feat: add valkey backed store

Signed-off-by: Xe Iaso <me@xeiaso.net>

internal/store/valkey/valkey.go

@@ -0,0 +1,86 @@
+package valkey
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+
+	valkey "github.com/redis/go-redis/v9"
+)
+
+type Store struct {
+	rdb *valkey.Client
+}
+
+func New(rdb *valkey.Client) *Store {
+	return &Store{rdb: rdb}
+}
+
+func (s *Store) Increment(ctx context.Context, segments []string) error {
+	key := fmt.Sprintf("anubis:%s", strings.Join(segments, ":"))
+	if err := s.rdb.Incr(ctx, key).Err(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (s *Store) GetInt(ctx context.Context, segments []string) (int, error) {
+	key := fmt.Sprintf("anubis:%s", strings.Join(segments, ":"))
+	numStr, err := s.rdb.Get(ctx, key).Result()
+	if err != nil {
+		return 0, err
+	}
+
+	num, err := strconv.Atoi(numStr)
+	if err != nil {
+		return 0, err
+	}
+
+	return num, nil
+}
+
+func (s *Store) MultiGetInt(ctx context.Context, segments [][]string) ([]int, error) {
+	var keys []string
+	for _, segment := range segments {
+		key := fmt.Sprintf("anubis:%s", strings.Join(segment, ":"))
+		keys = append(keys, key)
+	}
+
+	values, err := s.rdb.MGet(ctx, keys...).Result()
+	if err != nil {
+		return nil, err
+	}
+
+	var errs []error
+
+	result := make([]int, len(values))
+	for i, val := range values {
+		if val == nil {
+			result[i] = 0
+			errs = append(errs, fmt.Errorf("can't get key %s: value is null", keys[i]))
+			continue
+		}
+
+		switch v := val.(type) {
+		case string:
+			num, err := strconv.Atoi(v)
+			if err != nil {
+				errs = append(errs, fmt.Errorf("can't parse key %s: %w", keys[i], err))
+				continue
+			}
+
+			result[i] = num
+		default:
+			errs = append(errs, fmt.Errorf("can't parse key %s: wanted type string but got type %T", keys[i], val))
+		}
+	}
+
+	if len(errs) != 0 {
+		return nil, fmt.Errorf("can't read from valkey: %w", errors.Join(errs...))
+	}
+
+	return result, nil
+}