Add daily coverage planning helper

internal/app/batch_plan.go

@@ -0,0 +1,66 @@
+package app
+
+import (
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
+)
+
+func eligibleDailyDates(hourly *weatherdata.ForecastRun, now time.Time, location *time.Location) []time.Time {
+	if hourly == nil || location == nil || hourly.Product != "hourly" || len(hourly.Periods) == 0 {
+		return nil
+	}
+
+	hourlyStarts := make(map[time.Time]struct{}, len(hourly.Periods))
+	var maxLocalDate time.Time
+	for _, period := range hourly.Periods {
+		if !isHourlyPeriod(period) {
+			continue
+		}
+		start := period.StartTime
+		hourlyStarts[instantKey(start)] = struct{}{}
+		localDate := localDateStart(start, location)
+		if maxLocalDate.IsZero() || localDate.After(maxLocalDate) {
+			maxLocalDate = localDate
+		}
+	}
+	if len(hourlyStarts) == 0 || maxLocalDate.IsZero() {
+		return nil
+	}
+
+	startDate := localDateStart(now.In(location).AddDate(0, 0, 2), location)
+	var dates []time.Time
+	for candidate := startDate; !candidate.After(maxLocalDate); candidate = candidate.AddDate(0, 0, 1) {
+		if hasFullHourlyCoverage(candidate, location, hourlyStarts) {
+			dates = append(dates, candidate)
+		}
+	}
+	return dates
+}
+
+func isHourlyPeriod(period weatherdata.ForecastPeriod) bool {
+	if period.StartTime.IsZero() || period.EndTime.IsZero() {
+		return false
+	}
+	return period.EndTime.Equal(period.StartTime.Add(time.Hour))
+}
+
+func hasFullHourlyCoverage(date time.Time, location *time.Location, hourlyStarts map[time.Time]struct{}) bool {
+	day := timeutil.CivilDay(date, location)
+	for required := day.Start; required.Before(day.End); required = required.Add(time.Hour) {
+		if _, ok := hourlyStarts[instantKey(required)]; !ok {
+			return false
+		}
+	}
+	return true
+}
+
+func instantKey(value time.Time) time.Time {
+	return value.UTC()
+}
+
+func localDateStart(value time.Time, location *time.Location) time.Time {
+	local := value.In(location)
+	return time.Date(local.Year(), local.Month(), local.Day(), 0, 0, 0, 0, location)
+}

internal/app/batch_plan_test.go

@@ -0,0 +1,217 @@
+package app
+
+import (
+	"strings"
+	"testing"
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
+)
+
+func TestEligibleDailyDatesRequiresFullOrdinaryLocalDay(t *testing.T) {
+	location := mustLoadTestLocation(t, "America/Chicago")
+	hourly := hourlyRun(fullDayPeriods(t, "2026-05-31", location)...)
+
+	got := eligibleDailyDates(hourly, mustParse("2026-05-29T08:00:00-05:00"), location)
+	assertLocalDates(t, got, location, "2026-05-31")
+}
+
+func TestEligibleDailyDatesMatchesFixedOffsetStartInstants(t *testing.T) {
+	location := mustLoadTestLocation(t, "America/Chicago")
+	hourly := hourlyRun(fixedOffsetPeriods(t, fullDayPeriods(t, "2026-05-31", location))...)
+
+	got := eligibleDailyDates(hourly, mustParse("2026-05-29T08:00:00-05:00"), location)
+	assertLocalDates(t, got, location, "2026-05-31")
+}
+
+func TestEligibleDailyDatesSkipsDayWithMissingRequiredHour(t *testing.T) {
+	location := mustLoadTestLocation(t, "America/Chicago")
+	periods := fullDayPeriods(t, "2026-05-31", location)
+	periods = append(periods[:12], periods[13:]...)
+	hourly := hourlyRun(periods...)
+
+	got := eligibleDailyDates(hourly, mustParse("2026-05-29T08:00:00-05:00"), location)
+	assertLocalDates(t, got, location)
+}
+
+func TestEligibleDailyDatesSkipsPartialFinalDay(t *testing.T) {
+	location := mustLoadTestLocation(t, "America/Chicago")
+	periods := fullDayPeriods(t, "2026-05-31", location)
+	periods = append(periods, partialDayPeriods(t, "2026-06-01", location, 12)...)
+	hourly := hourlyRun(periods...)
+
+	got := eligibleDailyDates(hourly, mustParse("2026-05-29T08:00:00-05:00"), location)
+	assertLocalDates(t, got, location, "2026-05-31")
+}
+
+func TestEligibleDailyDatesStartsAfterTomorrow(t *testing.T) {
+	location := mustLoadTestLocation(t, "America/Chicago")
+	periods := fullDayPeriods(t, "2026-05-29", location)
+	periods = append(periods, fullDayPeriods(t, "2026-05-30", location)...)
+	periods = append(periods, fullDayPeriods(t, "2026-05-31", location)...)
+	hourly := hourlyRun(periods...)
+
+	got := eligibleDailyDates(hourly, mustParse("2026-05-29T08:00:00-05:00"), location)
+	assertLocalDates(t, got, location, "2026-05-31")
+}
+
+func TestEligibleDailyDatesReturnsMultipleFutureDatesInOrder(t *testing.T) {
+	location := mustLoadTestLocation(t, "America/Chicago")
+	periods := fullDayPeriods(t, "2026-05-31", location)
+	periods = append(periods, fullDayPeriods(t, "2026-06-01", location)...)
+	hourly := hourlyRun(periods...)
+
+	got := eligibleDailyDates(hourly, mustParse("2026-05-29T08:00:00-05:00"), location)
+	assertLocalDates(t, got, location, "2026-05-31", "2026-06-01")
+}
+
+func TestEligibleDailyDatesIgnoresNonHourlyAndInvalidPeriods(t *testing.T) {
+	location := mustLoadTestLocation(t, "America/Chicago")
+	day := timeutil.CivilDay(mustParseLocalDate(t, "2026-05-31", location), location)
+	periods := []weatherdata.ForecastPeriod{
+		{StartTime: day.Start, EndTime: day.Start.Add(2 * time.Hour)},
+		{StartTime: day.Start.Add(time.Hour), EndTime: day.Start.Add(time.Hour)},
+		{StartTime: time.Time{}, EndTime: day.Start.Add(3 * time.Hour)},
+	}
+	periods = append(periods, fullDayPeriods(t, "2026-06-01", location)...)
+	hourly := hourlyRun(periods...)
+
+	got := eligibleDailyDates(hourly, mustParse("2026-05-29T08:00:00-05:00"), location)
+	assertLocalDates(t, got, location, "2026-06-01")
+}
+
+func TestEligibleDailyDatesUsesDSTCivilDayInstants(t *testing.T) {
+	location := mustLoadTestLocation(t, "America/New_York")
+	tests := []struct {
+		name string
+		now  string
+		date string
+	}{
+		{
+			name: "spring forward",
+			now:  "2026-03-06T08:00:00-05:00",
+			date: "2026-03-08",
+		},
+		{
+			name: "fall back",
+			now:  "2026-10-30T08:00:00-04:00",
+			date: "2026-11-01",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			hourly := hourlyRun(fullDayPeriods(t, tt.date, location)...)
+
+			got := eligibleDailyDates(hourly, mustParse(tt.now), location)
+			assertLocalDates(t, got, location, tt.date)
+		})
+	}
+}
+
+func TestEligibleDailyDatesReturnsNoneWithoutHourlyForecast(t *testing.T) {
+	location := mustLoadTestLocation(t, "America/Chicago")
+	fullDay := fullDayPeriods(t, "2026-05-31", location)
+
+	tests := []struct {
+		name   string
+		hourly *weatherdata.ForecastRun
+	}{
+		{name: "nil run"},
+		{name: "empty periods", hourly: hourlyRun()},
+		{name: "non-hourly product", hourly: forecastRun("narrative", fullDay...)},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := eligibleDailyDates(tt.hourly, mustParse("2026-05-29T08:00:00-05:00"), location)
+			assertLocalDates(t, got, location)
+		})
+	}
+}
+
+func hourlyRun(periods ...weatherdata.ForecastPeriod) *weatherdata.ForecastRun {
+	return forecastRun("hourly", periods...)
+}
+
+func forecastRun(product string, periods ...weatherdata.ForecastPeriod) *weatherdata.ForecastRun {
+	return &weatherdata.ForecastRun{
+		Product: product,
+		Periods: periods,
+	}
+}
+
+func fullDayPeriods(t *testing.T, date string, location *time.Location) []weatherdata.ForecastPeriod {
+	t.Helper()
+	day := timeutil.CivilDay(mustParseLocalDate(t, date, location), location)
+	var periods []weatherdata.ForecastPeriod
+	for start := day.Start; start.Before(day.End); start = start.Add(time.Hour) {
+		periods = append(periods, weatherdata.ForecastPeriod{
+			StartTime: start,
+			EndTime:   start.Add(time.Hour),
+		})
+	}
+	return periods
+}
+
+func partialDayPeriods(t *testing.T, date string, location *time.Location, count int) []weatherdata.ForecastPeriod {
+	t.Helper()
+	periods := fullDayPeriods(t, date, location)
+	if count > len(periods) {
+		count = len(periods)
+	}
+	return periods[:count]
+}
+
+func fixedOffsetPeriods(t *testing.T, periods []weatherdata.ForecastPeriod) []weatherdata.ForecastPeriod {
+	t.Helper()
+	out := make([]weatherdata.ForecastPeriod, 0, len(periods))
+	for _, period := range periods {
+		start, err := time.Parse(time.RFC3339, period.StartTime.Format(time.RFC3339))
+		if err != nil {
+			t.Fatalf("parse fixed-offset start: %v", err)
+		}
+		end, err := time.Parse(time.RFC3339, period.EndTime.Format(time.RFC3339))
+		if err != nil {
+			t.Fatalf("parse fixed-offset end: %v", err)
+		}
+		out = append(out, weatherdata.ForecastPeriod{StartTime: start, EndTime: end})
+	}
+	return out
+}
+
+func assertLocalDates(t *testing.T, got []time.Time, location *time.Location, want ...string) {
+	t.Helper()
+	gotDates := make([]string, 0, len(got))
+	for _, date := range got {
+		gotDates = append(gotDates, date.In(location).Format(timeutil.DateLayout))
+	}
+	if strings.Join(gotDates, ",") != strings.Join(want, ",") {
+		t.Fatalf("eligibleDailyDates() = [%s], want [%s]", strings.Join(gotDates, ","), strings.Join(want, ","))
+	}
+	for _, date := range got {
+		day := timeutil.CivilDay(date, location)
+		if !date.Equal(day.Start) {
+			t.Fatalf("eligible date %s is not local civil day start %s", date, day.Start)
+		}
+	}
+}
+
+func mustLoadTestLocation(t *testing.T, name string) *time.Location {
+	t.Helper()
+	location, err := time.LoadLocation(name)
+	if err != nil {
+		t.Fatalf("LoadLocation(%q) error = %v", name, err)
+	}
+	return location
+}
+
+func mustParseLocalDate(t *testing.T, value string, location *time.Location) time.Time {
+	t.Helper()
+	parsed, err := timeutil.ParseLocalDate(value, location)
+	if err != nil {
+		t.Fatalf("ParseLocalDate(%q) error = %v", value, err)
+	}
+	return parsed
+}