Add collected and derived fact contracts

internal/facts/facts.go

@@ -0,0 +1,139 @@
+// Package facts defines collected and derived report facts.
+package facts
+
+import (
+	"fmt"
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
+)
+
+type CollectedFacts struct {
+	FetchedAt    time.Time
+	Observation  *weatherdata.Observation
+	Current      *weatherdata.Current
+	Hourly       *weatherdata.ForecastRun
+	Narrative    *weatherdata.ForecastRun
+	Alerts       *weatherdata.AlertRun
+	Discussion   *weatherdata.Discussion
+	Daily        *weatherdata.ForecastRun
+	WeatherStory *weatherdata.WeatherStory
+
+	SourceProvenance []weatherdata.Source
+	SourceWarnings   []weatherdata.SourceWarning
+}
+
+func BuildCollected(bundle *weatherdata.Bundle) CollectedFacts {
+	if bundle == nil {
+		return CollectedFacts{}
+	}
+	return CollectedFacts{
+		FetchedAt:        bundle.FetchedAt,
+		Observation:      bundle.Observation,
+		Current:          bundle.Current,
+		Hourly:           bundle.Hourly,
+		Narrative:        bundle.Narrative,
+		Alerts:           bundle.Alerts,
+		Discussion:       bundle.Discussion,
+		Daily:            bundle.Daily,
+		WeatherStory:     bundle.WeatherStory,
+		SourceProvenance: append([]weatherdata.Source(nil), bundle.Sources...),
+		SourceWarnings:   append([]weatherdata.SourceWarning(nil), bundle.Warnings...),
+	}
+}
+
+func (f CollectedFacts) Bundle() *weatherdata.Bundle {
+	return &weatherdata.Bundle{
+		FetchedAt:    f.FetchedAt,
+		Observation:  f.Observation,
+		Current:      f.Current,
+		Hourly:       f.Hourly,
+		Narrative:    f.Narrative,
+		Alerts:       f.Alerts,
+		Discussion:   f.Discussion,
+		Daily:        f.Daily,
+		WeatherStory: f.WeatherStory,
+		Sources:      append([]weatherdata.Source(nil), f.SourceProvenance...),
+		Warnings:     append([]weatherdata.SourceWarning(nil), f.SourceWarnings...),
+	}
+}
+
+type BuildDerivedRequest struct {
+	Resolved  report.Resolved
+	Timezone  string
+	Dayparts  []forecast.DaypartDefinition
+	Collected CollectedFacts
+}
+
+type DerivedFacts struct {
+	ValidPeriodHourlyPeriods    []weatherdata.ForecastPeriod
+	ValidPeriodNarrativePeriods []weatherdata.ForecastPeriod
+	ValidPeriodDailyPeriods     []weatherdata.ForecastPeriod
+	AlertOverlaps               []forecast.AlertOverlap
+	DailySummaries              []forecast.DailySummary
+	DaypartSummaries            []forecast.DaypartSummary
+	StormWindowSummary          *forecast.DaypartSummary
+}
+
+func (f DerivedFacts) FirstDailySummary() *forecast.DailySummary {
+	if len(f.DailySummaries) == 0 {
+		return nil
+	}
+	return &f.DailySummaries[0]
+}
+
+func BuildDerived(req BuildDerivedRequest) (DerivedFacts, error) {
+	if !req.Resolved.ValidPeriod.IsValid() {
+		return DerivedFacts{}, fmt.Errorf("resolved valid period is required")
+	}
+	location, err := timeutil.LoadLocation(req.Timezone)
+	if err != nil {
+		return DerivedFacts{}, fmt.Errorf("load report timezone %q: %w", req.Timezone, err)
+	}
+	bundle := req.Collected.Bundle()
+	period := req.Resolved.ValidPeriod
+	derived := DerivedFacts{
+		ValidPeriodHourlyPeriods:    forecast.SelectHourlyPeriods(req.Collected.Hourly, period),
+		ValidPeriodNarrativePeriods: forecast.SelectHourlyPeriods(req.Collected.Narrative, period),
+		ValidPeriodDailyPeriods:     forecast.SelectHourlyPeriods(req.Collected.Daily, period),
+		AlertOverlaps:               forecast.AlertOverlaps(req.Collected.Alerts, period),
+	}
+
+	switch req.Resolved.Definition.ID {
+	case report.DailyToday, report.DailyTomorrow:
+		summary, err := forecast.BuildDailySummary(bundle, period.Start, location, req.Dayparts)
+		if err != nil {
+			return DerivedFacts{}, err
+		}
+		derived.DailySummaries = []forecast.DailySummary{*summary}
+	case report.ThreeDay, report.Weekend:
+		summaries, err := forecast.BuildPeriodDailySummaries(bundle, period, location, req.Dayparts)
+		if err != nil {
+			return DerivedFacts{}, err
+		}
+		derived.DailySummaries = summaries
+	case report.Storm:
+		summary := forecast.SummarizeDaypart("storm window", period, derived.ValidPeriodHourlyPeriods)
+		summary.AlertOverlaps = derived.AlertOverlaps
+		derived.StormWindowSummary = &summary
+	default:
+		return DerivedFacts{}, fmt.Errorf("derived facts are not implemented for report %q", req.Resolved.Definition.ID)
+	}
+
+	derived.DaypartSummaries = collectDaypartSummaries(derived)
+	return derived, nil
+}
+
+func collectDaypartSummaries(derived DerivedFacts) []forecast.DaypartSummary {
+	var out []forecast.DaypartSummary
+	for _, summary := range derived.DailySummaries {
+		out = append(out, summary.Dayparts...)
+	}
+	if derived.StormWindowSummary != nil {
+		out = append(out, *derived.StormWindowSummary)
+	}
+	return out
+}