Optimized (sub-)booking methods and index view for eager loading.

app/Booking.php

@@ -6,50 +6,92 @@ use Illuminate\Database\Eloquent\Model;
 
 class Booking extends Model
 {
-    public function amount()
-    {
-        return $this->subBookings()->sum('amount');
-    }
-
-    public function signedAmount()
-    {
-        return $this->subBookings()->withSignedAmount()->get()
-                    ->sum('signedAmount');
-    }
+    /**************************************************************************
+     * DIRECT RELATIONS                                                       *
+     **************************************************************************/
 
+    /**
+     * Return all sub-bookings which belong to the booking.
+     *
+     * @return Illuminate\Database\Eloquent\Relations\HasMany
+     */
     public function subBookings()
     {
         return $this->hasMany('App\SubBooking');
     }
 
+    /**************************************************************************
+     * INDIRECT RELATIONS                                                     *
+     **************************************************************************/
+
+    /**
+     * Get the project to which the booking belongs. If the booking consists of
+     * more than one sub-booking, null is returned.
+     *
+     * @return App\Project
+     */
+    public function project()
+    {
+        if ($this->isSimple()) {
+            return $this->subBookings->first()->project;
+        }
+
+        return null;
+    }
+
+    /**
+     * Get the account type of the booking. If the booking consists of more than
+     * one sub-booking, null is returned.
+     *
+     * @return App\AccountType
+     */
+    public function accountType()
+    {
+        if ($this->isSimple()) {
+            return $this->subBookings->first()->accountType;
+        }
+
+        return null;
+    }
+
+    /**************************************************************************
+     * INDIRECT PROPERTIES                                                    *
+     **************************************************************************/
+
+    /**
+     * Get the (unsigned) amount of all sub-bookings.
+     *
+     * @return float
+     */
+    public function amount()
+    {
+        return $this->subBookings->sum('amount');
+    }
+
+    /**
+     * Return the sum of all signed amounts of all sub-bookings related to the
+     * booking.
+     *
+     * @return float
+     */
+    public function signedAmount()
+    {
+        $sum = 0;
+
+        foreach ($this->subBookings as $subBooking) {
+          $sum += $subBooking->signedAmount();
+        }
+
+        return $sum;
+    }
+
     /**
      * Return true, if the booking consists only of one sub-booking.
-     * NOTICE: The book instance has to be loaded with the
-     * ->withCount('subBookings') method to be able to access the comments
-     * count.
      *
      * @return boolean
      */
     public function isSimple()
     {
-        return $this->sub_bookings_count === 1;
-    }
-
-    public function project()
-    {
-        if ($this->isSimple()) {
-            return $this->subBookings()->first()->project();
-        }
-
-        return null;
-    }
-    
-    public function accountType()
-    {
-        if ($this->isSimple()) {
-            return $this->subBookings()->first()->accountType();
-        }
-
-        return null;
+        return $this->subBookings->count() === 1;
     }
 }