Feature: Removing an image from an article

  As an authenticated RenewCMS user managing the CMS
  I want to delete an already-uploaded image by its id
  So that a removed image's file and row are actually gone, and a delete on
    an unknown article or an unknown image answers 404 the same way every
    other article write does

  Background:
    Given internal/infrastructure/useCases.DeleteImageUseCase.DeleteImage(imageId)
      already exists and calls image.Repository.Delete(imageId), which returns
      image.ErrImageNotFound for an unknown id and, on the real ImageRepository,
      also removes the uploaded file from UPLOAD_DIR, per
      features/delete_article_cascades_images.feature
    And this slice changes POST /v1/article/{id}/image's success response
      (api/handlers/image.Handler.PostImage, features/upload_article_image.feature)
      to also return the created image's numeric id, so the 201 body becomes
      {"id": ..., "location": ...}; this lets a client address the image later
      through this slice's DELETE route
    And this slice mounts DELETE /v1/article/{articleId}/image/{imageId} in
      api/router.go, in the same jwtauth Verifier + Authenticator group as
      POST .../image
    And this slice adds a DeleteImage method to api/handlers/image.Handler,
      grows NewHandler's signature to also take DeleteImageUseCase, and wires
      it in api/router.go
    And DeleteImage parses articleId and imageId from the URL, answering 400
      with apperr.IdUint32ErrorMessage if either isn't a valid uint32
    And DeleteImage first calls GetArticleUseCase.GetArticle(articleId);
      errors.Is(err, article.ErrArticleNotFound) answers 404 with
      apperr.ArticleNotFoundErrorMessage; this only confirms the article id
      in the URL names a real article, and does not verify that the image id
      belongs to that article's Images slice (a shallow existence check on
      both ids, not an ownership check)
    And DeleteImage then calls DeleteImageUseCase.DeleteImage(imageId);
      errors.Is(err, image.ErrImageNotFound) answers 404 with the new
      apperr.ImageNotFoundErrorMessage = "Image not found"; any other error
      falls back to the existing generic 500
    And on success DeleteImage answers 204 with an empty body, the same shape
      as DELETE /v1/article/{id}

  Scenario: Removing an image from an article it belongs to succeeds
    Given a valid jwt cookie for a user with id 1
    And the article repository contains an article with id 1 titled
      "Backyard Renovation Update" whose Images slice holds image id 10
    And the image repository contains an image with id 10
    When the client sends DELETE /v1/article/1/image/10 with that cookie
    Then the response status is 204
    And the response body is empty
    And the image repository no longer contains an image with id 10

  Scenario: Removing an image from an unknown article answers 404 and never touches the image repository
    Given a valid jwt cookie for a user with id 1
    And the article repository has no article with id 9999
    And the image repository contains an image with id 10
    When the client sends DELETE /v1/article/9999/image/10 with that cookie
    Then the response status is 404
    And the response body is the text "Article not found"
    And the image repository's Delete is never called
    And the image repository still contains the image with id 10

  Scenario: Removing an unknown image from an existing article answers 404
    Given a valid jwt cookie for a user with id 1
    And the article repository contains an article with id 1 titled
      "Backyard Renovation Update"
    And the image repository has no image with id 9999
    When the client sends DELETE /v1/article/1/image/9999 with that cookie
    Then the response status is 404
    And the response body is the text "Image not found"

  Scenario: Removing an image id that belongs to a different article still succeeds, because the check is shallow
    Given a valid jwt cookie for a user with id 1
    And the article repository contains an article with id 1 titled
      "Backyard Renovation Update" whose Images slice is empty
    And the article repository contains a second article with id 2 whose
      Images slice holds image id 10
    And the image repository contains an image with id 10
    When the client sends DELETE /v1/article/1/image/10 with that cookie
    Then the response status is 204
    And the image repository no longer contains an image with id 10

  Scenario: Removing an image still requires authentication
    Given no jwt cookie is sent
    And the article repository contains an article with id 1 titled
      "Backyard Renovation Update" whose Images slice holds image id 10
    And the image repository contains an image with id 10
    When the client sends DELETE /v1/article/1/image/10 without a cookie
    Then the response status is 401
    And the image repository still contains the image with id 10

  Scenario Outline: A malformed id in the URL answers 400 before either repository is touched
    Given a valid jwt cookie for a user with id 1
    When the client sends DELETE /v1/article/<article_id>/image/<image_id> with that cookie
    Then the response status is 400
    And the response body is the text "The server expects the ID to be in the format of an unsigned 32-bit integer (uint32)."

    Examples:
      | article_id | image_id |
      | abc        | 10       |
      | 1          | abc      |