Implemented the weather forecast discussion product from weatherfeeder v0.8.3

internal/adapters/outbound/postgres/discussion_read.go

@@ -0,0 +1,74 @@
+// discussion_read.go executes forecast discussion queries.
+// Layer: adapters/outbound/postgres discussion feature.
+package postgres
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+
+	"gitea.maximumdirect.net/ejr/weatherfeeder/model"
+)
+
+func (r *Repository) LatestForecastDiscussion(ctx context.Context) (*model.WeatherForecastDiscussion, error) {
+	if r == nil || r.db == nil {
+		return nil, fmt.Errorf("postgres repository is not configured")
+	}
+
+	var row discussionParentRow
+	err := r.db.QueryRowContext(ctx, queryLatestForecastDiscussion).Scan(
+		&row.EventID,
+		&row.OfficeID,
+		&row.OfficeName,
+		&row.IssuedAt,
+		&row.UpdatedAt,
+		&row.Product,
+		&row.ShortTermQualifier,
+		&row.ShortTermIssuedAt,
+		&row.ShortTermText,
+		&row.LongTermQualifier,
+		&row.LongTermIssuedAt,
+		&row.LongTermText,
+	)
+	if errors.Is(err, sql.ErrNoRows) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("query latest forecast discussion: %w", err)
+	}
+
+	run := mapDiscussionParentRow(row)
+
+	keyMessages, err := r.loadForecastDiscussionKeyMessages(ctx, row.EventID)
+	if err != nil {
+		return nil, err
+	}
+	run.KeyMessages = keyMessages
+
+	return &run, nil
+}
+
+func (r *Repository) loadForecastDiscussionKeyMessages(ctx context.Context, eventID string) ([]string, error) {
+	rows, err := r.db.QueryContext(ctx, queryForecastDiscussionKeyMessages, eventID)
+	if err != nil {
+		return nil, fmt.Errorf("query forecast discussion key messages: %w", err)
+	}
+	defer rows.Close()
+
+	out := make([]string, 0)
+	for rows.Next() {
+		var row discussionKeyMessageRow
+		if err := rows.Scan(
+			&row.MessageIndex,
+			&row.MessageText,
+		); err != nil {
+			return nil, fmt.Errorf("scan forecast discussion key message row: %w", err)
+		}
+		out = append(out, mapDiscussionKeyMessageRow(row))
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("iterate forecast discussion key message rows: %w", err)
+	}
+	return out, nil
+}