package promql

import (
	"fmt"
	"reflect"
	"strconv"
	"strings"
	"testing"

	"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus"
	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
)

func TestFixBrokenBuckets(t *testing.T) {
	f := func(values, expectedResult []float64) {
		t.Helper()
		xss := make([]leTimeseries, len(values))
		for i, v := range values {
			xss[i].ts = &timeseries{
				Values: []float64{v},
			}
		}
		fixBrokenBuckets(0, xss)
		result := make([]float64, len(values))
		for i, xs := range xss {
			result[i] = xs.ts.Values[0]
		}
		if !reflect.DeepEqual(result, expectedResult) {
			t.Fatalf("unexpected result for values=%v\ngot\n%v\nwant\n%v", values, result, expectedResult)
		}
	}
	f(nil, []float64{})
	f([]float64{1}, []float64{1})
	f([]float64{1, 2}, []float64{1, 2})
	f([]float64{2, 1}, []float64{2, 2})
	f([]float64{1, 2, 3, nan, nan}, []float64{1, 2, 3, 3, 3})
	f([]float64{5, 1, 2, 3, nan}, []float64{5, 5, 5, 5, 5})
	f([]float64{1, 5, 2, nan, 6, 3}, []float64{1, 5, 5, 5, 6, 6})
	f([]float64{5, 10, 4, 3}, []float64{5, 10, 10, 10})
}

func TestVmrangeBucketsToLE(t *testing.T) {
	f := func(buckets, bucketsExpected string) {
		t.Helper()
		tss := promMetricsToTimeseries(buckets)
		result := vmrangeBucketsToLE(tss)
		resultBuckets := timeseriesToPromMetrics(result)
		if !reflect.DeepEqual(resultBuckets, bucketsExpected) {
			t.Fatalf("unexpected vmrangeBucketsToLE(); got\n%v\nwant\n%v", resultBuckets, bucketsExpected)
		}
	}

	// A single non-empty vmrange bucket
	f(
		`foo{vmrange="4.084e+02...4.642e+02"} 2 123`,
		`foo{le="4.084e+02"} 0 123
foo{le="4.642e+02"} 2 123
foo{le="+Inf"} 2 123`,
	)
	f(
		`foo{vmrange="0...+Inf"} 5 123`,
		`foo{le="+Inf"} 5 123`,
	)
	f(
		`foo{vmrange="-Inf...0"} 4 123`,
		`foo{le="-Inf"} 0 123
foo{le="0"} 4 123
foo{le="+Inf"} 4 123`,
	)
	f(
		`foo{vmrange="-Inf...+Inf"} 1.23 456`,
		`foo{le="-Inf"} 0 456
foo{le="+Inf"} 1.23 456`,
	)
	f(
		`foo{vmrange="0...0"} 5.3 0`,
		`foo{le="0"} 5.3 0
foo{le="+Inf"} 5.3 0`,
	)

	// Adjacent empty vmrange bucket
	f(
		`foo{vmrange="7.743e+05...8.799e+05"} 5 123
foo{vmrange="6.813e+05...7.743e+05"} 0 123`,
		`foo{le="7.743e+05"} 0 123
foo{le="8.799e+05"} 5 123
foo{le="+Inf"} 5 123`,
	)

	// Multiple adjacent empty vmrange bucket
	f(
		`foo{vmrange="7.743e+05...8.799e+05"} 5 123
foo{vmrange="6.813e+05...7.743e+05"} 0 123
foo{vmrange="5.813e+05...6.813e+05"} 0 123
`,
		`foo{le="7.743e+05"} 0 123
foo{le="8.799e+05"} 5 123
foo{le="+Inf"} 5 123`,
	)
	f(
		`foo{vmrange="8.799e+05...9.813e+05"} 0 123
foo{vmrange="7.743e+05...8.799e+05"} 5 123
foo{vmrange="6.813e+05...7.743e+05"} 0 123
foo{vmrange="5.813e+05...6.813e+05"} 0 123
`,
		`foo{le="7.743e+05"} 0 123
foo{le="8.799e+05"} 5 123
foo{le="+Inf"} 5 123`,
	)

	// Multiple non-empty vmrange buckets
	f(
		`foo{vmrange="4.084e+02...4.642e+02"} 2 123
foo{vmrange="1.234e+02...4.084e+02"} 3 123
`,
		`foo{le="1.234e+02"} 0 123
foo{le="4.084e+02"} 3 123
foo{le="4.642e+02"} 5 123
foo{le="+Inf"} 5 123`,
	)

	// Multiple disjoint vmrange buckets
	f(
		`foo{vmrange="1...2"} 2 123
foo{vmrange="4...6"} 3 123
`,
		`foo{le="1"} 0 123
foo{le="2"} 2 123
foo{le="4"} 2 123
foo{le="6"} 5 123
foo{le="+Inf"} 5 123`,
	)

	// Multiple intersected vmrange buckets
	f(
		`foo{vmrange="1...5"} 2 123
foo{vmrange="4...6"} 3 123
`,
		`foo{le="1"} 0 123
foo{le="5"} 2 123
foo{le="4"} 2 123
foo{le="6"} 5 123
foo{le="+Inf"} 5 123`,
	)

	// Multiple vmrange buckets with the same end range
	f(
		`foo{vmrange="1...5"} 2 123
foo{vmrange="0...5"} 3 123
`,
		`foo{le="1"} 0 123
foo{le="5"} 2 123
foo{le="0"} 2 123
foo{le="+Inf"} 2 123`,
	)

	// A single empty vmrange bucket
	f(
		`foo{vmrange="0...1"} 0 123`,
		``,
	)
	f(
		`foo{vmrange="0...+Inf"} 0 123`,
		``,
	)
	f(
		`foo{vmrange="-Inf...0"} 0 123`,
		``,
	)
	f(
		`foo{vmrange="0...0"} 0 0`,
		``,
	)
	f(
		`foo{vmrange="-Inf...+Inf"} 0 456`,
		``,
	)

	// Multiple empty vmrange buckets
	f(
		`foo{vmrange="2...3"} 0 123
foo{vmrange="1...2"} 0 123`,
		``,
	)

	// The bucket with negative value
	f(
		`foo{vmrange="4.084e+02...4.642e+02"} -5 1`,
		``,
	)

	// Missing vmrange in the original metric
	f(
		`foo 3 6`,
		``,
	)

	// Missing le label in the original metric
	f(
		`foo{le="456"} 3 6`,
		`foo{le="456"} 3 6`,
	)

	// Invalid vmrange label value
	f(
		`foo{vmrange="foo...bar"} 1 1`,
		``,
	)
	f(
		`foo{vmrange="4.084e+02"} 1 1`,
		``,
	)
	f(
		`foo{vmrange="4.084e+02...foo"} 1 1`,
		``,
	)
}

func promMetricsToTimeseries(s string) []*timeseries {
	var rows prometheus.Rows
	rows.UnmarshalWithErrLogger(s, func(errStr string) {
		panic(fmt.Errorf("cannot parse %q: %s", s, errStr))
	})
	var tss []*timeseries
	for _, row := range rows.Rows {
		var tags []storage.Tag
		for _, tag := range row.Tags {
			tags = append(tags, storage.Tag{
				Key:   []byte(tag.Key),
				Value: []byte(tag.Value),
			})
		}
		var ts timeseries
		ts.MetricName.MetricGroup = []byte(row.Metric)
		ts.MetricName.Tags = tags
		ts.Timestamps = append(ts.Timestamps, row.Timestamp/1000)
		ts.Values = append(ts.Values, row.Value)
		tss = append(tss, &ts)
	}
	return tss
}

func timeseriesToPromMetrics(tss []*timeseries) string {
	var a []string
	for _, ts := range tss {
		metricName := ts.MetricName.String()
		for i := range ts.Timestamps {
			line := fmt.Sprintf("%s %v %d", metricName, ts.Values[i], ts.Timestamps[i])
			a = append(a, line)
		}
	}
	return strings.Join(a, "\n")
}

func TestGetNumPrefix(t *testing.T) {
	f := func(s, prefixExpected string) {
		t.Helper()
		prefix := getNumPrefix(s)
		if prefix != prefixExpected {
			t.Fatalf("unexpected getNumPrefix(%q): got %q; want %q", s, prefix, prefixExpected)
		}
		if len(prefix) > 0 {
			if _, err := strconv.ParseFloat(prefix, 64); err != nil {
				t.Fatalf("cannot parse num %q: %s", prefix, err)
			}
		}
	}

	f("", "")
	f("foo", "")
	f("-", "")
	f(".", "")
	f("-.", "")
	f("+..", "")
	f("1", "1")
	f("12", "12")
	f("1foo", "1")
	f("-123", "-123")
	f("-123bar", "-123")
	f("+123", "+123")
	f("+123.", "+123.")
	f("+123..", "+123.")
	f("+123.-", "+123.")
	f("12.34..", "12.34")
	f("-12.34..", "-12.34")
	f("-12.-34..", "-12.")
}

func TestNumericLess(t *testing.T) {
	f := func(a, b string, want bool) {
		t.Helper()
		if got := numericLess(a, b); got != want {
			t.Fatalf("unexpected numericLess(%q, %q): got %v; want %v", a, b, got, want)
		}
	}
	// empty strings
	f("", "", false)
	f("", "321", true)
	f("321", "", false)
	f("", "abc", true)
	f("abc", "", false)
	f("foo", "123", false)
	f("123", "foo", true)
	// same length numbers
	f("123", "321", true)
	f("321", "123", false)
	f("123", "123", false)
	// same length strings
	f("a", "b", true)
	f("b", "a", false)
	f("a", "a", false)
	// identical string prefix
	f("foo123", "foo", false)
	f("foo", "foo123", true)
	f("foo", "foo", false)
	// identical num prefix
	f("123foo", "123bar", false)
	f("123bar", "123foo", true)
	f("123bar", "123bar", false)
	// numbers with special chars
	f("1:0:0", "1:0:2", true)
	// numbers with special chars and different number rank
	f("1:0:15", "1:0:2", false)
	// multiple zeroes"
	f("0", "00", false)
	// only chars
	f("aa", "ab", true)
	// strings with different lengths
	f("ab", "abc", true)
	// multiple zeroes after equal char
	f("a0001", "a0000001", false)
	// short first string with numbers and highest rank
	f("a10", "abcdefgh2", true)
	// less as second string
	f("a1b", "a01b", false)
	// equal strings by length with different number rank
	f("a001b01", "a01b001", false)
	// different numbers rank
	f("a01b001", "a001b01", false)
	// different numbers rank
	f("a01b001", "a001b01", false)
	// highest char and number
	f("a1", "a1x", true)
	// highest number reverse chars
	f("1b", "1ax", false)
	// numbers with leading zero
	f("082", "83", true)
	// numbers with leading zero and chars
	f("083a", "9a", false)
	f("083a", "94a", true)
	// negative number
	f("-123", "123", true)
	f("-123", "+123", true)
	f("-123", "-123", false)
	f("123", "-123", false)
	// fractional number
	f("12.9", "12.56", false)
	f("12.56", "12.9", true)
	f("12.9", "12.9", false)
}