Empty tag search will look for not tagged links

Fixes #784

From now, searching for tags with an empty value will return only not tagged links,
with the search bar showing `x results [not tagged]`.

Note that using the api, the searchtags request parameter must be set to `false` to get the same result.

  - [ ] Update API doc

4 files changed, 44 insertions, 22 deletions

diff --git a/application/FeedBuilder.php b/application/FeedBuilder.php
index a1f4da48..7377bcec 100644
--- a/application/FeedBuilder.php
+++ b/application/FeedBuilder.php
@@ -97,6 +97,11 @@ class FeedBuilder
      */
     public function buildData()
     {
+        // Search for untagged links
+        if (isset($this->userInput['searchtags']) && empty($this->userInput['searchtags'])) {
+            $this->userInput['searchtags'] = false;
+        }
+
         // Optionally filter the results:
         $linksToDisplay = $this->linkDB->filterSearch($this->userInput);
 
diff --git a/application/LinkDB.php b/application/LinkDB.php
index 4cee2af9..a03c2c06 100644
--- a/application/LinkDB.php
+++ b/application/LinkDB.php
@@ -450,29 +450,12 @@ You use the community supported version of the original Shaarli project, by Seba
     public function filterSearch($filterRequest = array(), $casesensitive = false, $visibility = 'all')
     {
         // Filter link database according to parameters.
-        $searchtags = !empty($filterRequest['searchtags']) ? escape($filterRequest['searchtags']) : '';
-        $searchterm = !empty($filterRequest['searchterm']) ? escape($filterRequest['searchterm']) : '';
+        $searchtags = isset($filterRequest['searchtags']) ? escape($filterRequest['searchtags']) : '';
+        $searchterm = isset($filterRequest['searchterm']) ? escape($filterRequest['searchterm']) : '';
 
-        // Search tags + fullsearch.
-        if (! empty($searchtags) && ! empty($searchterm)) {
-            $type = LinkFilter::$FILTER_TAG | LinkFilter::$FILTER_TEXT;
-            $request = array($searchtags, $searchterm);
-        }
-        // Search by tags.
-        elseif (! empty($searchtags)) {
-            $type = LinkFilter::$FILTER_TAG;
-            $request = $searchtags;
-        }
-        // Fulltext search.
-        elseif (! empty($searchterm)) {
-            $type = LinkFilter::$FILTER_TEXT;
-            $request = $searchterm;
-        }
-        // Otherwise, display without filtering.
-        else {
-            $type = '';
-            $request = '';
-        }
+        // Search tags + fullsearch - blank string parameter will return all links.
+        $type = LinkFilter::$FILTER_TAG | LinkFilter::$FILTER_TEXT;
+        $request = [$searchtags, $searchterm];
 
         $linkFilter = new LinkFilter($this);
         return $linkFilter->filter($type, $request, $casesensitive, $visibility);
diff --git a/application/LinkFilter.php b/application/LinkFilter.php
index 81832a4b..0e887d38 100644
--- a/application/LinkFilter.php
+++ b/application/LinkFilter.php
@@ -253,6 +253,9 @@ class LinkFilter
     {
         // Implode if array for clean up.
         $tags = is_array($tags) ? trim(implode(' ', $tags)) : $tags;
+        if ($tags === false) {
+            return $this->filterUntagged($visibility);
+        }
         if (empty($tags)) {
             return $this->noFilter($visibility);
         }
@@ -296,6 +299,33 @@ class LinkFilter
     }
 
     /**
+     * Return only links without any tag.
+     *
+     * @param string $visibility return only all/private/public links.
+     *
+     * @return array filtered links.
+     */
+    public function filterUntagged($visibility)
+    {
+        $filtered = [];
+        foreach ($this->links as $key => $link) {
+            if ($visibility !== 'all') {
+                if (! $link['private'] && $visibility === 'private') {
+                    continue;
+                } else if ($link['private'] && $visibility === 'public') {
+                    continue;
+                }
+            }
+
+            if (empty(trim($link['tags']))) {
+                $filtered[$key] = $link;
+            }
+        }
+
+        return $filtered;
+    }
+
+    /**
      * Returns the list of articles for a given day, chronologically sorted
      *
      * Day must be in the form 'YYYYMMDD' (e.g. '20120125'), e.g.
diff --git a/application/Utils.php b/application/Utils.php
index 5c077450..87e5cc8f 100644
--- a/application/Utils.php
+++ b/application/Utils.php
@@ -91,6 +91,10 @@ function endsWith($haystack, $needle, $case = true)
  */
 function escape($input)
 {
+    if (is_bool($input)) {
+        return $input;
+    }
+
     if (is_array($input)) {
         $out = array();
         foreach($input as $key => $value) {