weatherreporter/internal/briefing/derived_daypart_summaries_module.go

package briefing

import (
	"fmt"
	"strings"
	"unicode"

	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
)

type DerivedDaypartSummaryModule struct {
	Date                   string   `json:"date,omitempty"`
	DisplayName            string   `json:"display_name,omitempty"`
	PeriodBegins           string   `json:"period_begins,omitempty"`
	PeriodEnds             string   `json:"period_ends,omitempty"`
	TempRangeF             string   `json:"temp_range_f,omitempty"`
	TemperaturePhraseF     string   `json:"temperature_phrase_f,omitempty"`
	ApparentTempRangeF     string   `json:"apparent_temp_range_f,omitempty"`
	MaxPopPercent          *int     `json:"max_pop_percent,omitempty"`
	MaxPopTime             string   `json:"max_pop_time,omitempty"`
	MaxPopTimeLabel        string   `json:"max_pop_time_label,omitempty"`
	MentionPrecipitation   bool     `json:"mention_precipitation,omitempty"`
	MaxWindGustMph         *int     `json:"max_wind_gust_mph,omitempty"`
	MaxWindGustTime        string   `json:"max_wind_gust_time,omitempty"`
	DominantCondition      string   `json:"dominant_condition,omitempty"`
	DominantConditionLower string   `json:"dominant_condition_lower,omitempty"`
	NotableConditions      []string `json:"notable_conditions,omitempty"`
	Snow                   bool     `json:"snow,omitempty"`
	Ice                    bool     `json:"ice,omitempty"`
	Fog                    bool     `json:"fog,omitempty"`
	Heat                   bool     `json:"heat,omitempty"`
	Cold                   bool     `json:"cold,omitempty"`
	Wind                   bool     `json:"wind,omitempty"`
	RelevantAlertCount     int      `json:"relevant_alert_count,omitempty"`
}

func buildDerivedDaypartSummariesModule(ctx ModuleContext, _ any) (*module.Output, error) {
	if len(ctx.Derived.DaypartSummaries) == 0 {
		return nil, fmt.Errorf("daypart summary facts are required")
	}
	value := map[string]DerivedDaypartSummaryModule{}
	prefixDates := multipleSummaryDates(ctx.Derived.DailySummaries)
	for _, daypart := range ctx.Derived.DaypartSummaries {
		key := daypartKey(daypart, prefixDates)
		value[key] = derivedDaypartSummaryValue(daypart, ctx.Timezone)
	}
	return &module.Output{ID: module.DerivedDaypartSummaries, StanzaName: "derived_daypart_summaries", Value: value}, nil
}

func derivedDaypartSummaryValue(daypart forecast.DaypartSummary, timezone string) DerivedDaypartSummaryModule {
	value := DerivedDaypartSummaryModule{
		Date:                   localDateLabel(daypart.Period.Start, timezone),
		DisplayName:            titleWord(strings.TrimSpace(daypart.Name)),
		PeriodBegins:           friendlyPeriodBeginsLabel(daypart.Period, timezone),
		PeriodEnds:             friendlyPeriodEndsLabel(daypart.Period, timezone),
		TempRangeF:             rangeLabel(daypart.Temperature),
		TemperaturePhraseF:     temperaturePhraseF(daypart.Temperature),
		ApparentTempRangeF:     daypartApparentRangeLabel(daypart.ApparentTemperature),
		DominantCondition:      daypart.DominantCondition,
		DominantConditionLower: strings.ToLower(daypart.DominantCondition),
		NotableConditions:      append([]string(nil), daypart.NotableConditions...),
		Snow:                   daypart.Indicators.Snow,
		Ice:                    daypart.Indicators.Ice,
		Fog:                    daypart.Indicators.Fog,
		Heat:                   daypart.Indicators.Heat,
		Cold:                   daypart.Indicators.Cold,
		Wind:                   daypart.Indicators.Wind,
		RelevantAlertCount:     len(daypart.AlertOverlaps),
	}
	if daypart.MaxPrecipitationProbability != nil {
		value.MaxPopPercent = roundedInt(&daypart.MaxPrecipitationProbability.Value)
		value.MaxPopTime = clockLabel(daypart.MaxPrecipitationProbability.Time, timezone)
		value.MaxPopTimeLabel = hourMinuteLabel(daypart.MaxPrecipitationProbability.Time, timezone)
		value.MentionPrecipitation = mentionHourlyForecastPrecipitation(&daypart.MaxPrecipitationProbability.Value, DefaultHourlyForecastPrecipMentionProbabilityThreshold)
	}
	if daypart.PeakWindGust != nil {
		value.MaxWindGustMph = roundedInt(&daypart.PeakWindGust.Value)
		value.MaxWindGustTime = clockLabel(daypart.PeakWindGust.Time, timezone)
	}
	return value
}

func temperaturePhraseF(value forecast.Range) string {
	if value.Min == nil && value.Max == nil {
		return ""
	}
	if value.Min != nil && value.Max != nil {
		low := roundedInt(value.Min)
		high := roundedInt(value.Max)
		if low == nil || high == nil {
			return ""
		}
		lowPhrase := temperatureBandPhrase(*low)
		highPhrase := temperatureBandPhrase(*high)
		if lowPhrase == highPhrase {
			return lowPhrase
		}
		return lowPhrase + " to " + highPhrase
	}
	if value.Min != nil {
		low := roundedInt(value.Min)
		if low == nil {
			return ""
		}
		return temperatureBandPhrase(*low)
	}
	high := roundedInt(value.Max)
	if high == nil {
		return ""
	}
	return temperatureBandPhrase(*high)
}

func temperatureBandPhrase(value int) string {
	decade := (value / 10) * 10
	remainder := value - decade
	if remainder < 0 {
		remainder = -remainder
	}
	qualifier := "mid"
	switch {
	case remainder <= 3:
		qualifier = "low"
	case remainder >= 7:
		qualifier = "upper"
	}
	return fmt.Sprintf("%s %ds", qualifier, decade)
}

func multipleSummaryDates(summaries []forecast.DailySummary) bool {
	seen := map[string]struct{}{}
	for _, summary := range summaries {
		seen[summary.Date] = struct{}{}
	}
	return len(seen) > 1
}

func daypartKey(daypart forecast.DaypartSummary, prefixDate bool) string {
	key := normalizedKey(daypart.Name)
	if key == "" {
		key = "unnamed"
	}
	if !prefixDate {
		return key
	}
	return daypart.Period.Start.Format(timeutil.DateLayout) + "_" + key
}

func normalizedKey(value string) string {
	lower := strings.ToLower(strings.TrimSpace(value))
	var out strings.Builder
	lastUnderscore := false
	for _, r := range lower {
		if unicode.IsLetter(r) || unicode.IsDigit(r) {
			out.WriteRune(r)
			lastUnderscore = false
			continue
		}
		if !lastUnderscore {
			out.WriteByte('_')
			lastUnderscore = true
		}
	}
	return strings.Trim(out.String(), "_")
}