Make first balance update email delay shorter than interval

This makes sure the first balance update email is sent within a week
after the user first uses the application. All subsequent updates will
be sent at a month interval.

webapp/app/Jobs/SendBalanceUpdates.php

@@ -30,6 +30,11 @@ class SendBalanceUpdates implements ShouldQueue {
      */
     const UPDATE_INTERVAL = 60 * 60 * 24 * 30;
 
+    /**
+     * Time in seconds for the first updat eemail to be send to each user.
+     */
+    const UPDATE_FIRST_DELAY = 60 * 60 * 24 * 7;
+
     /**
      * Allowed update interval play in seconds.
      *
@@ -80,17 +85,24 @@ class SendBalanceUpdates implements ShouldQueue {
         // Send an update to each listed user
         $users->each(function($user) {
             DB::transaction(function() use($user) {
-                // Update email history time
-                $history = EmailHistory::updateOrCreate([
-                    'user_id' => $user->id,
-                    'type' => EmailHistory::TYPE_BALANCE_UPDATE,
-                ], [
-                    'last_at' => now(),
-                ]);
+                // Find the email history entry
+                $email_history = EmailHistory::user($user)
+                    ->type(EmailHistory::TYPE_BALANCE_UPDATE)
+                    ->first();
 
-                // Do not send the first time, if create/update time are the same
-                if($history->created_at == $history->updated_at)
+                // Create new entry if non existant
+                if($email_history == null) {
+                    $email_history = new EmailHistory();
+                    $email_history->user_id = $user->id;
+                    $email_history->type = EmailHistory::TYPE_BALANCE_UPDATE;
+                    $email_history->last_at = now()->subSeconds(Self::UPDATE_INTERVAL)->addSeconds(Self::UPDATE_FIRST_DELAY);
+                    $email_history->save();
                     return;
+                }
+
+                // Update last time in existing entity
+                $email_history->last_at = now();
+                $email_history->save();
 
                 // Schedule a job to send the balance update for the user
                 SendBalanceUpdate::dispatch($user->id);

webapp/app/Models/EmailHistory.php

@@ -2,6 +2,7 @@
 
 namespace App\Models;
 
+use App\Models\Users;
 use App\Utils\EmailRecipient;
 use Carbon\Carbon;
 use Illuminate\Database\Eloquent\Model;
@@ -38,6 +39,19 @@ class EmailHistory extends Model {
      */
     const TYPE_BALANCE_UPDATE = 1;
 
+    /**
+     * A scope for selecting a specific user.
+     *
+     * @param User|int $user_id The user.
+     */
+    public function scopeUser($query, $user_id) {
+        if($user_id instanceof User)
+            $user_id = $user_id->id;
+        if($user_id == null)
+            throw new \Exception("User cannot be null");
+        return $query->where('user_id', $user_id);
+    }
+
     /**
      * A scope for selecting a specific email type.
      */