From 98a29785a7d5f81621d844d6e92509d92f6c1a57 Mon Sep 17 00:00:00 2001
From: Maikel Linke <maikel@email.org.au>
Date: Fri, 17 May 2024 16:11:28 +1000
Subject: [PATCH 1/2] Load large on-screen reports on demand

Sending large reports via Cable Ready is unreliable. The events are
dropped at an unknown point and the report is never displayed to the
user. Instead we just send a link to the report via Cable Ready and
offer a button to load the report on screen.

This has the UX benefit of warning the user about the size as well.
Weaker devices can struggle rendering big HTML documents.
---
 app/jobs/report_job.rb                     |  9 +++++++-
 app/views/admin/reports/_display.html.haml |  5 +++++
 config/locales/en.yml                      |  3 +++
 spec/system/admin/reports_spec.rb          | 24 ++++++++++++++++++++++
 4 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 app/views/admin/reports/_display.html.haml

diff --git a/app/jobs/report_job.rb b/app/jobs/report_job.rb
index c72cb98b2e..a372dd26e2 100644
--- a/app/jobs/report_job.rb
+++ b/app/jobs/report_job.rb
@@ -53,7 +53,14 @@ class ReportJob < ApplicationJob
   end
 
   def actioncable_content(format, blob)
-    return blob.result if format.to_sym == :html
+    if format.to_sym == :html
+      return blob.result if blob.byte_size < 10**6 # 1 MB
+
+      return render(
+        partial: "admin/reports/display",
+        locals: { file_url: blob.expiring_service_url }
+      )
+    end
 
     render(partial: "admin/reports/download", locals: { file_url: blob.expiring_service_url })
   end
diff --git a/app/views/admin/reports/_display.html.haml b/app/views/admin/reports/_display.html.haml
new file mode 100644
index 0000000000..b87ab0345d
--- /dev/null
+++ b/app/views/admin/reports/_display.html.haml
@@ -0,0 +1,5 @@
+.download
+  %p.notice= t ".report_is_big"
+  %p= link_to t(".display_anyway"), file_url, target: "_blank",
+    class: "button icon icon-file",
+    onclick: "(async function (element) { element.outerHTML = await (await (await fetch(element.href))).text() })(this); return false;"
diff --git a/config/locales/en.yml b/config/locales/en.yml
index e4be4f6843..1f840a585a 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -1670,6 +1670,9 @@ en:
       pack_by_customer: Pack By Customer
       pack_by_supplier: Pack By Supplier
       pack_by_product: Pack By Product
+      display:
+        report_is_big: "This report is big and may slow down your device."
+        display_anyway: "Display anyway"
       download:
         button: "Download Report"
       show:
diff --git a/spec/system/admin/reports_spec.rb b/spec/system/admin/reports_spec.rb
index a8de146328..ba860cf264 100644
--- a/spec/system/admin/reports_spec.rb
+++ b/spec/system/admin/reports_spec.rb
@@ -55,6 +55,30 @@ RSpec.describe '
       expect(page).to have_content "Müller"
     end
 
+    it "requires confirmation to display big reports" do
+      # Mock data is much faster and accurate than creating many orders:
+      allow_any_instance_of(Reporting::Reports::Customers::Base)
+        .to receive(:columns).and_return(
+          {
+            first_name: proc { |_| "Little Bobby Tables " * (10**5) }, # 2 MB
+          }
+        )
+
+      # We still need an order for the report to render a row:
+      create(:completed_order_with_totals)
+
+      login_as_admin
+      visit admin_report_path(report_type: :customers)
+      run_report
+
+      expect(page).to have_content "This report is big"
+      expect(page).not_to have_content "Little Bobby Tables"
+
+      click_on "Display anyway"
+      expect(page).to have_content "FIRST NAME"
+      expect(page).to have_content "Little Bobby Tables"
+    end
+
     it "displays a friendly timeout message and offers download" do
       login_as_admin
       visit admin_report_path(report_type: :customers)

From c8e134cef55686696ff9140e90b839525ddc6668 Mon Sep 17 00:00:00 2001
From: Maikel <maikel@email.org.au>
Date: Tue, 25 Jun 2024 11:50:01 +1000
Subject: [PATCH 2/2] Remove redundant `wait` loading report content

Co-authored-by: Gaetan Craig-Riou <40413322+rioug@users.noreply.github.com>
---
 app/views/admin/reports/_display.html.haml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/views/admin/reports/_display.html.haml b/app/views/admin/reports/_display.html.haml
index b87ab0345d..777710540c 100644
--- a/app/views/admin/reports/_display.html.haml
+++ b/app/views/admin/reports/_display.html.haml
@@ -2,4 +2,4 @@
   %p.notice= t ".report_is_big"
   %p= link_to t(".display_anyway"), file_url, target: "_blank",
     class: "button icon icon-file",
-    onclick: "(async function (element) { element.outerHTML = await (await (await fetch(element.href))).text() })(this); return false;"
+    onclick: "(async function (element) { element.outerHTML = await (await fetch(element.href)).text() })(this); return false;"