feat: custom stickers apis

internal/service/sadhna_service.go

@@ -16,7 +16,12 @@ package service
 
 import (
 	"context"
+	crand "crypto/rand"
+	"encoding/hex"
+	"errors"
 	"math/rand"
+	"regexp"
+	"strings"
 	"time"
 
 	"github.com/prabhupadasays/spsays-bff/internal/model"
@@ -64,7 +69,10 @@ type SadhnaService struct {
 	posts   *repository.PostRepo
 	users   *repository.UserRepo
 	rewards *repository.RewardRepo
-	logger  *zap.Logger
+	// r2 stores custom gift artwork. Optional: nil disables custom gifts
+	// rather than failing anything that already works.
+	r2     *repository.R2
+	logger *zap.Logger
 }
 
 func NewSadhnaService(
@@ -72,9 +80,13 @@ func NewSadhnaService(
 	posts *repository.PostRepo,
 	users *repository.UserRepo,
 	rewards *repository.RewardRepo,
+	r2 *repository.R2,
 	logger *zap.Logger,
 ) *SadhnaService {
-	return &SadhnaService{logs: logs, posts: posts, users: users, rewards: rewards, logger: logger}
+	return &SadhnaService{
+		logs: logs, posts: posts, users: users, rewards: rewards,
+		r2: r2, logger: logger,
+	}
 }
 
 const dayFmt = "2006-01-02"
@@ -415,6 +427,57 @@ func (s *SadhnaService) GiftToEveryone(ctx context.Context, rewardKey string) (i
 	return s.rewards.GrantGiftToEveryone(ctx, reward.ID)
 }
 
+// customKeyPrefix namespaces admin-made rewards away from the seeded catalog,
+// so Seed can never collide with one.
+const customKeyPrefix = "custom_"
+
+var nonSlug = regexp.MustCompile(`[^a-z0-9]+`)
+
+// customRewardKey derives a stable, unique key from a name.
+//
+// The random suffix is what makes it unique: two gifts may reasonably share a
+// name, and a collision would overwrite the first one's artwork.
+func customRewardKey(name string) (string, error) {
+	slug := strings.Trim(nonSlug.ReplaceAllString(strings.ToLower(name), "_"), "_")
+	if slug == "" {
+		slug = "gift"
+	}
+	if len(slug) > 32 {
+		slug = slug[:32]
+	}
+	suffix := make([]byte, 4)
+	if _, err := crand.Read(suffix); err != nil {
+		return "", err
+	}
+	return customKeyPrefix + slug + "_" + hex.EncodeToString(suffix), nil
+}
+
+// CreateCustomGift adds a new sticker to the catalog. It is not granted to
+// anyone until it is sent.
+func (s *SadhnaService) CreateCustomGift(ctx context.Context, name, meaning, imageURL string) (*model.SadhnaReward, error) {
+	name = strings.TrimSpace(name)
+	if name == "" {
+		return nil, errors.New("a gift needs a name")
+	}
+	if strings.TrimSpace(imageURL) == "" {
+		return nil, errors.New("a gift needs an image")
+	}
+	key, err := customRewardKey(name)
+	if err != nil {
+		return nil, err
+	}
+	return s.rewards.CreateCustom(ctx, key, name, strings.TrimSpace(meaning), imageURL)
+}
+
+// PresignGiftImage issues an upload URL for custom sticker artwork.
+//
+// Returns the PUBLIC URL, not a key: sadhna_rewards.image_url stores an
+// absolute address, and stickers render for every participant in a chat, so
+// the artwork belongs in the public bucket alongside avatars and post images.
+func (s *SadhnaService) PresignGiftImage(ctx context.Context, contentType string) (uploadURL, publicURL string, err error) {
+	return presignImage(ctx, s.r2, "reward-gifts", "custom", contentType)
+}
+
 // GiftableRewards is the catalog an admin picks from.
 func (s *SadhnaService) GiftableRewards(ctx context.Context) ([]model.SadhnaReward, error) {
 	return s.rewards.ListGiftable(ctx)