All code for reminders based on piggy banks. I hope.

app/models/PiggybankReminder.php

@@ -0,0 +1,63 @@
+<?php
+use Carbon\Carbon;
+
+/**
+ * Class PiggybankReminder
+ */
+class PiggybankReminder extends Reminder
+{
+    protected $isSubclass = true;
+
+
+    public function amountToSave()
+    {
+        /** @var \Piggybank $piggyBank */
+        $piggyBank = $this->piggybank;
+        /** @var \PiggybankRepetition $repetition */
+        $repetition = $piggyBank->currentRelevantRep();
+
+        $today = new Carbon;
+        $diff = $today->diff($repetition->targetdate);
+        $left = $piggyBank->targetamount - $repetition->currentamount;
+        // to prevent devide by zero:
+        $piggyBank->reminder_skip = $piggyBank->reminder_skip < 1 ? 1 : $piggyBank->reminder_skip;
+        $toSave = 0;
+        switch ($piggyBank->reminder) {
+            case 'day':
+                throw new \Firefly\Exception\FireflyException('No impl day reminder/ PiggyBankReminder Render');
+                break;
+            case 'week':
+                throw new \Firefly\Exception\FireflyException('No impl week reminder/ PiggyBankReminder Render');
+                break;
+            case 'month':
+                $toSave = $left / ($diff->m / $piggyBank->reminder_skip);
+                break;
+            case 'year':
+                throw new \Firefly\Exception\FireflyException('No impl year reminder/ PiggyBankReminder Render');
+                break;
+        }
+        return floatval($toSave);
+    }
+
+    /**
+     * @return string
+     * @throws Firefly\Exception\FireflyException
+     */
+    public function render()
+    {
+        /** @var \Piggybank $piggyBank */
+        $piggyBank = $this->piggybank;
+
+
+        $fullText
+            = 'In order to save enough money for <a href="' . route('piggybanks.show', $piggyBank->id) . '">"' . e(
+                $piggyBank->name
+            ) . '"</a> you';
+
+        $fullText .= ' should save at least ' . mf($this->amountToSave(), false) . ' this ' . $piggyBank->reminder
+            . ', before ' . $this->enddate->format('M jS, Y');
+
+        return $fullText;
+    }
+
+}