9 files changed, 557 insertions, 371 deletions

diff --git a/application/bookmark/Bookmark.php b/application/bookmark/Bookmark.php
index f9b21d3d..4810c5e6 100644
--- a/application/bookmark/Bookmark.php
+++ b/application/bookmark/Bookmark.php
@@ -1,8 +1,11 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Shaarli\Bookmark;
 
 use DateTime;
+use DateTimeInterface;
 use Shaarli\Bookmark\Exception\InvalidBookmarkException;
 
 /**
@@ -36,21 +39,24 @@ class Bookmark
     /** @var array List of bookmark's tags */
     protected $tags;
 
-    /** @var string Thumbnail's URL - false if no thumbnail could be found */
+    /** @var string|bool|null Thumbnail's URL - initialized at null, false if no thumbnail could be found */
     protected $thumbnail;
 
     /** @var bool Set to true if the bookmark is set as sticky */
     protected $sticky;
 
-    /** @var DateTime Creation datetime */
+    /** @var DateTimeInterface Creation datetime */
     protected $created;
 
-    /** @var DateTime Update datetime */
+    /** @var DateTimeInterface datetime */
     protected $updated;
 
     /** @var bool True if the bookmark can only be seen while logged in */
     protected $private;
 
+    /** @var mixed[] Available to store any additional content for a bookmark. Currently used for search highlight. */
+    protected $additionalContent = [];
+
     /**
      * Initialize a link from array data. Especially useful to create a Bookmark from former link storage format.
      *
@@ -58,25 +64,25 @@ class Bookmark
      *
      * @return $this
      */
-    public function fromArray($data)
+    public function fromArray(array $data): Bookmark
     {
-        $this->id = $data['id'];
-        $this->shortUrl = $data['shorturl'];
-        $this->url = $data['url'];
-        $this->title = $data['title'];
-        $this->description = $data['description'];
-        $this->thumbnail = isset($data['thumbnail']) ? $data['thumbnail'] : null;
-        $this->sticky = isset($data['sticky']) ? $data['sticky'] : false;
-        $this->created = $data['created'];
+        $this->id = $data['id'] ?? null;
+        $this->shortUrl = $data['shorturl'] ?? null;
+        $this->url = $data['url'] ?? null;
+        $this->title = $data['title'] ?? null;
+        $this->description = $data['description'] ?? null;
+        $this->thumbnail = $data['thumbnail'] ?? null;
+        $this->sticky = $data['sticky'] ?? false;
+        $this->created = $data['created'] ?? null;
         if (is_array($data['tags'])) {
             $this->tags = $data['tags'];
         } else {
-            $this->tags = preg_split('/\s+/', $data['tags'], -1, PREG_SPLIT_NO_EMPTY);
+            $this->tags = preg_split('/\s+/', $data['tags'] ?? '', -1, PREG_SPLIT_NO_EMPTY);
         }
         if (! empty($data['updated'])) {
             $this->updated = $data['updated'];
         }
-        $this->private = $data['private'] ? true : false;
+        $this->private = ($data['private'] ?? false) ? true : false;
 
         return $this;
     }
@@ -92,24 +98,28 @@ class Bookmark
      *   - the URL with the permalink
      *   - the title with the URL
      *
+     * Also make sure that we do not save search highlights in the datastore.
+     *
      * @throws InvalidBookmarkException
      */
-    public function validate()
+    public function validate(): void
     {
         if ($this->id === null
             || ! is_int($this->id)
             || empty($this->shortUrl)
             || empty($this->created)
-            || ! $this->created instanceof DateTime
         ) {
             throw new InvalidBookmarkException($this);
         }
         if (empty($this->url)) {
-            $this->url = '?'. $this->shortUrl;
+            $this->url = '/shaare/'. $this->shortUrl;
         }
         if (empty($this->title)) {
             $this->title = $this->url;
         }
+        if (array_key_exists('search_highlight', $this->additionalContent)) {
+            unset($this->additionalContent['search_highlight']);
+        }
     }
 
     /**
@@ -118,11 +128,11 @@ class Bookmark
      *   - created: with the current datetime
      *   - shortUrl: with a generated small hash from the date and the given ID
      *
-     * @param int $id
+     * @param int|null $id
      *
      * @return Bookmark
      */
-    public function setId($id)
+    public function setId(?int $id): Bookmark
     {
         $this->id = $id;
         if (empty($this->created)) {
@@ -138,9 +148,9 @@ class Bookmark
     /**
      * Get the Id.
      *
-     * @return int
+     * @return int|null
      */
-    public function getId()
+    public function getId(): ?int
     {
         return $this->id;
     }
@@ -148,9 +158,9 @@ class Bookmark
     /**
      * Get the ShortUrl.
      *
-     * @return string
+     * @return string|null
      */
-    public function getShortUrl()
+    public function getShortUrl(): ?string
     {
         return $this->shortUrl;
     }
@@ -158,9 +168,9 @@ class Bookmark
     /**
      * Get the Url.
      *
-     * @return string
+     * @return string|null
      */
-    public function getUrl()
+    public function getUrl(): ?string
     {
         return $this->url;
     }
@@ -170,7 +180,7 @@ class Bookmark
      *
      * @return string
      */
-    public function getTitle()
+    public function getTitle(): ?string
     {
         return $this->title;
     }
@@ -180,7 +190,7 @@ class Bookmark
      *
      * @return string
      */
-    public function getDescription()
+    public function getDescription(): string
     {
         return ! empty($this->description) ? $this->description : '';
     }
@@ -188,9 +198,9 @@ class Bookmark
     /**
      * Get the Created.
      *
-     * @return DateTime
+     * @return DateTimeInterface
      */
-    public function getCreated()
+    public function getCreated(): ?DateTimeInterface
     {
         return $this->created;
     }
@@ -198,9 +208,9 @@ class Bookmark
     /**
      * Get the Updated.
      *
-     * @return DateTime
+     * @return DateTimeInterface
      */
-    public function getUpdated()
+    public function getUpdated(): ?DateTimeInterface
     {
         return $this->updated;
     }
@@ -208,11 +218,11 @@ class Bookmark
     /**
      * Set the ShortUrl.
      *
-     * @param string $shortUrl
+     * @param string|null $shortUrl
      *
      * @return Bookmark
      */
-    public function setShortUrl($shortUrl)
+    public function setShortUrl(?string $shortUrl): Bookmark
     {
         $this->shortUrl = $shortUrl;
 
@@ -222,14 +232,14 @@ class Bookmark
     /**
      * Set the Url.
      *
-     * @param string $url
-     * @param array  $allowedProtocols
+     * @param string|null $url
+     * @param string[]    $allowedProtocols
      *
      * @return Bookmark
      */
-    public function setUrl($url, $allowedProtocols = [])
+    public function setUrl(?string $url, array $allowedProtocols = []): Bookmark
     {
-        $url = trim($url);
+        $url = $url !== null ? trim($url) : '';
         if (! empty($url)) {
             $url = whitelist_protocols($url, $allowedProtocols);
         }
@@ -241,13 +251,13 @@ class Bookmark
     /**
      * Set the Title.
      *
-     * @param string $title
+     * @param string|null $title
      *
      * @return Bookmark
      */
-    public function setTitle($title)
+    public function setTitle(?string $title): Bookmark
     {
-        $this->title = trim($title);
+        $this->title = $title !== null ? trim($title) : '';
 
         return $this;
     }
@@ -255,11 +265,11 @@ class Bookmark
     /**
      * Set the Description.
      *
-     * @param string $description
+     * @param string|null $description
      *
      * @return Bookmark
      */
-    public function setDescription($description)
+    public function setDescription(?string $description): Bookmark
     {
         $this->description = $description;
 
@@ -270,11 +280,11 @@ class Bookmark
      * Set the Created.
      * Note: you shouldn't set this manually except for special cases (like bookmark import)
      *
-     * @param DateTime $created
+     * @param DateTimeInterface|null $created
      *
      * @return Bookmark
      */
-    public function setCreated($created)
+    public function setCreated(?DateTimeInterface $created): Bookmark
     {
         $this->created = $created;
 
@@ -284,11 +294,11 @@ class Bookmark
     /**
      * Set the Updated.
      *
-     * @param DateTime $updated
+     * @param DateTimeInterface|null $updated
      *
      * @return Bookmark
      */
-    public function setUpdated($updated)
+    public function setUpdated(?DateTimeInterface $updated): Bookmark
     {
         $this->updated = $updated;
 
@@ -300,7 +310,7 @@ class Bookmark
      *
      * @return bool
      */
-    public function isPrivate()
+    public function isPrivate(): bool
     {
         return $this->private ? true : false;
     }
@@ -308,11 +318,11 @@ class Bookmark
     /**
      * Set the Private.
      *
-     * @param bool $private
+     * @param bool|null $private
      *
      * @return Bookmark
      */
-    public function setPrivate($private)
+    public function setPrivate(?bool $private): Bookmark
     {
         $this->private = $private ? true : false;
 
@@ -322,9 +332,9 @@ class Bookmark
     /**
      * Get the Tags.
      *
-     * @return array
+     * @return string[]
      */
-    public function getTags()
+    public function getTags(): array
     {
         return is_array($this->tags) ? $this->tags : [];
     }
@@ -332,13 +342,13 @@ class Bookmark
     /**
      * Set the Tags.
      *
-     * @param array $tags
+     * @param string[]|null $tags
      *
      * @return Bookmark
      */
-    public function setTags($tags)
+    public function setTags(?array $tags): Bookmark
     {
-        $this->setTagsString(implode(' ', $tags));
+        $this->setTagsString(implode(' ', $tags ?? []));
 
         return $this;
     }
@@ -346,7 +356,7 @@ class Bookmark
     /**
      * Get the Thumbnail.
      *
-     * @return string|bool
+     * @return string|bool|null Thumbnail's URL - initialized at null, false if no thumbnail could be found
      */
     public function getThumbnail()
     {
@@ -356,11 +366,11 @@ class Bookmark
     /**
      * Set the Thumbnail.
      *
-     * @param string|bool $thumbnail
+     * @param string|bool|null $thumbnail Thumbnail's URL - false if no thumbnail could be found
      *
      * @return Bookmark
      */
-    public function setThumbnail($thumbnail)
+    public function setThumbnail($thumbnail): Bookmark
     {
         $this->thumbnail = $thumbnail;
 
@@ -368,11 +378,29 @@ class Bookmark
     }
 
     /**
+     * Return true if:
+     *   - the bookmark's thumbnail is not already set to false (= not found)
+     *   - it's not a note
+     *   - it's an HTTP(S) link
+     *   - the thumbnail has not yet be retrieved (null) or its associated cache file doesn't exist anymore
+     *
+     * @return bool True if the bookmark's thumbnail needs to be retrieved.
+     */
+    public function shouldUpdateThumbnail(): bool
+    {
+        return $this->thumbnail !== false
+            && !$this->isNote()
+            && startsWith(strtolower($this->url), 'http')
+            && (null === $this->thumbnail || !is_file($this->thumbnail))
+        ;
+    }
+
+    /**
      * Get the Sticky.
      *
      * @return bool
      */
-    public function isSticky()
+    public function isSticky(): bool
     {
         return $this->sticky ? true : false;
     }
@@ -380,11 +408,11 @@ class Bookmark
     /**
      * Set the Sticky.
      *
-     * @param bool $sticky
+     * @param bool|null $sticky
      *
      * @return Bookmark
      */
-    public function setSticky($sticky)
+    public function setSticky(?bool $sticky): Bookmark
     {
         $this->sticky = $sticky ? true : false;
 
@@ -394,7 +422,7 @@ class Bookmark
     /**
      * @return string Bookmark's tags as a string, separated by a space
      */
-    public function getTagsString()
+    public function getTagsString(): string
     {
         return implode(' ', $this->getTags());
     }
@@ -402,10 +430,10 @@ class Bookmark
     /**
      * @return bool
      */
-    public function isNote()
+    public function isNote(): bool
     {
         // We check empty value to get a valid result if the link has not been saved yet
-        return empty($this->url) || $this->url[0] === '?';
+        return empty($this->url) || startsWith($this->url, '/shaare/') || $this->url[0] === '?';
     }
 
     /**
@@ -415,14 +443,14 @@ class Bookmark
      *   - multiple spaces will be removed
      *   - trailing dash in tags will be removed
      *
-     * @param string $tags
+     * @param string|null $tags
      *
      * @return $this
      */
-    public function setTagsString($tags)
+    public function setTagsString(?string $tags): Bookmark
     {
         // Remove first '-' char in tags.
-        $tags = preg_replace('/(^| )\-/', '$1', $tags);
+        $tags = preg_replace('/(^| )\-/', '$1', $tags ?? '');
         // Explode all tags separted by spaces or commas
         $tags = preg_split('/[\s,]+/', $tags);
         // Remove eventual empty values
@@ -434,12 +462,50 @@ class Bookmark
     }
 
     /**
+     * Get entire additionalContent array.
+     *
+     * @return mixed[]
+     */
+    public function getAdditionalContent(): array
+    {
+        return $this->additionalContent;
+    }
+
+    /**
+     * Set a single entry in additionalContent, by key.
+     *
+     * @param string     $key
+     * @param mixed|null $value Any type of value can be set.
+     *
+     * @return $this
+     */
+    public function addAdditionalContentEntry(string $key, $value): self
+    {
+        $this->additionalContent[$key] = $value;
+
+        return $this;
+    }
+
+    /**
+     * Get a single entry in additionalContent, by key.
+     *
+     * @param string $key
+     * @param mixed|null $default
+     *
+     * @return mixed|null can be any type or even null.
+     */
+    public function getAdditionalContentEntry(string $key, $default = null)
+    {
+        return array_key_exists($key, $this->additionalContent) ? $this->additionalContent[$key] : $default;
+    }
+
+    /**
      * Rename a tag in tags list.
      *
      * @param string $fromTag
      * @param string $toTag
      */
-    public function renameTag($fromTag, $toTag)
+    public function renameTag(string $fromTag, string $toTag): void
     {
         if (($pos = array_search($fromTag, $this->tags)) !== false) {
             $this->tags[$pos] = trim($toTag);
@@ -451,7 +517,7 @@ class Bookmark
      *
      * @param string $tag
      */
-    public function deleteTag($tag)
+    public function deleteTag(string $tag): void
     {
         if (($pos = array_search($tag, $this->tags)) !== false) {
             unset($this->tags[$pos]);
diff --git a/application/bookmark/BookmarkArray.php b/application/bookmark/BookmarkArray.php
index d87d43b4..67bb3b73 100644
--- a/application/bookmark/BookmarkArray.php
+++ b/application/bookmark/BookmarkArray.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Shaarli\Bookmark;
 
 use Shaarli\Bookmark\Exception\InvalidBookmarkException;
@@ -187,13 +189,13 @@ class BookmarkArray implements \Iterator, \Countable, \ArrayAccess
     /**
      * Returns a bookmark offset in bookmarks array from its unique ID.
      *
-     * @param int $id Persistent ID of a bookmark.
+     * @param int|null $id Persistent ID of a bookmark.
      *
      * @return int Real offset in local array, or null if doesn't exist.
      */
-    protected function getBookmarkOffset($id)
+    protected function getBookmarkOffset(?int $id): ?int
     {
-        if (isset($this->ids[$id])) {
+        if ($id !== null && isset($this->ids[$id])) {
             return $this->ids[$id];
         }
         return null;
@@ -205,7 +207,7 @@ class BookmarkArray implements \Iterator, \Countable, \ArrayAccess
      *
      * @return int next ID.
      */
-    public function getNextId()
+    public function getNextId(): int
     {
         if (!empty($this->ids)) {
             return max(array_keys($this->ids)) + 1;
@@ -214,11 +216,11 @@ class BookmarkArray implements \Iterator, \Countable, \ArrayAccess
     }
 
     /**
-     * @param $url
+     * @param string $url
      *
      * @return Bookmark|null
      */
-    public function getByUrl($url)
+    public function getByUrl(string $url): ?Bookmark
     {
         if (! empty($url)
             && isset($this->urls[$url])
@@ -234,16 +236,17 @@ class BookmarkArray implements \Iterator, \Countable, \ArrayAccess
      *
      * Also update the urls and ids mapping arrays.
      *
-     * @param string $order ASC|DESC
+     * @param string $order        ASC|DESC
+     * @param bool   $ignoreSticky If set to true, sticky bookmarks won't be first
      */
-    public function reorder($order = 'DESC')
+    public function reorder(string $order = 'DESC', bool $ignoreSticky = false): void
     {
         $order = $order === 'ASC' ? -1 : 1;
         // Reorder array by dates.
-        usort($this->bookmarks, function ($a, $b) use ($order) {
+        usort($this->bookmarks, function ($a, $b) use ($order, $ignoreSticky) {
             /** @var $a Bookmark */
             /** @var $b Bookmark */
-            if ($a->isSticky() !== $b->isSticky()) {
+            if (false === $ignoreSticky && $a->isSticky() !== $b->isSticky()) {
                 return $a->isSticky() ? -1 : 1;
             }
             return $a->getCreated() < $b->getCreated() ? 1 * $order : -1 * $order;
diff --git a/application/bookmark/BookmarkFileService.php b/application/bookmark/BookmarkFileService.php
index 9c59e139..3ea98a45 100644
--- a/application/bookmark/BookmarkFileService.php
+++ b/application/bookmark/BookmarkFileService.php
@@ -1,17 +1,21 @@
 <?php
 
+declare(strict_types=1);
 
 namespace Shaarli\Bookmark;
 
-
+use DateTime;
 use Exception;
+use malkusch\lock\mutex\Mutex;
 use Shaarli\Bookmark\Exception\BookmarkNotFoundException;
+use Shaarli\Bookmark\Exception\DatastoreNotInitializedException;
 use Shaarli\Bookmark\Exception\EmptyDataStoreException;
 use Shaarli\Config\ConfigManager;
 use Shaarli\Formatter\BookmarkMarkdownFormatter;
 use Shaarli\History;
 use Shaarli\Legacy\LegacyLinkDB;
 use Shaarli\Legacy\LegacyUpdater;
+use Shaarli\Render\PageCacheManager;
 use Shaarli\Updater\UpdaterUtils;
 
 /**
@@ -39,17 +43,25 @@ class BookmarkFileService implements BookmarkServiceInterface
     /** @var History instance */
     protected $history;
 
+    /** @var PageCacheManager instance */
+    protected $pageCacheManager;
+
     /** @var bool true for logged in users. Default value to retrieve private bookmarks. */
     protected $isLoggedIn;
 
+    /** @var Mutex */
+    protected $mutex;
+
     /**
      * @inheritDoc
      */
-    public function __construct(ConfigManager $conf, History $history, $isLoggedIn)
+    public function __construct(ConfigManager $conf, History $history, Mutex $mutex, bool $isLoggedIn)
     {
         $this->conf = $conf;
         $this->history = $history;
-        $this->bookmarksIO = new BookmarkIO($this->conf);
+        $this->mutex = $mutex;
+        $this->pageCacheManager = new PageCacheManager($this->conf->get('resource.page_cache'), $isLoggedIn);
+        $this->bookmarksIO = new BookmarkIO($this->conf, $this->mutex);
         $this->isLoggedIn = $isLoggedIn;
 
         if (!$this->isLoggedIn && $this->conf->get('privacy.hide_public_links', false)) {
@@ -57,10 +69,16 @@ class BookmarkFileService implements BookmarkServiceInterface
         } else {
             try {
                 $this->bookmarks = $this->bookmarksIO->read();
-            } catch (EmptyDataStoreException $e) {
+            } catch (EmptyDataStoreException|DatastoreNotInitializedException $e) {
                 $this->bookmarks = new BookmarkArray();
-                if ($isLoggedIn) {
-                    $this->save();
+
+                if ($this->isLoggedIn) {
+                    // Datastore file does not exists, we initialize it with default bookmarks.
+                    if ($e instanceof DatastoreNotInitializedException) {
+                        $this->initialize();
+                    } else {
+                        $this->save();
+                    }
                 }
             }
 
@@ -79,22 +97,25 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function findByHash($hash)
+    public function findByHash(string $hash, string $privateKey = null): Bookmark
     {
         $bookmark = $this->bookmarkFilter->filter(BookmarkFilter::$FILTER_HASH, $hash);
         // PHP 7.3 introduced array_key_first() to avoid this hack
         $first = reset($bookmark);
-        if (! $this->isLoggedIn && $first->isPrivate()) {
-            throw new Exception('Not authorized');
+        if (!$this->isLoggedIn
+            && $first->isPrivate()
+            && (empty($privateKey) || $privateKey !== $first->getAdditionalContentEntry('private_key'))
+        ) {
+            throw new BookmarkNotFoundException();
         }
 
-        return $bookmark;
+        return $first;
     }
 
     /**
      * @inheritDoc
      */
-    public function findByUrl($url)
+    public function findByUrl(string $url): ?Bookmark
     {
         return $this->bookmarks->getByUrl($url);
     }
@@ -102,19 +123,28 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function search($request = [], $visibility = null, $caseSensitive = false, $untaggedOnly = false)
-    {
+    public function search(
+        array $request = [],
+        string $visibility = null,
+        bool $caseSensitive = false,
+        bool $untaggedOnly = false,
+        bool $ignoreSticky = false
+    ) {
         if ($visibility === null) {
             $visibility = $this->isLoggedIn ? BookmarkFilter::$ALL : BookmarkFilter::$PUBLIC;
         }
 
         // Filter bookmark database according to parameters.
-        $searchtags = isset($request['searchtags']) ? $request['searchtags'] : '';
-        $searchterm = isset($request['searchterm']) ? $request['searchterm'] : '';
+        $searchTags = isset($request['searchtags']) ? $request['searchtags'] : '';
+        $searchTerm = isset($request['searchterm']) ? $request['searchterm'] : '';
+
+        if ($ignoreSticky) {
+            $this->bookmarks->reorder('DESC', true);
+        }
 
         return $this->bookmarkFilter->filter(
             BookmarkFilter::$FILTER_TAG | BookmarkFilter::$FILTER_TEXT,
-            [$searchtags, $searchterm],
+            [$searchTags, $searchTerm],
             $caseSensitive,
             $visibility,
             $untaggedOnly
@@ -124,7 +154,7 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function get($id, $visibility = null)
+    public function get(int $id, string $visibility = null): Bookmark
     {
         if (! isset($this->bookmarks[$id])) {
             throw new BookmarkNotFoundException();
@@ -147,20 +177,17 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function set($bookmark, $save = true)
+    public function set(Bookmark $bookmark, bool $save = true): Bookmark
     {
-        if ($this->isLoggedIn !== true) {
+        if (true !== $this->isLoggedIn) {
             throw new Exception(t('You\'re not authorized to alter the datastore'));
         }
-        if (! $bookmark instanceof Bookmark) {
-            throw new Exception(t('Provided data is invalid'));
-        }
         if (! isset($this->bookmarks[$bookmark->getId()])) {
             throw new BookmarkNotFoundException();
         }
         $bookmark->validate();
 
-        $bookmark->setUpdated(new \DateTime());
+        $bookmark->setUpdated(new DateTime());
         $this->bookmarks[$bookmark->getId()] = $bookmark;
         if ($save === true) {
             $this->save();
@@ -172,15 +199,12 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function add($bookmark, $save = true)
+    public function add(Bookmark $bookmark, bool $save = true): Bookmark
     {
-        if ($this->isLoggedIn !== true) {
+        if (true !== $this->isLoggedIn) {
             throw new Exception(t('You\'re not authorized to alter the datastore'));
         }
-        if (! $bookmark instanceof Bookmark) {
-            throw new Exception(t('Provided data is invalid'));
-        }
-        if (! empty($bookmark->getId())) {
+        if (!empty($bookmark->getId())) {
             throw new Exception(t('This bookmarks already exists'));
         }
         $bookmark->setId($this->bookmarks->getNextId());
@@ -197,14 +221,11 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function addOrSet($bookmark, $save = true)
+    public function addOrSet(Bookmark $bookmark, bool $save = true): Bookmark
     {
-        if ($this->isLoggedIn !== true) {
+        if (true !== $this->isLoggedIn) {
             throw new Exception(t('You\'re not authorized to alter the datastore'));
         }
-        if (! $bookmark instanceof Bookmark) {
-            throw new Exception('Provided data is invalid');
-        }
         if ($bookmark->getId() === null) {
             return $this->add($bookmark, $save);
         }
@@ -214,14 +235,11 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function remove($bookmark, $save = true)
+    public function remove(Bookmark $bookmark, bool $save = true): void
     {
-        if ($this->isLoggedIn !== true) {
+        if (true !== $this->isLoggedIn) {
             throw new Exception(t('You\'re not authorized to alter the datastore'));
         }
-        if (! $bookmark instanceof Bookmark) {
-            throw new Exception(t('Provided data is invalid'));
-        }
         if (! isset($this->bookmarks[$bookmark->getId()])) {
             throw new BookmarkNotFoundException();
         }
@@ -236,7 +254,7 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function exists($id, $visibility = null)
+    public function exists(int $id, string $visibility = null): bool
     {
         if (! isset($this->bookmarks[$id])) {
             return false;
@@ -259,7 +277,7 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function count($visibility = null)
+    public function count(string $visibility = null): int
     {
         return count($this->search([], $visibility));
     }
@@ -267,21 +285,22 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function save()
+    public function save(): void
     {
-        if (!$this->isLoggedIn) {
+        if (true !== $this->isLoggedIn) {
             // TODO: raise an Exception instead
             die('You are not authorized to change the database.');
         }
+
         $this->bookmarks->reorder();
         $this->bookmarksIO->write($this->bookmarks);
-        invalidateCaches($this->conf->get('resource.page_cache'));
+        $this->pageCacheManager->invalidateCaches();
     }
 
     /**
      * @inheritDoc
      */
-    public function bookmarksCountPerTag($filteringTags = [], $visibility = null)
+    public function bookmarksCountPerTag(array $filteringTags = [], string $visibility = null): array
     {
         $bookmarks = $this->search(['searchtags' => $filteringTags], $visibility);
         $tags = [];
@@ -291,6 +310,7 @@ class BookmarkFileService implements BookmarkServiceInterface
                 if (empty($tag)
                     || (! $this->isLoggedIn && startsWith($tag, '.'))
                     || $tag === BookmarkMarkdownFormatter::NO_MD_TAG
+                    || in_array($tag, $filteringTags, true)
                 ) {
                     continue;
                 }
@@ -316,45 +336,68 @@ class BookmarkFileService implements BookmarkServiceInterface
         $keys = array_keys($tags);
         $tmpTags = array_combine($keys, $keys);
         array_multisort($tags, SORT_DESC, $tmpTags, SORT_ASC, $tags);
+
         return $tags;
     }
 
     /**
      * @inheritDoc
      */
-    public function days()
-    {
-        $bookmarkDays = [];
-        foreach ($this->search() as $bookmark) {
-            $bookmarkDays[$bookmark->getCreated()->format('Ymd')] = 0;
+    public function findByDate(
+        \DateTimeInterface $from,
+        \DateTimeInterface $to,
+        ?\DateTimeInterface &$previous,
+        ?\DateTimeInterface &$next
+    ): array {
+        $out = [];
+        $previous = null;
+        $next = null;
+
+        foreach ($this->search([], null, false, false, true) as $bookmark) {
+            if ($to < $bookmark->getCreated()) {
+                $next = $bookmark->getCreated();
+            } else if ($from < $bookmark->getCreated() && $to > $bookmark->getCreated()) {
+                $out[] = $bookmark;
+            } else {
+                if ($previous !== null) {
+                    break;
+                }
+                $previous = $bookmark->getCreated();
+            }
         }
-        $bookmarkDays = array_keys($bookmarkDays);
-        sort($bookmarkDays);
 
-        return $bookmarkDays;
+        return $out;
     }
 
     /**
      * @inheritDoc
      */
-    public function filterDay($request)
+    public function getLatest(): ?Bookmark
     {
-        return $this->bookmarkFilter->filter(BookmarkFilter::$FILTER_DAY, $request);
+        foreach ($this->search([], null, false, false, true) as $bookmark) {
+            return $bookmark;
+        }
+
+        return null;
     }
 
     /**
      * @inheritDoc
      */
-    public function initialize()
+    public function initialize(): void
     {
         $initializer = new BookmarkInitializer($this);
         $initializer->initialize();
+
+        if (true === $this->isLoggedIn) {
+            $this->save();
+        }
     }
 
     /**
      * Handles migration to the new database format (BookmarksArray).
      */
-    protected function migrate()
+    protected function migrate(): void
     {
         $bookmarkDb = new LegacyLinkDB(
             $this->conf->get('resource.datastore'),
diff --git a/application/bookmark/BookmarkFilter.php b/application/bookmark/BookmarkFilter.php
index fd556679..c79386ea 100644
--- a/application/bookmark/BookmarkFilter.php
+++ b/application/bookmark/BookmarkFilter.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Shaarli\Bookmark;
 
 use Exception;
@@ -77,8 +79,13 @@ class BookmarkFilter
      *
      * @throws BookmarkNotFoundException
      */
-    public function filter($type, $request, $casesensitive = false, $visibility = 'all', $untaggedonly = false)
-    {
+    public function filter(
+        string $type,
+        $request,
+        bool $casesensitive = false,
+        string $visibility = 'all',
+        bool $untaggedonly = false
+    ) {
         if (!in_array($visibility, ['all', 'public', 'private'])) {
             $visibility = 'all';
         }
@@ -115,7 +122,7 @@ class BookmarkFilter
                     return $this->filterTags($request, $casesensitive, $visibility);
                 }
             case self::$FILTER_DAY:
-                return $this->filterDay($request);
+                return $this->filterDay($request, $visibility);
             default:
                 return $this->noFilter($visibility);
         }
@@ -128,7 +135,7 @@ class BookmarkFilter
      *
      * @return Bookmark[] filtered bookmarks.
      */
-    private function noFilter($visibility = 'all')
+    private function noFilter(string $visibility = 'all')
     {
         if ($visibility === 'all') {
             return $this->bookmarks;
@@ -151,11 +158,11 @@ class BookmarkFilter
      *
      * @param string $smallHash permalink hash.
      *
-     * @return array $filtered array containing permalink data.
+     * @return Bookmark[] $filtered array containing permalink data.
      *
-     * @throws \Shaarli\Bookmark\Exception\BookmarkNotFoundException if the smallhash doesn't match any link.
+     * @throws BookmarkNotFoundException if the smallhash doesn't match any link.
      */
-    private function filterSmallHash($smallHash)
+    private function filterSmallHash(string $smallHash)
     {
         foreach ($this->bookmarks as $key => $l) {
             if ($smallHash == $l->getShortUrl()) {
@@ -186,15 +193,15 @@ class BookmarkFilter
      * @param string $searchterms search query.
      * @param string $visibility  Optional: return only all/private/public bookmarks.
      *
-     * @return array search results.
+     * @return Bookmark[] search results.
      */
-    private function filterFulltext($searchterms, $visibility = 'all')
+    private function filterFulltext(string $searchterms, string $visibility = 'all')
     {
         if (empty($searchterms)) {
             return $this->noFilter($visibility);
         }
 
-        $filtered = array();
+        $filtered = [];
         $search = mb_convert_case(html_entity_decode($searchterms), MB_CASE_LOWER, 'UTF-8');
         $exactRegex = '/"([^"]+)"/';
         // Retrieve exact search terms.
@@ -206,8 +213,8 @@ class BookmarkFilter
         $explodedSearchAnd = array_values(array_filter($explodedSearchAnd));
 
         // Filter excluding terms and update andSearch.
-        $excludeSearch = array();
-        $andSearch = array();
+        $excludeSearch = [];
+        $andSearch = [];
         foreach ($explodedSearchAnd as $needle) {
             if ($needle[0] == '-' && strlen($needle) > 1) {
                 $excludeSearch[] = substr($needle, 1);
@@ -227,33 +234,38 @@ class BookmarkFilter
                 }
             }
 
-            // Concatenate link fields to search across fields.
-            // Adds a '\' separator for exact search terms.
-            $content  = mb_convert_case($link->getTitle(), MB_CASE_LOWER, 'UTF-8') .'\\';
-            $content .= mb_convert_case($link->getDescription(), MB_CASE_LOWER, 'UTF-8') .'\\';
-            $content .= mb_convert_case($link->getUrl(), MB_CASE_LOWER, 'UTF-8') .'\\';
-            $content .= mb_convert_case($link->getTagsString(), MB_CASE_LOWER, 'UTF-8') .'\\';
+            $lengths = [];
+            $content = $this->buildFullTextSearchableLink($link, $lengths);
 
             // Be optimistic
             $found = true;
+            $foundPositions = [];
 
             // First, we look for exact term search
-            for ($i = 0; $i < count($exactSearch) && $found; $i++) {
-                $found = strpos($content, $exactSearch[$i]) !== false;
-            }
-
-            // Iterate over keywords, if keyword is not found,
+            // Then iterate over keywords, if keyword is not found,
             // no need to check for the others. We want all or nothing.
-            for ($i = 0; $i < count($andSearch) && $found; $i++) {
-                $found = strpos($content, $andSearch[$i]) !== false;
+            foreach ([$exactSearch, $andSearch] as $search) {
+                for ($i = 0; $i < count($search) && $found !== false; $i++) {
+                    $found = mb_strpos($content, $search[$i]);
+                    if ($found === false) {
+                        break;
+                    }
+
+                    $foundPositions[] = ['start' => $found, 'end' => $found + mb_strlen($search[$i])];
+                }
             }
 
             // Exclude terms.
-            for ($i = 0; $i < count($excludeSearch) && $found; $i++) {
+            for ($i = 0; $i < count($excludeSearch) && $found !== false; $i++) {
                 $found = strpos($content, $excludeSearch[$i]) === false;
             }
 
-            if ($found) {
+            if ($found !== false) {
+                $link->addAdditionalContentEntry(
+                    'search_highlight',
+                    $this->postProcessFoundPositions($lengths, $foundPositions)
+                );
+
                 $filtered[$id] = $link;
             }
         }
@@ -268,7 +280,7 @@ class BookmarkFilter
      *
      * @return string generated regex fragment
      */
-    private static function tag2regex($tag)
+    private static function tag2regex(string $tag): string
     {
         $len = strlen($tag);
         if (!$len || $tag === "-" || $tag === "*") {
@@ -314,13 +326,13 @@ class BookmarkFilter
      * You can specify one or more tags, separated by space or a comma, e.g.
      *  print_r($mydb->filterTags('linux programming'));
      *
-     * @param string $tags          list of tags separated by commas or blank spaces.
-     * @param bool   $casesensitive ignore case if false.
-     * @param string $visibility    Optional: return only all/private/public bookmarks.
+     * @param string|array $tags          list of tags, separated by commas or blank spaces if passed as string.
+     * @param bool         $casesensitive ignore case if false.
+     * @param string       $visibility    Optional: return only all/private/public bookmarks.
      *
-     * @return array filtered bookmarks.
+     * @return Bookmark[] filtered bookmarks.
      */
-    public function filterTags($tags, $casesensitive = false, $visibility = 'all')
+    public function filterTags($tags, bool $casesensitive = false, string $visibility = 'all')
     {
         // get single tags (we may get passed an array, even though the docs say different)
         $inputTags = $tags;
@@ -396,9 +408,9 @@ class BookmarkFilter
      *
      * @param string $visibility return only all/private/public bookmarks.
      *
-     * @return array filtered bookmarks.
+     * @return Bookmark[] filtered bookmarks.
      */
-    public function filterUntagged($visibility)
+    public function filterUntagged(string $visibility)
     {
         $filtered = [];
         foreach ($this->bookmarks as $key => $link) {
@@ -425,21 +437,26 @@ class BookmarkFilter
      *  print_r($mydb->filterDay('20120125'));
      *
      * @param string $day day to filter.
-     *
-     * @return array all link matching given day.
+     * @param string $visibility return only all/private/public bookmarks.
+
+     * @return Bookmark[] all link matching given day.
      *
      * @throws Exception if date format is invalid.
      */
-    public function filterDay($day)
+    public function filterDay(string $day, string $visibility)
     {
         if (!checkDateFormat('Ymd', $day)) {
             throw new Exception('Invalid date format');
         }
 
-        $filtered = array();
-        foreach ($this->bookmarks as $key => $l) {
-            if ($l->getCreated()->format('Ymd') == $day) {
-                $filtered[$key] = $l;
+        $filtered = [];
+        foreach ($this->bookmarks as $key => $bookmark) {
+            if ($visibility === static::$PUBLIC && $bookmark->isPrivate()) {
+                continue;
+            }
+
+            if ($bookmark->getCreated()->format('Ymd') == $day) {
+                $filtered[$key] = $bookmark;
             }
         }
 
@@ -455,9 +472,9 @@ class BookmarkFilter
      * @param string $tags          string containing a list of tags.
      * @param bool   $casesensitive will convert everything to lowercase if false.
      *
-     * @return array filtered tags string.
+     * @return string[] filtered tags string.
      */
-    public static function tagsStrToArray($tags, $casesensitive)
+    public static function tagsStrToArray(string $tags, bool $casesensitive): array
     {
         // We use UTF-8 conversion to handle various graphemes (i.e. cyrillic, or greek)
         $tagsOut = $casesensitive ? $tags : mb_convert_case($tags, MB_CASE_LOWER, 'UTF-8');
@@ -465,4 +482,74 @@ class BookmarkFilter
 
         return preg_split('/\s+/', $tagsOut, -1, PREG_SPLIT_NO_EMPTY);
     }
+
+    /**
+     * This method finalize the content of the foundPositions array,
+     * by associated all search results to their associated bookmark field,
+     * making sure that there is no overlapping results, etc.
+     *
+     * @param array $fieldLengths   Start and end positions of every bookmark fields in the aggregated bookmark content.
+     * @param array $foundPositions Positions where the search results were found in the aggregated content.
+     *
+     * @return array Updated $foundPositions, by bookmark field.
+     */
+    protected function postProcessFoundPositions(array $fieldLengths, array $foundPositions): array
+    {
+        // Sort results by starting position ASC.
+        usort($foundPositions, function (array $entryA, array $entryB): int {
+            return $entryA['start'] > $entryB['start'] ? 1 : -1;
+        });
+
+        $out = [];
+        $currentMax = -1;
+        foreach ($foundPositions as $foundPosition) {
+            // we do not allow overlapping highlights
+            if ($foundPosition['start'] < $currentMax) {
+                continue;
+            }
+
+            $currentMax = $foundPosition['end'];
+            foreach ($fieldLengths as $part => $length) {
+                if ($foundPosition['start'] < $length['start'] || $foundPosition['start'] > $length['end']) {
+                    continue;
+                }
+
+                $out[$part][] = [
+                    'start' => $foundPosition['start'] - $length['start'],
+                    'end' => $foundPosition['end'] - $length['start'],
+                ];
+                break;
+            }
+        }
+
+        return $out;
+    }
+
+    /**
+     * Concatenate link fields to search across fields. Adds a '\' separator for exact search terms.
+     * Also populate $length array with starting and ending positions of every bookmark field
+     * inside concatenated content.
+     *
+     * @param Bookmark $link
+     * @param array    $lengths (by reference)
+     *
+     * @return string Lowercase concatenated fields content.
+     */
+    protected function buildFullTextSearchableLink(Bookmark $link, array &$lengths): string
+    {
+        $content  = mb_convert_case($link->getTitle(), MB_CASE_LOWER, 'UTF-8') .'\\';
+        $content .= mb_convert_case($link->getDescription(), MB_CASE_LOWER, 'UTF-8') .'\\';
+        $content .= mb_convert_case($link->getUrl(), MB_CASE_LOWER, 'UTF-8') .'\\';
+        $content .= mb_convert_case($link->getTagsString(), MB_CASE_LOWER, 'UTF-8') .'\\';
+
+        $lengths['title'] = ['start' => 0, 'end' => mb_strlen($link->getTitle())];
+        $nextField = $lengths['title']['end'] + 1;
+        $lengths['description'] = ['start' => $nextField, 'end' => $nextField + mb_strlen($link->getDescription())];
+        $nextField = $lengths['description']['end'] + 1;
+        $lengths['url'] = ['start' => $nextField, 'end' => $nextField + mb_strlen($link->getUrl())];
+        $nextField = $lengths['url']['end'] + 1;
+        $lengths['tags'] = ['start' => $nextField, 'end' => $nextField + mb_strlen($link->getTagsString())];
+
+        return $content;
+    }
 }
diff --git a/application/bookmark/BookmarkIO.php b/application/bookmark/BookmarkIO.php
index ae9ffcb4..f40fa476 100644
--- a/application/bookmark/BookmarkIO.php
+++ b/application/bookmark/BookmarkIO.php
@@ -1,7 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Shaarli\Bookmark;
 
+use malkusch\lock\mutex\Mutex;
+use malkusch\lock\mutex\NoMutex;
+use Shaarli\Bookmark\Exception\DatastoreNotInitializedException;
 use Shaarli\Bookmark\Exception\EmptyDataStoreException;
 use Shaarli\Bookmark\Exception\NotWritableDataStoreException;
 use Shaarli\Config\ConfigManager;
@@ -26,11 +31,14 @@ class BookmarkIO
      */
     protected $conf;
 
+
+    /** @var Mutex */
+    protected $mutex;
+
     /**
      * string Datastore PHP prefix
      */
     protected static $phpPrefix = '<?php /* ';
-
     /**
      * string Datastore PHP suffix
      */
@@ -41,35 +49,46 @@ class BookmarkIO
      *
      * @param ConfigManager $conf instance
      */
-    public function __construct($conf)
+    public function __construct(ConfigManager $conf, Mutex $mutex = null)
     {
+        if ($mutex === null) {
+            // This should only happen with legacy classes
+            $mutex = new NoMutex();
+        }
         $this->conf = $conf;
         $this->datastore = $conf->get('resource.datastore');
+        $this->mutex = $mutex;
     }
 
     /**
      * Reads database from disk to memory
      *
-     * @return BookmarkArray instance
+     * @return Bookmark[]
      *
-     * @throws NotWritableDataStoreException Data couldn't be loaded
-     * @throws EmptyDataStoreException       Datastore doesn't exist
+     * @throws NotWritableDataStoreException    Data couldn't be loaded
+     * @throws EmptyDataStoreException          Datastore file exists but does not contain any bookmark
+     * @throws DatastoreNotInitializedException File does not exists
      */
     public function read()
     {
         if (! file_exists($this->datastore)) {
-            throw new EmptyDataStoreException();
+            throw new DatastoreNotInitializedException();
         }
 
         if (!is_writable($this->datastore)) {
             throw new NotWritableDataStoreException($this->datastore);
         }
 
+        $content = null;
+        $this->mutex->synchronized(function () use (&$content) {
+            $content = file_get_contents($this->datastore);
+        });
+
         // Note that gzinflate is faster than gzuncompress.
         // See: http://www.php.net/manual/en/function.gzdeflate.php#96439
         $links = unserialize(gzinflate(base64_decode(
-            substr(file_get_contents($this->datastore),
-                strlen(self::$phpPrefix), -strlen(self::$phpSuffix)))));
+            substr($content, strlen(self::$phpPrefix), -strlen(self::$phpSuffix))
+        )));
 
         if (empty($links)) {
             if (filesize($this->datastore) > 100) {
@@ -84,7 +103,7 @@ class BookmarkIO
     /**
      * Saves the database from memory to disk
      *
-     * @param BookmarkArray $links instance.
+     * @param Bookmark[] $links
      *
      * @throws NotWritableDataStoreException the datastore is not writable
      */
@@ -98,11 +117,13 @@ class BookmarkIO
             throw new NotWritableDataStoreException(dirname($this->datastore));
         }
 
-        file_put_contents(
-            $this->datastore,
-            self::$phpPrefix.base64_encode(gzdeflate(serialize($links))).self::$phpSuffix
-        );
+        $data = self::$phpPrefix.base64_encode(gzdeflate(serialize($links))).self::$phpSuffix;
 
-        invalidateCaches($this->conf->get('resource.page_cache'));
+        $this->mutex->synchronized(function () use ($data) {
+            file_put_contents(
+                $this->datastore,
+                $data
+            );
+        });
     }
 }
diff --git a/application/bookmark/BookmarkInitializer.php b/application/bookmark/BookmarkInitializer.php
index 9eee9a35..04b996f3 100644
--- a/application/bookmark/BookmarkInitializer.php
+++ b/application/bookmark/BookmarkInitializer.php
@@ -1,13 +1,14 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Shaarli\Bookmark;
 
 /**
  * Class BookmarkInitializer
  *
  * This class is used to initialized default bookmarks after a fresh install of Shaarli.
- * It is no longer call when the data store is empty,
- * because user might want to delete default bookmarks after the install.
+ * It should be only called if the datastore file does not exist(users might want to delete the default bookmarks).
  *
  * To prevent data corruption, it does not overwrite existing bookmarks,
  * even though there should not be any.
@@ -24,7 +25,7 @@ class BookmarkInitializer
      *
      * @param BookmarkServiceInterface $bookmarkService
      */
-    public function __construct($bookmarkService)
+    public function __construct(BookmarkServiceInterface $bookmarkService)
     {
         $this->bookmarkService = $bookmarkService;
     }
@@ -32,28 +33,80 @@ class BookmarkInitializer
     /**
      * Initialize the data store with default bookmarks
      */
-    public function initialize()
+    public function initialize(): void
     {
         $bookmark = new Bookmark();
-        $bookmark->setTitle(t('My secret stuff... - Pastebin.com'));
-        $bookmark->setUrl('http://sebsauvage.net/paste/?8434b27936c09649#bR7XsXhoTiLcqCpQbmOpBi3rq2zzQUC5hBI7ZT1O3x8=', []);
-        $bookmark->setDescription(t('Shhhh! I\'m a private link only YOU can see. You can delete me too.'));
-        $bookmark->setTagsString('secretstuff');
+        $bookmark->setTitle('quicksilver (loop) on Vimeo ' . t('(private bookmark with thumbnail demo)'));
+        $bookmark->setUrl('https://vimeo.com/153493904');
+        $bookmark->setDescription(t(
+'Shaarli will automatically pick up the thumbnail for links to a variety of websites.
+
+Explore your new Shaarli instance by trying out controls and menus.
+Visit the project on [Github](https://github.com/shaarli/Shaarli) or [the documentation](https://shaarli.readthedocs.io/en/master/) to learn more about Shaarli.
+
+Now you can edit or delete the default shaares.
+'
+        ));
+        $bookmark->setTagsString('shaarli help thumbnail');
+        $bookmark->setPrivate(true);
+        $this->bookmarkService->add($bookmark, false);
+
+        $bookmark = new Bookmark();
+        $bookmark->setTitle(t('Note: Shaare descriptions'));
+        $bookmark->setDescription(t(
+'Adding a shaare without entering a URL creates a text-only "note" post such as this one.
+This note is private, so you are the only one able to see it while logged in.
+
+You can use this to keep notes, post articles, code snippets, and much more.
+
+The Markdown formatting setting allows you to format your notes and bookmark description:
+
+### Title headings
+
+#### Multiple headings levels
+  * bullet lists
+  * _italic_ text
+  * **bold** text
+  * ~~strike through~~ text
+  * `code` blocks
+  * images
+  * [links](https://en.wikipedia.org/wiki/Markdown)
+
+Markdown also supports tables:
+
+| Name    | Type      | Color  | Qty   |
+| ------- | --------- | ------ | ----- |
+| Orange  | Fruit     | Orange | 126   |
+| Apple   | Fruit     | Any    | 62    |
+| Lemon   | Fruit     | Yellow | 30    |
+| Carrot  | Vegetable | Red    | 14    |
+'
+        ));
+        $bookmark->setTagsString('shaarli help');
         $bookmark->setPrivate(true);
-        $this->bookmarkService->add($bookmark);
+        $this->bookmarkService->add($bookmark, false);
 
         $bookmark = new Bookmark();
-        $bookmark->setTitle(t('The personal, minimalist, super-fast, database free, bookmarking service'));
-        $bookmark->setUrl('https://shaarli.readthedocs.io', []);
+        $bookmark->setTitle(
+            'Shaarli - ' . t('The personal, minimalist, super-fast, database free, bookmarking service')
+        );
         $bookmark->setDescription(t(
-            'Welcome to Shaarli! This is your first public bookmark. '
-            . 'To edit or delete me, you must first login.
+'Welcome to Shaarli!
+
+Shaarli allows you to bookmark your favorite pages, and share them with others or store them privately.
+You can add a description to your bookmarks, such as this one, and tag them.
+
+Create a new shaare by clicking the `+Shaare` button, or using any of the recommended tools (browser extension, mobile app, bookmarklet, REST API, etc.).
 
-To learn how to use Shaarli, consult the link "Documentation" at the bottom of this page.
+You can easily retrieve your links, even with thousands of them, using the internal search engine, or search through tags (e.g. this Shaare is tagged with `shaarli` and `help`).
+Hashtags such as #shaarli #help are also supported.
+You can also filter the available [RSS feed](/feed/atom) and picture wall by tag or plaintext search.
 
-You use the community supported version of the original Shaarli project, by Sebastien Sauvage.'
+We hope that you will enjoy using Shaarli, maintained with ❤️ by the community!
+Feel free to open [an issue](https://github.com/shaarli/Shaarli/issues) if you have a suggestion or encounter an issue.
+'
         ));
-        $bookmark->setTagsString('opensource software');
-        $this->bookmarkService->add($bookmark);
+        $bookmark->setTagsString('shaarli help');
+        $this->bookmarkService->add($bookmark, false);
     }
 }
diff --git a/application/bookmark/BookmarkServiceInterface.php b/application/bookmark/BookmarkServiceInterface.php
index 7b7a4f09..08cdbb4e 100644
--- a/application/bookmark/BookmarkServiceInterface.php
+++ b/application/bookmark/BookmarkServiceInterface.php
@@ -1,73 +1,73 @@
 <?php
 
-namespace Shaarli\Bookmark;
+declare(strict_types=1);
 
+namespace Shaarli\Bookmark;
 
 use Shaarli\Bookmark\Exception\BookmarkNotFoundException;
 use Shaarli\Bookmark\Exception\NotWritableDataStoreException;
-use Shaarli\Config\ConfigManager;
-use Shaarli\Exceptions\IOException;
-use Shaarli\History;
 
 /**
  * Class BookmarksService
  *
  * This is the entry point to manipulate the bookmark DB.
+ *
+ * Regarding return types of a list of bookmarks, it can either be an array or an ArrayAccess implementation,
+ * so until PHP 8.0 is the minimal supported version with union return types it cannot be explicitly added.
  */
 interface BookmarkServiceInterface
 {
     /**
-     * BookmarksService constructor.
-     *
-     * @param ConfigManager $conf       instance
-     * @param History       $history    instance
-     * @param bool          $isLoggedIn true if the current user is logged in
-     */
-    public function __construct(ConfigManager $conf, History $history, $isLoggedIn);
-
-    /**
      * Find a bookmark by hash
      *
-     * @param string $hash
+     * @param string      $hash       Bookmark's hash
+     * @param string|null $privateKey Optional key used to access private links while logged out
      *
-     * @return mixed
+     * @return Bookmark
      *
      * @throws \Exception
      */
-    public function findByHash($hash);
+    public function findByHash(string $hash, string $privateKey = null);
 
     /**
      * @param $url
      *
      * @return Bookmark|null
      */
-    public function findByUrl($url);
+    public function findByUrl(string $url): ?Bookmark;
 
     /**
      * Search bookmarks
      *
-     * @param mixed  $request
-     * @param string $visibility
-     * @param bool   $caseSensitive
-     * @param bool   $untaggedOnly
+     * @param array   $request
+     * @param ?string $visibility
+     * @param bool    $caseSensitive
+     * @param bool    $untaggedOnly
+     * @param bool    $ignoreSticky
      *
      * @return Bookmark[]
      */
-    public function search($request = [], $visibility = null, $caseSensitive = false, $untaggedOnly = false);
+    public function search(
+        array $request = [],
+        string $visibility = null,
+        bool $caseSensitive = false,
+        bool $untaggedOnly = false,
+        bool $ignoreSticky = false
+    );
 
     /**
      * Get a single bookmark by its ID.
      *
-     * @param int    $id         Bookmark ID
-     * @param string $visibility all|public|private e.g. with public, accessing a private bookmark will throw an
-     *                           exception
+     * @param int    $id          Bookmark ID
+     * @param ?string $visibility all|public|private e.g. with public, accessing a private bookmark will throw an
+     *                            exception
      *
      * @return Bookmark
      *
      * @throws BookmarkNotFoundException
      * @throws \Exception
      */
-    public function get($id, $visibility = null);
+    public function get(int $id, string $visibility = null);
 
     /**
      * Updates an existing bookmark (depending on its ID).
@@ -80,7 +80,7 @@ interface BookmarkServiceInterface
      * @throws BookmarkNotFoundException
      * @throws \Exception
      */
-    public function set($bookmark, $save = true);
+    public function set(Bookmark $bookmark, bool $save = true): Bookmark;
 
     /**
      * Adds a new bookmark (the ID must be empty).
@@ -92,7 +92,7 @@ interface BookmarkServiceInterface
      *
      * @throws \Exception
      */
-    public function add($bookmark, $save = true);
+    public function add(Bookmark $bookmark, bool $save = true): Bookmark;
 
     /**
      * Adds or updates a bookmark depending on its ID:
@@ -106,7 +106,7 @@ interface BookmarkServiceInterface
      *
      * @throws \Exception
      */
-    public function addOrSet($bookmark, $save = true);
+    public function addOrSet(Bookmark $bookmark, bool $save = true): Bookmark;
 
     /**
      * Deletes a bookmark.
@@ -116,65 +116,72 @@ interface BookmarkServiceInterface
      *
      * @throws \Exception
      */
-    public function remove($bookmark, $save = true);
+    public function remove(Bookmark $bookmark, bool $save = true): void;
 
     /**
      * Get a single bookmark by its ID.
      *
-     * @param int    $id         Bookmark ID
-     * @param string $visibility all|public|private e.g. with public, accessing a private bookmark will throw an
-     *                           exception
+     * @param int     $id         Bookmark ID
+     * @param ?string $visibility all|public|private e.g. with public, accessing a private bookmark will throw an
+     *                            exception
      *
      * @return bool
      */
-    public function exists($id, $visibility = null);
+    public function exists(int $id, string $visibility = null): bool;
 
     /**
      * Return the number of available bookmarks for given visibility.
      *
-     * @param string $visibility public|private|all
+     * @param ?string $visibility public|private|all
      *
      * @return int Number of bookmarks
      */
-    public function count($visibility = null);
+    public function count(string $visibility = null): int;
 
     /**
      * Write the datastore.
      *
      * @throws NotWritableDataStoreException
      */
-    public function save();
+    public function save(): void;
 
     /**
      * Returns the list tags appearing in the bookmarks with the given tags
      *
-     * @param array  $filteringTags tags selecting the bookmarks to consider
-     * @param string $visibility    process only all/private/public bookmarks
+     * @param array|null  $filteringTags tags selecting the bookmarks to consider
+     * @param string|null $visibility    process only all/private/public bookmarks
      *
      * @return array tag => bookmarksCount
      */
-    public function bookmarksCountPerTag($filteringTags = [], $visibility = 'all');
+    public function bookmarksCountPerTag(array $filteringTags = [], ?string $visibility = null): array;
 
     /**
-     * Returns the list of days containing articles (oldest first)
+     * Return a list of bookmark matching provided period of time.
+     * It also update directly previous and next date outside of given period found in the datastore.
+     *
+     * @param \DateTimeInterface      $from     Starting date.
+     * @param \DateTimeInterface      $to       Ending date.
+     * @param \DateTimeInterface|null $previous (by reference) updated with first created date found before $from.
+     * @param \DateTimeInterface|null $next     (by reference) updated with first created date found after $to.
      *
-     * @return array containing days (in format YYYYMMDD).
+     * @return array List of bookmarks matching provided period of time.
      */
-    public function days();
+    public function findByDate(
+        \DateTimeInterface $from,
+        \DateTimeInterface $to,
+        ?\DateTimeInterface &$previous,
+        ?\DateTimeInterface &$next
+    ): array;
 
     /**
-     * Returns the list of articles for a given day.
+     * Returns the latest bookmark by creation date.
      *
-     * @param string $request day to filter. Format: YYYYMMDD.
-     *
-     * @return Bookmark[] list of shaare found.
-     *
-     * @throws BookmarkNotFoundException
+     * @return Bookmark|null Found Bookmark or null if the datastore is empty.
      */
-    public function filterDay($request);
+    public function getLatest(): ?Bookmark;
 
     /**
      * Creates the default database after a fresh install.
      */
-    public function initialize();
+    public function initialize(): void;
 }
diff --git a/application/bookmark/LinkUtils.php b/application/bookmark/LinkUtils.php
index 88379430..faf5dbfd 100644
--- a/application/bookmark/LinkUtils.php
+++ b/application/bookmark/LinkUtils.php
@@ -3,112 +3,6 @@
 use Shaarli\Bookmark\Bookmark;
 
 /**
- * Get cURL callback function for CURLOPT_WRITEFUNCTION
- *
- * @param string $charset     to extract from the downloaded page (reference)
- * @param string $title       to extract from the downloaded page (reference)
- * @param string $description to extract from the downloaded page (reference)
- * @param string $keywords    to extract from the downloaded page (reference)
- * @param bool   $retrieveDescription Automatically tries to retrieve description and keywords from HTML content
- * @param string $curlGetInfo Optionally overrides curl_getinfo function
- *
- * @return Closure
- */
-function get_curl_download_callback(
-    &$charset,
-    &$title,
-    &$description,
-    &$keywords,
-    $retrieveDescription,
-    $curlGetInfo = 'curl_getinfo'
-) {
-    $isRedirected = false;
-    $currentChunk = 0;
-    $foundChunk = null;
-
-    /**
-     * cURL callback function for CURLOPT_WRITEFUNCTION (called during the download).
-     *
-     * While downloading the remote page, we check that the HTTP code is 200 and content type is 'html/text'
-     * Then we extract the title and the charset and stop the download when it's done.
-     *
-     * @param resource $ch   cURL resource
-     * @param string   $data chunk of data being downloaded
-     *
-     * @return int|bool length of $data or false if we need to stop the download
-     */
-    return function (&$ch, $data) use (
-        $retrieveDescription,
-        $curlGetInfo,
-        &$charset,
-        &$title,
-        &$description,
-        &$keywords,
-        &$isRedirected,
-        &$currentChunk,
-        &$foundChunk
-    ) {
-        $currentChunk++;
-        $responseCode = $curlGetInfo($ch, CURLINFO_RESPONSE_CODE);
-        if (!empty($responseCode) && in_array($responseCode, [301, 302])) {
-            $isRedirected = true;
-            return strlen($data);
-        }
-        if (!empty($responseCode) && $responseCode !== 200) {
-            return false;
-        }
-        // After a redirection, the content type will keep the previous request value
-        // until it finds the next content-type header.
-        if (! $isRedirected || strpos(strtolower($data), 'content-type') !== false) {
-            $contentType = $curlGetInfo($ch, CURLINFO_CONTENT_TYPE);
-        }
-        if (!empty($contentType) && strpos($contentType, 'text/html') === false) {
-            return false;
-        }
-        if (!empty($contentType) && empty($charset)) {
-            $charset = header_extract_charset($contentType);
-        }
-        if (empty($charset)) {
-            $charset = html_extract_charset($data);
-        }
-        if (empty($title)) {
-            $title = html_extract_title($data);
-            $foundChunk = ! empty($title) ? $currentChunk : $foundChunk;
-        }
-        if ($retrieveDescription && empty($description)) {
-            $description = html_extract_tag('description', $data);
-            $foundChunk = ! empty($description) ? $currentChunk : $foundChunk;
-        }
-        if ($retrieveDescription && empty($keywords)) {
-            $keywords = html_extract_tag('keywords', $data);
-            if (! empty($keywords)) {
-                $foundChunk = $currentChunk;
-                // Keywords use the format tag1, tag2 multiple words, tag
-                // So we format them to match Shaarli's separator and glue multiple words with '-'
-                $keywords = implode(' ', array_map(function($keyword) {
-                    return implode('-', preg_split('/\s+/', trim($keyword)));
-                }, explode(',', $keywords)));
-            }
-        }
-
-        // We got everything we want, stop the download.
-        // If we already found either the title, description or keywords,
-        // it's highly unlikely that we'll found the other metas further than
-        // in the same chunk of data or the next one. So we also stop the download after that.
-        if ((!empty($responseCode) && !empty($contentType) && !empty($charset)) && $foundChunk !== null
-            && (! $retrieveDescription
-                || $foundChunk < $currentChunk
-                || (!empty($title) && !empty($description) && !empty($keywords))
-            )
-        ) {
-            return false;
-        }
-
-        return strlen($data);
-    };
-}
-
-/**
  * Extract title from an HTML document.
  *
  * @param string $html HTML content where to look for a title.
@@ -132,7 +26,7 @@ function html_extract_title($html)
  */
 function header_extract_charset($header)
 {
-    preg_match('/charset="?([^; ]+)/i', $header, $match);
+    preg_match('/charset=["\']?([^; "\']+)/i', $header, $match);
     if (! empty($match[1])) {
         return strtolower(trim($match[1]));
     }
@@ -172,11 +66,13 @@ function html_extract_tag($tag, $html)
 {
     $propertiesKey = ['property', 'name', 'itemprop'];
     $properties = implode('|', $propertiesKey);
+    // We need a OR here to accept either 'property=og:noquote' or 'property="og:unrelated og:my-tag"'
+    $orCondition  = '["\']?(?:og:)?'. $tag .'["\']?|["\'][^\'"]*?(?:og:)?' . $tag . '[^\'"]*?[\'"]';
     // Try to retrieve OpenGraph image.
-    $ogRegex = '#<meta[^>]+(?:'. $properties .')=["\']?(?:og:)?'. $tag .'["\'\s][^>]*content=["\']?(.*?)["\'/>]#';
+    $ogRegex = '#<meta[^>]+(?:'. $properties .')=(?:'. $orCondition .')[^>]*content=["\'](.*?)["\'].*?>#';
     // If the attributes are not in the order property => content (e.g. Github)
     // New regex to keep this readable... more or less.
-    $ogRegexReverse = '#<meta[^>]+content=["\']([^"\']+)[^>]+(?:'. $properties .')=["\']?(?:og)?:'. $tag .'["\'\s/>]#';
+    $ogRegexReverse = '#<meta[^>]+content=["\'](.*?)["\'][^>]+(?:'. $properties .')=(?:'. $orCondition .').*?>#';
 
     if (preg_match($ogRegex, $html, $matches) > 0
         || preg_match($ogRegexReverse, $html, $matches) > 0
@@ -220,7 +116,7 @@ function hashtag_autolink($description, $indexUrl = '')
      * \p{Mn} - any non marking space (accents, umlauts, etc)
      */
     $regex = '/(^|\s)#([\p{Pc}\p{N}\p{L}\p{Mn}]+)/mui';
-    $replacement = '$1<a href="'. $indexUrl .'?addtag=$2" title="Hashtag $2">#$2</a>';
+    $replacement = '$1<a href="'. $indexUrl .'./add-tag/$2" title="Hashtag $2">#$2</a>';
     return preg_replace($regex, $replacement, $description);
 }
 
diff --git a/application/bookmark/exception/DatastoreNotInitializedException.php b/application/bookmark/exception/DatastoreNotInitializedException.php
new file mode 100644
index 00000000..f495049d
--- /dev/null
+++ b/application/bookmark/exception/DatastoreNotInitializedException.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shaarli\Bookmark\Exception;
+
+class DatastoreNotInitializedException extends \Exception
+{
+
+}