Merge branch 'main' into issue-3911issue-3911

34 files changed, 78 insertions, 166 deletions

diff --git a/lib/models/Courseware/BlockTypes/Audio.php b/lib/models/Courseware/BlockTypes/Audio.php
index dd2588a..22dc167 100644
--- a/lib/models/Courseware/BlockTypes/Audio.php
+++ b/lib/models/Courseware/BlockTypes/Audio.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware audio block.
  *
@@ -42,11 +40,10 @@ class Audio extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Audio.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     /**
diff --git a/lib/models/Courseware/BlockTypes/BeforeAfter.php b/lib/models/Courseware/BlockTypes/BeforeAfter.php
index b4f33ca..e174bff 100644
--- a/lib/models/Courseware/BlockTypes/BeforeAfter.php
+++ b/lib/models/Courseware/BlockTypes/BeforeAfter.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware before after block.
  *
@@ -41,11 +39,10 @@ class BeforeAfter extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/BeforeAfter.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     /**
diff --git a/lib/models/Courseware/BlockTypes/BiographyAchievements.php b/lib/models/Courseware/BlockTypes/BiographyAchievements.php
index 3af5d64..2f8aeb7 100644
--- a/lib/models/Courseware/BlockTypes/BiographyAchievements.php
+++ b/lib/models/Courseware/BlockTypes/BiographyAchievements.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware biography achievements block.
  *
@@ -57,11 +55,10 @@ class BiographyAchievements extends BlockType
         parent::setPayload($payload);
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/BiographyAchievements.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/BiographyCareer.php b/lib/models/Courseware/BlockTypes/BiographyCareer.php
index ebd1a85..9425cfe 100644
--- a/lib/models/Courseware/BlockTypes/BiographyCareer.php
+++ b/lib/models/Courseware/BlockTypes/BiographyCareer.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware biography career block.
  *
@@ -48,11 +46,11 @@ class BiographyCareer extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/BiographyCareer.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/BiographyGoals.php b/lib/models/Courseware/BlockTypes/BiographyGoals.php
index dcfb76c..b4f1b64 100644
--- a/lib/models/Courseware/BlockTypes/BiographyGoals.php
+++ b/lib/models/Courseware/BlockTypes/BiographyGoals.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware biography personal goals block.
  *
@@ -53,11 +51,11 @@ class BiographyGoals extends BlockType
         parent::setPayload($payload);
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/BiographyGoals.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/BiographyPersonalInformation.php b/lib/models/Courseware/BlockTypes/BiographyPersonalInformation.php
index 8f3c0c1..bb11f53 100644
--- a/lib/models/Courseware/BlockTypes/BiographyPersonalInformation.php
+++ b/lib/models/Courseware/BlockTypes/BiographyPersonalInformation.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware biography personal information block.
  *
@@ -41,11 +39,11 @@ class BiographyPersonalInformation extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/BiographyPersonalInformation.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/BlockType.php b/lib/models/Courseware/BlockTypes/BlockType.php
index b3d5abf..37e617b 100644
--- a/lib/models/Courseware/BlockTypes/BlockType.php
+++ b/lib/models/Courseware/BlockTypes/BlockType.php
@@ -3,7 +3,6 @@
 namespace Courseware\BlockTypes;
 
 use Courseware\CoursewarePlugin;
-use Opis\JsonSchema\Schema;
 use Opis\JsonSchema\Validator;
 
 /**
@@ -52,9 +51,9 @@ abstract class BlockType
      * Returns the JSON schema which is used to validate the payload of
      * instances of this type of block.
      *
-     * @return Schema the JSON schema to be used
+     * @return string the JSON schema to be used
      */
-    abstract public static function getJsonSchema(): Schema;
+    abstract public static function getJsonSchema(): string;
 
     /**
      * Returns a list of categories to which this type of block is associated.
@@ -192,10 +191,8 @@ abstract class BlockType
      */
     public function validatePayload($payload): bool
     {
-        $schema = static::getJsonSchema();
         $validator = new Validator();
-        $result = $validator->schemaValidation($payload, $schema);
-
+        $result = $validator->validate($payload, static::getJsonSchema());
         return $result->isValid();
     }
 
@@ -441,9 +438,9 @@ abstract class BlockType
      * It turns the classname into snakecase in order to find the
      * template file in templates/courseware/block_types.
      *
-     * @return mixed the \Flexi_Template instance if exists, otherwise null.
+     * @return \Flexi\Template|null the \Flexi\Template instance if exists, otherwise null.
      */
-    public function getPdfHtmlTemplate(): ?\Flexi_Template
+    public function getPdfHtmlTemplate(): ?\Flexi\Template
     {
         $template = null;
         try {
diff --git a/lib/models/Courseware/BlockTypes/Canvas.php b/lib/models/Courseware/BlockTypes/Canvas.php
index e7b14e9..cc2196a 100644
--- a/lib/models/Courseware/BlockTypes/Canvas.php
+++ b/lib/models/Courseware/BlockTypes/Canvas.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware canvas block.
  *
@@ -40,11 +38,11 @@ class Canvas extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Canvas.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     /**
diff --git a/lib/models/Courseware/BlockTypes/Chart.php b/lib/models/Courseware/BlockTypes/Chart.php
index 196e90f..147c3c5 100644
--- a/lib/models/Courseware/BlockTypes/Chart.php
+++ b/lib/models/Courseware/BlockTypes/Chart.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware chart block.
  *
@@ -38,11 +36,11 @@ class Chart extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Chart.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Code.php b/lib/models/Courseware/BlockTypes/Code.php
index 5b1454c..d5bd1c5 100644
--- a/lib/models/Courseware/BlockTypes/Code.php
+++ b/lib/models/Courseware/BlockTypes/Code.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware code block.
  *
@@ -37,11 +35,11 @@ class Code extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Code.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Confirm.php b/lib/models/Courseware/BlockTypes/Confirm.php
index bb6738d..2c25316 100644
--- a/lib/models/Courseware/BlockTypes/Confirm.php
+++ b/lib/models/Courseware/BlockTypes/Confirm.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware confirm block.
  *
@@ -36,11 +34,11 @@ class Confirm extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Confirm.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Date.php b/lib/models/Courseware/BlockTypes/Date.php
index 46e77d8..548e648 100644
--- a/lib/models/Courseware/BlockTypes/Date.php
+++ b/lib/models/Courseware/BlockTypes/Date.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware date block.
  *
@@ -37,11 +35,11 @@ class Date extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Date.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/DialogCards.php b/lib/models/Courseware/BlockTypes/DialogCards.php
index 74b843c..875a0b3 100644
--- a/lib/models/Courseware/BlockTypes/DialogCards.php
+++ b/lib/models/Courseware/BlockTypes/DialogCards.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware dialog cards block.
  *
@@ -96,11 +94,11 @@ class DialogCards extends BlockType
         return $payload;
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/DialogCards.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Document.php b/lib/models/Courseware/BlockTypes/Document.php
index db1ba6e..562ec08 100644
--- a/lib/models/Courseware/BlockTypes/Document.php
+++ b/lib/models/Courseware/BlockTypes/Document.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware document block.
  *
@@ -39,11 +37,10 @@ class Document extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Document.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     /**
diff --git a/lib/models/Courseware/BlockTypes/Download.php b/lib/models/Courseware/BlockTypes/Download.php
index d736009..e7bb65c 100644
--- a/lib/models/Courseware/BlockTypes/Download.php
+++ b/lib/models/Courseware/BlockTypes/Download.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware download block.
  *
@@ -72,11 +70,11 @@ class Download extends BlockType
         return $payload;
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Download.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Embed.php b/lib/models/Courseware/BlockTypes/Embed.php
index cb997ee..1b36624 100644
--- a/lib/models/Courseware/BlockTypes/Embed.php
+++ b/lib/models/Courseware/BlockTypes/Embed.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware embed block.
  *
@@ -40,11 +38,10 @@ class Embed extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Embed.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public function getPayload()
diff --git a/lib/models/Courseware/BlockTypes/Error.php b/lib/models/Courseware/BlockTypes/Error.php
index 2e15456..3f290b1 100644
--- a/lib/models/Courseware/BlockTypes/Error.php
+++ b/lib/models/Courseware/BlockTypes/Error.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware error block.
  *
@@ -34,11 +32,11 @@ class Error extends BlockType
         return [];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Error.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Folder.php b/lib/models/Courseware/BlockTypes/Folder.php
index 2eed4b0..9f186df 100644
--- a/lib/models/Courseware/BlockTypes/Folder.php
+++ b/lib/models/Courseware/BlockTypes/Folder.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware folder block.
  *
@@ -55,7 +53,7 @@ class Folder extends BlockType
         if ($folder) {
             $typedFolder = $folder->getTypedFolder();
             $payload['folder-type'] = $typedFolder->folder_type;
-            if ($typedFolder->isReadable($user->id)) {   
+            if ($typedFolder->isReadable($user->id) || $typedFolder->folder_type === 'HomeworkFolder') {   
                 foreach ($typedFolder->getFiles() as $folderFile) {
                     $file['id'] = $folderFile->id;
                     $file['attributes'] = [
@@ -116,11 +114,10 @@ class Folder extends BlockType
         return $payload;
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Folder.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Gallery.php b/lib/models/Courseware/BlockTypes/Gallery.php
index 5f9bb0b..5041573 100644
--- a/lib/models/Courseware/BlockTypes/Gallery.php
+++ b/lib/models/Courseware/BlockTypes/Gallery.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware gallery block.
  *
@@ -133,11 +131,11 @@ class Gallery extends BlockType
         return $payload;
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Gallery.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Headline.php b/lib/models/Courseware/BlockTypes/Headline.php
index 0c82138..616af88 100644
--- a/lib/models/Courseware/BlockTypes/Headline.php
+++ b/lib/models/Courseware/BlockTypes/Headline.php
@@ -2,7 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
 use Opis\JsonSchema\Validator;
 
 /**
@@ -49,11 +48,10 @@ class Headline extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Headline.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     /**
@@ -88,11 +86,8 @@ class Headline extends BlockType
     public function validatePayload($payload): bool
     {
         unset($payload->background_image);
-        $schema = static::getJsonSchema();
-        $validator = new Validator();
-        $result = $validator->schemaValidation($payload, $schema);
 
-        return $result->isValid();
+        return parent::validatePayload($payload);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/IFrame.php b/lib/models/Courseware/BlockTypes/IFrame.php
index 5c914f9..f697e74 100644
--- a/lib/models/Courseware/BlockTypes/IFrame.php
+++ b/lib/models/Courseware/BlockTypes/IFrame.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware iFrame block.
  *
@@ -45,11 +43,10 @@ class IFrame extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/IFrame.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/ImageMap.php b/lib/models/Courseware/BlockTypes/ImageMap.php
index e275c46..d9ad845 100644
--- a/lib/models/Courseware/BlockTypes/ImageMap.php
+++ b/lib/models/Courseware/BlockTypes/ImageMap.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware image map block.
  *
@@ -66,11 +64,11 @@ class ImageMap extends BlockType
         return $payload;
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/ImageMap.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/KeyPoint.php b/lib/models/Courseware/BlockTypes/KeyPoint.php
index 8599704..d1e6c34 100644
--- a/lib/models/Courseware/BlockTypes/KeyPoint.php
+++ b/lib/models/Courseware/BlockTypes/KeyPoint.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware key point block.
  *
@@ -38,11 +36,11 @@ class KeyPoint extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/KeyPoint.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Link.php b/lib/models/Courseware/BlockTypes/Link.php
index ccf9f66..3282e2c 100644
--- a/lib/models/Courseware/BlockTypes/Link.php
+++ b/lib/models/Courseware/BlockTypes/Link.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware link block.
  *
@@ -39,11 +37,10 @@ class Link extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Link.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Lti.php b/lib/models/Courseware/BlockTypes/Lti.php
index 8b527c1..193bfb5 100644
--- a/lib/models/Courseware/BlockTypes/Lti.php
+++ b/lib/models/Courseware/BlockTypes/Lti.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware LTI block.
  *
@@ -44,11 +42,10 @@ class Lti extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Lti.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public function getPayload()
diff --git a/lib/models/Courseware/BlockTypes/TableOfContents.php b/lib/models/Courseware/BlockTypes/TableOfContents.php
index c48b683..f0485b9 100644
--- a/lib/models/Courseware/BlockTypes/TableOfContents.php
+++ b/lib/models/Courseware/BlockTypes/TableOfContents.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware table of contents block.
  *
@@ -37,11 +35,11 @@ class TableOfContents extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/TableOfContents.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Text.php b/lib/models/Courseware/BlockTypes/Text.php
index 441da89..1da7cbe 100644
--- a/lib/models/Courseware/BlockTypes/Text.php
+++ b/lib/models/Courseware/BlockTypes/Text.php
@@ -2,9 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-require_once 'lib/classes/Markup.class.php';
-
 /**
  * This class represents the content of a Courseware text block.
  *
@@ -66,11 +63,10 @@ class Text extends BlockType
         parent::setPayload($payload);
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Text.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     /**
@@ -192,7 +188,7 @@ class Text extends BlockType
 
             }
 
-            return array();
+            return null;
         });
     }
 }
diff --git a/lib/models/Courseware/BlockTypes/Timeline.php b/lib/models/Courseware/BlockTypes/Timeline.php
index 81802ce..5647e92 100644
--- a/lib/models/Courseware/BlockTypes/Timeline.php
+++ b/lib/models/Courseware/BlockTypes/Timeline.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware timeline block.
  *
@@ -45,11 +43,10 @@ class Timeline extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Timeline.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Typewriter.php b/lib/models/Courseware/BlockTypes/Typewriter.php
index 2544dde..b303fb3 100644
--- a/lib/models/Courseware/BlockTypes/Typewriter.php
+++ b/lib/models/Courseware/BlockTypes/Typewriter.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware typewriter block.
  *
@@ -39,11 +37,11 @@ class Typewriter extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Typewriter.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     public static function getCategories(): array
diff --git a/lib/models/Courseware/BlockTypes/Video.php b/lib/models/Courseware/BlockTypes/Video.php
index 431f69b..1ad7064 100644
--- a/lib/models/Courseware/BlockTypes/Video.php
+++ b/lib/models/Courseware/BlockTypes/Video.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\BlockTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware video block.
  *
@@ -42,11 +40,10 @@ class Video extends BlockType
         ];
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/Video.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 
     /**
diff --git a/lib/models/Courseware/ContainerTypes/AccordionContainer.php b/lib/models/Courseware/ContainerTypes/AccordionContainer.php
index 185b6d1..cd00a06 100644
--- a/lib/models/Courseware/ContainerTypes/AccordionContainer.php
+++ b/lib/models/Courseware/ContainerTypes/AccordionContainer.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\ContainerTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware accordion container stored in payload.
  *
@@ -54,10 +52,10 @@ class AccordionContainer extends ContainerType
         $this->setPayload($payload);
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/AccordionContainer.json';
 
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 }
diff --git a/lib/models/Courseware/ContainerTypes/ContainerType.php b/lib/models/Courseware/ContainerTypes/ContainerType.php
index e358c9c..4e816be 100644
--- a/lib/models/Courseware/ContainerTypes/ContainerType.php
+++ b/lib/models/Courseware/ContainerTypes/ContainerType.php
@@ -3,7 +3,6 @@
 namespace Courseware\ContainerTypes;
 
 use Courseware\CoursewarePlugin;
-use Opis\JsonSchema\Schema;
 use Opis\JsonSchema\Validator;
 
 /**
@@ -28,9 +27,9 @@ abstract class ContainerType
      * Returns the JSON schema which is used to validate the payload of
      * instances of this type of container.
      *
-     * @return Schema the JSON schema to be used
+     * @return string the JSON schema to be used
      */
-    abstract public static function getJsonSchema(): Schema;
+    abstract public static function getJsonSchema(): string;
 
     /**
      * Returns a short string describing this type of container.
@@ -150,10 +149,8 @@ abstract class ContainerType
      */
     public function validatePayload($payload): bool
     {
-        $schema = static::getJsonSchema();
         $validator = new Validator();
-        $result = $validator->schemaValidation($payload, $schema);
-
+        $result = $validator->validate($payload, static::getJsonSchema());
         return $result->isValid();
     }
 
@@ -199,7 +196,7 @@ abstract class ContainerType
             foreach ($section['blocks'] as &$block) {
                 $block = $block_map[$block] ?? null;
             }
-            $section['blocks'] = array_filter($section['blocks']);
+            $section['blocks'] = array_values(array_filter($section['blocks']));
         }
 
         return $payload;
@@ -252,9 +249,9 @@ abstract class ContainerType
      * It turns the classname into snakecase in order to find the
      * template file in templates/courseware/container_types.
      *
-     * @return mixed the \Flexi_Template instance if exists, otherwise null.
+     * @return \Flexi\Template|null the \Flexi\Template instance if exists, otherwise null.
      */
-    public function getPdfHtmlTemplate(): ?\Flexi_Template
+    public function getPdfHtmlTemplate(): ?\Flexi\Template
     {
         $template = null;
         try {
diff --git a/lib/models/Courseware/ContainerTypes/ListContainer.php b/lib/models/Courseware/ContainerTypes/ListContainer.php
index b98d8a1..adbf7c3 100644
--- a/lib/models/Courseware/ContainerTypes/ListContainer.php
+++ b/lib/models/Courseware/ContainerTypes/ListContainer.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\ContainerTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware list container stored in payload.
  *
@@ -50,10 +48,9 @@ class ListContainer extends ContainerType
         $this->setPayload($payload);
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/ListContainer.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 }
diff --git a/lib/models/Courseware/ContainerTypes/TabsContainer.php b/lib/models/Courseware/ContainerTypes/TabsContainer.php
index 01f3d45..66a56b8 100644
--- a/lib/models/Courseware/ContainerTypes/TabsContainer.php
+++ b/lib/models/Courseware/ContainerTypes/TabsContainer.php
@@ -2,8 +2,6 @@
 
 namespace Courseware\ContainerTypes;
 
-use Opis\JsonSchema\Schema;
-
 /**
  * This class represents the content of a Courseware tabs container stored in payload.
  *
@@ -54,10 +52,9 @@ class TabsContainer extends ContainerType
         $this->setPayload($payload);
     }
 
-    public static function getJsonSchema(): Schema
+    public static function getJsonSchema(): string
     {
         $schemaFile = __DIR__.'/TabsContainer.json';
-
-        return Schema::fromJsonString(file_get_contents($schemaFile));
+        return file_get_contents($schemaFile);
     }
 }