package features

import (
	"testing"
	"time"
)

func TestBuildLabelsSpikeUsingOnlyEarlierSameTimeWindows(t *testing.T) {
	base := time.Date(2026, 9, 15, 12, 0, 0, 0, time.UTC)
	events := make([]Event, 0)
	// The prior two daily windows have 10 events and one error each.
	for day := 1; day <= 2; day++ {
		for i := 0; i < 10; i++ {
			events = append(events, Event{Timestamp: base.AddDate(0, 0, -day).Add(time.Duration(i) * time.Second), Service: "api", Kind: "span", IsError: i == 0, DurationMS: float64(i)})
		}
	}
	// Current row is non-error telemetry. The following fifteen minutes have
	// five errors out of ten events: 5x the 10% baseline and above the floor.
	for i := 0; i < 10; i++ {
		events = append(events, Event{Timestamp: base.Add(time.Duration(i) * time.Second), Service: "api", Release: "v2", Kind: "span", IsError: false, DurationMS: float64(i)})
	}
	for i := 0; i < 10; i++ {
		events = append(events, Event{Timestamp: base.Add(5 * time.Minute).Add(time.Duration(i) * time.Second), Service: "api", Kind: "log", IsError: i < 5})
	}
	// The source export's explicit exclusive watermark proves that the rest of
	// the future interval was observed even though it was quiet.
	rows := Build(events, Config{Window: 5 * time.Minute, Step: 5 * time.Minute, Future: 15 * time.Minute, ObservedUntil: base.Add(20 * time.Minute), BaselineDays: 2, MinBaselineSamples: 2, SpikeMultiple: 3, MinFutureErrors: 5})
	var row *Row
	for i := range rows {
		if rows[i].WindowStart.Equal(base) && rows[i].Service == "api" && rows[i].Release == "v2" {
			row = &rows[i]
			break
		}
	}
	if row == nil {
		t.Fatal("missing current api/v2 row")
	}
	if !row.LabelKnown || !row.Label {
		t.Fatalf("expected a known positive label, got %+v", *row)
	}
	if row.BaselineErrorRate != .1 || row.FutureErrorRate != .5 || row.FutureErrorCount != 5 {
		t.Fatalf("unexpected label inputs: %+v", *row)
	}
	if row.P50Duration != 4 || row.P95Duration != 8 || row.SpanCount != 10 {
		t.Fatalf("unexpected fixed-width features: %+v", *row)
	}
}

func TestBuildWithholdsLabelWithoutCompleteBaseline(t *testing.T) {
	base := time.Date(2026, 9, 15, 12, 0, 0, 0, time.UTC)
	events := []Event{{Timestamp: base, Service: "api", Kind: "log"}, {Timestamp: base.Add(20 * time.Minute), Service: "other", Kind: "log"}}
	rows := Build(events, Config{Window: 5 * time.Minute, Step: 5 * time.Minute, Future: 15 * time.Minute, BaselineDays: 7, MinBaselineSamples: 7})
	if len(rows) == 0 || rows[0].LabelKnown {
		t.Fatalf("short history must not be labelled: %+v", rows)
	}
}

func TestBuildLogicalRequestFeatures(t *testing.T) {
	at := time.Date(2026, 9, 19, 12, 0, 0, 0, time.UTC)
	mk := func(client string, dup bool, class string) Event {
		return Event{Timestamp: at, Service: "nginx", Kind: "span", IsError: true, PatternSignature: "p", ClientIP: client, IsDuplicate: dup, UAClass: class}
	}
	rows := Build([]Event{mk("a", false, "ai_crawler"), mk("a", true, "ai_crawler"), mk("a", false, "browser"), mk("b", false, "browser")}, Config{})
	if len(rows) == 0 {
		t.Fatal("no rows")
	}
	r := rows[0]
	if r.ErrorCount != 4 || r.DuplicateErrors != 1 || r.LogicalErrors != 3 {
		t.Fatalf("logical errors wrong: %+v", r)
	}
	if r.DistinctClients != 2 || r.TopClientShare < 0.66 || r.TopClientShare > 0.67 {
		t.Fatalf("client features wrong: %+v", r)
	}
	if r.BotErrorShare < 0.33 || r.BotErrorShare > 0.34 {
		t.Fatalf("bot share wrong: %v", r.BotErrorShare)
	}
}