beggining of core field types

src/classes/entities/class-tainacan-item-metadata-entity.php

@@ -137,11 +137,10 @@ class Item_Metadata_Entity extends Entity {
             return false;
         }
 
-        $field_type = $field->get_field_type();
-        if( class_exists( $field_type ) ){
-            $classFieldType = new $field_type();
+        $classFieldType = $field->get_field_type_object();
+        if( is_object( $classFieldType ) ){
             if( method_exists ( $classFieldType , 'validate' ) ){
-                if( ! $classFieldType->validate( $value ) ) {
+                if( ! $classFieldType->validate( $this ) ) {
                     $this->add_error('field_type_error', $classFieldType->get_errors() );
                     return false;
                 }

src/classes/field-types/core-title/class-tainacan-core-title.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace Tainacan\Field_Types;
+
+defined( 'ABSPATH' ) or die( 'No script kiddies please!' );
+
+/**
+ * Class TainacanFieldType
+ */
+class Core_Title extends Field_Type {
+
+    function __construct(){
+        // call field type constructor
+        parent::__construct();
+        parent::set_primitive_type('string');
+        $this->core = true;
+        $this->related_mapped_prop = 'title';
+    }
+
+    /**
+     * @param $itemMetadata \Tainacan\Entities\Item_Metadata_Entity The instace of the entity itemMetadata
+     * @return string
+     */
+
+    public function render( $itemMetadata ){
+        return '<tainacan-text field_id ="'.$itemMetadata->get_field()->get_id().'" 
+                               item_id="'.$itemMetadata->get_item()->get_id().'"    
+                               value=\''.json_encode( $itemMetadata->get_value() ).'\'  
+                               name="'.$itemMetadata->get_field()->get_name().'"></tainacan-text>';
+    }
+
+    /**
+     * generate the fields for this field type
+     */
+    public function form(){
+
+    }
+    
+    /**
+     * Title core Field type is stored as the item title
+     *
+     * Lets validate it as the item title
+     *
+     * @param  TainacanEntitiesItem_Metadata_Entity $item_metadata
+     * @return bool Valid or not
+     */
+    public function validate(\Tainacan\Entities\Item_Metadata_Entity $item_metadata) {
+        
+        $item = $item_metadata->get_item();
+        
+        if ( !in_array($item->get_status(), apply_filters('tainacan-status-require-validation', ['publish','future','private'])) )
+            return true;
+        
+        $item->set_title($item_metadata->get_value());
+        
+        return $item->validate_prop('title');
+        
+    }
+    
+}

src/classes/field-types/field-type/class-tainacan-field-type.php

@@ -12,6 +12,21 @@ abstract class Field_Type  {
     private $primitive_type;
     public $options;
     public $errors;
+    
+    /**
+     * Indicates wether this is a core Field Type or not
+     *
+     * Core field types are used by Title and description fields. These fields:
+     * * Can only be used once, they belong to the repository and can not be deleted
+     * * Its values are saved in th wp_post table, and not as post_meta 
+     * 
+     */
+    public $core = false;
+    
+    /**
+     * Used by core field types to indicate where it should be saved
+     */
+    public $related_mapped_prop = false;
 
     abstract function render( $itemMetadata );
 
@@ -24,7 +39,7 @@ abstract class Field_Type  {
         $Tainacan_Fields->register_field_type( $this );
     }
 
-    public function validate($value) {
+    public function validate(\Tainacan\Entities\Item_Metadata_Entity $item_metadata) {
         return true;
     }
     

src/classes/repositories/class-tainacan-item-metadata.php

@@ -12,7 +12,21 @@ class Item_Metadata extends Repository {
         $unique = !$item_metadata->is_multiple();
 
         if ($unique) {
-            add_post_meta($item_metadata->item->get_id(), $item_metadata->field->get_id(), wp_slash( $item_metadata->get_value() ) );
+            $field_type = $item_metadata->get_field()->get_field_type_object();
+            if ($field_type->core) {
+                $item = $item_metadata->get_item();
+                $set_method = 'set_' . $field_type->related_mapped_prop;
+                $item->$set_method($item_metadata->get_value());
+                if ($item->validate()) {
+                    global $TainacanItems;
+                    $TainacanItems->insert($item);
+                } else {
+                    throw new \Exception('Item metadata should be validated beforehand');
+                }
+            } else {
+                add_post_meta($item_metadata->item->get_id(), $item_metadata->field->get_id(), wp_slash( $item_metadata->get_value() ) );
+            }
+            
         } else {
             delete_post_meta($item_metadata->item->get_id(), $item_metadata->field->get_id());