Extend invoices and invoice items to keep more information.

app/Models/Invoice.php

@@ -23,6 +23,13 @@ class Invoice extends Model
         'status',
         'sum',
         'tax',
+        'project_id',
+        'project_count',
+        'is_template',
+        'currency_code',
+        'due_date',
+        'cash_discount',
+        'cash_discount_date',
     ];
 
     /**
@@ -36,6 +43,25 @@ class Invoice extends Model
         'localized_state'
     ];
 
+    /**
+     * Set the project_count variable automatically, if a project is related to this invoice.
+     */
+    public static function boot(): void
+    {
+        parent::boot();
+        self::creating(function (Invoice $invoice) {
+            if (is_null($invoice->project_id)) {
+                return true;
+            }
+            if ($invoice->type != '326') {
+                return true;
+            }
+            $projectMax = Invoice::where('project_id', '=', $invoice->project_id)->max('project_count') + 1;
+            $invoice->project_count = $projectMax;
+            return true;
+        });
+    }
+
     /**
      * Get the invoice state as translated string.
      */
@@ -107,4 +133,9 @@ class Invoice extends Model
     {
         return $this->hasMany(Payment::class);
     }
+
+    public function project(): BelongsTo
+    {
+        return $this->belongsTo(Project::class);
+    }
 }

app/Models/Invoiceitem.php

@@ -14,6 +14,7 @@ class Invoiceitem extends Model
      */
     protected $fillable = [
         'invoice_id',
+        'article_number',
         'amount',
         'discount',
         'tax',

app/Models/Project.php

@@ -5,6 +5,7 @@ namespace App\Models;
 use Carbon\Carbon;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\SoftDeletes;
 
 class Project extends Model
@@ -33,8 +34,20 @@ class Project extends Model
     protected $appends = [
         'start',
         'end',
+        'customer_email',
+        'customer_name',
     ];
 
+
+    public function getCustomerNameAttribute(): string
+    {
+        return $this->customer->name;
+    }
+    public function getCustomerEmailAttribute(): string
+    {
+        return $this->customer->email;
+    }
+
     /**
      * Get the end_date attribute in local format.
      */
@@ -58,4 +71,9 @@ class Project extends Model
     {
         return $this->belongsTo(Customer::class);
     }
+
+    public function invoices(): HasMany
+    {
+        return $this->hasMany(Invoice::class);
+    }
 }