
			shard:    nil,
			expected: fromShards(2),
		},
		{
			name:    "out of bounds shard returns 0 matches",
			queries: fromShards(2),
			shard: &astmapper.ShardAnnotation{
				Shard: 3,
			},
			expected: nil,
		},
		{
			name:    "return correct shard",
			queries: fromShards(3),
			shard: &astmapper.ShardAnnotation{
				Shard: 1,
			},
			expected: []IndexQuery{fromShards(2)[1]},
		},
	}

	for _, c := range testExprs {
		t.Run(c.name, func(t *testing.T) {
			s := v10Entries{}
			filtered := s.FilterReadQueries(c.queries, c.shard)
			require.Equal(t, c.expected, filtered)
		})
	}
}