diff --git a/app/DataMapper/CompanySettings.php b/app/DataMapper/CompanySettings.php
index a3d272a5c410..a3ed7d2fb4d2 100644
--- a/app/DataMapper/CompanySettings.php
+++ b/app/DataMapper/CompanySettings.php
@@ -116,6 +116,9 @@ class CompanySettings extends BaseSettings
     public $project_number_pattern = ''; //@implemented
     public $project_number_counter = 1; //@implemented
 
+    public $purchase_order_number_pattern = ''; //@implemented
+    public $purchase_order_number_counter = 1; //@implemented
+
     public $shared_invoice_quote_counter = false; //@implemented
     public $shared_invoice_credit_counter = false; //@implemented
     public $recurring_number_prefix = ''; //@implemented
diff --git a/app/Helpers/Invoice/InvoiceSum.php b/app/Helpers/Invoice/InvoiceSum.php
index 8121cbfcc04e..8e3313fb49f2 100644
--- a/app/Helpers/Invoice/InvoiceSum.php
+++ b/app/Helpers/Invoice/InvoiceSum.php
@@ -224,6 +224,14 @@ class InvoiceSum
         return $this->invoice;
     }
 
+    public function getPurchaseOrder()
+    {
+        $this->setCalculatedAttributes();
+        $this->invoice->saveQuietly();
+
+        return $this->invoice;
+    }
+
     public function getRecurringInvoice()
     {
         $this->invoice->amount = $this->formatValue($this->getTotal(), $this->invoice->client->currency()->precision);
diff --git a/app/Helpers/Invoice/InvoiceSumInclusive.php b/app/Helpers/Invoice/InvoiceSumInclusive.php
index 0cdb1638045d..eeb344a50c3d 100644
--- a/app/Helpers/Invoice/InvoiceSumInclusive.php
+++ b/app/Helpers/Invoice/InvoiceSumInclusive.php
@@ -229,6 +229,15 @@ class InvoiceSumInclusive
         return $this->invoice;
     }
 
+    public function getPurchaseOrder()
+    {
+        //Build invoice values here and return Invoice
+        $this->setCalculatedAttributes();
+        $this->invoice->saveQuietly();
+
+        return $this->invoice;
+    }
+
     /**
      * Build $this->invoice variables after
      * calculations have been performed.
diff --git a/app/Http/Controllers/PurchaseOrderController.php b/app/Http/Controllers/PurchaseOrderController.php
index 677e00196903..b07f068aec3b 100644
--- a/app/Http/Controllers/PurchaseOrderController.php
+++ b/app/Http/Controllers/PurchaseOrderController.php
@@ -174,8 +174,6 @@ class PurchaseOrderController extends BaseController
     public function store(StorePurchaseOrderRequest $request)
     {
 
-        $client = Client::find($request->get('client_id'));
-
         $purchase_order = $this->purchase_order_repository->save($request->all(), PurchaseOrderFactory::create(auth()->user()->company()->id, auth()->user()->id));
 
         $purchase_order = $purchase_order->service()
diff --git a/app/Http/Requests/PurchaseOrder/StorePurchaseOrderRequest.php b/app/Http/Requests/PurchaseOrder/StorePurchaseOrderRequest.php
index 1f531178050b..ef97d446ad58 100644
--- a/app/Http/Requests/PurchaseOrder/StorePurchaseOrderRequest.php
+++ b/app/Http/Requests/PurchaseOrder/StorePurchaseOrderRequest.php
@@ -38,8 +38,7 @@ class StorePurchaseOrderRequest extends Request
     {
         $rules = [];
 
-        $rules['client_id'] = 'required';
-
+        $rules['vendor_id'] = 'required';
 
         $rules['number'] = ['nullable', Rule::unique('purchase_orders')->where('company_id', auth()->user()->company()->id)];
         $rules['discount']  = 'sometimes|numeric';
diff --git a/app/Http/Requests/PurchaseOrder/UpdatePurchaseOrderRequest.php b/app/Http/Requests/PurchaseOrder/UpdatePurchaseOrderRequest.php
index 55e8f5354490..d2e83154fb95 100644
--- a/app/Http/Requests/PurchaseOrder/UpdatePurchaseOrderRequest.php
+++ b/app/Http/Requests/PurchaseOrder/UpdatePurchaseOrderRequest.php
@@ -55,7 +55,6 @@ class UpdatePurchaseOrderRequest extends Request
 
         $input = $this->decodePrimaryKeys($input);
 
-
         $input['id'] = $this->purchase_order->id;
 
         $this->replace($input);
diff --git a/app/Models/PurchaseOrder.php b/app/Models/PurchaseOrder.php
index 4d73c609559d..b1e6e87addd7 100644
--- a/app/Models/PurchaseOrder.php
+++ b/app/Models/PurchaseOrder.php
@@ -12,6 +12,8 @@
 namespace App\Models;
 
 
+use App\Helpers\Invoice\InvoiceSum;
+use App\Helpers\Invoice\InvoiceSumInclusive;
 use App\Services\PurchaseOrder\PurchaseOrderService;
 use Illuminate\Database\Eloquent\SoftDeletes;
 
@@ -92,8 +94,9 @@ class PurchaseOrder extends BaseModel
 
     const STATUS_DRAFT = 1;
     const STATUS_SENT = 2;
-    const STATUS_PARTIAL = 3;
-    const STATUS_APPLIED = 4;
+    const STATUS_APPROVED = 3;
+    const STATUS_CONVERTED = 4;
+    const STATUS_EXPIRED = -1;
 
     public function assigned_user()
     {
@@ -130,7 +133,6 @@ class PurchaseOrder extends BaseModel
         return $this->belongsTo(Client::class)->withTrashed();
     }
 
-
     public function invitations()
     {
         return $this->hasMany(CreditInvitation::class);
@@ -166,4 +168,17 @@ class PurchaseOrder extends BaseModel
         return $this->morphMany(Document::class, 'documentable');
     }
 
+    public function calc()
+    {
+        $credit_calc = null;
+
+        if ($this->uses_inclusive_taxes) {
+            $credit_calc = new InvoiceSumInclusive($this);
+        } else {
+            $credit_calc = new InvoiceSum($this);
+        }
+
+        return $credit_calc->build();
+    }
+
 }
diff --git a/app/Models/Vendor.php b/app/Models/Vendor.php
index bae220a60698..1076ecb29528 100644
--- a/app/Models/Vendor.php
+++ b/app/Models/Vendor.php
@@ -11,6 +11,7 @@
 
 namespace App\Models;
 
+use App\DataMapper\CompanySettings;
 use App\Models\Presenters\VendorPresenter;
 use App\Utils\Traits\GeneratesCounter;
 use Illuminate\Database\Eloquent\SoftDeletes;
@@ -109,4 +110,40 @@ class Vendor extends BaseModel
     {
         return ctrans('texts.vendor');
     }
+
+    public function setCompanyDefaults($data, $entity_name) :array
+    {
+        $defaults = [];
+
+        if (! (array_key_exists('terms', $data) && strlen($data['terms']) > 1)) {
+            $defaults['terms'] = $this->getSetting($entity_name.'_terms');
+        } elseif (array_key_exists('terms', $data)) {
+            $defaults['terms'] = $data['terms'];
+        }
+
+        if (! (array_key_exists('footer', $data) && strlen($data['footer']) > 1)) {
+            $defaults['footer'] = $this->getSetting($entity_name.'_footer');
+        } elseif (array_key_exists('footer', $data)) {
+            $defaults['footer'] = $data['footer'];
+        }
+
+        if (strlen($this->public_notes) >= 1) {
+            $defaults['public_notes'] = $this->public_notes;
+        }
+
+        return $defaults;
+    }
+
+    public function getSetting($setting)
+    {
+        if ((property_exists($this->company->settings, $setting) != false) && (isset($this->company->settings->{$setting}) !== false)) {
+            return $this->company->settings->{$setting};
+        }
+
+        elseif( property_exists(CompanySettings::defaults(), $setting) ) {
+            return CompanySettings::defaults()->{$setting};
+        }
+
+        return '';
+    }
 }
diff --git a/app/Repositories/PurchaseOrderRepository.php b/app/Repositories/PurchaseOrderRepository.php
index cf0653c25c8a..f6ab93d5b5d3 100644
--- a/app/Repositories/PurchaseOrderRepository.php
+++ b/app/Repositories/PurchaseOrderRepository.php
@@ -11,8 +11,10 @@
 
 namespace App\Repositories;
 
-
+use App\Factory\PurchaseOrderFactory;
 use App\Models\PurchaseOrder;
+use App\Models\Vendor;
+use App\Models\VendorContact;
 use App\Utils\Traits\MakesHash;
 
 class PurchaseOrderRepository extends BaseRepository
@@ -25,10 +27,144 @@ class PurchaseOrderRepository extends BaseRepository
 
     public function save(array $data, PurchaseOrder $purchase_order) : ?PurchaseOrder
     {
-        $purchase_order->fill($data);
+
+        if(array_key_exists('vendor_id', $data)) 
+            $purchase_order->vendor_id = $data['vendor_id'];
+
+        $vendor = Vendor::where('id', $purchase_order->vendor_id)->withTrashed()->firstOrFail();    
+
+        $state = [];
+
+        $resource = class_basename($purchase_order); //ie Invoice
+
+        if (! $purchase_order->id) {
+            $company_defaults = $vendor->setCompanyDefaults($data, lcfirst($resource));
+            $purchase_order->uses_inclusive_taxes = $vendor->getSetting('inclusive_taxes');
+            $data = array_merge($company_defaults, $data);
+        }
+
+        $tmp_data = $data; //preserves the $data array
+
+        /* We need to unset some variable as we sometimes unguard the model */
+        if (isset($tmp_data['invitations'])) 
+            unset($tmp_data['invitations']);
+        
+        if (isset($tmp_data['vendor_contacts'])) 
+            unset($tmp_data['vendor_contacts']);
+        
+        $purchase_order->fill($tmp_data);
+
+        $purchase_order->custom_surcharge_tax1 = $vendor->company->custom_surcharge_taxes1;
+        $purchase_order->custom_surcharge_tax2 = $vendor->company->custom_surcharge_taxes2;
+        $purchase_order->custom_surcharge_tax3 = $vendor->company->custom_surcharge_taxes3;
+        $purchase_order->custom_surcharge_tax4 = $vendor->company->custom_surcharge_taxes4;
+
+        if(!$purchase_order->id)
+            $this->new_model = true;
+        
+        $purchase_order->saveQuietly();
+
+        /* Save any documents */
+        if (array_key_exists('documents', $data)) 
+            $this->saveDocuments($data['documents'], $purchase_order);
+
+        if (array_key_exists('file', $data)) 
+            $this->saveDocuments($data['file'], $purchase_order);
+
+        /* If invitations are present we need to filter existing invitations with the new ones */
+        if (isset($data['invitations'])) {
+            $invitations = collect($data['invitations']);
+
+            /* Get array of Keys which have been removed from the invitations array and soft delete each invitation */
+            $purchase_order->invitations->pluck('key')->diff($invitations->pluck('key'))->each(function ($invitation) {
+                $invitation = PurchaseOrderInvitation::where('key', $invitation)->first();
+
+                if ($invitation) 
+                    $invitation->delete();
+                
+            });
+
+            foreach ($data['invitations'] as $invitation) {
+
+                //if no invitations are present - create one.
+                if (! $this->getInvitation($invitation, $resource)) {
+
+                    if (isset($invitation['id'])) 
+                        unset($invitation['id']);
+
+                    //make sure we are creating an invite for a contact who belongs to the client only!
+                    $contact = VendorContact::find($invitation['vendor_contact_id']);
+
+                    if ($contact && $purchase_order->client_id == $contact->client_id) {
+
+                        $new_invitation = PurchaseOrderInvitation::withTrashed()
+                                            ->where('vendor_contact_id', $contact->id)
+                                            ->where('purchase_order_id', $purchase_order->id)
+                                            ->first();
+
+                        if ($new_invitation && $new_invitation->trashed()) {
+
+                            $new_invitation->restore();
+
+                        } else {
+
+                            $new_invitation = PurchaseOrderFactory::create($purchase_order->company_id, $purchase_order->user_id);
+                            $new_invitation->purchase_order_id = $purchase_order->id;
+                            $new_invitation->vendor_contact_id = $contact->id;
+                            $new_invitation->key = $this->createDbHash($purchase_order->company->db);
+                            $new_invitation->save();
+
+                        }
+                    }
+                }
+            }
+        }
+
+        /* If no invitations have been created, this is our fail safe to maintain state*/
+        if ($purchase_order->invitations()->count() == 0) 
+            $purchase_order->service()->createInvitations();
+
+        /* Apply entity number */
+        $purchase_order = $purchase_order->service()->applyNumber()->save();
+
+        /* Handle attempts where the deposit is greater than the amount/balance of the invoice */
+        if((int)$purchase_order->balance != 0 && $purchase_order->partial > $purchase_order->amount)
+            $purchase_order->partial = min($purchase_order->amount, $purchase_order->balance);
+
+        $purchase_order = $purchase_order->calc()->getPurchaseOrder();
+
+        if (! $purchase_order->design_id) 
+            $purchase_order->design_id = $this->decodePrimaryKey($client->getSetting('credit_design_id'));
+
+        if(array_key_exists('invoice_id', $data) && $data['invoice_id'])
+            $purchase_order->invoice_id = $data['invoice_id'];
+
+        if($this->new_model)
+            event('eloquent.created: App\Models\PurchaseOrder', $purchase_order);            
+        else
+            event('eloquent.updated: App\Models\PurchaseOrder', $purchase_order);
+
+
         $purchase_order->save();
 
-        return $purchase_order;
+        return $purchase_order->fresh();
+
+
+        // $purchase_order->fill($data);
+        // $purchase_order->save();
+
+        // return $purchase_order;
     }
 
+    public function getInvitation($invitation, $resource)
+    {
+        // if (is_array($invitation) && ! array_key_exists('key', $invitation))
+        //     return false;
+        
+        // $invitation = PurchaseOrderInvitation::where('key', $invitation['key'])->first();
+
+        return $invitation;
+    }
+
+
 }
diff --git a/app/Services/PurchaseOrder/ApplyNumber.php b/app/Services/PurchaseOrder/ApplyNumber.php
new file mode 100644
index 000000000000..bf4a33ddbcdf
--- /dev/null
+++ b/app/Services/PurchaseOrder/ApplyNumber.php
@@ -0,0 +1,88 @@
+<?php
+/**
+ * Invoice Ninja (https://invoiceninja.com).
+ *
+ * @link https://github.com/invoiceninja/invoiceninja source repository
+ *
+ * @copyright Copyright (c) 2022. Invoice Ninja LLC (https://invoiceninja.com)
+ *
+ * @license https://www.elastic.co/licensing/elastic-license
+ */
+
+namespace App\Services\PurchaseOrder;
+
+use App\Models\PurchaseOrder;
+use App\Models\Vendor;
+use App\Services\AbstractService;
+use App\Utils\Traits\GeneratesCounter;
+use Illuminate\Database\QueryException;
+
+class ApplyNumber extends AbstractService
+{
+    use GeneratesCounter;
+
+    private $vendor;
+
+    private $purchase_order;
+
+    private $completed = true;
+
+    public function __construct(Vendor $vendor, PurchaseOrder $purchase_order)
+    {
+        $this->vendor = $vendor;
+
+        $this->purchase_order = $purchase_order;
+    }
+
+    public function run()
+    {
+        if ($this->purchase_order->number != '') {
+            return $this->purchase_order;
+        }
+
+        switch ($this->client->getSetting('counter_number_applied')) {
+            case 'when_saved':
+                $this->trySaving();
+                break;
+            case 'when_sent':
+                if ($this->purchase_order->status_id == PurchaseOrder::STATUS_SENT) {
+                    $this->trySaving();
+                }
+                break;
+
+            default:
+                break;
+        }
+
+        return $this->purchase_order;
+    }
+
+    private function trySaving()
+    {
+
+        $x=1;
+
+        do{
+
+            try{
+
+                $this->purchase_order->number = $this->getNextPurchaseOrderNumber($this->purchase_order);
+                $this->purchase_order->saveQuietly();
+
+                $this->completed = false;
+                
+
+            }
+            catch(QueryException $e){
+
+                $x++;
+
+                if($x>10)
+                    $this->completed = false;
+            }
+        
+        }
+        while($this->completed);
+
+    }
+}
diff --git a/app/Services/PurchaseOrder/CreateInvitations.php b/app/Services/PurchaseOrder/CreateInvitations.php
new file mode 100644
index 000000000000..301f21806509
--- /dev/null
+++ b/app/Services/PurchaseOrder/CreateInvitations.php
@@ -0,0 +1,104 @@
+<?php
+/**
+ * Invoice Ninja (https://invoiceninja.com).
+ *
+ * @link https://github.com/invoiceninja/invoiceninja source repository
+ *
+ * @copyright Copyright (c) 2022. Invoice Ninja LLC (https://invoiceninja.com)
+ *
+ * @license https://www.elastic.co/licensing/elastic-license
+ */
+
+namespace App\Services\PurchaseOrder;
+
+use App\Factory\ClientContactFactory;
+use App\Factory\PurchaseOrderInvitationFactory;
+use App\Models\Invoice;
+use App\Models\PurchaseOrder;
+use App\Models\PurchaseOrderInvitation;
+use App\Services\AbstractService;
+use App\Utils\Traits\MakesHash;
+use Illuminate\Support\Str;
+
+class CreateInvitations extends AbstractService
+{
+    use MakesHash;
+    
+    private $purchase_order;
+
+    public function __construct(PurchaseOrder $purchase_order)
+    {
+        $this->purchase_order = $purchase_order;
+    }
+
+    public function run()
+    {
+
+        $contacts = $this->purchase_order->vendor->contacts()->where('send_email', true)->get();
+
+        if($contacts->count() == 0){
+            $this->createBlankContact();
+
+            $this->purchase_order->refresh();
+            $contacts = $this->purchase_order->vendor->contacts;
+        }
+
+        $contacts->each(function ($contact) {
+            $invitation = PurchaseOrderInvitation::where('company_id', $this->purchase_order->company_id)
+                                        ->where('vendor_contact_id', $contact->id)
+                                        ->where('purchase_order_id', $this->purchase_order->id)
+                                        ->withTrashed()
+                                        ->first();
+
+            if (! $invitation && $contact->send_email) {
+                $ii = PurchaseOrderInvitationFactory::create($this->purchase_order->company_id, $this->purchase_order->user_id);
+                $ii->key = $this->createDbHash($this->purchase_order->company->db);
+                $ii->purchase_order_id = $this->purchase_order->id;
+                $ii->vendor_contact_id = $contact->id;
+                $ii->save();
+            } elseif ($invitation && ! $contact->send_email) {
+                $invitation->delete();
+            }
+        });
+
+        if($this->purchase_order->invitations()->count() == 0) {
+            
+            if($contacts->count() == 0){
+                $contact = $this->createBlankContact();
+            }
+            else{
+                $contact = $contacts->first();
+
+                            $invitation = PurchaseOrderInvitation::where('company_id', $this->purchase_order->company_id)
+                                        ->where('vendor_contact_id', $contact->id)
+                                        ->where('purchase_order_id', $this->purchase_order->id)
+                                        ->withTrashed()
+                                        ->first();
+
+                            if($invitation){
+                                $invitation->restore();
+                                return $this->purchase_order;
+                            }
+            }
+
+                $ii = PurchaseOrderInvitationFactory::create($this->purchase_order->company_id, $this->purchase_order->user_id);
+                $ii->key = $this->createDbHash($this->purchase_order->company->db);
+                $ii->purchase_order_id = $this->purchase_order->id;
+                $ii->vendor_contact_id = $contact->id;
+                $ii->save();
+        }
+
+        return $this->purchase_order;
+    }
+
+    private function createBlankContact()
+    {
+        $new_contact = VendorContactFactory::create($this->purchase_order->company_id, $this->purchase_order->user_id);
+        $new_contact->vendor_id = $this->purchase_order->vendor_id;
+        $new_contact->contact_key = Str::random(40);
+        $new_contact->is_primary = true;
+        $new_contact->save();
+
+        return $new_contact;
+    }
+}
diff --git a/app/Services/PurchaseOrder/PurchaseOrderService.php b/app/Services/PurchaseOrder/PurchaseOrderService.php
index ffb2cb84d164..9328a2a016a9 100644
--- a/app/Services/PurchaseOrder/PurchaseOrderService.php
+++ b/app/Services/PurchaseOrder/PurchaseOrderService.php
@@ -13,6 +13,8 @@ namespace App\Services\PurchaseOrder;
 
 
 use App\Models\PurchaseOrder;
+use App\Services\PurchaseOrder\ApplyNumber;
+use App\Services\PurchaseOrder\CreateInvitations;
 use App\Utils\Traits\MakesHash;
 
 class PurchaseOrderService
@@ -37,19 +39,34 @@ class PurchaseOrderService
         return $this->purchase_order;
     }
 
+    public function createInvitations()
+    {
+
+        $this->purchase_order = (new CreateInvitations($this->purchase_order))->run();
+
+        return $this;
+    }
+
+    public function applyNumber()
+    {
+        $this->invoice = (new ApplyNumber($this->purchase_order->vendor, $this->purchase_order))->run();
+
+        return $this;
+    }
+
     public function fillDefaults()
     {
-        $settings = $this->purchase_order->client->getMergedSettings();
+        // $settings = $this->purchase_order->client->getMergedSettings();
 
-        //TODO implement design, footer, terms
+        // //TODO implement design, footer, terms
 
 
-        /* If client currency differs from the company default currency, then insert the client exchange rate on the model.*/
-        if (!isset($this->purchase_order->exchange_rate) && $this->purchase_order->client->currency()->id != (int)$this->purchase_order->company->settings->currency_id)
-            $this->purchase_order->exchange_rate = $this->purchase_order->client->currency()->exchange_rate;
+        // /* If client currency differs from the company default currency, then insert the client exchange rate on the model.*/
+        // if (!isset($this->purchase_order->exchange_rate) && $this->purchase_order->client->currency()->id != (int)$this->purchase_order->company->settings->currency_id)
+        //     $this->purchase_order->exchange_rate = $this->purchase_order->client->currency()->exchange_rate;
 
-        if (!isset($this->purchase_order->public_notes))
-            $this->purchase_order->public_notes = $this->purchase_order->client->public_notes;
+        // if (!isset($this->purchase_order->public_notes))
+        //     $this->purchase_order->public_notes = $this->purchase_order->client->public_notes;
 
 
         return $this;
diff --git a/app/Utils/Traits/GeneratesCounter.php b/app/Utils/Traits/GeneratesCounter.php
index b9606621246a..6e470292edee 100644
--- a/app/Utils/Traits/GeneratesCounter.php
+++ b/app/Utils/Traits/GeneratesCounter.php
@@ -18,6 +18,7 @@ use App\Models\Expense;
 use App\Models\Invoice;
 use App\Models\Payment;
 use App\Models\Project;
+use App\Models\PurchaseOrder;
 use App\Models\Quote;
 use App\Models\RecurringExpense;
 use App\Models\RecurringInvoice;
@@ -154,6 +155,10 @@ trait GeneratesCounter
                 return 'project_number_counter';
                 break;
 
+            case PurchaseOrder::class:
+                return 'purchase_order_number_counter';
+                break;
+
             default:
                 return 'default_number_counter';
                 break;
@@ -345,6 +350,23 @@ trait GeneratesCounter
 
     }
 
+    public function getNextPurchaseOrderNumber(PurchaseOrder $purchase_order) :string
+    {
+        $this->resetCompanyCounters($purchase_order->company);
+
+        $counter = $purchase_order->company->settings->purchase_order_number_counter;
+        $setting_entity = $purchase_order->company->settings->purchase_order_number_counter;
+
+        $purchase_order_number = $this->checkEntityNumber(PurchaseOrder::class, $purchase_order, $counter, $purchase_order->company->settings->counter_padding, $purchase_order->company->settings->purchase_order_number_pattern);
+
+        $this->incrementCounter($purchase_order->company, 'purchase_order_number_pattern');
+
+        $entity_number = $purchase_order_number;
+
+        return $this->replaceUserVars($purchase_order, $entity_number);
+
+    }   
+
     /**
      * Gets the next expense number.
      *