Feature: Several unverified users can coexist, and deleting a user frees its username and email

  As the maintainer of RenewCMS
  I want an absent password reset code or verification code stored as no value instead of an empty
    string, and a deleted user's row actually removed
  So that several unverified users can register one after another without colliding on the unique
    reset-code column, and so that deleting a user lets the same username and email register again

  Background:
    Given internal/infrastructure/persistence/models.User stores PasswordResetCode and VerificationCode
      as nullable, unique columns, so a domain value of "" is persisted as no value (SQL NULL), and SQL
      NULL is exempt from the unique constraint
    And internal/infrastructure/persistence/mappers.UserToModel maps a domain "" for PasswordResetCode or
      VerificationCode to no value, and UserToDomain maps no value back to ""
    And internal/infrastructure/persistence/models.User no longer embeds gorm.Model, so
      UserRepository.Delete removes the row instead of leaving a soft-deleted row that still occupies the
      unique username and email
    And POST /v1/auth/register is public, and CreateUser stores a new user with is_verified false and
      PasswordResetCode "" as soon as the request is valid
    And Register only answers 403 once at least one existing user is verified (SomeUsersVerified), never
      because the user table already has rows
    And DeleteUser has no handler mounted in api/router.go today, so deletion in these scenarios is
      exercised through UserRepository.Delete / DeleteUserUseCase.DeleteUser directly, not through an
      HTTP route

  Scenario: Two unverified users can register one after another without a reset-code collision
    Given the user repository is empty
    When the client sends POST /v1/auth/register with username "alice", password "hunter2example12",
      email "alice@example.com"
    Then the response status is 200
    And a jwt cookie is set
    When the client sends POST /v1/auth/register with username "bob", password "hunter2example12",
      email "bob@example.com"
    Then the response status is 200
    And a jwt cookie is set
    And the user repository contains both "alice" and "bob", each with is_verified false and an empty
      password reset code

  Scenario: Creating two users with no active reset code does not violate the unique constraint
    Given a repository backed by an in-memory SQLite database with models.User migrated
    When Create is called with username "alice", email "alice@example.com", password_reset_code "" and
      verification_code "code-alice"
    And Create is called with username "bob", email "bob@example.com", password_reset_code "" and
      verification_code "code-bob"
    Then both calls succeed
    And GetByUsername "alice" and GetByUsername "bob" each return password_reset_code ""

  Scenario: The unique constraint still rejects two users sharing the same active reset code
    Given a repository backed by an in-memory SQLite database containing a user "alice" with
      password_reset_code "shared-code"
    When Create is called with username "bob", email "bob@example.com" and password_reset_code
      "shared-code"
    Then the Create call returns an error
    And GetByUsername "bob" still returns user.ErrUserNotFound

  Scenario: Deleting a user removes the row so the same username and email can register again
    Given a repository backed by an in-memory SQLite database containing a user with id 1, username
      "alice" and email "alice@example.com"
    When Delete is called with id 1
    And Create is called with username "alice", email "alice@example.com" and a new password
    Then the Create call succeeds
    And the newly created user's id is different from 1
    And Get with id 1 returns user.ErrUserNotFound

  Scenario: Registering the same username while the first account still exists is still rejected
    Given a repository backed by an in-memory SQLite database containing a user with username "alice"
      and email "alice@example.com"
    When Create is called with username "alice", email "someone-else@example.com" and a new password
    Then the Create call returns an error
    And the user repository still contains exactly one user with username "alice"