Add a /conditions/current endpoint

internal/adapters/outbound/postgres/repository.go

@@ -36,6 +36,51 @@ FROM observations
 ORDER BY observed_at DESC, event_emitted_at DESC
 LIMIT 1`
 
+	queryCurrentConditions = `
+WITH windowed AS (
+  SELECT
+    temperature_c,
+    apparent_temperature_c,
+    dewpoint_c,
+    relative_humidity_percent,
+    wind_speed_kmh,
+    wind_direction_degrees,
+    condition_code,
+    is_day,
+    observed_at
+  FROM observations
+  WHERE observed_at > CURRENT_TIMESTAMP - make_interval(mins => $1)
+)
+SELECT
+  COUNT(*) AS sample_count,
+  AVG(temperature_c) AS temperature_c,
+  AVG(apparent_temperature_c) AS apparent_temperature_c,
+  AVG(dewpoint_c) AS dewpoint_c,
+  AVG(relative_humidity_percent) AS relative_humidity_percent,
+  AVG(wind_speed_kmh) AS wind_speed_kmh,
+  CASE
+    WHEN atan2d(
+      AVG(sind(wind_direction_degrees)),
+      AVG(cosd(wind_direction_degrees))
+    ) < 0
+    THEN atan2d(
+      AVG(sind(wind_direction_degrees)),
+      AVG(cosd(wind_direction_degrees))
+    ) + 360.0
+    ELSE atan2d(
+      AVG(sind(wind_direction_degrees)),
+      AVG(cosd(wind_direction_degrees))
+    )
+  END AS wind_direction_degrees,
+  MAX(condition_code) AS condition_code,
+  (
+    SELECT is_day
+    FROM windowed
+    ORDER BY observed_at DESC
+    LIMIT 1
+  ) AS is_day
+FROM windowed`
+
 	queryObservationPresentWeather = `
 SELECT weather_index, raw_text
 FROM observation_present_weather
@@ -193,6 +238,33 @@ func (r *Repository) LatestObservation(ctx context.Context) (*model.WeatherObser
 	return &obs, nil
 }
 
+func (r *Repository) CurrentConditions(ctx context.Context, observationWindowMinutes int) (*core.CurrentConditions, error) {
+	if r == nil || r.db == nil {
+		return nil, fmt.Errorf("postgres repository is not configured")
+	}
+
+	var row currentConditionsRow
+	err := r.db.QueryRowContext(ctx, queryCurrentConditions, observationWindowMinutes).Scan(
+		&row.SampleCount,
+		&row.TemperatureC,
+		&row.ApparentTemperatureC,
+		&row.DewpointC,
+		&row.RelativeHumidityPercent,
+		&row.WindSpeedKmh,
+		&row.WindDirectionDegrees,
+		&row.ConditionCode,
+		&row.IsDay,
+	)
+	if errors.Is(err, sql.ErrNoRows) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("query current conditions: %w", err)
+	}
+
+	return mapCurrentConditionsRow(row), nil
+}
+
 func (r *Repository) LatestHourlyForecast(ctx context.Context) (*model.WeatherForecastRun, error) {
 	if r == nil || r.db == nil {
 		return nil, fmt.Errorf("postgres repository is not configured")
@@ -419,6 +491,40 @@ type observationParentRow struct {
 	ApparentTemperatureC    sql.NullFloat64
 }
 
+type currentConditionsRow struct {
+	SampleCount             int64
+	TemperatureC            sql.NullFloat64
+	ApparentTemperatureC    sql.NullFloat64
+	DewpointC               sql.NullFloat64
+	RelativeHumidityPercent sql.NullFloat64
+	WindSpeedKmh            sql.NullFloat64
+	WindDirectionDegrees    sql.NullFloat64
+	ConditionCode           sql.NullInt64
+	IsDay                   sql.NullBool
+}
+
+func mapCurrentConditionsRow(row currentConditionsRow) *core.CurrentConditions {
+	if row.SampleCount == 0 {
+		return nil
+	}
+
+	conditionCode := model.WMOUnknown
+	if row.ConditionCode.Valid {
+		conditionCode = model.WMOCode(row.ConditionCode.Int64)
+	}
+
+	return &core.CurrentConditions{
+		TemperatureC:            float64Ptr(row.TemperatureC),
+		ApparentTemperatureC:    float64Ptr(row.ApparentTemperatureC),
+		DewpointC:               float64Ptr(row.DewpointC),
+		RelativeHumidityPercent: float64Ptr(row.RelativeHumidityPercent),
+		WindSpeedKmh:            float64Ptr(row.WindSpeedKmh),
+		WindDirectionDegrees:    float64Ptr(row.WindDirectionDegrees),
+		ConditionCode:           conditionCode,
+		IsDay:                   boolPtr(row.IsDay),
+	}
+}
+
 func mapObservationParentRow(row observationParentRow) model.WeatherObservation {
 	return model.WeatherObservation{
 		StationID:               stringValue(row.StationID),