<?php

class User
{
    private $id;
    private $email;
    private $password;
    private $name;
    private $birthDay

    public function __construct(UserBuilder $builder)
    {
        $this->email = $builder->getEmail();
        $this->password = $builder->getPassword();
        $this->name = $builder->getName();
        $this->birthDay = $builder->birthDay();
    }
}

class UserBuilder
{
    private $email;
    private $password;
    private $name;
    private $birthDay;

    public function withEmail($email): User
    {
        $this->email = $email;
        return $this;
    }

    public function withPassword($password): User
    {
        $this->password = $password;
        return $this;
    }

    public function withName($name): User
    {
        $this->name = $name;
        return $this;
    }

    public function withBirthDay($birthDay): User
    {
        $this->birthDay = $birthDay;
        return $this;
    }

    public function getEmail()
    {
        return $this->email;
    }

    public function getPassword()
    {
        return $this->password;
    }

    public function getName()
    {
        return $this->name;
    }

    public function getBirthDay()
    {
        return $this->birthDay;
    }

    public function build(): User
    {
        if (empty($this->email)
            || empty($this->password)
            || empty($this->name) {
            throw \InvalidArgumentException('...');
        }

        return new User($this);
    }
}

// usage
$user = (new UserBuilder()
       ->withEmail($email)
       ->withPassword($password)
       ->withName($name)
       ->withBirthDay($birthday))
       ->build();