= Use-case 0001 Implementation - Login

'''Initiating actor:''' Guest

'''Other actors:''' None

'''Description:'''
A guest wants to access their personalized profile in the system. If the guest attempts to perform a restricted action, they must log in. The guest logs in by providing a username and password. The system verifies the credentials and if valid, starts an authenticated session.

'''Scenario:'''
 1. Guest goes to the login page.

[[Image(UC0001LogIn_1.png)]]

 2. Guest enters their username and password credentials.
 3. Guest submits the form.
 3. System checks the database to verify if the credentials exist and if they are correct:
{{{
#!sql
Hibernate: 
    select
        u1_0.user_id,
        case 
            when u1_1.user_id is not null 
                then 1 
            when u1_2.user_id is not null 
                then 2 
            when u1_0.user_id is not null 
                then 0 
            end,
            u1_0.email,
            u1_0.first_name,
            u1_0.last_name,
            u1_0.password,
            u1_0.username,
            u1_2.user_id 
        from
            project.users u1_0 
        left join
            project.pet_owners u1_1 
                on u1_0.user_id=u1_1.user_id 
        left join
            project.pet_sitters u1_2 
                on u1_0.user_id=u1_2.user_id 
        where
            u1_0.username=?

}}}
 4. The user logs in, the system determines their role (Owner, Sitter, or Admin), and redirects them to their dashboard.

[[Image(UC0001LogIn_2.png)]]