feat: ASCOR emissions chart data

app/assets/stylesheets/tpi/pages/ascor.scss

@@ -140,6 +140,32 @@
     }
   }
 
+  .emissions-chart-header {
+    margin-bottom: 20px;
+
+    @include desktop {
+      display: flex;
+      justify-content: space-between;
+      align-items: center;
+    }
+
+    &__assessment-dropdown {
+      display: flex;
+      align-items: center;
+      gap: 10px;
+    }
+  }
+
+  .emissions-chart-description {
+    margin-bottom: 40px;
+    font-size: 14px;
+    line-height: 1.75;
+
+    @include desktop {
+      max-width: 60%;
+    }
+  }
+
   section {
     margin-top: 70px;
 

app/controllers/tpi/ascor_controller.rb

@@ -3,6 +3,7 @@ class ASCORController < TPIController
     before_action :fetch_ascor_countries, only: [:index, :show]
     before_action :fetch_ascor_country, only: [:show]
     before_action :fetch_assessment_date, only: [:index, :show, :index_assessment]
+    before_action :fetch_emissions_assessment_date, only: [:index]
     before_action :fetch_ascor_assessment_results, only: [:index, :index_assessment]
 
     def index
@@ -22,6 +23,19 @@ def show
 
     def index_assessment; end
 
+    def index_emissions_assessment; end
+
+    def emissions_chart_data
+      data = ::Api::ASCOR::EmissionsChart.new(
+        @emissions_assessment_date,
+        params[:emissions_metric],
+        params[:emissions_boundary],
+        params[:country_ids]
+      ).call
+
+      render json: data.chart_json
+    end
+
     def user_download
       render zip: {
         'ASCOR_countries.xlsx' => Api::CSVToExcel.new(CSVExport::ASCOR::Countries.new.call).call,
@@ -47,6 +61,10 @@ def fetch_assessment_date
       @assessment_date = params[:assessment_date] || ASCOR::Assessment.maximum(:assessment_date)
     end
 
+    def fetch_emissions_assessment_date
+      @emissions_assessment_date = params[:emissions_assessment_date] || ASCOR::Assessment.maximum(:assessment_date)
+    end
+
     def fetch_ascor_assessment_results
       @ascor_assessment_results = Api::ASCOR::BubbleChart.new(@assessment_date).call
     end

app/models/ascor/country.rb

@@ -38,6 +38,7 @@ class ASCOR::Country < ApplicationRecord
     'Annex I',
     'Non-Annex I'
   ].freeze
+  DEFAULT_COUNTRIES = %w[USA CAN GBR FRA DEU ITA JPN RUS].freeze
 
   friendly_id :name, use: [:slugged, :history], routes: :default
 

app/services/api/ascor/emissions_chart.rb

@@ -0,0 +1,51 @@
+module Api
+  module ASCOR
+    class EmissionsChart
+      attr_accessor :assessment_date, :emissions_assessment_date, :emissions_metric, :emissions_boundary, :country_ids
+
+      def initialize(assessment_date, emissions_metric, emissions_boundary, country_ids)
+        @assessment_date = assessment_date
+        @emissions_metric = emissions_metric || 'Absolute'
+        @emissions_boundary = emissions_boundary || 'Production - excluding LULUCF'
+        @country_ids = country_ids
+      end
+
+      def call
+        {data: collect_data, metadata: collect_metadata}
+      end
+
+      private
+
+      def collect_data
+        countries.each_with_object({}) do |country, result|
+          pathway = pathways[country.id]&.first
+          result[country.id] = {
+            emissions: pathway&.emissions || {},
+            last_historical_year: pathway&.last_historical_year
+          }
+        end
+      end
+
+      def collect_metadata
+        {unit: pathways.values.flatten.first.units}
+      end
+
+      def countries
+        @countries ||= if country_ids.blank?
+                         ::ASCOR::Country.where(iso: ::ASCOR::Country::DEFAULT_COUNTRIES)
+                       else
+                         ::ASCOR::Country.where(id: country_ids)
+                       end
+      end
+
+      def pathways
+        @pathways ||= ::ASCOR::Pathway.where(
+          country: countries,
+          emissions_metric: emissions_metric,
+          emissions_boundary: emissions_boundary,
+          assessment_date: assessment_date
+        ).group_by(&:country_id)
+      end
+    end
+  end
+end

app/views/tpi/ascor/_emissions_chart.html.erb

@@ -0,0 +1,10 @@
+<!-- TODO: React components need to be replaced!!! -->
+<%#= react_component('TODO', {
+  emissions_metric_filter: ASCOR::EmissionsMetric::VALUES,
+  default_emissions_metric_filter: 'Absolute',
+  emissions_boundary_filter: ASCOR::EmissionsBoundary::VALUES,
+  default_emissions_boundary_filter: 'Production - excluding LULUCF',
+  countries: ASCOR::Country.all.map { |c| { id: c.id, iso: c.iso, name: c.name } },
+  default_countries: ASCOR::Country.where(iso: ASCOR::Country::DEFAULT_COUNTRIES).map(&:id),
+  emissions_data_url: index_emissions_assessment_tpi_ascor_index_path
+}) %>

app/views/tpi/ascor/_index_emissions_assessment.js.erb

@@ -0,0 +1,7 @@
+(function () {
+    document.getElementById('emissions-chart').innerHTML = "<%= j render('emissions_chart') %>";
+    const newUrl = new URL(window.location.href);
+    newUrl.searchParams.set('emissions_assessment_date', <%= @assessment_date %>);
+    window.history.replaceState({}, '', newUrl.href);
+    ReactRailsUJS.mountComponents('#emissions-charts');
+})();

app/views/tpi/ascor/index.html.erb

@@ -62,6 +62,37 @@
     </div>
   </section>
 
+  <!-- TODO: Finalise emissions chart section -->
+  <!-- All React component code goes into tpi/ascor/emissions_chart partial -->
+  <section class="container">
+    <div class="emissions-chart-header">
+      <h2 class="is-size-4">
+        Country emission pathways
+      </h2>
+
+      <div class="emissions-chart-header__assessment-dropdown">
+        <div class="caption">
+          Assessment Date:
+        </div>
+        <div class="date-dropdown">
+          <%= react_component('RemoteDropdown', {
+            name: 'emissions_assessment_date',
+            remote: true,
+            url: index_emissions_assessment_tpi_ascor_index_path,
+            data: @assessment_dates.map {|v| {label: v&.strftime('%d %B %Y'), value: v}},
+            selected: @emissions_assessment_date
+          }) %>
+        </div>
+      </div>
+    </div>
+    <div class="emissions-chart-description">
+      Country emission pathways are assessed in several ways to account for a variety of factors and uncertainties. The emission metrics considered include the following options: production and consumption-based emissions; exclusion of LULUCF emissions and LULUCF emissions alone; and emissions on an absolute and intensity basis (per capita and per PPP-adjusted GDP). Targeted future pathways are included only for absolute production-based emissions excluding LULUCF as this is the basis on which 2030 targets are assessed. Note that pathways end in 2030 because long-term net zero targets are often stated on a different emission boundary from the one considered in the 2030 target assessments (e.g. including only CO₂ emissions rather than all Kyoto greenhouse gases).
+    </div>
+    <div id="emissions-chart">
+      <%= render 'tpi/ascor/emissions_chart' %>
+    </div>
+  </section>
+
   <% if @methodology_publication.present? %>
     <section id="methodology" class="container">
       <div class="columns">

config/routes.rb

@@ -57,6 +57,8 @@
       resources :ascor, only: [:show, :index] do
         collection do
           get :index_assessment
+          get :index_emissions_assessment
+          get :emissions_chart_data
           get :user_download
         end
       end

spec/services/api/ascor/emissions_chart_spec.rb

@@ -0,0 +1,99 @@
+require 'rails_helper'
+
+RSpec.describe Api::ASCOR::EmissionsChart do
+  subject { described_class.new(assessment_date, emissions_metric, emissions_boundary, country_ids).call }
+
+  before_all do
+    @usa = create(:ascor_country, id: 1, name: 'USA', iso: 'USA')
+    @czechia = create(:ascor_country, id: 2, name: 'Czechia', iso: 'CZE')
+
+    create :ascor_pathway,
+           country: @usa,
+           assessment_date: Date.new(2019, 1, 1),
+           emissions_metric: 'Intensity per capita',
+           emissions_boundary: 'Consumption - excluding LULUCF',
+           emissions: {2013 => 100, 2014 => 100, 2015 => 100}
+    create :ascor_pathway,
+           country: @usa,
+           assessment_date: Date.new(2019, 2, 1),
+           emissions_metric: 'Intensity per capita',
+           emissions_boundary: 'Consumption - excluding LULUCF',
+           emissions: {2013 => 110, 2014 => 110, 2015 => 110}
+    create :ascor_pathway,
+           country: @czechia,
+           assessment_date: Date.new(2019, 2, 1),
+           emissions_metric: 'Intensity per capita',
+           emissions_boundary: 'Consumption - excluding LULUCF',
+           emissions: {2013 => 120, 2014 => 120, 2015 => 120}
+    create :ascor_pathway,
+           country: @usa,
+           assessment_date: Date.new(2019, 2, 1),
+           emissions_metric: 'Absolute',
+           emissions_boundary: 'Production - excluding LULUCF',
+           emissions: {2013 => 130, 2014 => 130, 2015 => 130}
+    create :ascor_pathway,
+           country: @czechia,
+           assessment_date: Date.new(2019, 2, 1),
+           emissions_metric: 'Absolute',
+           emissions_boundary: 'Production - excluding LULUCF',
+           emissions: {2013 => 140, 2014 => 140, 2015 => 140}
+  end
+
+  let(:assessment_date) { Date.new(2019, 2, 1) }
+  let(:emissions_metric) { 'Intensity per capita' }
+  let(:emissions_boundary) { 'Consumption - excluding LULUCF' }
+  let(:country_ids) { [@usa.id, @czechia.id] }
+
+  it 'returns expected result' do
+    expect(subject).to eq(
+      data: {
+        @usa.id => {
+          emissions: {'2013' => 110, '2014' => 110, '2015' => 110},
+          last_historical_year: 2010
+        },
+        @czechia.id => {
+          emissions: {'2013' => 120, '2014' => 120, '2015' => 120},
+          last_historical_year: 2010
+        }
+      },
+      metadata: {unit: 'MtCO2e'}
+    )
+  end
+
+  context 'when country_ids are nil' do
+    let(:country_ids) { nil }
+
+    it 'returns expected result' do
+      expect(subject).to eq(
+        data: {
+          @usa.id => {
+            emissions: {'2013' => 110, '2014' => 110, '2015' => 110},
+            last_historical_year: 2010
+          }
+        },
+        metadata: {unit: 'MtCO2e'}
+      )
+    end
+  end
+
+  context 'when emissions_metric and emissions_boundary is nil' do
+    let(:emissions_metric) { nil }
+    let(:emissions_boundary) { nil }
+
+    it 'returns expected result' do
+      expect(subject).to eq(
+        data: {
+          @usa.id => {
+            emissions: {'2013' => 130, '2014' => 130, '2015' => 130},
+            last_historical_year: 2010
+          },
+          @czechia.id => {
+            emissions: {'2013' => 140, '2014' => 140, '2015' => 140},
+            last_historical_year: 2010
+          }
+        },
+        metadata: {unit: 'MtCO2e'}
+      )
+    end
+  end
+end