zones: introduce ScanOption/ScanOptions for New()/NewFS()

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/zones/options.go

@@ -0,0 +1,63 @@
+package zones
+
+import (
+	"io/fs"
+	"path/filepath"
+
+	"darvaza.org/resolver"
+	"github.com/hack-pad/hackpadfs/os"
+)
+
+// A ScanOption preconfigures the Zones before scanning
+type ScanOption func(*Zones, *ScanOptions) error
+
+// ScanOptions contains flags used by the initial scan
+type ScanOptions struct{}
+
+func (*Zones) setDefaults(_ *ScanOptions) error {
+	return nil
+}
+
+// NewFS builds a [Zones] tree using the given directory
+func NewFS(dir fs.FS, domain string, opts ...ScanOption) (*Zones, error) {
+	var scanOptions ScanOptions
+
+	lockuper := resolver.NewCloudflareLookuper()
+
+	z := &Zones{
+		dir:      dir,
+		resolver: resolver.NewResolver(lockuper),
+		domain:   domain,
+	}
+
+	for _, opt := range opts {
+		if err := opt(z, &scanOptions); err != nil {
+			return nil, err
+		}
+	}
+
+	if err := z.setDefaults(&scanOptions); err != nil {
+		return nil, err
+	}
+
+	if err := z.scan(&scanOptions); err != nil {
+		return nil, err
+	}
+
+	return z, nil
+}
+
+// New builds a [Zones] tree using the given directory
+func New(dir, domain string, opts ...ScanOption) (*Zones, error) {
+	dir, err := filepath.Abs(dir)
+	if err != nil {
+		return nil, err
+	}
+
+	base, err := os.NewFS().Sub(dir[1:])
+	if err != nil {
+		return nil, err
+	}
+
+	return NewFS(base, domain, opts...)
+}