Add multi user support and subscriptions (#359)

This pull request adds support to multi users in one account. It also introduces the notion of subscriptions.

Accounts can now have multiple users.

Subscriptions are defined by a new env variable called REQUIRES_SUBSCRIPTION, and defaults to false. As promised, all the paid features on .com will be free if you download and host Monica on your own server.

app/Http/Controllers/Settings/SubscriptionsController.php

@@ -0,0 +1,110 @@
+<?php
+
+namespace App\Http\Controllers\Settings;
+
+use App\Contact;
+use Illuminate\Http\Request;
+use App\Http\Controllers\Controller;
+
+class SubscriptionsController extends Controller
+{
+    /**
+     * Display a listing of the resource.
+     *
+     * @return \Illuminate\Http\Response
+     */
+    public function index()
+    {
+        if (! config('monica.requires_subscription')) {
+            return redirect('settings/');
+        }
+
+        return view('settings.subscriptions.account');
+    }
+
+    /**
+     * Display the upgrade view page.
+     *
+     * @return \Illuminate\Http\Response
+     */
+    public function upgrade()
+    {
+        if (! config('monica.requires_subscription')) {
+            return redirect('settings/');
+        }
+
+        $account = auth()->user()->account;
+
+        if ($account->isSubscribed()) {
+            return redirect('/settings/subscriptions');
+        }
+
+        return view('settings.subscriptions.upgrade');
+    }
+
+    /**
+     * Display the downgrade view page.
+     *
+     * @return \Illuminate\Http\Response
+     */
+    public function downgrade()
+    {
+        if (! config('monica.requires_subscription')) {
+            return redirect('settings/');
+        }
+
+        if (! auth()->user()->account->subscribed(config('monica.paid_plan_friendly_name'))) {
+            return redirect('/settings');
+        }
+
+        return view('settings.subscriptions.downgrade-checklist');
+    }
+
+    /**
+     * Process the downgrade process
+     *
+     * @return \Illuminate\Http\Response
+     */
+    public function processDowngrade()
+    {
+        if (! auth()->user()->account->canDowngrade()) {
+            return redirect('/settings/users/subscriptions/downgrade');
+        }
+
+        auth()->user()->account->subscription(config('monica.paid_plan_friendly_name'))->cancelNow();
+
+        return redirect('/settings/subscriptions');
+    }
+
+    /**
+     * Process the upgrade payment
+     *
+     * @return \Illuminate\Http\Response
+     */
+    public function processPayment(Request $request)
+    {
+        if (! config('monica.requires_subscription')) {
+            return redirect('settings/');
+        }
+
+        $stripeToken = $request->input('stripeToken');
+
+        auth()->user()->account->newSubscription(config('monica.paid_plan_friendly_name'), config('monica.paid_plan_id'))
+                    ->create($stripeToken);
+
+        return redirect('settings/subscriptions');
+    }
+
+    /**
+     * Download the invoice as PDF
+     *
+     * @return \Illuminate\Http\Response
+     */
+    public function downloadInvoice(Request $request, $invoiceId)
+    {
+        return auth()->user()->account->downloadInvoice($invoiceId, [
+            'vendor'  => 'Monica',
+            'product' => trans('settings.subscriptions_pdf_title', ['name' => config('monica.paid_plan_friendly_name')]),
+        ]);
+    }
+}