weatherreporter/internal/forecast/derive_test.go

package forecast

import (
	"encoding/json"
	"os"
	"path/filepath"
	"testing"
	"time"

	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
)

func TestBuildDailySummaryGroupsDaypartsAndComputesMetrics(t *testing.T) {
	location := time.FixedZone("Test", -5*60*60)
	bundle := testBundle(location)
	date := time.Date(2026, 5, 29, 12, 0, 0, 0, location)
	dayparts := []DaypartDefinition{
		{Name: "overnight", Start: "00:00", End: "06:00"},
		{Name: "morning", Start: "06:00", End: "12:00"},
		{Name: "afternoon", Start: "12:00", End: "18:00"},
		{Name: "evening", Start: "18:00", End: "24:00"},
	}

	summary, err := BuildDailySummary(bundle, date, location, dayparts)
	if err != nil {
		t.Fatalf("BuildDailySummary() error = %v", err)
	}

	if len(summary.Dayparts) != 4 {
		t.Fatalf("Dayparts length = %d, want 4", len(summary.Dayparts))
	}
	morning := summary.Dayparts[1]
	if len(morning.HourlyPeriods) != 2 {
		t.Fatalf("morning periods = %d, want 2", len(morning.HourlyPeriods))
	}
	assertRange(t, "morning temperature", morning.Temperature, 58, 72)
	if morning.MaxPrecipitationProbability == nil || morning.MaxPrecipitationProbability.Value != 70 {
		t.Fatalf("morning max precip = %#v, want 70", morning.MaxPrecipitationProbability)
	}
	if morning.PeakWindGust == nil || morning.PeakWindGust.Value != 40 {
		t.Fatalf("morning peak gust = %#v, want 40", morning.PeakWindGust)
	}
	if morning.DominantCondition != "Thunderstorms and gusty wind" {
		t.Fatalf("morning dominant = %q, want raw forecast condition", morning.DominantCondition)
	}
	if !morning.Indicators.Wind {
		t.Fatalf("morning indicators = %#v, want wind", morning.Indicators)
	}

	afternoon := summary.Dayparts[2]
	assertRange(t, "afternoon apparent", afternoon.ApparentTemperature, 100, 100)
	if !afternoon.Indicators.Heat {
		t.Fatalf("afternoon indicators = %#v, want heat", afternoon.Indicators)
	}
	if len(summary.NarrativePeriods) != 1 {
		t.Fatalf("NarrativePeriods length = %d, want 1", len(summary.NarrativePeriods))
	}
	if len(summary.AlertOverlaps) != 1 {
		t.Fatalf("AlertOverlaps length = %d, want 1", len(summary.AlertOverlaps))
	}
	if len(morning.AlertOverlaps) != 1 {
		t.Fatalf("morning AlertOverlaps length = %d, want 1", len(morning.AlertOverlaps))
	}

	if _, err := json.Marshal(summary.Dayparts); err != nil {
		t.Fatalf("daypart summaries are not JSON inspectable: %v", err)
	}
}

func TestBuildDailySummaryFromFixtureBundle(t *testing.T) {
	data, err := os.ReadFile(filepath.Join("testdata", "daily_bundle.json"))
	if err != nil {
		t.Fatalf("read fixture bundle: %v", err)
	}
	var bundle weatherdata.Bundle
	if err := json.Unmarshal(data, &bundle); err != nil {
		t.Fatalf("decode fixture bundle: %v", err)
	}
	location := time.FixedZone("Test", -5*60*60)
	summary, err := BuildDailySummary(&bundle, mustParse("2026-05-29T12:00:00-05:00"), location, []DaypartDefinition{
		{Name: "morning", Start: "06:00", End: "12:00"},
		{Name: "afternoon", Start: "12:00", End: "18:00"},
	})
	if err != nil {
		t.Fatalf("BuildDailySummary() error = %v", err)
	}
	if len(summary.Dayparts) != 2 {
		t.Fatalf("Dayparts length = %d, want 2", len(summary.Dayparts))
	}
	if summary.Dayparts[0].DominantCondition != "Showers and thunderstorms" {
		t.Fatalf("morning dominant = %q, want raw forecast condition", summary.Dayparts[0].DominantCondition)
	}
	if len(summary.AlertOverlaps) != 1 {
		t.Fatalf("AlertOverlaps length = %d, want 1", len(summary.AlertOverlaps))
	}
}

func TestOvernightGroupingAcrossMidnight(t *testing.T) {
	location := time.FixedZone("Test", -5*60*60)
	date := time.Date(2026, 5, 29, 12, 0, 0, 0, location)
	bundle := &weatherdata.Bundle{Hourly: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
		hour(location, "2026-05-29T23:00:00-05:00", "2026-05-30T00:00:00-05:00", "Snow", 31, nil, nil, nil, nil),
		hour(location, "2026-05-30T05:00:00-05:00", "2026-05-30T06:00:00-05:00", "Fog", 30, nil, nil, nil, nil),
		hour(location, "2026-05-30T06:00:00-05:00", "2026-05-30T07:00:00-05:00", "Clear", 35, nil, nil, nil, nil),
	}}}

	summary, err := BuildDailySummary(bundle, date, location, []DaypartDefinition{
		{Name: "night", Start: "22:00", End: "06:00"},
	})
	if err != nil {
		t.Fatalf("BuildDailySummary() error = %v", err)
	}
	night := summary.Dayparts[0]
	if len(night.HourlyPeriods) != 2 {
		t.Fatalf("night periods = %d, want 2", len(night.HourlyPeriods))
	}
	if !night.Indicators.Snow || !night.Indicators.Fog || !night.Indicators.Cold {
		t.Fatalf("night indicators = %#v, want snow, fog, and cold", night.Indicators)
	}
}

func TestBoundaryTimestampsAtDaypartEdges(t *testing.T) {
	location := time.FixedZone("Test", -5*60*60)
	date := time.Date(2026, 5, 29, 12, 0, 0, 0, location)
	bundle := &weatherdata.Bundle{Hourly: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
		hour(location, "2026-05-29T05:00:00-05:00", "2026-05-29T06:00:00-05:00", "Before", 55, nil, nil, nil, nil),
		hour(location, "2026-05-29T06:00:00-05:00", "2026-05-29T07:00:00-05:00", "Start", 56, nil, nil, nil, nil),
		hour(location, "2026-05-29T12:00:00-05:00", "2026-05-29T13:00:00-05:00", "After", 70, nil, nil, nil, nil),
	}}}

	summary, err := BuildDailySummary(bundle, date, location, []DaypartDefinition{
		{Name: "morning", Start: "06:00", End: "12:00"},
	})
	if err != nil {
		t.Fatalf("BuildDailySummary() error = %v", err)
	}
	morning := summary.Dayparts[0]
	if len(morning.HourlyPeriods) != 1 {
		t.Fatalf("morning periods = %d, want only start-boundary period", len(morning.HourlyPeriods))
	}
	if morning.HourlyPeriods[0].TextDescription != "Start" {
		t.Fatalf("selected period = %q, want Start", morning.HourlyPeriods[0].TextDescription)
	}
}

func TestBuildDailySummaryRequiresHourlyData(t *testing.T) {
	location := time.UTC
	_, err := BuildDailySummary(&weatherdata.Bundle{}, time.Now(), location, []DaypartDefinition{
		{Name: "morning", Start: "06:00", End: "12:00"},
	})
	if err == nil {
		t.Fatal("BuildDailySummary() error = nil, want missing hourly error")
	}
}

func TestBuildPeriodDailySummariesClipsPartialDays(t *testing.T) {
	location := time.FixedZone("Test", -5*60*60)
	bundle := &weatherdata.Bundle{Hourly: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
		hour(location, "2026-05-29T05:00:00-05:00", "2026-05-29T06:00:00-05:00", "Before", 50, nil, nil, nil, nil),
		hour(location, "2026-05-29T08:00:00-05:00", "2026-05-29T09:00:00-05:00", "Showers", 60, nil, ptr(60), nil, nil),
		hour(location, "2026-05-30T14:00:00-05:00", "2026-05-30T15:00:00-05:00", "Hot", 95, nil, nil, nil, nil),
		hour(location, "2026-05-31T20:00:00-05:00", "2026-05-31T21:00:00-05:00", "Wind", 70, nil, nil, nil, ptr(35)),
	}}}
	period := timeutil.Period{
		Start: mustParse("2026-05-29T07:00:00-05:00").In(location),
		End:   mustParse("2026-06-01T00:00:00-05:00").In(location),
	}

	summaries, err := BuildPeriodDailySummaries(bundle, period, location, []DaypartDefinition{
		{Name: "morning", Start: "06:00", End: "12:00"},
		{Name: "afternoon", Start: "12:00", End: "18:00"},
		{Name: "evening", Start: "18:00", End: "24:00"},
	})
	if err != nil {
		t.Fatalf("BuildPeriodDailySummaries() error = %v", err)
	}
	if len(summaries) != 3 {
		t.Fatalf("summaries length = %d, want 3", len(summaries))
	}
	if summaries[0].Period.Start.Format(time.RFC3339) != "2026-05-29T07:00:00-05:00" {
		t.Fatalf("first period start = %s, want clipped start", summaries[0].Period.Start.Format(time.RFC3339))
	}
	if len(summaries[0].Dayparts[0].HourlyPeriods) != 1 || summaries[0].Dayparts[0].HourlyPeriods[0].TextDescription != "Showers" {
		t.Fatalf("first morning periods = %#v, want only post-start hour", summaries[0].Dayparts[0].HourlyPeriods)
	}
	if summaries[2].Dayparts[2].PeakWindGust == nil || summaries[2].Dayparts[2].PeakWindGust.Value != 35 {
		t.Fatalf("third evening gust = %#v, want 35", summaries[2].Dayparts[2].PeakWindGust)
	}
}

func TestAlertOverlap(t *testing.T) {
	location := time.FixedZone("Test", -5*60*60)
	raw := json.RawMessage(`{"event":"Flood Watch","headline":"Flooding possible","severity":"Moderate","effective":"2026-05-29T07:00:00-05:00","expires":"2026-05-29T10:00:00-05:00"}`)
	alertRun := &weatherdata.AlertRun{Alerts: []json.RawMessage{raw}}
	period := timeutil.Period{
		Start: mustParse("2026-05-29T06:00:00-05:00").In(location),
		End:   mustParse("2026-05-29T09:00:00-05:00").In(location),
	}

	overlaps := AlertOverlaps(alertRun, period)
	if len(overlaps) != 1 {
		t.Fatalf("overlaps length = %d, want 1", len(overlaps))
	}
	if overlaps[0].Overlap.Start.Format(time.RFC3339) != "2026-05-29T07:00:00-05:00" {
		t.Fatalf("overlap start = %s, want alert start", overlaps[0].Overlap.Start.Format(time.RFC3339))
	}
	if overlaps[0].Overlap.End.Format(time.RFC3339) != "2026-05-29T09:00:00-05:00" {
		t.Fatalf("overlap end = %s, want period end", overlaps[0].Overlap.End.Format(time.RFC3339))
	}
}

func TestAlertOverlapUsesOnsetAndEnds(t *testing.T) {
	raw := json.RawMessage(`{"event":"Wind Advisory","headline":"Wind Advisory issued June 16 at 12:39PM CDT until June 17 at 8:00PM CDT by NWS St Louis MO","severity":"Moderate","description":"Southwest winds 20 to 30 mph with gusts up to 45 mph expected.","instruction":"Secure outdoor objects.\n\nUse  extra\tcaution.","effective":"2026-06-16T17:39:00Z","onset":"2026-06-17T18:00:00Z","ends":"2026-06-18T01:00:00Z","expires":"2026-06-17T08:45:00Z"}`)
	alertRun := &weatherdata.AlertRun{Alerts: []json.RawMessage{raw}}
	period := timeutil.Period{
		Start: mustParse("2026-06-17T12:00:00-05:00"),
		End:   mustParse("2026-06-17T21:00:00-05:00"),
	}

	overlaps := AlertOverlaps(alertRun, period)
	if len(overlaps) != 1 {
		t.Fatalf("overlaps length = %d, want 1", len(overlaps))
	}
	if overlaps[0].Period.Start.Format(time.RFC3339) != "2026-06-17T18:00:00Z" {
		t.Fatalf("alert period start = %s, want onset", overlaps[0].Period.Start.Format(time.RFC3339))
	}
	if overlaps[0].Period.End.Format(time.RFC3339) != "2026-06-18T01:00:00Z" {
		t.Fatalf("alert period end = %s, want ends", overlaps[0].Period.End.Format(time.RFC3339))
	}
	if overlaps[0].Overlap.Start.Format(time.RFC3339) != "2026-06-17T18:00:00Z" {
		t.Fatalf("overlap start = %s, want onset", overlaps[0].Overlap.Start.Format(time.RFC3339))
	}
	if overlaps[0].Overlap.End.Format(time.RFC3339) != "2026-06-18T01:00:00Z" {
		t.Fatalf("overlap end = %s, want alert ends", overlaps[0].Overlap.End.Format(time.RFC3339))
	}
	if overlaps[0].Description != "Southwest winds 20 to 30 mph with gusts up to 45 mph expected." {
		t.Fatalf("Description = %q, want preserved description", overlaps[0].Description)
	}
	if overlaps[0].Instruction != "Secure outdoor objects. Use extra caution." {
		t.Fatalf("Instruction = %q, want preserved instruction", overlaps[0].Instruction)
	}
}

func TestCollapseWhitespace(t *testing.T) {
	tests := []struct {
		name  string
		value string
		want  string
	}{
		{name: "newlines", value: "Secure outdoor objects.\nUse extra caution.", want: "Secure outdoor objects. Use extra caution."},
		{name: "crlf", value: "Secure outdoor objects.\r\nUse extra caution.", want: "Secure outdoor objects. Use extra caution."},
		{name: "tabs and repeated spaces", value: "Secure\toutdoor   objects.", want: "Secure outdoor objects."},
		{name: "leading trailing", value: "  Secure outdoor objects.  ", want: "Secure outdoor objects."},
		{name: "empty", value: "", want: ""},
		{name: "all whitespace", value: " \n\t\r\n ", want: ""},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := collapseWhitespace(tt.value); got != tt.want {
				t.Fatalf("collapseWhitespace(%q) = %q, want %q", tt.value, got, tt.want)
			}
		})
	}
}

func TestAlertOverlapUsesOnsetAndEndsForLocalDateRelevance(t *testing.T) {
	location, err := time.LoadLocation("America/Chicago")
	if err != nil {
		t.Fatalf("load location: %v", err)
	}
	raw := json.RawMessage(`{"event":"Wind Advisory","headline":"Wind Advisory issued June 16 at 12:39PM CDT until June 17 at 8:00PM CDT by NWS St Louis MO","severity":"Moderate","effective":"2026-06-16T17:39:00Z","onset":"2026-06-17T18:00:00Z","ends":"2026-06-18T01:00:00Z","expires":"2026-06-17T08:45:00Z"}`)
	alertRun := &weatherdata.AlertRun{Alerts: []json.RawMessage{raw}}
	june16 := timeutil.CivilDay(time.Date(2026, 6, 16, 12, 0, 0, 0, location), location)
	june17Afternoon := timeutil.Period{
		Start: time.Date(2026, 6, 17, 12, 0, 0, 0, location),
		End:   time.Date(2026, 6, 17, 21, 0, 0, 0, location),
	}

	if overlaps := AlertOverlaps(alertRun, june16); len(overlaps) != 0 {
		t.Fatalf("June 16 overlaps length = %d, want none: %#v", len(overlaps), overlaps)
	}
	if overlaps := AlertOverlaps(alertRun, june17Afternoon); len(overlaps) != 1 {
		t.Fatalf("June 17 afternoon overlaps length = %d, want 1: %#v", len(overlaps), overlaps)
	}
}

func TestAlertOverlapSupportsOlderEffectiveExpiresPayload(t *testing.T) {
	raw := json.RawMessage(`{"event":"Flood Watch","headline":"Flooding possible","severity":"Moderate","effective":"2026-05-29T07:00:00-05:00","expires":"2026-05-29T10:00:00-05:00"}`)
	alertRun := &weatherdata.AlertRun{Alerts: []json.RawMessage{raw}}
	period := timeutil.Period{
		Start: mustParse("2026-05-29T06:00:00-05:00"),
		End:   mustParse("2026-05-29T11:00:00-05:00"),
	}

	overlaps := AlertOverlaps(alertRun, period)
	if len(overlaps) != 1 {
		t.Fatalf("overlaps length = %d, want 1", len(overlaps))
	}
	if overlaps[0].Period.Start.Format(time.RFC3339) != "2026-05-29T07:00:00-05:00" {
		t.Fatalf("alert period start = %s, want effective fallback", overlaps[0].Period.Start.Format(time.RFC3339))
	}
	if overlaps[0].Period.End.Format(time.RFC3339) != "2026-05-29T10:00:00-05:00" {
		t.Fatalf("alert period end = %s, want expires fallback", overlaps[0].Period.End.Format(time.RFC3339))
	}
}

func TestAlertOverlapSkipsInvalidSelectedPeriod(t *testing.T) {
	raw := json.RawMessage(`{"event":"Wind Advisory","headline":"Invalid event period","severity":"Moderate","onset":"2026-06-17T18:00:00Z","ends":"2026-06-17T08:45:00Z"}`)
	alertRun := &weatherdata.AlertRun{Alerts: []json.RawMessage{raw}}
	period := timeutil.Period{
		Start: mustParse("2026-06-17T00:00:00Z"),
		End:   mustParse("2026-06-18T00:00:00Z"),
	}

	if overlaps := AlertOverlaps(alertRun, period); len(overlaps) != 0 {
		t.Fatalf("overlaps length = %d, want invalid alert skipped: %#v", len(overlaps), overlaps)
	}
}

func TestBuildPrecipTimingBuildsThresholdWindows(t *testing.T) {
	location := time.FixedZone("Test", -5*60*60)
	periods := []weatherdata.ForecastPeriod{
		hour(location, "2026-05-29T08:00:00-05:00", "2026-05-29T09:00:00-05:00", "Cloudy", 70, nil, ptr(0), nil, nil),
		hour(location, "2026-05-29T12:00:00-05:00", "2026-05-29T13:00:00-05:00", "Thunderstorms", 70, nil, ptr(80), nil, nil),
		hour(location, "2026-05-29T11:00:00-05:00", "2026-05-29T12:00:00-05:00", "Brief lull", 70, nil, ptr(39.999), nil, nil),
		hour(location, "2026-05-29T13:00:00-05:00", "2026-05-29T14:00:00-05:00", "Unknown rain chance", 70, nil, nil, nil, nil),
		hour(location, "2026-05-29T10:00:00-05:00", "2026-05-29T11:00:00-05:00", "Rain likely", 70, nil, ptr(60), nil, nil),
		hour(location, "2026-05-29T09:00:00-05:00", "2026-05-29T10:00:00-05:00", "Showers", 70, nil, ptr(40), nil, nil),
	}

	timing := BuildPrecipTiming(periods)

	if timing.FirstPrecipitation == nil || timing.FirstPrecipitation.Time.Format(time.RFC3339) != "2026-05-29T09:00:00-05:00" {
		t.Fatalf("FirstPrecipitation = %#v, want first threshold window start", timing.FirstPrecipitation)
	}
	if timing.LastPrecipitation == nil || timing.LastPrecipitation.Time.Format(time.RFC3339) != "2026-05-29T13:00:00-05:00" {
		t.Fatalf("LastPrecipitation = %#v, want final closed threshold window end", timing.LastPrecipitation)
	}
	if timing.MaxPrecipitationProbability == nil || timing.MaxPrecipitationProbability.Value != 80 {
		t.Fatalf("MaxPrecipitationProbability = %#v, want 80", timing.MaxPrecipitationProbability)
	}
	if timing.ProbabilityThreshold != DefaultPrecipWindowProbabilityThreshold {
		t.Fatalf("ProbabilityThreshold = %v, want default threshold", timing.ProbabilityThreshold)
	}
	if len(timing.PrecipitationWindows) != 2 {
		t.Fatalf("PrecipitationWindows length = %d, want 2: %#v", len(timing.PrecipitationWindows), timing.PrecipitationWindows)
	}
	first := timing.PrecipitationWindows[0]
	if first.Start.Format(time.RFC3339) != "2026-05-29T09:00:00-05:00" || first.End == nil || first.End.Format(time.RFC3339) != "2026-05-29T11:00:00-05:00" {
		t.Fatalf("first window = %#v, want 9-11 AM", first)
	}
	if first.MaxPrecipitationProbability.Value != 60 || first.MaxPrecipitationProbability.Time.Format(time.RFC3339) != "2026-05-29T10:00:00-05:00" {
		t.Fatalf("first window max = %#v, want 60 at 10 AM", first.MaxPrecipitationProbability)
	}
	if len(first.TextDescriptions) != 2 || first.TextDescriptions[0] != "Showers" || first.TextDescriptions[1] != "Rain likely" {
		t.Fatalf("first window text descriptions = %#v, want contributing hourly descriptions", first.TextDescriptions)
	}
	second := timing.PrecipitationWindows[1]
	if second.Start.Format(time.RFC3339) != "2026-05-29T12:00:00-05:00" || second.End == nil || second.End.Format(time.RFC3339) != "2026-05-29T13:00:00-05:00" {
		t.Fatalf("second window = %#v, want noon-1 PM", second)
	}
	if len(second.TextDescriptions) != 1 || second.TextDescriptions[0] != "Thunderstorms" {
		t.Fatalf("second window text descriptions = %#v, want thunderstorm description", second.TextDescriptions)
	}
	if !timing.ThunderMentioned {
		t.Fatal("ThunderMentioned = false, want true")
	}
}

func TestBuildPrecipTimingLeavesFinalWindowOpen(t *testing.T) {
	location := time.FixedZone("Test", -5*60*60)
	periods := []weatherdata.ForecastPeriod{
		hour(location, "2026-05-29T08:00:00-05:00", "2026-05-29T09:00:00-05:00", "Cloudy", 70, nil, ptr(0), nil, nil),
		hour(location, "2026-05-29T09:00:00-05:00", "2026-05-29T10:00:00-05:00", "Showers", 70, nil, ptr(45), nil, nil),
		hour(location, "2026-05-29T10:00:00-05:00", "2026-05-29T11:00:00-05:00", "Rain likely", 70, nil, ptr(60), nil, nil),
	}

	timing := BuildPrecipTiming(periods)

	if len(timing.PrecipitationWindows) != 1 {
		t.Fatalf("PrecipitationWindows length = %d, want 1", len(timing.PrecipitationWindows))
	}
	if timing.PrecipitationWindows[0].End != nil {
		t.Fatalf("open window End = %v, want nil", timing.PrecipitationWindows[0].End)
	}
	if timing.LastPrecipitation != nil {
		t.Fatalf("LastPrecipitation = %#v, want nil for open final window", timing.LastPrecipitation)
	}
}

func TestBuildPrecipTimingSupportsNonDefaultThreshold(t *testing.T) {
	location := time.FixedZone("Test", -5*60*60)
	periods := []weatherdata.ForecastPeriod{
		hour(location, "2026-05-29T08:00:00-05:00", "2026-05-29T09:00:00-05:00", "Showers", 70, nil, ptr(50), nil, nil),
		hour(location, "2026-05-29T09:00:00-05:00", "2026-05-29T10:00:00-05:00", "Rain likely", 70, nil, ptr(60), nil, nil),
		hour(location, "2026-05-29T10:00:00-05:00", "2026-05-29T11:00:00-05:00", "Showers", 70, nil, ptr(55), nil, nil),
		hour(location, "2026-05-29T11:00:00-05:00", "2026-05-29T12:00:00-05:00", "Drying out", 70, nil, ptr(20), nil, nil),
	}

	timing := buildPrecipTimingWithThreshold(periods, 55)

	if timing.ProbabilityThreshold != 55 {
		t.Fatalf("ProbabilityThreshold = %v, want 55", timing.ProbabilityThreshold)
	}
	if len(timing.PrecipitationWindows) != 1 {
		t.Fatalf("PrecipitationWindows length = %d, want 1", len(timing.PrecipitationWindows))
	}
	window := timing.PrecipitationWindows[0]
	if window.Start.Format(time.RFC3339) != "2026-05-29T09:00:00-05:00" || window.End == nil || window.End.Format(time.RFC3339) != "2026-05-29T11:00:00-05:00" {
		t.Fatalf("window = %#v, want 9-11 AM", window)
	}
}

func TestBuildPrecipTimingHandlesDryForecast(t *testing.T) {
	location := time.FixedZone("Test", -5*60*60)
	periods := []weatherdata.ForecastPeriod{
		hour(location, "2026-05-29T08:00:00-05:00", "2026-05-29T09:00:00-05:00", "Sunny", 70, nil, ptr(0), nil, nil),
	}

	timing := BuildPrecipTiming(periods)

	if timing.FirstPrecipitation != nil || timing.LastPrecipitation != nil || len(timing.PrecipitationWindows) != 0 || timing.ThunderMentioned {
		t.Fatalf("dry timing = %#v, want no precip timing and no thunder", timing)
	}
	if timing.ProbabilityThreshold != DefaultPrecipWindowProbabilityThreshold {
		t.Fatalf("ProbabilityThreshold = %v, want default threshold", timing.ProbabilityThreshold)
	}
	if timing.MaxPrecipitationProbability == nil || timing.MaxPrecipitationProbability.Value != 0 {
		t.Fatalf("dry max precip = %#v, want checked zero chance", timing.MaxPrecipitationProbability)
	}
}

func TestThresholdHelpers(t *testing.T) {
	if !DifferenceAtLeast(50, 56, 5) {
		t.Fatal("DifferenceAtLeast = false, want true")
	}
	if !CrossesAtOrAbove(29, 32, 32) {
		t.Fatal("CrossesAtOrAbove = false, want true")
	}
	if !CrossesBelow(35, 31, 32) {
		t.Fatal("CrossesBelow = false, want true")
	}
}

func testBundle(location *time.Location) *weatherdata.Bundle {
	return &weatherdata.Bundle{
		Hourly: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
			hour(location, "2026-05-29T05:00:00-05:00", "2026-05-29T06:00:00-05:00", "Cloudy", 55, nil, nil, nil, nil),
			hour(location, "2026-05-29T06:00:00-05:00", "2026-05-29T07:00:00-05:00", "Thunderstorms and gusty wind", 58, ptr(57), ptr(70), ptr(22), ptr(40)),
			hour(location, "2026-05-29T11:00:00-05:00", "2026-05-29T12:00:00-05:00", "Thunderstorms and gusty wind", 72, ptr(74), ptr(60), ptr(18), ptr(35)),
			hour(location, "2026-05-29T14:00:00-05:00", "2026-05-29T15:00:00-05:00", "Hot and sunny", 96, ptr(100), ptr(5), ptr(10), ptr(12)),
		}},
		Narrative: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
			hour(location, "2026-05-29T06:00:00-05:00", "2026-05-29T18:00:00-05:00", "Storms early, hot later.", 96, nil, nil, nil, nil),
		}},
		Alerts: &weatherdata.AlertRun{Alerts: []json.RawMessage{
			json.RawMessage(`{"event":"Severe Thunderstorm Watch","headline":"Storms possible","severity":"Severe","effective":"2026-05-29T06:30:00-05:00","expires":"2026-05-29T11:30:00-05:00"}`),
		}},
		Discussion: &weatherdata.Discussion{Product: "discussion", KeyMessages: []string{"Storms possible."}},
		Sources:    []weatherdata.Source{{Name: "hourly"}},
		Warnings:   []weatherdata.SourceWarning{{Source: "daily", Code: "missing_source"}},
	}
}

func hour(location *time.Location, start string, end string, text string, temperature float64, apparent *float64, precip *float64, wind *float64, gust *float64) weatherdata.ForecastPeriod {
	startTime := mustParse(start).In(location)
	endTime := mustParse(end).In(location)
	temp := temperature
	return weatherdata.ForecastPeriod{
		StartTime:                         startTime,
		EndTime:                           endTime,
		TextDescription:                   text,
		TemperatureF:                      &temp,
		ApparentTemperatureF:              apparent,
		ProbabilityOfPrecipitationPercent: precip,
		WindSpeedMph:                      wind,
		WindGustMph:                       gust,
	}
}

func mustParse(value string) time.Time {
	parsed, err := time.Parse(time.RFC3339, value)
	if err != nil {
		panic(err)
	}
	return parsed
}

func ptr(value float64) *float64 {
	return &value
}

func assertRange(t *testing.T, name string, got Range, wantMin float64, wantMax float64) {
	t.Helper()
	if got.Min == nil || got.Max == nil {
		t.Fatalf("%s = %#v, want min and max", name, got)
	}
	if *got.Min != wantMin || *got.Max != wantMax {
		t.Fatalf("%s = [%v,%v], want [%v,%v]", name, *got.Min, *got.Max, wantMin, wantMax)
	}
}