feat: account connect

internal/repository/user_repo.go

@@ -380,6 +380,32 @@ func (r *AuthTokenRepo) FindValid(ctx context.Context, tokenHash, purpose string
 	return t, nil
 }
 
+// FindValidForUser returns a non-used, non-expired token by user + hash +
+// purpose. Used by the OTP login flow where the keyspace is small (6
+// digits) — scoping by user_id prevents a global hash-collision lookup.
+func (r *AuthTokenRepo) FindValidForUser(ctx context.Context, userID, tokenHash, purpose string) (*model.AuthToken, error) {
+	const q = `
+		SELECT id, user_id, purpose, token_hash, expires_at, used_at, created_at
+		FROM auth_tokens
+		WHERE user_id    = $1
+		  AND token_hash = $2
+		  AND purpose    = $3
+		  AND used_at    IS NULL
+		  AND expires_at > now()
+		LIMIT 1`
+
+	t := &model.AuthToken{}
+	err := r.pg.Pool.QueryRow(ctx, q, userID, tokenHash, purpose).
+		Scan(&t.ID, &t.UserID, &t.Purpose, &t.TokenHash, &t.ExpiresAt, &t.UsedAt, &t.CreatedAt)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, ErrUserNotFound
+		}
+		return nil, fmt.Errorf("find token: %w", err)
+	}
+	return t, nil
+}
+
 // Consume marks a token as used. After this call the token can never be
 // honoured again, even if it has not yet expired.
 func (r *AuthTokenRepo) Consume(ctx context.Context, id string) error {