Feature: An authenticated user can edit an article's body

  As an authenticated RenewCMS user managing the CMS
  I want to change an existing article's body from an HTTP endpoint
  So that a published or draft article's content can be corrected or updated without
    deleting and recreating it

  Background:
    Given internal/domain/article.Repository already exposes
      UpdateBody(id uint32, body string) (Article, error), and
      UpdateArticleUseCase.UpdateBody delegates to it unchanged
    And UpdateArticleUseCase is already built in api/dependecyInjection.go as
      container.UpdateArticleUseCase, but before this slice no handler or route calls
      UpdateBody
    And this slice adds Handler.UpdateArticleBody, backed by
      UpdateArticleUseCase.UpdateBody(id, body)
    And this slice mounts PATCH /v1/article/{id} inside the same jwtauth Verifier +
      Authenticator group as GET /v1/article/{id}, POST /v1/article/,
      DELETE /v1/article/{id}, PATCH /v1/article/{id}/publish and
      PATCH /v1/article/{id}/unpublish in api/router.go, so it also requires a valid
      jwt cookie
    And the request body is JSON {"body": "..."}; the Body field carries no validate tag
      (no max, not required), as PostArticle.Body, per
      features/article_body_unlimited.feature
    And a successful edit answers 200 with the JSON body of the updated article.Article,
      the same shape GetArticle, PostArticle, PublishArticle and UnpublishArticle
      already return; the article's title, is_online flag and images are unchanged
    And an id that does not parse as a uint32 answers 400 with body
      apperr.IdUint32ErrorMessage, the same as GetArticle, DeleteArticle,
      PublishArticle and UnpublishArticle
    And a body that is not valid JSON answers 400 with body apperr.BodyErrorMessage,
      the same as PostArticle
    And no body value fails validation: an empty or absent body and a body of any length
      are accepted
    And an id absent from the article repository answers 404 with body
      apperr.ArticleNotFoundErrorMessage, backed by
      errors.Is(err, article.ErrArticleNotFound), the same as DeleteArticle,
      PublishArticle and UnpublishArticle already do per
      features/write_not_found_errors.feature
    And this slice does not add any way to change an article's title after creation,
      per features/article_title_rules.feature

  Scenario: Editing an existing article's body updates only the body
    Given a valid jwt cookie for a user with id 1
    And the article repository contains an online article titled
      "Backyard Renovation Update" with id 1 and body "Old body text"
    When the client sends PATCH /v1/article/1 with that cookie and body
      {"body": "New body text"}
    Then the response status is 200
    And the response body is the article with id 1, "body": "New body text",
      "title": "Backyard Renovation Update" and "is_online": true

  Scenario: Editing an offline article's body leaves it offline
    Given a valid jwt cookie for a user with id 1
    And the article repository contains an offline article titled
      "Draft: Kitchen Remodel" with id 2 and body "Draft notes"
    When the client sends PATCH /v1/article/2 with that cookie and body
      {"body": "Revised draft notes"}
    Then the response status is 200
    And the response body is the article with id 2, "body": "Revised draft notes"
      and "is_online": false

  Scenario: Editing an unknown article answers 404
    Given a valid jwt cookie for a user with id 1
    And the article repository has no article with id 9999
    When the client sends PATCH /v1/article/9999 with that cookie and body
      {"body": "New body text"}
    Then the response status is 404
    And the response body is the text "Article not found"

  Scenario: A malformed id answers 400 before any repository call
    Given a valid jwt cookie for a user with id 1
    When the client sends PATCH /v1/article/not-a-number with that cookie and body
      {"body": "New body text"}
    Then the response status is 400
    And the response body is the text apperr.IdUint32ErrorMessage

  Scenario: A non-JSON request body answers 400 with the body error message
    Given a valid jwt cookie for a user with id 1
    And the article repository contains an article with id 1
    When the client sends PATCH /v1/article/1 with that cookie and a body that is not
      valid JSON
    Then the response status is 400
    And the response body is the text apperr.BodyErrorMessage

  Scenario Outline: A body of any length, including empty, is accepted
    Given a valid jwt cookie for a user with id 1
    And the article repository contains an article with id 1
    When the client sends PATCH /v1/article/1 with that cookie and body <payload>
    Then the response status is 200
    And the stored body equals the sent body

    Examples:
      | payload                              |
      | {"body": ""}                         |
      | {"body": "<10001-character string>"} |

  Scenario: Editing an article requires authentication
    Given no jwt cookie is sent
    And the article repository contains an article with id 1
    When the client sends PATCH /v1/article/1 without a cookie and body
      {"body": "New body text"}
    Then the response status is 401