Refactored the application structure to better separate concerns between files and packages

internal/adapters/outbound/postgres/observations_read.go

@@ -0,0 +1,79 @@
+// observations_read.go executes observation and present-weather queries.
+// Layer: adapters/outbound/postgres observations feature.
+package postgres
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+
+	"gitea.maximumdirect.net/ejr/weatherfeeder/model"
+)
+
+func (r *Repository) LatestObservation(ctx context.Context) (*model.WeatherObservation, error) {
+	if r == nil || r.db == nil {
+		return nil, fmt.Errorf("postgres repository is not configured")
+	}
+
+	var row observationParentRow
+	err := r.db.QueryRowContext(ctx, queryLatestObservation).Scan(
+		&row.EventID,
+		&row.StationID,
+		&row.StationName,
+		&row.ObservedAt,
+		&row.ConditionCode,
+		&row.IsDay,
+		&row.TextDescription,
+		&row.TemperatureC,
+		&row.DewpointC,
+		&row.WindDirectionDegrees,
+		&row.WindSpeedKmh,
+		&row.WindGustKmh,
+		&row.BarometricPressurePa,
+		&row.VisibilityMeters,
+		&row.RelativeHumidityPercent,
+		&row.ApparentTemperatureC,
+	)
+	if errors.Is(err, sql.ErrNoRows) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("query latest observation: %w", err)
+	}
+
+	obs := mapObservationParentRow(row)
+
+	presentWeather, err := r.loadObservationPresentWeather(ctx, row.EventID)
+	if err != nil {
+		return nil, err
+	}
+	obs.PresentWeather = presentWeather
+
+	return &obs, nil
+}
+
+func (r *Repository) loadObservationPresentWeather(ctx context.Context, eventID string) ([]model.PresentWeather, error) {
+	rows, err := r.db.QueryContext(ctx, queryObservationPresentWeather, eventID)
+	if err != nil {
+		return nil, fmt.Errorf("query observation present weather: %w", err)
+	}
+	defer rows.Close()
+
+	out := make([]model.PresentWeather, 0)
+	for rows.Next() {
+		var row observationPresentWeatherRow
+		if err := rows.Scan(&row.WeatherIndex, &row.RawText); err != nil {
+			return nil, fmt.Errorf("scan observation present weather row: %w", err)
+		}
+		pw, err := mapObservationPresentWeatherRow(row)
+		if err != nil {
+			return nil, fmt.Errorf("decode observation present weather row (index=%d): %w", row.WeatherIndex, err)
+		}
+		out = append(out, pw)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("iterate observation present weather rows: %w", err)
+	}
+	return out, nil
+}