Offer lnurl-pay QR codes for download on the Lightning page

app/controllers/services/lightning_controller.rb

@@ -1,4 +1,5 @@
 require "rqrcode"
+require "lnurl"
 
 class Services::LightningController < ApplicationController
   before_action :authenticate_user!
@@ -8,9 +9,55 @@ class Services::LightningController < ApplicationController
 
   def index
     @wallet_url = "lndhub://#{current_user.ln_account}:#{current_user.ln_password}@#{ENV['LNDHUB_PUBLIC_URL']}"
+    initialize_lndhub_qr_code
+  end
 
-    qrcode = RQRCode::QRCode.new(@wallet_url)
-    @svg = qrcode.as_svg(
+  def transactions
+    @transactions = fetch_transactions
+  end
+
+  def qr_lnurlp
+    lnurlp_url = "https://kosmos.org/.well-known/lnurlp/#{current_user.cn}"
+    lnurlp_bech32 = Lnurl.new(lnurlp_url).to_bech32
+    qr_code = RQRCode::QRCode.new("lightning:" + lnurlp_bech32)
+
+    if params[:format] == "svg"
+      qr_svg = qr_code.as_svg(
+        color: "000",
+        shape_rendering: "crispEdges",
+        module_size: 6,
+        standalone: true,
+        use_path: true,
+        svg_attributes: {
+          class: 'inline-block'
+        }
+      )
+      send_data(
+        qr_svg,
+        filename: "bitcoin-lightning-#{current_user.address}.svg",
+        type: "image/svg+xml"
+      )
+    elsif params[:format] == "png"
+      qr_png = qr_code.as_png(
+        fill: "white",
+        color: "black",
+        size: 1024,
+      )
+      send_data(
+        qr_png,
+        filename: "bitcoin-lightning-#{current_user.address}.png",
+        type: "image/png"
+      )
+    else
+      http_status :not_found
+    end
+  end
+
+  private
+
+  def initialize_lndhub_qr_code
+    qr_code = RQRCode::QRCode.new(@wallet_url)
+    @lndhub_qr_svg = qr_code.as_svg(
       color: "000",
       shape_rendering: "crispEdges",
       module_size: 6,
@@ -22,12 +69,6 @@ class Services::LightningController < ApplicationController
     )
   end
 
-  def transactions
-    @transactions = fetch_transactions
-  end
-
-  private
-
   def authenticate_with_lndhub(options={})
     if session[:ln_auth_token].present? && !options[:force_reauth]
       @ln_auth_token = session[:ln_auth_token]