add badger

internal/storage/badger/category.go

@@ -0,0 +1,143 @@
+package badger
+
+import (
+	"context"
+	"encoding/binary"
+	"errors"
+	"fmt"
+
+	"git.loyso.art/frx/eway/internal/encoding/fbs"
+	"git.loyso.art/frx/eway/internal/entity"
+
+	badger "github.com/dgraph-io/badger/v4"
+	"github.com/rs/zerolog"
+)
+
+type categoryClient struct {
+	db     *badger.DB
+	seqGen *badger.Sequence
+}
+
+func newCategoryClient(db *badger.DB, seqGen *badger.Sequence) categoryClient {
+	return categoryClient{
+		db:     db,
+		seqGen: seqGen,
+	}
+}
+
+func (categoryClient) prefix() []byte {
+	return []byte("!!category!!")
+}
+
+func (c categoryClient) prefixed(key []byte) []byte {
+	return append(c.prefix(), key...)
+}
+
+func (c categoryClient) prefixedInt(key int64) []byte {
+	var keyBytes [8]byte
+	binary.BigEndian.PutUint64(keyBytes[:], uint64(key))
+
+	return c.prefixed(keyBytes[:])
+}
+
+func (c categoryClient) List(
+	ctx context.Context,
+) (out []entity.Category, err error) {
+	err = c.db.View(func(txn *badger.Txn) error {
+		opts := badger.DefaultIteratorOptions
+		opts.PrefetchSize = 10
+		opts.PrefetchValues = true
+
+		iter := txn.NewIterator(opts)
+		defer iter.Close()
+
+		prefix := c.prefix()
+		for iter.Seek(prefix); iter.ValidForPrefix(prefix); iter.Next() {
+			current := iter.Item()
+			err = current.Value(func(val []byte) error {
+				category := fbs.ParseCategory(val)
+				out = append(out, category)
+
+				return nil
+			})
+			if err != nil {
+				return fmt.Errorf("getting value: %w", err)
+			}
+		}
+
+		return nil
+	})
+	if err != nil {
+		return nil, fmt.Errorf("viewing: %w", err)
+	}
+
+	return out, nil
+}
+
+func (c categoryClient) Get(ctx context.Context, id int64) (out entity.Category, err error) {
+	err = c.db.View(func(txn *badger.Txn) error {
+		key := c.prefixedInt(id)
+		item, err := txn.Get(key)
+		if err != nil {
+			return fmt.Errorf("getting key: %w", err)
+		}
+
+		err = item.Value(func(val []byte) error {
+			out = fbs.ParseCategory(val)
+			return nil
+		})
+		if err != nil {
+			return fmt.Errorf("reading value: %w", err)
+		}
+
+		return nil
+	})
+	if err != nil {
+		if errors.Is(err, badger.ErrKeyNotFound) {
+			return out, entity.ErrNotFound
+		}
+
+		return out, fmt.Errorf("viewing: %w", err)
+	}
+
+	return out, nil
+}
+
+// Create new category inside DB. It also applies new id to it.
+func (c categoryClient) Create(ctx context.Context, name string) (out entity.Category, err error) {
+	seqGen, err := c.db.GetSequence(categorySequenceIDKey, 1)
+	if err != nil {
+		return out, fmt.Errorf("getting sequence for categories: %w", err)
+	}
+	defer func() {
+		errRelese := seqGen.Release()
+		if errRelese != nil {
+			zerolog.Ctx(ctx).Warn().Err(err).Msg("unable to release seq")
+		}
+	}()
+
+	nextid, err := seqGen.Next()
+	if err != nil {
+		return out, fmt.Errorf("getting next id: %w", err)
+	}
+
+	out = entity.Category{
+		ID:   int64(nextid),
+		Name: name,
+	}
+
+	err = c.db.Update(func(txn *badger.Txn) error {
+		key := c.prefixedInt(out.ID)
+		err = txn.Set(key, fbs.MakeCategoryFinished(out))
+		if err != nil {
+			return fmt.Errorf("setting: %w", err)
+		}
+
+		return nil
+	})
+	if err != nil {
+		return out, fmt.Errorf("updating: %w", err)
+	}
+
+	return out, nil
+}