Add form to delete placeholders

lib/Ebook.php

@@ -2156,6 +2156,27 @@ final class Ebook{
 		}
 	}
 
+	public function Delete(): void{
+		$this->RemoveTags();
+		$this->RemoveLocSubjects();
+		$this->RemoveCollectionMemberships();
+		$this->RemoveGitCommits();
+		$this->RemoveSources();
+		$this->RemoveContributors();
+		$this->RemoveTocEntries();
+		$this->RemoveEbookPlaceholder();
+
+		foreach($this->Projects as $project){
+			$project->Delete();
+		}
+
+		Db::Query('
+			DELETE
+			from Ebooks
+			where EbookId = ?
+		', [$this->EbookId]);
+	}
+
 	// ***********
 	// ORM METHODS
 	// ***********

lib/Project.php

@@ -455,6 +455,20 @@ final class Project{
 		}
 	}
 
+	public function Delete(): void{
+		Db::Query('
+			DELETE
+			from ProjectReminders
+			where ProjectId = ?
+		', [$this->ProjectId]);
+
+		Db::Query('
+			DELETE
+			from Projects
+			where ProjectId = ?
+		', [$this->ProjectId]);
+	}
+
 	public function FillFromHttpPost(): void{
 		$this->PropertyFromHttp('EbookId');
 		$this->PropertyFromHttp('ProducerName');

templates/EbookMetadata.php

@@ -21,6 +21,16 @@ $showPlaceholderMetadata = $showPlaceholderMetadata ?? false;
 	<section id="placeholder-metadata">
 		<h2>Placeholder metadata</h2>
 		<p><a href="<?= $ebook->EditUrl ?>">Edit placeholder</a></p>
+		<details>
+			<summary>Delete placeholder</summary>
+			<form method="<?= Enums\HttpMethod::Post->value ?>" action="<?= $ebook->Url ?>">
+				<input type="hidden" name="_method" value="<?= Enums\HttpMethod::Delete->value ?>" />
+				<p>Delete the <code>Ebook</code>, <code>EbookPlaceholder</code>, <code>Project</code>, and other related objects.</p>
+				<div class="footer">
+					<button class="delete">Delete</button>
+				</div>
+			</form>
+		</details>
 		<table class="admin-table">
 			<tbody>
 				<tr>

www/css/core.css

@@ -933,6 +933,14 @@ main.front-page > a.button{
 	text-align: center;
 }
 
+button.delete{
+	background-color: maroon;
+}
+
+button.delete:hover{
+	background-color: firebrick;
+}
+
 article.ebook ul,
 article.ebook ol{
 	list-style: none;

www/ebook-placeholders/new.php

@@ -5,9 +5,11 @@ session_start();
 
 $isCreated = HttpInput::Bool(SESSION, 'is-ebook-placeholder-created') ?? false;
 $isOnlyProjectCreated = HttpInput::Bool(SESSION, 'is-only-ebook-project-created') ?? false;
+$isDeleted = HttpInput::Bool(SESSION, 'is-ebook-placeholder-deleted') ?? false;
 $exception = HttpInput::SessionObject('exception', Exceptions\AppException::class);
 $ebook = HttpInput::SessionObject('ebook', Ebook::class);
 $project = HttpInput::SessionObject('project', Project::class);
+$deletedEbookTitle = '';
 
 try{
 	if(Session::$User === null){
@@ -45,6 +47,13 @@ try{
 
 		session_unset();
 	}
+	elseif($isDeleted){
+		if($ebook !== null){
+			$deletedEbookTitle = $ebook->Title;
+			$ebook = null;
+		}
+		session_unset();
+	}
 	elseif($exception){
 		// We got here because an `Ebook` submission had errors and the user has to try again.
 		http_response_code(Enums\HttpCode::UnprocessableContent->value);
@@ -78,6 +87,8 @@ catch(Exceptions\InvalidPermissionsException){
 			<? }elseif($isCreated){ ?>
 				<p class="message success">Ebook placeholder created: <a href="<?= $createdEbook->Url ?>"><?= Formatter::EscapeHtml($createdEbook->Title) ?></a>!</p>
 			<? } ?>
+		<? }elseif($isDeleted){ ?>
+			<p class="message success">Ebook placeholder deleted: <?= Formatter::EscapeHtml($deletedEbookTitle) ?></p>
 		<? } ?>
 
 		<form class="create-update-ebook-placeholder" method="<?= Enums\HttpMethod::Post->value ?>" action="/ebook-placeholders" autocomplete="off">

www/ebook-placeholders/post.php

@@ -5,7 +5,7 @@ $ebook = null;
 
 try{
 	session_start();
-	$httpMethod = HttpInput::ValidateRequestMethod([Enums\HttpMethod::Post, Enums\HttpMethod::Put]);
+	$httpMethod = HttpInput::ValidateRequestMethod([Enums\HttpMethod::Post, Enums\HttpMethod::Put, Enums\HttpMethod::Delete]);
 	$exceptionRedirectUrl = '/ebook-placeholders/new';
 
 	if(Session::$User === null){
@@ -78,6 +78,20 @@ try{
 		http_response_code(Enums\HttpCode::SeeOther->value);
 		header('Location: ' . $ebook->Url);
 	}
+
+	// DELETE an `EbookPlaceholder`.
+	if($httpMethod == Enums\HttpMethod::Delete){
+		$ebook = Ebook::GetByIdentifier($identifier);
+		$exceptionRedirectUrl = $ebook->Url;
+
+		$ebook->Delete();
+
+		$_SESSION['ebook'] = $ebook;
+		$_SESSION['is-ebook-placeholder-deleted'] = true;
+
+		http_response_code(Enums\HttpCode::SeeOther->value);
+		header('Location: /ebook-placeholders/new');
+	}
 }
 catch(Exceptions\LoginRequiredException){
 	Template::RedirectToLogin();