Added post history

TODO

@@ -7,8 +7,6 @@ everything related to posts:
         - score
         - editing
             - ability to loop video posts
-            - post edit history (think
-              http://konachan.com/history?search=post%3A188614)
         - previous and next post (difficult)
             - extract Pager from PagedCollectionPresenter
             - rename PagedCollectionPresenter to PagerPresenter

data/config.ini

@@ -53,6 +53,8 @@ changePostRelations     = regularUser, powerUser, moderator, administrator
 
 listTags                = anonymous, regularUser, powerUser, moderator, administrator
 
+viewHistory             = anonymous, regularUser, powerUser, moderator, administrator
+
 [users]
 minUserNameLength = 1
 maxUserNameLength = 32

public_html/css/history.css

@@ -0,0 +1,50 @@
+table.history {
+	font-size: 80%;
+}
+table.history .addition {
+	color: forestgreen;
+}
+table.history .addition:before {
+	content: '+';
+}
+
+table.history .removal {
+	color: red;
+}
+table.history .removal:before {
+	content: '-';
+}
+
+table.history .time,
+table.history .user,
+table.history .subject {
+	white-space: nowrap;
+}
+
+table.history .user img {
+	vertical-align: middle;
+}
+
+table.history td {
+	padding: 0.1em 0.25em;
+}
+
+table.history ul {
+	margin: 0;
+	padding: 0;
+	list-style-type: none;
+	display: inline;
+}
+table.history ul:before {
+	content: ' (';
+}
+table.history ul:after {
+	content: ')';
+}
+
+table.history li {
+	display: inline;
+}
+table.history li:not(:last-of-type):after {
+	content: ', ';
+}

public_html/css/post.css

@@ -124,3 +124,8 @@
 #post-view-wrapper .post-edit-wrapper .file-handler {
 	margin: 0.5em 0;
 }
+
+#post-view-wrapper .post-history-wrapper {
+	padding: 1em;
+	display: none;
+}

public_html/index.html

@@ -32,6 +32,7 @@
 	<link rel="stylesheet" type="text/css" href="/css/post-list.css"/>
 	<link rel="stylesheet" type="text/css" href="/css/post.css"/>
 	<link rel="stylesheet" type="text/css" href="/css/home.css"/>
+	<link rel="stylesheet" type="text/css" href="/css/history.css"/>
 	<!-- /build -->
 </head>
 

public_html/js/Auth.js

@@ -33,6 +33,8 @@ App.Auth = function(_, jQuery, util, api, appState, promise) {
 		changePostRelations: 'changePostRelations',
 
 		listTags: 'listTags',
+
+		viewHistory: 'viewHistory',
 	};
 
 	function loginFromCredentials(userNameOrEmail, password, remember) {

public_html/js/Presenters/PostPresenter.js

@@ -15,13 +15,19 @@ App.Presenters.PostPresenter = function(
 
 	var $el = jQuery('#content');
 	var $messages = $el;
+
 	var postTemplate;
 	var postEditTemplate;
 	var postContentTemplate;
+	var historyTemplate;
+
 	var post;
+	var postHistory;
 	var postNameOrId;
+
 	var privileges = {};
 	var editPrivileges = {};
+
 	var tagInput;
 	var postContentFileDropper;
 	var postThumbnailFileDropper;
@@ -33,6 +39,7 @@ App.Presenters.PostPresenter = function(
 
 		privileges.canDeletePosts = auth.hasPrivilege(auth.privileges.deletePosts);
 		privileges.canFeaturePosts = auth.hasPrivilege(auth.privileges.featurePosts);
+		privileges.canViewHistory = auth.hasPrivilege(auth.privileges.viewHistory);
 		editPrivileges.canChangeSafety = auth.hasPrivilege(auth.privileges.changePostSafety);
 		editPrivileges.canChangeSource = auth.hasPrivilege(auth.privileges.changePostSource);
 		editPrivileges.canChangeTags = auth.hasPrivilege(auth.privileges.changePostTags);
@@ -43,15 +50,17 @@ App.Presenters.PostPresenter = function(
 		promise.waitAll(
 				util.promiseTemplate('post'),
 				util.promiseTemplate('post-edit'),
-				util.promiseTemplate('post-content'))
+				util.promiseTemplate('post-content'),
+				util.promiseTemplate('history'))
 			.then(function(
 					postTemplateHtml,
 					postEditTemplateHtml,
 					postContentTemplateHtml,
-					response) {
+					historyTemplateHtml) {
 				postTemplate = _.template(postTemplateHtml);
 				postEditTemplate = _.template(postEditTemplateHtml);
 				postContentTemplate = _.template(postContentTemplateHtml);
+				historyTemplate = _.template(historyTemplateHtml);
 
 				reinit(args, loaded);
 			}).fail(showGenericError);
@@ -60,9 +69,14 @@ App.Presenters.PostPresenter = function(
 	function reinit(args, loaded) {
 		postNameOrId = args.postNameOrId;
 
-		promise.wait(api.get('/posts/' + postNameOrId))
+		promise.waitAll(
-			.then(function(response) {
+				api.get('/posts/' + postNameOrId),
-				post = response.json;
+				privileges.canViewHistory ?
+					api.get('/posts/' + postNameOrId + '/history') :
+					null)
+			.then(function(postResponse, postHistoryResponse) {
+				post = postResponse.json;
+				postHistory = postHistoryResponse && postHistoryResponse.json && postHistoryResponse.json.data;
 				topNavigationPresenter.changeTitle('@' + post.id);
 				render();
 				loaded();
@@ -92,9 +106,10 @@ App.Presenters.PostPresenter = function(
 		}
 
 		$el.find('.post-edit-wrapper form').submit(editFormSubmitted);
-		$el.find('.delete').click(deleteButtonClicked);
+		$el.find('#sidebar .delete').click(deleteButtonClicked);
-		$el.find('.feature').click(featureButtonClicked);
+		$el.find('#sidebar .feature').click(featureButtonClicked);
-		$el.find('.edit').click(editButtonClicked);
+		$el.find('#sidebar .edit').click(editButtonClicked);
+		$el.find('#sidebar .history').click(historyButtonClicked);
 	}
 
 	function renderSidebar() {
@@ -104,10 +119,12 @@ App.Presenters.PostPresenter = function(
 	function renderPostTemplate() {
 		return postTemplate({
 			post: post,
+			postHistory: postHistory,
 			formatRelativeTime: util.formatRelativeTime,
 			formatFileSize: util.formatFileSize,
 			postContentTemplate: postContentTemplate,
 			postEditTemplate: postEditTemplate,
+			historyTemplate: historyTemplate,
 			privileges: privileges,
 			editPrivileges: editPrivileges,
 		});
@@ -228,6 +245,23 @@ App.Presenters.PostPresenter = function(
 		});
 	}
 
+	function historyButtonClicked(e) {
+		e.preventDefault();
+		if ($el.find('.post-history-wrapper').is(':visible')) {
+			hideHistory();
+		} else {
+			showHistory();
+		}
+	}
+
+	function hideHistory() {
+		$el.find('.post-history-wrapper').slideUp('slow');
+	}
+
+	function showHistory() {
+		$el.find('.post-history-wrapper').slideDown('slow');
+	}
+
 	function showEditError(response) {
 		window.alert(response.json && response.json.error || response);
 	}

public_html/templates/history.tpl

@@ -0,0 +1,63 @@
+<table class="history">
+	<tbody>
+		<% _.each(history, function( historyEntry) { %>
+			<tr>
+				<td class="time">
+					<%= formatRelativeTime(historyEntry.time) %>
+				</td>
+
+				<td class="user">
+					<% var userName = historyEntry.user && historyEntry.user.name || '' %>
+
+					<% if (userName) { %>
+						<a href="#/user/<%= userName %>">
+					<% } %>
+
+					<img class="author-avatar"
+						src="/data/thumbnails/20x20/avatars/<%= userName || '!' %>"
+						alt="<%= userName || 'Anonymous user' %>"/>
+
+					<%= userName || 'Anonymous user' %>
+
+					<% if (userName) { %>
+						</a>
+					<% } %>
+				</td>
+
+				<td class="subject">
+					<% if (historyEntry.type == 0) { %>
+						<a href="#/post/<%= historyEntry.primaryKey %>">
+							@<%= historyEntry.primaryKey %>
+						</a>
+					<% } else { %>
+						?
+					<% } %>
+				</td>
+
+				<td class="difference">
+					<% if (historyEntry.operation == 1) { %>
+						deleted
+					<% } else { %>
+						changed
+
+						<% if (historyEntry.dataDifference) { %>
+							<ul><!--
+								--><% _.each(historyEntry.dataDifference['+'], function (difference) { %><!--
+									--><li class="addition difference-<%= difference[0] %>"><!--
+										--><%= difference[0] + ':' + difference[1] %><!--
+									--></li><!--
+								--><% }) %><!--
+
+								--><% _.each(historyEntry.dataDifference['-'], function (difference) { %><!--
+									--><li class="removal difference-<%= difference[0] %>"><!--
+										--><%= difference[0] + ':' + difference[1] %><!--
+									--></li><!--
+								--><% }) %><!--
+							--></ul>
+						<% } %>
+					<% } %>
+				</td>
+			</tr>
+		<% }) %>
+	</tbody>
+</table>

public_html/templates/home.tpl

@@ -20,11 +20,20 @@
 
 				<span class="right">
 					featured by
+
+					<% if (post.user.name) { %>
+						<a href="#/user/<%= post.user.name %>">
+					<% } %>
+
 					<img class="author-avatar"
 						src="/data/thumbnails/25x25/avatars/<%= post.user.name || '!' %>"
 						alt="<%= post.user.name || 'Anonymous user' %>"/>
 
 					<%= post.user.name || 'Anonymous user' %>
+
+					<% if (post.user.name) { %>
+						</a>
+					<% } %>
 				</span>
 
 			</div>

public_html/templates/post.tpl

@@ -134,6 +134,14 @@
 						</a>
 					</li>
 				<% } %>
+
+				<% if (privileges.canViewHistory) { %>
+					<li>
+						<a href="#" class="history">
+							History
+						</a>
+					</li>
+				<% } %>
 			</ul>
 		<% } %>
 
@@ -147,5 +155,14 @@
 		</div>
 
 		<%= postContentTemplate({post: post}) %>
+
+		<% if (privileges.canViewHistory) { %>
+			<div class="post-history-wrapper">
+				<%= historyTemplate({
+					history: postHistory,
+					formatRelativeTime: formatRelativeTime
+				}) %>
+			</div>
+		<% } %>
 	</div>
 </div>

src/Controllers/HistoryController.php

@@ -0,0 +1,44 @@
+<?php
+namespace Szurubooru\Controllers;
+
+final class HistoryController extends AbstractController
+{
+	private $historyService;
+	private $privilegeService;
+	private $snapshotSearchParser;
+	private $inputReader;
+	private $snapshotViewProxy;
+
+	public function __construct(
+		\Szurubooru\Services\HistoryService $historyService,
+		\Szurubooru\Services\PrivilegeService $privilegeService,
+		\Szurubooru\SearchServices\Parsers\SnapshotSearchParser $snapshotSearchParser,
+		\Szurubooru\Helpers\InputReader $inputReader,
+		\Szurubooru\Controllers\ViewProxies\SnapshotViewProxy $snapshotViewProxy)
+	{
+		$this->historyService = $historyService;
+		$this->privilegeService = $privilegeService;
+		$this->snapshotSearchParser = $snapshotSearchParser;
+		$this->inputReader = $inputReader;
+		$this->snapshotViewProxy = $snapshotViewProxy;
+	}
+
+	public function registerRoutes(\Szurubooru\Router $router)
+	{
+		$router->get('/api/history', [$this, 'getFiltered']);
+	}
+
+	public function getFiltered()
+	{
+		$this->privilegeService->assertPrivilege(\Szurubooru\Privilege::VIEW_HISTORY);
+
+		$filter = $this->snapshotSearchParser->createFilterFromInputReader($this->inputReader);
+		$filter->setPageSize(50);
+		$result = $this->historyService->getFiltered($filter);
+		$entities = $this->snapshotViewProxy->fromArray($result->getEntities());
+		return [
+			'data' => $entities,
+			'pageSize' => $result->getPageSize(),
+			'totalRecords' => $result->getTotalRecords()];
+	}
+}

src/Controllers/PostController.php

@@ -9,6 +9,7 @@ final class PostController extends AbstractController
 	private $postSearchParser;
 	private $inputReader;
 	private $postViewProxy;
+	private $snapshotViewProxy;
 
 	public function __construct(
 		\Szurubooru\Config $config,
@@ -16,7 +17,8 @@ final class PostController extends AbstractController
 		\Szurubooru\Services\PostService $postService,
 		\Szurubooru\SearchServices\Parsers\PostSearchParser $postSearchParser,
 		\Szurubooru\Helpers\InputReader $inputReader,
-		\Szurubooru\Controllers\ViewProxies\PostViewProxy $postViewProxy)
+		\Szurubooru\Controllers\ViewProxies\PostViewProxy $postViewProxy,
+		\Szurubooru\Controllers\ViewProxies\SnapshotViewProxy $snapshotViewProxy)
 	{
 		$this->config = $config;
 		$this->privilegeService = $privilegeService;
@@ -24,30 +26,31 @@ final class PostController extends AbstractController
 		$this->postSearchParser = $postSearchParser;
 		$this->inputReader = $inputReader;
 		$this->postViewProxy = $postViewProxy;
+		$this->snapshotViewProxy = $snapshotViewProxy;
 	}
 
 	public function registerRoutes(\Szurubooru\Router $router)
 	{
 		$router->post('/api/posts', [$this, 'createPost']);
 		$router->get('/api/posts', [$this, 'getFiltered']);
-		$router->get('/api/posts/featured', [$this, 'getFeatured']);
 		$router->get('/api/posts/:postNameOrId', [$this, 'getByNameOrId']);
+		$router->get('/api/posts/:postNameOrId/history', [$this, 'getHistory']);
 		$router->put('/api/posts/:postNameOrId', [$this, 'updatePost']);
 		$router->delete('/api/posts/:postNameOrId', [$this, 'deletePost']);
 		$router->post('/api/posts/:postNameOrId/feature', [$this, 'featurePost']);
 		$router->put('/api/posts/:postNameOrId/feature', [$this, 'featurePost']);
 	}
 
-	public function getFeatured()
+	public function getByNameOrId($postNameOrId)
 	{
-		$post = $this->postService->getFeatured();
+		$post = $this->getByNameOrIdWithoutProxy($postNameOrId);
 		return $this->postViewProxy->fromEntity($post, $this->getFullFetchConfig());
 	}
 
-	public function getByNameOrId($postNameOrId)
+	public function getHistory($postNameOrId)
 	{
-		$post = $this->postService->getByNameOrId($postNameOrId);
+		$post = $this->getByNameOrIdWithoutProxy($postNameOrId);
-		return $this->postViewProxy->fromEntity($post, $this->getFullFetchConfig());
+		return ['data' => $this->snapshotViewProxy->fromArray($this->postService->getHistory($post))];
 	}
 
 	public function getFiltered()
@@ -113,6 +116,14 @@ final class PostController extends AbstractController
 		$this->postService->featurePost($post);
 	}
 
+	private function getByNameOrIdWithoutProxy($postNameOrId)
+	{
+		if ($postNameOrId === 'featured')
+			return $this->postService->getFeatured();
+		else
+			return $this->postService->getByNameOrId($postNameOrId);
+	}
+
 	private function getFullFetchConfig()
 	{
 		return

src/Controllers/ViewProxies/SnapshotViewProxy.php

@@ -0,0 +1,29 @@
+<?php
+namespace Szurubooru\Controllers\ViewProxies;
+
+class SnapshotViewProxy extends AbstractViewProxy
+{
+	private $userViewProxy;
+
+	public function __construct(UserViewProxy $userViewProxy)
+	{
+		$this->userViewProxy = $userViewProxy;
+	}
+
+	public function fromEntity($snapshot, $config = [])
+	{
+		$result = new \StdClass;
+		if ($snapshot)
+		{
+			$result->time = $snapshot->getTime();
+			$result->type = $snapshot->getType();
+			$result->primaryKey = $snapshot->getPrimaryKey();
+			$result->operation = $snapshot->getOperation();
+			$result->user = $this->userViewProxy->fromEntity($snapshot->getUser());
+			$result->data = $snapshot->getData();
+			$result->dataDifference = $snapshot->getDataDifference();
+		}
+		return $result;
+	}
+}
+

src/Dao/EntityConverters/SnapshotEntityConverter.php

@@ -0,0 +1,34 @@
+<?php
+namespace Szurubooru\Dao\EntityConverters;
+
+class SnapshotEntityConverter extends AbstractEntityConverter implements IEntityConverter
+{
+	public function toArray(\Szurubooru\Entities\Entity $entity)
+	{
+		return
+		[
+			'id' => $entity->getId(),
+			'time' => $entity->getTime(),
+			'type' => $entity->getType(),
+			'primaryKey' => $entity->getPrimaryKey(),
+			'userId' => $entity->getUserId(),
+			'operation' => $entity->getOperation(),
+			'data' => json_encode($entity->getData()),
+			'dataDifference' => json_encode($entity->getDataDifference()),
+		];
+	}
+
+	public function toBasicEntity(array $array)
+	{
+		$entity = new \Szurubooru\Entities\Snapshot(intval($array['id']));
+		$entity->setTime($array['time']);
+		$entity->setType(intval($array['type']));
+		$entity->setPrimaryKey($array['primaryKey']);
+		$entity->setUserId($array['userId']);
+		$entity->setOperation($array['operation']);
+		$entity->setData(json_decode($array['data'], true));
+		$entity->setDataDifference(json_decode($array['dataDifference'], true));
+		return $entity;
+	}
+}
+

src/Dao/SnapshotDao.php

@@ -0,0 +1,45 @@
+<?php
+namespace Szurubooru\Dao;
+
+class SnapshotDao extends AbstractDao
+{
+	private $userDao;
+
+	public function __construct(
+		\Szurubooru\DatabaseConnection $databaseConnection,
+		\Szurubooru\Dao\UserDao $userDao)
+	{
+		parent::__construct(
+			$databaseConnection,
+			'snapshots',
+			new \Szurubooru\Dao\EntityConverters\SnapshotEntityConverter());
+
+		$this->userDao = $userDao;
+	}
+
+	public function findByTypeAndKey($type, $primaryKey)
+	{
+		$query = $this->fpdo
+			->from($this->tableName)
+			->where('type', $type)
+			->where('primaryKey', $primaryKey)
+			->orderBy('time DESC');
+		return $this->arrayToEntities(iterator_to_array($query));
+	}
+
+	public function afterLoad(\Szurubooru\Entities\Entity $snapshot)
+	{
+		$snapshot->setLazyLoader(
+			\Szurubooru\Entities\Snapshot::LAZY_LOADER_USER,
+			function (\Szurubooru\Entities\Snapshot $snapshot)
+			{
+				return $this->getUser($snapshot);
+			});
+	}
+
+	private function getUser(\Szurubooru\Entities\Snapshot $snapshot)
+	{
+		$userId =  $snapshot->getUserId();
+		return $this->userDao->findById($userId);
+	}
+}

src/Entities/Post.php

@@ -220,14 +220,7 @@ final class Post extends Entity
 	public function setUser(\Szurubooru\Entities\User $user = null)
 	{
 		$this->lazySave(self::LAZY_LOADER_USER, $user);
-		if ($user)
+		$this->userId = $user ? $user->getId() : null;
-		{
-			$this->userId = $user->getId();
-		}
-		else
-		{
-			$this->userId = null;
-		}
 	}
 
 	public function getContent()

src/Entities/Snapshot.php

@@ -0,0 +1,101 @@
+<?php
+namespace Szurubooru\Entities;
+
+final class Snapshot extends Entity
+{
+	const TYPE_POST = 0;
+
+	const OPERATION_CHANGE = 0;
+	const OPERATION_DELETE = 1;
+
+	const LAZY_LOADER_USER = 'user';
+
+	private $time;
+	private $type;
+	private $primaryKey;
+	private $operation;
+	private $userId;
+	private $data;
+	private $dataDifference;
+
+	public function getTime()
+	{
+		return $this->time;
+	}
+
+	public function setTime($time)
+	{
+		$this->time = $time;
+	}
+
+	public function getType()
+	{
+		return $this->type;
+	}
+
+	public function setType($type)
+	{
+		$this->type = $type;
+	}
+
+	public function getPrimaryKey()
+	{
+		return $this->primaryKey;
+	}
+
+	public function setPrimaryKey($primaryKey)
+	{
+		$this->primaryKey = $primaryKey;
+	}
+
+	public function getOperation()
+	{
+		return $this->operation;
+	}
+
+	public function setOperation($operation)
+	{
+		$this->operation = $operation;
+	}
+
+	public function getUserId()
+	{
+		return $this->userId;
+	}
+
+	public function setUserId($userId)
+	{
+		$this->userId = $userId;
+	}
+
+	public function getData()
+	{
+		return $this->data;
+	}
+
+	public function setData($data)
+	{
+		$this->data = $data;
+	}
+
+	public function getDataDifference()
+	{
+		return $this->dataDifference;
+	}
+
+	public function setDataDifference($dataDifference)
+	{
+		$this->dataDifference = $dataDifference;
+	}
+
+	public function getUser()
+	{
+		return $this->lazyLoad(self::LAZY_LOADER_USER, null);
+	}
+
+	public function setUser(\Szurubooru\Entities\User $user = null)
+	{
+		$this->lazySave(self::LAZY_LOADER_USER, $user);
+		$this->userId = $user ? $user->getId() : null;
+	}
+}

src/Helpers/EnumHelper.php

@@ -35,6 +35,11 @@ class EnumHelper
 		'youtube' => \Szurubooru\Entities\Post::POST_TYPE_YOUTUBE,
 	];
 
+	private static $snapshotTypeMap =
+	[
+		'post' => \Szurubooru\Entities\Snapshot::TYPE_POST,
+	];
+
 	public static function accessRankToString($accessRank)
 	{
 		return self::enumToString(self::$accessRankMap, $accessRank);
@@ -70,6 +75,11 @@ class EnumHelper
 		return self::enumToString(self::$postTypeMap, $postType);
 	}
 
+	public static function snapshotTypeFromString($snapshotTypeString)
+	{
+		return self::stringToEnum(self::$snapshotTypeMap, $snapshotTypeString);
+	}
+
 	private static function enumToString($enumMap, $enumValue)
 	{
 		$reverseMap = array_flip($enumMap);

src/Privilege.php

@@ -33,4 +33,6 @@ class Privilege
 	const CHANGE_POST_RELATIONS = 'changePostRelations';
 
 	const LIST_TAGS = 'listTags';
+
+	const VIEW_HISTORY = 'viewHistory';
 }

src/SearchServices/Filters/SnapshotFilter.php

@@ -0,0 +1,8 @@
+<?php
+namespace Szurubooru\SearchServices\Filters;
+
+class SnapshotFilter extends BasicFilter implements IFilter
+{
+	const REQUIREMENT_PRIMARY_KEY = 'primaryKey';
+	const REQUIREMENT_TYPE = 'type';
+}

src/SearchServices/Parsers/SnapshotSearchParser.php

@@ -0,0 +1,41 @@
+<?php
+namespace Szurubooru\SearchServices\Parsers;
+
+class SnapshotSearchParser extends AbstractSearchParser
+{
+	protected function createFilter()
+	{
+		return new \Szurubooru\SearchServices\Filters\SnapshotFilter;
+	}
+
+	protected function decorateFilterFromToken($filter, $token)
+	{
+		if (substr_count($token->getValue(), ',') !== 1)
+			throw new \BadMethodCallException('Not supported');
+
+		if ($token->isNegated())
+			throw new \BadMethodCallException('Not supported');
+
+		list ($type, $primaryKey) = explode(',', $token->getValue());
+
+		$requirement = new \Szurubooru\SearchServices\Requirements\Requirement();
+		$requirement->setType(\Szurubooru\SearchServices\Filters\SnapshotFilter::REQUIREMENT_PRIMARY_KEY);
+		$requirement->setValue($primaryKey);
+		$filter->addRequirement($requirement);
+
+		$requirement = new \Szurubooru\SearchServices\Requirements\Requirement();
+		$requirement->setType(\Szurubooru\SearchServices\Filters\SnapshotFilter::REQUIREMENT_TYPE);
+		$requirement->setValue(\Szurubooru\Helpers\EnumHelper::snapshotTypeFromString($type));
+		$filter->addRequirement($requirement);
+	}
+
+	protected function decorateFilterFromNamedToken($filter, $namedToken)
+	{
+		throw new \BadMethodCallException('Not supported');
+	}
+
+	protected function getOrderColumn($token)
+	{
+		throw new \BadMethodCallException('Not supported');
+	}
+}

src/Services/HistoryService.php

@@ -0,0 +1,145 @@
+<?php
+namespace Szurubooru\Services;
+
+class HistoryService
+{
+	private $validator;
+	private $snapshotDao;
+	private $globalParamDao;
+	private $timeService;
+	private $authService;
+	private $transactionManager;
+
+	public function __construct(
+		\Szurubooru\Validator $validator,
+		\Szurubooru\Dao\SnapshotDao $snapshotDao,
+		\Szurubooru\Dao\GlobalParamDao $globalParamDao,
+		\Szurubooru\Dao\TransactionManager $transactionManager,
+		\Szurubooru\Services\TimeService $timeService,
+		\Szurubooru\Services\AuthService $authService)
+	{
+		$this->validator = $validator;
+		$this->snapshotDao = $snapshotDao;
+		$this->globalParamDao = $globalParamDao;
+		$this->timeService = $timeService;
+		$this->authService = $authService;
+		$this->transactionManager = $transactionManager;
+	}
+
+	public function getFiltered(\Szurubooru\SearchServices\Filters\SnapshotFilter $filter)
+	{
+		$transactionFunc = function() use ($filter)
+		{
+			return $this->snapshotDao->findFiltered($filter);
+		};
+		return $this->transactionManager->rollback($transactionFunc);
+	}
+
+	public function saveSnapshot(\Szurubooru\Entities\Snapshot $snapshot)
+	{
+		$transactionFunc = function() use ($snapshot)
+		{
+			$otherSnapshots = $this->snapshotDao->findByTypeAndKey($snapshot->getType(), $snapshot->getPrimaryKey());
+			if ($otherSnapshots)
+			{
+				$lastSnapshot = array_shift($otherSnapshots);
+				if ($lastSnapshot->getData() === $snapshot->getData())
+					return $lastSnapshot;
+
+				$dataDifference = $this->getSnapshotDataDifference($snapshot->getData(), $lastSnapshot->getData());
+				$snapshot->setDataDifference($dataDifference);
+			}
+			else
+			{
+				$dataDifference = $this->getSnapshotDataDifference($snapshot->getData(), []);
+				$snapshot->setDataDifference($dataDifference);
+			}
+
+			$snapshot->setTime($this->timeService->getCurrentTime());
+			$snapshot->setUser($this->authService->getLoggedInUser());
+			return $this->snapshotDao->save($snapshot);
+		};
+		return $this->transactionManager->commit($transactionFunc);
+	}
+
+	public function getPostDeleteSnapshot(\Szurubooru\Entities\Post $post)
+	{
+		$snapshot = $this->getPostSnapshot($post);
+		$snapshot->setOperation(\Szurubooru\Entities\Snapshot::OPERATION_DELETE);
+		return $snapshot;
+	}
+
+	public function getPostChangeSnapshot(\Szurubooru\Entities\Post $post)
+	{
+		$featuredPostParam = $this->globalParamDao->findByKey(\Szurubooru\Entities\GlobalParam::KEY_FEATURED_POST);
+		$isFeatured = ($featuredPostParam and intval($featuredPostParam->getValue()) === $post->getId());
+
+		$data =
+		[
+			'source' => $post->getSource(),
+			'safety' => \Szurubooru\Helpers\EnumHelper::postSafetyToString($post->getSafety()),
+			'contentChecksum' => $post->getContentChecksum(),
+			'featured' => $isFeatured,
+
+			'tags' =>
+				array_map(
+					function ($tag)
+					{
+						return $tag->getName();
+					},
+					$post->getTags()),
+
+			'relations' =>
+				array_map(
+					function ($post)
+					{
+						return $post->getId();
+					},
+					$post->getRelatedPosts()),
+
+		];
+
+		$snapshot = $this->getPostSnapshot($post);
+		$snapshot->setOperation(\Szurubooru\Entities\Snapshot::OPERATION_CHANGE);
+		$snapshot->setData($data);
+		return $snapshot;
+	}
+
+	public function getSnapshotDataDifference($newData, $oldData)
+	{
+		$diffFunction = function($base, $other)
+		{
+			$result = [];
+			foreach ($base as $key => $value)
+			{
+				if (is_array($base[$key]))
+				{
+					foreach ($base[$key] as $subValue)
+					{
+						if (!isset($other[$key]) or !in_array($subValue, $other[$key]))
+							$result[] = [$key, $subValue];
+					}
+				}
+				elseif (!isset($other[$key]) or $base[$key] !== $other[$key])
+				{
+					$result[] = [$key, $value];
+				}
+			}
+			return $result;
+
+		};
+
+		return [
+			'+' => $diffFunction($newData, $oldData),
+			'-' => $diffFunction($oldData, $newData),
+		];
+	}
+
+	private function getPostSnapshot(\Szurubooru\Entities\Post $post)
+	{
+		$snapshot = new \Szurubooru\Entities\Snapshot();
+		$snapshot->setType(\Szurubooru\Entities\Snapshot::TYPE_POST);
+		$snapshot->setPrimaryKey($post->getId());
+		return $snapshot;
+	}
+}

src/Services/PostService.php

@@ -11,6 +11,7 @@ class PostService
 	private $timeService;
 	private $authService;
 	private $fileService;
+	private $historyService;
 	private $imageManipulator;
 
 	public function __construct(
@@ -22,6 +23,7 @@ class PostService
 		\Szurubooru\Services\AuthService $authService,
 		\Szurubooru\Services\TimeService $timeService,
 		\Szurubooru\Services\FileService $fileService,
+		\Szurubooru\Services\HistoryService $historyService,
 		\Szurubooru\Services\ImageManipulation\ImageManipulator $imageManipulator)
 	{
 		$this->config = $config;
@@ -32,6 +34,7 @@ class PostService
 		$this->timeService = $timeService;
 		$this->authService = $authService;
 		$this->fileService = $fileService;
+		$this->historyService = $historyService;
 		$this->imageManipulator = $imageManipulator;
 	}
 
@@ -82,6 +85,27 @@ class PostService
 		return $this->transactionManager->rollback($transactionFunc);
 	}
 
+	public function getHistory(\Szurubooru\Entities\Post $post)
+	{
+		$transactionFunc = function() use ($post)
+		{
+			$filter = new \Szurubooru\SearchServices\Filters\SnapshotFilter();
+
+			$requirement = new \Szurubooru\SearchServices\Requirement();
+			$requirement->setType(\Szurubooru\SearchServices\Filters\SnapshotFilter::REQUIREMENT_PRIMARY_KEY);
+			$requirement->setValue($post->getId());
+			$filter->addRequirement($requirement);
+
+			$requirement = new \Szurubooru\SearchServices\Requirement();
+			$requirement->setType(\Szurubooru\SearchServices\Filters\SnapshotFilter::REQUIREMENT_TYPE);
+			$requirement->setValue(\Szurubooru\Entities\Snapshot::TYPE_POST);
+			$filter->addRequirement($requirement);
+
+			return $this->historyService->getFiltered($filter)->getEntities();
+		};
+		return $this->transactionManager->rollback($transactionFunc);
+	}
+
 	public function createPost(\Szurubooru\FormData\UploadFormData $formData)
 	{
 		$transactionFunc = function() use ($formData)
@@ -100,7 +124,10 @@ class PostService
 			$this->updatePostTags($post, $formData->tags);
 			$this->updatePostContentFromStringOrUrl($post, $formData->content, $formData->url);
 
-			return $this->postDao->save($post);
+			$savedPost = $this->postDao->save($post);
+
+			$this->historyService->saveSnapshot($this->historyService->getPostChangeSnapshot($savedPost));
+			return $savedPost;
 		};
 		return $this->transactionManager->commit($transactionFunc);
 	}
@@ -134,6 +161,7 @@ class PostService
 			if ($formData->relations !== null)
 				$this->updatePostRelations($post, $formData->relations);
 
+			$this->historyService->saveSnapshot($this->historyService->getPostChangeSnapshot($post));
 			return $this->postDao->save($post);
 		};
 		return $this->transactionManager->commit($transactionFunc);
@@ -246,8 +274,10 @@ class PostService
 	{
 		$relatedPosts = $this->postDao->findByIds($newRelatedPostIds);
 		foreach ($newRelatedPostIds as $postId)
+		{
 			if (!isset($relatedPosts[$postId]))
 				throw new \DomainException('Post with id "' . $postId . '" was not found.');
+		}
 
 		$post->setRelatedPosts($relatedPosts);
 	}
@@ -256,6 +286,7 @@ class PostService
 	{
 		$transactionFunc = function() use ($post)
 		{
+			$this->historyService->saveSnapshot($this->historyService->getPostDeleteSnapshot($post));
 			$this->postDao->deleteById($post->getId());
 		};
 		$this->transactionManager->commit($transactionFunc);
@@ -265,6 +296,8 @@ class PostService
 	{
 		$transactionFunc = function() use ($post)
 		{
+			$previousFeaturedPost = $this->getFeatured();
+
 			$post->setLastFeatureTime($this->timeService->getCurrentTime());
 			$post->setFeatureCount($post->getFeatureCount() + 1);
 			$this->postDao->save($post);
@@ -272,6 +305,10 @@ class PostService
 			$globalParam->setKey(\Szurubooru\Entities\GlobalParam::KEY_FEATURED_POST);
 			$globalParam->setValue($post->getId());
 			$this->globalParamDao->save($globalParam);
+
+			if ($previousFeaturedPost)
+				$this->historyService->saveSnapshot($this->historyService->getPostChangeSnapshot($previousFeaturedPost));
+			$this->historyService->saveSnapshot($this->historyService->getPostChangeSnapshot($post));
 		};
 		$this->transactionManager->commit($transactionFunc);
 	}

src/Upgrades/Upgrade08.php

@@ -16,4 +16,3 @@ class Upgrade08 implements IUpgrade
 			)');
 	}
 }
-

src/Upgrades/Upgrade09.php

@@ -0,0 +1,40 @@
+<?php
+namespace Szurubooru\Upgrades;
+
+class Upgrade09 implements IUpgrade
+{
+	private $postDao;
+	private $historyService;
+
+	public function __construct(
+		\Szurubooru\Dao\PostDao $postDao,
+		\Szurubooru\Services\HistoryService $historyService)
+	{
+		$this->postDao = $postDao;
+		$this->historyService = $historyService;
+	}
+
+	public function run(\Szurubooru\DatabaseConnection $databaseConnection)
+	{
+		$pdo = $databaseConnection->getPDO();
+
+		$pdo->exec('DROP TABLE IF EXISTS snapshots');
+
+		$pdo->exec('CREATE TABLE snapshots
+			(
+				id INTEGER PRIMARY KEY NOT NULL,
+				time TIMESTAMP NOT NULL,
+				type INTEGER NOT NULL,
+				primaryKey TEXT NOT NULL,
+				operation INTEGER NOT NULL,
+				userId INTEGER,
+				data BLOB,
+				dataDifference BLOB
+			)');
+
+		foreach ($this->postDao->findAll() as $post)
+		{
+			$this->historyService->saveSnapshot($this->historyService->getPostChangeSnapshot($post));
+		}
+	}
+}

src/di.php

@@ -24,6 +24,7 @@ return [
 			$container->get(\Szurubooru\Upgrades\Upgrade06::class),
 			$container->get(\Szurubooru\Upgrades\Upgrade07::class),
 			$container->get(\Szurubooru\Upgrades\Upgrade08::class),
+			$container->get(\Szurubooru\Upgrades\Upgrade09::class),
 		];
 	}),
 
@@ -35,6 +36,7 @@ return [
 			$container->get(\Szurubooru\Controllers\PostController::class),
 			$container->get(\Szurubooru\Controllers\PostContentController::class),
 			$container->get(\Szurubooru\Controllers\GlobalParamController::class),
+			$container->get(\Szurubooru\Controllers\HistoryController::class),
 		];
 	}),
 ];

tests/Dao/SnapshotDaoTest.php

@@ -0,0 +1,55 @@
+<?php
+namespace Szurubooru\Tests\Dao;
+
+class SnapshotDaoTest extends \Szurubooru\Tests\AbstractDatabaseTestCase
+{
+	public function setUp()
+	{
+		parent::setUp();
+		$this->userDaoMock = $this->mock(\Szurubooru\Dao\UserDao::class);
+	}
+
+	public function testSaving()
+	{
+		$snapshot = $this->getTestSnapshot();
+		$snapshotDao = $this->getSnapshotDao();
+		$snapshotDao->save($snapshot);
+		$this->assertNotNull($snapshot->getId());
+		$this->assertEntitiesEqual($snapshot, $snapshotDao->findById($snapshot->getId()));
+	}
+
+	public function testUserLazyLoader()
+	{
+		$snapshot = $this->getTestSnapshot();
+		$snapshot->setUser(new \Szurubooru\Entities\User(5));
+		$this->assertEquals(5, $snapshot->getUserId());
+		$snapshotDao = $this->getSnapshotDao();
+		$snapshotDao->save($snapshot);
+		$savedSnapshot = $snapshotDao->findById($snapshot->getId());
+		$this->assertEquals(5, $savedSnapshot->getUserId());
+
+		$this->userDaoMock
+			->expects($this->once())
+			->method('findById');
+		$savedSnapshot->getUser();
+	}
+
+	private function getTestSnapshot()
+	{
+		$snapshot = new \Szurubooru\Entities\Snapshot();
+		$snapshot->setType(\Szurubooru\Entities\Snapshot::TYPE_POST);
+		$snapshot->setData(['wake up', 'neo', ['follow' => 'white rabbit']]);
+		$snapshot->setPrimaryKey(1);
+		$snapshot->setTime('whateveer');
+		$snapshot->setUserId(null);
+		$snapshot->setOperation(\Szurubooru\Entities\Snapshot::OPERATION_CHANGE);
+		return $snapshot;
+	}
+
+	private function getSnapshotDao()
+	{
+		return new \Szurubooru\Dao\SnapshotDao(
+			$this->databaseConnection,
+			$this->userDaoMock);
+	}
+}

tests/Services/HistoryServiceTest.php

@@ -0,0 +1,183 @@
+<?php
+namespace Szurubooru\Tests\Services;
+
+class HistoryServiceTest extends \Szurubooru\Tests\AbstractTestCase
+{
+	private $validatorMock;
+	private $snapshotDaoMock;
+	private $globalParamDaoMock;
+	private $timeServiceMock;
+	private $authServiceMock;
+	private $transactionManagerMock;
+
+	public static function snapshotDataDifferenceProvider()
+	{
+		yield
+		[
+				[],
+				[],
+				['+' => [], '-' => []]
+		];
+
+		yield
+		[
+				['key' => 'unchangedValue'],
+				['key' => 'unchangedValue'],
+				['+' => [], '-' => []]
+		];
+
+		yield
+		[
+			['key' => 'newValue'],
+			[],
+			[
+				'+' => [['key', 'newValue']],
+				'-' => []
+			]
+		];
+
+		yield
+		[
+			[],
+			['key' => 'deletedValue'],
+			[
+				'+' => [],
+				'-' => [['key', 'deletedValue']]
+			]
+		];
+
+		yield
+		[
+			['key' => 'changedValue'],
+			['key' => 'oldValue'],
+			[
+				'+' => [['key', 'changedValue']],
+				'-' => [['key', 'oldValue']]
+			]
+		];
+
+		yield
+		[
+			['key' => []],
+			['key' => []],
+			[
+				'+' => [],
+				'-' => []
+			]
+		];
+
+		yield
+		[
+			['key' => ['newArrayElement']],
+			['key' => []],
+			[
+				'+' => [['key', 'newArrayElement']],
+				'-' => []
+			]
+		];
+
+		yield
+		[
+			['key' => []],
+			['key' => ['removedArrayElement']],
+			[
+				'+' => [],
+				'-' => [['key', 'removedArrayElement']]
+			]
+		];
+
+		yield
+		[
+			['key' => ['unchangedValue', 'newValue']],
+			['key' => ['unchangedValue', 'oldValue']],
+			[
+				'+' => [['key', 'newValue']],
+				'-' => [['key', 'oldValue']]
+			]
+		];
+	}
+
+	public function setUp()
+	{
+		parent::setUp();
+		$this->validatorMock = $this->mock(\Szurubooru\Validator::class);
+		$this->snapshotDaoMock = $this->mock(\Szurubooru\Dao\SnapshotDao::class);
+		$this->globalParamDaoMock = $this->mock(\Szurubooru\Dao\GlobalParamDao::class);
+		$this->transactionManagerMock = $this->mock(\Szurubooru\Dao\TransactionManager::class);
+		$this->timeServiceMock = $this->mock(\Szurubooru\Services\TimeService::class);
+		$this->authServiceMock = $this->mock(\Szurubooru\Services\AuthService::class);
+	}
+
+	public function testPostChangeSnapshot()
+	{
+		$tag1 = new \Szurubooru\Entities\Tag();
+		$tag2 = new \Szurubooru\Entities\Tag();
+		$tag1->setName('tag1');
+		$tag2->setName('tag2');
+		$post1 = new \Szurubooru\Entities\Post(1);
+		$post2 = new \Szurubooru\Entities\Post(2);
+
+		$post = new \Szurubooru\Entities\Post(5);
+		$post->setTags([$tag1, $tag2]);
+		$post->setRelatedPosts([$post1, $post2]);
+		$post->setContentChecksum('checksum');
+		$post->setSafety(\Szurubooru\Entities\Post::POST_SAFETY_SKETCHY);
+		$post->setSource('amazing source');
+
+		$historyService = $this->getHistoryService();
+		$snapshot = $historyService->getPostChangeSnapshot($post);
+
+		$this->assertEquals([
+			'source' => 'amazing source',
+			'safety' => 'sketchy',
+			'contentChecksum' => 'checksum',
+			'featured' => false,
+			'tags' => ['tag1', 'tag2'],
+			'relations' => [1, 2]
+		], $snapshot->getData());
+
+		$this->assertEquals(\Szurubooru\Entities\Snapshot::TYPE_POST, $snapshot->getType());
+		$this->assertEquals(5, $snapshot->getPrimaryKey());
+
+		return $post;
+	}
+
+	/**
+	 * @depends testPostChangeSnapshot
+	 */
+	public function testPostChangeSnapshotFeature($post)
+	{
+		$param = new \Szurubooru\Entities\GlobalParam;
+		$param->setValue($post->getId());
+		$this->globalParamDaoMock
+			->expects($this->once())
+			->method('findByKey')
+			->with(\Szurubooru\Entities\GlobalParam::KEY_FEATURED_POST)
+			->willReturn($param);
+
+		$historyService = $this->getHistoryService();
+		$snapshot = $historyService->getPostChangeSnapshot($post);
+
+		$this->assertTrue($snapshot->getData()['featured']);
+	}
+
+	/**
+	 * @dataProvider snapshotDataDifferenceProvider
+	 */
+	public function testSnapshotDataDifference($newData, $oldData, $expectedResult)
+	{
+		$historyService = $this->getHistoryService();
+		$this->assertEquals($expectedResult, $historyService->getSnapshotDataDifference($newData, $oldData));
+	}
+
+	private function getHistoryService()
+	{
+		return new \Szurubooru\Services\HistoryService(
+			$this->validatorMock,
+			$this->snapshotDaoMock,
+			$this->globalParamDaoMock,
+			$this->transactionManagerMock,
+			$this->timeServiceMock,
+			$this->authServiceMock);
+	}
+}

tests/Services/PostServiceTest.php

@@ -11,6 +11,7 @@ class PostServiceTest extends \Szurubooru\Tests\AbstractTestCase
 	private $authServiceMock;
 	private $timeServiceMock;
 	private $fileServiceMock;
+	private $historyServiceMock;
 	private $imageManipulatorMock;
 
 	public function setUp()
@@ -23,6 +24,7 @@ class PostServiceTest extends \Szurubooru\Tests\AbstractTestCase
 		$this->authServiceMock = $this->mock(\Szurubooru\Services\AuthService::class);
 		$this->timeServiceMock = $this->mock(\Szurubooru\Services\TimeService::class);
 		$this->fileServiceMock = $this->mock(\Szurubooru\Services\FileService::class);
+		$this->historyServiceMock = $this->mock(\Szurubooru\Services\HistoryService::class);
 		$this->configMock->set('database/maxPostSize', 1000000);
 		$this->imageManipulatorMock = $this->mock(\Szurubooru\Services\ImageManipulation\ImageManipulator::class);
 	}
@@ -37,6 +39,7 @@ class PostServiceTest extends \Szurubooru\Tests\AbstractTestCase
 
 		$this->postDaoMock->expects($this->once())->method('save')->will($this->returnArgument(0));
 		$this->authServiceMock->expects($this->once())->method('getLoggedInUser')->willReturn(new \Szurubooru\Entities\User(5));
+		$this->historyServiceMock->expects($this->once())->method('getPostChangeSnapshot')->willReturn(new \Szurubooru\Entities\Snapshot());
 
 		$this->postService = $this->getPostService();
 		$savedPost = $this->postService->createPost($formData);
@@ -65,6 +68,7 @@ class PostServiceTest extends \Szurubooru\Tests\AbstractTestCase
 		$this->postDaoMock->expects($this->once())->method('save')->will($this->returnArgument(0));
 		$this->imageManipulatorMock->expects($this->once())->method('getImageWidth')->willReturn(640);
 		$this->imageManipulatorMock->expects($this->once())->method('getImageHeight')->willReturn(480);
+		$this->historyServiceMock->expects($this->once())->method('getPostChangeSnapshot')->willReturn(new \Szurubooru\Entities\Snapshot());
 
 		$this->postService = $this->getPostService();
 		$savedPost = $this->postService->createPost($formData);
@@ -85,6 +89,7 @@ class PostServiceTest extends \Szurubooru\Tests\AbstractTestCase
 		$formData->contentFileName = 'blah';
 
 		$this->postDaoMock->expects($this->once())->method('save')->will($this->returnArgument(0));
+		$this->historyServiceMock->expects($this->once())->method('getPostChangeSnapshot')->willReturn(new \Szurubooru\Entities\Snapshot());
 
 		$this->postService = $this->getPostService();
 		$savedPost = $this->postService->createPost($formData);
@@ -103,6 +108,7 @@ class PostServiceTest extends \Szurubooru\Tests\AbstractTestCase
 		$formData->contentFileName = 'blah';
 
 		$this->postDaoMock->expects($this->once())->method('save')->will($this->returnArgument(0));
+		$this->historyServiceMock->expects($this->once())->method('getPostChangeSnapshot')->willReturn(new \Szurubooru\Entities\Snapshot());
 
 		$this->postService = $this->getPostService();
 		$savedPost = $this->postService->createPost($formData);
@@ -165,6 +171,7 @@ class PostServiceTest extends \Szurubooru\Tests\AbstractTestCase
 
 		$this->postDaoMock->expects($this->once())->method('save')->will($this->returnArgument(0));
 		$this->authServiceMock->expects($this->never())->method('getLoggedInUser');
+		$this->historyServiceMock->expects($this->once())->method('getPostChangeSnapshot')->willReturn(new \Szurubooru\Entities\Snapshot());
 
 		$this->postService = $this->getPostService();
 		$savedPost = $this->postService->createPost($formData);
@@ -182,6 +189,7 @@ class PostServiceTest extends \Szurubooru\Tests\AbstractTestCase
 			$this->authServiceMock,
 			$this->timeServiceMock,
 			$this->fileServiceMock,
+			$this->historyServiceMock,
 			$this->imageManipulatorMock);
 	}
 }