[FS-13] Show QR code in app panel (#30)

Gemfile

@@ -83,3 +83,4 @@ gem "combined_time_select", "~> 2.0"
 gem "devise", "~> 4.9"
 gem "ice_cube", "~> 0.17.0"
 gem "pundit", "~> 2.4"
+gem "rqrcode", "~> 2.2", require: false

Gemfile.lock

@@ -97,6 +97,7 @@ GEM
       regexp_parser (>= 1.5, < 3.0)
       xpath (~> 3.2)
     choice (0.2.0)
+    chunky_png (1.4.0)
     combined_time_select (2.0.0)
       rails (>= 5.0.0)
     concurrent-ruby (1.3.5)
@@ -283,6 +284,10 @@ GEM
       actionpack (>= 5.2)
       railties (>= 5.2)
     rexml (3.4.0)
+    rqrcode (2.2.0)
+      chunky_png (~> 1.0)
+      rqrcode_core (~> 1.0)
+    rqrcode_core (1.2.0)
     rspec-core (3.13.2)
       rspec-support (~> 3.13.0)
     rspec-expectations (3.13.3)
@@ -446,6 +451,7 @@ DEPENDENCIES
   pundit (~> 2.4)
   rails (~> 8.0.1)
   rails-erd (~> 1.7)
+  rqrcode (~> 2.2)
   rspec-rails (~> 7.1)
   rubocop (~> 1.70)
   rubocop-capybara (~> 2.21)

app/lib/concerns/callable.rb

@@ -0,0 +1,15 @@
+module Callable
+  extend ActiveSupport::Concern
+
+  class_methods do
+    def call(*, **, &)
+      new(*, **).call(&)
+    end
+  end
+
+  included do
+    def call
+      raise NotImplementedError
+    end
+  end
+end

app/views/app/customers/show.html.erb

@@ -2,3 +2,12 @@
   <i class="bi bi-person-fill"></i>
   <%= @customer.name %>
 </h2>
+
+<div class="row">
+  <div class="col-md-4">
+    <%= QrCode.call Current.customer.id.to_s %>
+  </div>
+
+  <div class="col-md-8">
+  </div>
+</div>

lib/qr_code.rb

@@ -0,0 +1,16 @@
+require "rqrcode"
+
+class QrCode
+  include Callable
+
+  attr_reader :text, :offset
+
+  def initialize(text, offset: 30)
+    @text = text
+    @offset = offset
+  end
+
+  def call
+    RQRCode::QRCode.new(text).as_svg(offset:, viewbox: true).html_safe
+  end
+end

spec/lib/qr_code_spec.rb

@@ -0,0 +1,19 @@
+require 'rails_helper'
+
+RSpec.describe QrCode, type: :model do
+  describe ".call" do
+    let(:text) { "whatever" }
+    let(:offset) { 100 }
+    let(:qr_code) { instance_double("RQRCode::QRCode") }
+    let(:result) { "some valid html" }
+
+    subject { described_class.call(text, offset:) }
+
+    before do
+      allow(RQRCode::QRCode).to receive(:new).with(text).and_return(qr_code)
+      allow(qr_code).to receive(:as_svg).with(offset:, viewbox: true).and_return(result)
+    end
+
+    it { is_expected.to eq(result) }
+  end
+end