refactor: Decompose find func

pkg/inventory/find.go

@@ -1,11 +1,54 @@
 package inventory
 
-import "archive/tar"
+import (
+	"archive/tar"
+	"context"
+	"regexp"
+
+	"github.com/pojntfx/stfs/internal/converters"
+	"github.com/pojntfx/stfs/internal/formatting"
+	"github.com/pojntfx/stfs/internal/persisters"
+)
 
 func Find(
 	state MetadataConfig,
 
 	expression string,
 ) ([]*tar.Header, error) {
-	return nil, nil
+	metadataPersister := persisters.NewMetadataPersister(state.Metadata)
+	if err := metadataPersister.Open(); err != nil {
+		return []*tar.Header{}, err
+	}
+
+	dbHdrs, err := metadataPersister.GetHeaders(context.Background())
+	if err != nil {
+		return []*tar.Header{}, err
+	}
+
+	headers := []*tar.Header{}
+	first := true
+	for _, dbhdr := range dbHdrs {
+		if regexp.MustCompile(expression).Match([]byte(dbhdr.Name)) {
+			if first {
+				if err := formatting.PrintCSV(formatting.TARHeaderCSV); err != nil {
+					return []*tar.Header{}, err
+				}
+
+				first = false
+			}
+
+			hdr, err := converters.DBHeaderToTarHeader(dbhdr)
+			if err != nil {
+				return []*tar.Header{}, err
+			}
+
+			if err := formatting.PrintCSV(formatting.GetTARHeaderAsCSV(dbhdr.Record, dbhdr.Block, hdr)); err != nil {
+				return []*tar.Header{}, err
+			}
+
+			headers = append(headers, hdr)
+		}
+	}
+
+	return headers, nil
 }