remove legacy setting option

app/DataMapper/CompanySettings.php

@@ -25,7 +25,6 @@ class CompanySettings extends BaseSettings
 
     /*Invoice*/
     public $auto_archive_invoice 		    = false;
-    public $lock_sent_invoices              = false;
 
     public $lock_invoices = 'off';          //off,when_sent,when_paid
 
@@ -391,7 +390,6 @@ class CompanySettings extends BaseSettings
         'show_currency_code'                 => 'bool',
         'send_reminders'                     => 'bool',
         'enable_client_portal_tasks'         => 'bool',
-        'lock_sent_invoices'                 => 'bool',
         'auto_archive_invoice'               => 'bool',
         'auto_archive_quote'                 => 'bool',
         'auto_convert_quote'                 => 'bool',

app/Http/Controllers/InvoiceController.php

@@ -392,6 +392,9 @@ class InvoiceController extends BaseController
             return $request->disallowUpdate();
         }
 
+        if($invoice->isLocked())
+            return response()->json(['message' => 'Invoice is locked, no modifications allowed']);
+
         $invoice = $this->invoice_repo->save($request->all(), $invoice);
 
         event(new InvoiceWasUpdated($invoice, $invoice->company, Ninja::eventVars()));

app/Http/Controllers/OpenAPI/CompanySettingsSchema.php

@@ -30,7 +30,7 @@
  *       @OA\Property(property="custom_message_unpaid_invoice", type="string", example="Please pay invoices immediately", description="____________"),
  *       @OA\Property(property="custom_message_paid_invoice", type="string", example="Thanks for paying this invoice!", description="____________"),
  *       @OA\Property(property="custom_message_unapproved_quote", type="string", example="Please approve quote", description="____________"),
- *       @OA\Property(property="lock_sent_invoices", type="boolean", example=true, description="____________"),
+ *       @OA\Property(property="lock_invoices", type="boolean", example=true, description="____________"),
  *       @OA\Property(property="auto_archive_invoice", type="boolean", example=true, description="____________"),
  *       @OA\Property(property="auto_archive_quote", type="boolean", example=true, description="____________"),
  *       @OA\Property(property="auto_convert_quote", type="boolean", example=true, description="____________"),

app/Models/Invoice.php

@@ -266,17 +266,6 @@ class Invoice extends BaseModel
         }
     }
 
-    /**
-     * If True, prevents an invoice from being
-     * modified once it has been marked as sent
-     *
-     * @return boolean isLocked
-     */
-    public function isLocked(): bool
-    {
-        return $this->client->getSetting('lock_sent_invoices');
-    }
-
     public function isPayable(): bool
     {
         if($this->status_id == Invoice::STATUS_DRAFT && $this->is_deleted == false){
@@ -437,6 +426,32 @@ class Invoice extends BaseModel
         });
     }
 
+    /**
+     * Filtering logic to determine
+     * whether an invoice is locked 
+     * based on the current status of the invoice
+     * @return boolean [description]
+     */
+    public function isLocked() :bool
+    {
+        $locked_status = $this->client->getSetting('lock_invoices');
+
+        switch ($locked_status) {
+            case 'off':
+                return false;
+                break;
+            case 'when_sent':
+                return $this->status_id == self::STATUS_DRAFT;
+                break;
+            case 'when_paid':
+                return $this->status_id == self::STATUS_PAID || $this->status_id == self::STATUS_PARTIAL;
+                break;            
+            default:
+                return false;
+                break;
+        }
+    }
+
     /* Graveyard */
 
 //    /**