New cron job for bills.

app/Mail/BillWarningMail.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace FireflyIII\Mail;
+
+use FireflyIII\Models\Bill;
+use Illuminate\Bus\Queueable;
+use Illuminate\Mail\Mailable;
+use Illuminate\Queue\SerializesModels;
+
+class BillWarningMail extends Mailable
+{
+    use Queueable, SerializesModels;
+
+    public Bill   $bill;
+    public string $field;
+    public int    $diff;
+    public string $ipAddress;
+
+    /**
+     * ConfirmEmailChangeMail constructor.
+     *
+     * @param Bill   $bill
+     * @param string $field
+     * @param int    $diff
+     * @param string $ipAddress
+     */
+    public function __construct(Bill $bill, string $field, int $diff, string $ipAddress)
+    {
+        $this->bill      = $bill;
+        $this->field     = $field;
+        $this->diff      = $diff;
+        $this->ipAddress = $ipAddress;
+    }
+
+    /**
+     * Build the message.
+     *
+     * @return $this
+     */
+    public function build(): self
+    {
+        $subject = (string) trans(sprintf('email.bill_warning_subject_%s', $this->field), ['diff' => $this->diff, 'name' => $this->bill->name]);
+        if (0 === $this->diff) {
+            $subject = (string) trans(sprintf('email.bill_warning_subject_now_%s', $this->field), ['diff' => $this->diff, 'name' => $this->bill->name]);
+        }
+
+        return $this
+            ->view('emails.bill-warning-html')
+            ->text('emails.bill-warning-text')
+            ->subject($subject);
+    }
+}