add text waste route

internal/services/user/user_service.go

@@ -4,11 +4,8 @@ import (
 	"context"
 	"crypto/md5"
 	"encoding/hex"
-	"errors"
-	"fmt"
 
 	"github.com/jackc/pgx/v5"
-	"github.com/jackc/pgx/v5/pgconn"
 	"github.com/jackc/pgx/v5/pgxpool"
 )
 
@@ -42,33 +39,20 @@ func NewUserService(
 	}
 }
 
-func (s *UserService) AddUser(ctx context.Context, user *UserEntity) (*UserEntity, error) {
-	query := `INSERT INTO users (username, password) VALUES (@username, @password) RETURNING id`
-	args := pgx.NamedArgs{
-		"username": user.Username,
-		"password": hashPassword(user.Username, user.Password, "crab"),
-	}
-	if err := s.db.QueryRow(ctx, query, args).Scan(&user.Id); err != nil {
-		var pgErr *pgconn.PgError
-		if errors.As(err, &pgErr) {
-			if pgErr.Code == "23505" && pgErr.ConstraintName == "users_username_key" { // unique_violation
-				return nil, &UsernameAlreadyExistsErr{}
-			}
-		}
-		return nil, fmt.Errorf("unable to insert row: %w", err)
-	}
-	return user, nil
-}
-
 func (s *UserService) Login(ctx context.Context, user *UserEntity) (*UserEntity, error) {
-	query := `SELECT id FROM users WHERE username = @username AND password = @password`
 	args := pgx.NamedArgs{
 		"username": user.Username,
 		"password": hashPassword(user.Username, user.Password, "crab"),
 	}
+
+	query := `SELECT id FROM users WHERE username = @username AND password = @password LIMIT 1`
 	if err := s.db.QueryRow(ctx, query, args).Scan(&user.Id); err != nil {
-		return nil, &UserNotFoundErr{}
+		query := `INSERT INTO users (username, password) VALUES (@username, @password) RETURNING id`
+		if err := s.db.QueryRow(ctx, query, args).Scan(&user.Id); err != nil {
+			return user, err
+		}
 	}
+
 	return user, nil
 }