Add Forms funnel and Ineligible forms funnel

These widget have the ability to change the date_range of the
formsfunnelquery but defaults to the last 24 hours.

The date range filter feature is soft launched at the moment and
is only usable via the url
`/system-admin/dashboard?date_range[unit]=hours&date_range[range_start]=48&date_range[range_end]=24`

app/controllers/system_admin/dashboard_controller.rb

@@ -1,7 +1,20 @@
 module SystemAdmin
   class DashboardController < AdminController
     def show
-      @kpis = Kpis.new
+      @kpis = Kpis.new(**kpi_params)
+    rescue ArgumentError => e
+      flash[:alert] = e.message
+      redirect_to(dashboard_path)
+    end
+
+  private
+
+    def kpi_params
+      params
+        .fetch(:date_range, {})
+        .permit(:unit, :range_start, :range_end)
+        .to_hash
+        .symbolize_keys
     end
   end
 end

app/models/kpis.rb

@@ -1,8 +1,11 @@
 class Kpis
-  def initialize
-    @applications = Applicant.all
+  def initialize(unit: "hours", range_start: "24", range_end: "0")
+    @date_range_params = parse_date_range(unit:, range_start:, range_end:)
+    @date_range = to_date_range(**@date_range_params)
   end
 
+  attr_reader :date_range, :date_range_params
+
   def total_applications
     Application.count
   end
@@ -66,4 +69,47 @@ def time_to_payment_confirmation
   def status_breakdown
     StatusBreakdownQuery.call
   end
+
+  def forms_funnel
+    forms_funnel_query
+  end
+
+  def ineligible_forms_funnel
+    normal_steps = %w[personal-details employment-details submission]
+
+    forms_funnel_query.except(*normal_steps)
+  end
+
+  def funnel_date_range_title
+    if date_range_params.fetch(:range_end).zero?
+      ["last", date_range_params.fetch(:range_start), date_range_params.fetch(:unit)].join(" ")
+    else
+      ["between", date_range_params.fetch(:range_start), "and", date_range_params.fetch(:range_end), date_range_params.fetch(:unit), "ago"].join(" ")
+    end
+  end
+
+private
+
+  def parse_date_range(unit:, range_start:, range_end:)
+    raise(ArgumentError, "invalid unit value, must be hours or days") unless %w[hours days].include?(unit)
+
+    range_end = range_end.to_i
+    range_start = range_start.to_i
+
+    raise(ArgumentError, "range_end and range_start must be positive numbers") if range_start.negative? || range_end.negative?
+    raise(ArgumentError, "range_end must be lower than range_start") if range_end >= range_start
+
+    { unit:, range_start:, range_end: }
+  end
+
+  def to_date_range(unit:, range_start:, range_end:)
+    Range.new(
+      range_start.public_send(unit).ago,
+      range_end.public_send(unit).ago,
+    )
+  end
+
+  def forms_funnel_query
+    @forms_funnel_query ||= FormsFunnelQuery.call(date_range:)
+  end
 end

app/views/system_admin/dashboard/show.html.erb

@@ -153,5 +153,30 @@
     </table>
   </div>
 
+  <div class="kpi-widget form-funnel">
+    <h3 class="title">Forms funnel</h3>
+    <h6 class="subtitle"><%= @kpis.funnel_date_range_title %></h6>
+    <table class="kpi-table">
+      <% @kpis.forms_funnel.each do |path,v|%>
+        <tr>
+          <td><%= path %></td>
+          <td><%= v[:eligible] %></td>
+        </tr>
+      <% end %>
+    </table>
+  </div>
+
+  <div class="kpi-widget ineligibility-funnel">
+    <h3 class="title">Ineligible forms funnel</h3>
+    <h6 class="subtitle"><%= @kpis.funnel_date_range_title %></h6>
+    <table class="kpi-table">
+      <% @kpis.ineligible_forms_funnel.each do |path,v|%>
+        <tr>
+          <td><%= path %></td>
+          <td><%= v[:ineligible] %></td>
+        </tr>
+      <% end %>
+    </table>
+  </div>
 
 </div>

spec/models/kpis_spec.rb

@@ -1,35 +1,77 @@
 require "rails_helper"
 
 RSpec.describe Kpis do
-  describe "#total_applications" do
-    it "returns the total number of applications" do
-      create_list(:application, 5)
+  subject(:kpis) { described_class.new(unit:, range_start:, range_end:) }
+
+  let(:unit) { "hours" }
+  let(:range_start) { "12" }
+  let(:range_end) { "0" }
 
-      kpis = described_class.new
+  let(:application) { create(:application) }
 
-      expect(kpis.total_applications).to eq(5)
+  describe "argument error on initialize" do
+    context "when unknown unit" do
+      let(:unit) { "bad" }
+
+      it { expect { kpis }.to raise_error(ArgumentError) }
     end
-  end
 
-  describe "#total_rejections" do
-    it "returns the total number of applications rejected" do
-      application = create(:application)
-      create_list(:application_progress, 5, :rejection_completed, application:)
+    context "when bad range_start and range_end" do
+      let(:range_start) { "bad" }
+      let(:range_end) { "bad" }
+
+      it { expect { kpis }.to raise_error(ArgumentError) }
+    end
+
+    context "when range_start negative" do
+      let(:range_start) { "-15" }
+
+      it { expect { kpis }.to raise_error(ArgumentError) }
+    end
+
+    context "when range_end negative" do
+      let(:range_end) { "-15" }
+
+      it { expect { kpis }.to raise_error(ArgumentError) }
+    end
 
-      stats = described_class.new
+    context "when range_end value greater than range_start" do
+      let(:range_start) { "15" }
+      let(:range_end) { "24" }
 
-      expect(stats.total_rejections).to eq(5)
+      it { expect { kpis }.to raise_error(ArgumentError) }
     end
   end
 
+  describe "#total_applications" do
+    before { create_list(:application, 5) }
+
+    it { expect(kpis.total_applications).to eq(5) }
+  end
+
+  describe "#total_rejections" do
+    before { create_list(:application_progress, 5, :rejection_completed, application:) }
+
+    it { expect(kpis.total_rejections).to eq(5) }
+  end
+
   describe "#total_paid" do
-    it "returns the total number of applications paid" do
-      application = create(:application)
-      create_list(:application_progress, 5, :banking_approval_completed, application:)
+    before { create_list(:application_progress, 5, :banking_approval_completed, application:) }
+
+    it { expect(kpis.total_paid).to eq(5) }
+  end
+
+  describe "funnel_date_range_title" do
+    context "when range_end is set to 0" do
+      let(:range_end) { 0 }
+
+      it { expect(kpis.funnel_date_range_title).to eq("last 12 hours") }
+    end
 
-      stats = described_class.new
+    context "when range_end is not 0" do
+      let(:range_end) { 6 }
 
-      expect(stats.total_paid).to eq(5)
+      it { expect(kpis.funnel_date_range_title).to eq("between 12 and 6 hours ago") }
     end
   end
 end