Add 'reading ease' and 'length' sorting methods

lib/Constants.php

@@ -4,6 +4,8 @@
 const EBOOKS_PER_PAGE = 12;
 const SORT_NEWEST = 'newest';
 const SORT_AUTHOR_ALPHA = 'author-alpha';
+const SORT_READING_EASE = 'reading-ease';
+const SORT_LENGTH = 'length';
 
 const GET = 0;
 const POST = 1;

lib/Library.php

@@ -50,6 +50,56 @@ class Library{
 				}
 				break;
 
+			case SORT_READING_EASE:
+				// Get all ebooks, sorted by easiest first.
+				try{
+					$ebooks = apcu_fetch('ebooks-reading-ease');
+				}
+				catch(Safe\Exceptions\ApcuException $ex){
+					$ebooks = Library::GetEbooks();
+
+					usort($ebooks, function($a, $b){
+						if($a->ReadingEase < $b->ReadingEase){
+							return -1;
+						}
+						elseif($a->ReadingEase == $b->ReadingEase){
+							return 0;
+						}
+						else{
+							return 1;
+						}
+					});
+
+					$ebooks = array_reverse($ebooks);
+
+					apcu_store('ebooks-reading-ease', $ebooks);
+				}
+				break;
+
+			case SORT_LENGTH:
+				// Get all ebooks, sorted by fewest words first.
+				try{
+					$ebooks = apcu_fetch('ebooks-length');
+				}
+				catch(Safe\Exceptions\ApcuException $ex){
+					$ebooks = Library::GetEbooks();
+
+					usort($ebooks, function($a, $b){
+						if($a->WordCount < $b->WordCount){
+							return -1;
+						}
+						elseif($a->WordCount == $b->WordCount){
+							return 0;
+						}
+						else{
+							return 1;
+						}
+					});
+
+					apcu_store('ebooks-length', $ebooks);
+				}
+				break;
+
 			default:
 				// Get all ebooks, unsorted.
 				try{

www/ebooks/index.php

@@ -16,7 +16,7 @@ try{
 		$page = 1;
 	}
 
-	if($sort != SORT_AUTHOR_ALPHA && $sort != SORT_NEWEST){
+	if($sort != SORT_AUTHOR_ALPHA && $sort != SORT_NEWEST && $sort != SORT_READING_EASE && $sort != SORT_LENGTH){
 		$sort = SORT_NEWEST;
 	}
 
@@ -72,6 +72,12 @@ try{
 			case SORT_AUTHOR_ALPHA:
 				$pageDescription .= 'alphabetically by author name.';
 				break;
+			case SORT_READING_EASE:
+				$pageDescription .= 'by easiest ebooks first.';
+				break;
+			case SORT_LENGTH:
+				$pageDescription .= 'by shortest ebooks first.';
+				break;
 		}
 	}
 }