Add item bookmark buttons (#14)

Implemented as a toggle button

- Move init_cap func where web can see it
- Bump version to alpha7

src/public/bookmark.php

@@ -0,0 +1,49 @@
+<?php
+
+/**
+ * Bookmark Partial Handler
+ *
+ * This will display a button which will either add or remove a bookmark for a given item.
+ */
+
+include '../start.php';
+
+$db = Data::getConnection();
+Security::verifyUser($db);
+
+$id = $_GET['id'];
+
+$existsQuery = $db->prepare(
+    'SELECT item.id FROM item INNER JOIN feed ON feed.id = item.feed_id WHERE item.id = :id AND feed.user_id = :user');
+$existsQuery->bindValue(':id',   $id);
+$existsQuery->bindValue(':user', $_SESSION[Key::USER_ID]);
+$existsResult = $existsQuery->execute();
+$exists = $existsResult ? $existsResult->fetchArray(SQLITE3_ASSOC) : false;
+
+if (!$exists) not_found();
+
+if (key_exists('action', $_GET)) {
+    if ($_GET['action'] == 'add') {
+        $flag = 1;
+    } elseif ($_GET['action'] == 'remove') {
+        $flag = 0;
+    }
+    if (isset($flag)) {
+        $update = $db->prepare('UPDATE item SET is_bookmarked = :flag WHERE id = :id');
+        $update->bindValue(':id',   $id);
+        $update->bindValue(':flag', $flag);
+        if (!$update->execute()) die(Data::error($db)['error']);
+    }
+}
+
+$bookQuery = $db->prepare('SELECT id, is_bookmarked FROM item WHERE id = :id');
+$bookQuery->bindValue(':id', $id);
+$bookResult = $bookQuery->execute();
+$bookmark = $bookResult ? $bookResult->fetchArray(SQLITE3_ASSOC) : ['id' => $id, 'is_bookmarked' => 0];
+
+$action = $bookmark['is_bookmarked'] ? 'remove' : 'add';
+$icon   = $bookmark['is_bookmarked'] ? 'added'  : 'add'; ?>
+<button class="bookmark <?=$action?>" type=button role=button hx-patch="/bookmark?id=<?=$id?>&action=<?=$action?>"
+        hx-target=this hx-swap=outerHTML hx-push-url=false title="<?=init_cap($action)?> Bookmark">
+    <img src=/assets/bookmark-<?=$icon?>.png alt="<?=$action?> bookmark">
+</button><?php