Seed from go-template-repo, renamed to simplexcalc

The template's files at a77fd30, without its history or LICENSE, after
script/rename simplexcalc.

Model: opus-5-5

internal/database/model_widget.go

@@ -0,0 +1,106 @@
+package database
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	// Go has no UUID in the standard library as of go1.25 — checked
+	// against this repo's toolchain, not assumed. Swap this import for
+	// the stdlib package the moment one lands; nothing else here
+	// depends on the implementation.
+	"github.com/google/uuid"
+)
+
+// timeFormat matches the strftime pattern the schema uses for its
+// defaults, so rows written by Go and rows written by a DEFAULT sort
+// against each other correctly.
+const timeFormat = "2006-01-02T15:04:05.000Z"
+
+// Widget is the example row type. It exists so that the migration
+// runner, the query layer, the templates and the tests all exercise
+// real data. Delete it when seeding a real project.
+type Widget struct {
+	ID        string
+	Name      string
+	SizeBytes int64
+	CreatedAt time.Time
+}
+
+// CreateWidget inserts a widget and returns it as stored.
+func (d *Database) CreateWidget(
+	ctx context.Context, name string, size int64,
+) (*Widget, error) {
+	w := &Widget{
+		ID:        uuid.NewString(),
+		Name:      name,
+		SizeBytes: size,
+		CreatedAt: time.Now().UTC(),
+	}
+
+	_, err := d.db.ExecContext(ctx,
+		`INSERT INTO widgets (id, name, size_bytes, created_at) VALUES (?, ?, ?, ?)`,
+		w.ID, w.Name, w.SizeBytes, w.CreatedAt.Format(timeFormat),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("inserting widget: %w", err)
+	}
+
+	return w, nil
+}
+
+// ListWidgets returns the most recently created widgets, newest first,
+// up to limit.
+func (d *Database) ListWidgets(ctx context.Context, limit int) ([]Widget, error) {
+	rows, err := d.db.QueryContext(ctx,
+		`SELECT id, name, size_bytes, created_at
+		   FROM widgets
+	      ORDER BY created_at DESC, id DESC
+		  LIMIT ?`,
+		limit,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("listing widgets: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	widgets := []Widget{}
+
+	for rows.Next() {
+		var (
+			w         Widget
+			createdAt string
+		)
+
+		scanErr := rows.Scan(&w.ID, &w.Name, &w.SizeBytes, &createdAt)
+		if scanErr != nil {
+			return nil, fmt.Errorf("scanning widget: %w", scanErr)
+		}
+
+		w.CreatedAt, scanErr = time.Parse(timeFormat, createdAt)
+		if scanErr != nil {
+			return nil, fmt.Errorf("parsing widget created_at %q: %w", createdAt, scanErr)
+		}
+
+		widgets = append(widgets, w)
+	}
+
+	err = rows.Err()
+	if err != nil {
+		return nil, fmt.Errorf("iterating widgets: %w", err)
+	}
+
+	return widgets, nil
+}
+
+// CountWidgets returns the number of widgets stored.
+func (d *Database) CountWidgets(ctx context.Context) (int, error) {
+	var n int
+
+	err := d.db.QueryRowContext(ctx, `SELECT COUNT(*) FROM widgets`).Scan(&n)
+	if err != nil {
+		return 0, fmt.Errorf("counting widgets: %w", err)
+	}
+
+	return n, nil
+}