add coupon

app/dashboard/templates/dashboard/coupon.html

@@ -0,0 +1,28 @@
+{% extends 'default.html' %}
+
+{% set active_page = "dashboard" %}
+
+{% block title %}
+  Coupon
+{% endblock %}
+
+{% block default_content %}
+  <div class="card">
+    <div class="card-body">
+      <h1 class="h2">Coupon</h1>
+
+      <div class="mb-4">
+        Please enter the coupon here to upgrade your account or extend your current subscription.
+      </div>
+
+      <form method="post">
+        {{ coupon_form.csrf_token }}
+
+        {{ coupon_form.code(class="form-control", placeholder="Licence Code") }}
+        {{ render_field_errors(coupon_form.code) }}
+        <button class="btn btn-success mt-2">Apply</button>
+      </form>
+    </div>
+  </div>
+
+{% endblock %}

app/dashboard/templates/dashboard/lifetime_licence.html

@@ -7,9 +7,9 @@
 {% endblock %}
 
 {% block default_content %}
-  <div class="row">
-    <div class="col">
-      <h1 class="h3">Lifetime Licence</h1>
+  <div class="card">
+    <div class="card-body">
+      <h1 class="h2">Lifetime Licence</h1>
 
       <div class="mb-4">
         If you have a lifetime licence, please paste it here. <br>

app/dashboard/views/coupon.py

@@ -0,0 +1,87 @@
+import arrow
+from flask import render_template, flash, redirect, url_for
+from flask_login import login_required, current_user
+from flask_wtf import FlaskForm
+from wtforms import StringField, validators
+
+from app.config import ADMIN_EMAIL
+from app.dashboard.base import dashboard_bp
+from app.email_utils import send_email
+from app.extensions import db
+from app.models import ManualSubscription, Coupon
+
+
+class CouponForm(FlaskForm):
+    code = StringField("Coupon Code", validators=[validators.DataRequired()])
+
+
+@dashboard_bp.route("/coupon", methods=["GET", "POST"])
+@login_required
+def coupon_route():
+    if current_user.lifetime:
+        flash("You already have a lifetime licence", "warning")
+        return redirect(url_for("dashboard.index"))
+
+    # handle case user already has an active subscription via another channel (Paddle, Apple, etc)
+    if current_user._lifetime_or_active_subscription():
+        manual_sub: ManualSubscription = ManualSubscription.get_by(
+            user_id=current_user.id
+        )
+
+        # user has an non-manual subscription
+        if not manual_sub or not manual_sub.is_active():
+            flash("You already have another subscription.", "warning")
+            return redirect(url_for("dashboard.index"))
+
+    coupon_form = CouponForm()
+
+    if coupon_form.validate_on_submit():
+        code = coupon_form.code.data
+
+        coupon: Coupon = Coupon.get_by(code=code)
+        if coupon and not coupon.used:
+            coupon.used_by_user_id = current_user.id
+            coupon.used = True
+            db.session.commit()
+
+            manual_sub: ManualSubscription = ManualSubscription.get_by(
+                user_id=current_user.id
+            )
+            if manual_sub:
+                # renew existing subscription
+                if manual_sub.end_at > arrow.now():
+                    manual_sub.end_at = manual_sub.end_at.shift(years=coupon.nb_year)
+                else:
+                    manual_sub.end_at = arrow.now().shift(years=coupon.nb_year, days=1)
+                db.session.commit()
+                flash(
+                    f"Your current subscription is extended to {manual_sub.end_at.humanize()}",
+                    "success",
+                )
+            else:
+                ManualSubscription.create(
+                    user_id=current_user.id,
+                    end_at=arrow.now().shift(years=coupon.nb_year, days=1),
+                    comment="using coupon code",
+                    is_giveaway=False,
+                    commit=True,
+                )
+                flash(
+                    f"Your account has been upgraded to Premium, thanks for your support!",
+                    "success",
+                )
+
+            # notify admin
+            send_email(
+                ADMIN_EMAIL,
+                subject=f"User {current_user} applies the coupon",
+                plaintext="",
+                html="",
+            )
+
+            return redirect(url_for("dashboard.index"))
+
+        else:
+            flash(f"Code *{code}* expired or invalid", "warning")
+
+    return render_template("dashboard/coupon.html", coupon_form=coupon_form)