Landing pages backend scaffold

app/controllers/landing_page_controller.rb

@@ -0,0 +1,32 @@
+class LandingPageController < ContentItemsController
+  # SCAFFOLDING: can be removed when basic content items are available
+  # from content-store
+  def request_content_item(_base_path)
+    GdsApi.content_store.content_item(request.path)
+  rescue StandardError
+    fake_data
+  end
+
+  # SCAFFOLDING: can be removed when basic content items are available
+  # from content-store
+  def fake_data
+    {
+      "base_path" => request.path,
+      "title" => "Landing Page",
+      "description" => "A landing page example",
+      "locale" => "en",
+      "document_type" => "landing_page",
+      "schema_name" => "landing_page",
+      "publishing_app" => "whitehall",
+      "rendering_app" => "frontend",
+      "update_type" => "major",
+      "details" => {},
+      "routes" => [
+        {
+          "type" => "exact",
+          "path" => request.path,
+        },
+      ],
+    }
+  end
+end

app/helpers/block_helper.rb

@@ -0,0 +1,45 @@
+module BlockHelper
+  def tab_items_to_component_format(tab_items)
+    tab_items.map do |ti|
+      {
+        id: ti["id"],
+        label: ti["label"],
+        content: sanitize("<p class=\"govuk-body-m\">#{ti['content']}</p>"),
+      }
+    end
+  end
+
+  def column_class_for_equal_columns(number_of_columns)
+    case number_of_columns
+    when 1
+      "govuk-grid-column"
+    when 2
+      "govuk-grid-column-one-half"
+    when 3
+      "govuk-grid-column-one-third"
+    else
+      "govuk-grid-column-one-quarter"
+    end
+  end
+
+  def column_class_for_assymetric_columns(number_of_columns, column_size)
+    case number_of_columns
+    when 3
+      case column_size
+      when 1
+        "govuk-grid-column-one-third"
+      when 2
+        "govuk-grid-column-two-thirds"
+      end
+    when 4
+      case column_size
+      when 1
+        "govuk-grid-column-one-quarter"
+      when 2
+        "govuk-grid-column-two-quarters"
+      when 3
+        "govuk-grid-column-three-quarters"
+      end
+    end
+  end
+end

app/models/block/base.rb

@@ -0,0 +1,11 @@
+module Block
+  class Base
+    attr_reader :id, :type, :data
+
+    def initialize(block_hash)
+      @data = block_hash
+      @id = data["id"]
+      @type = data["type"]
+    end
+  end
+end

app/models/block/columns_layout.rb

@@ -0,0 +1,5 @@
+module Block
+  class ColumnsLayout < Block::LayoutBase
+    alias_method :columns, :blocks
+  end
+end

app/models/block/layout_base.rb

@@ -0,0 +1,11 @@
+module Block
+  class LayoutBase < Block::Base
+    attr_reader :blocks
+
+    def initialize(block_hash)
+      super(block_hash)
+
+      @blocks = data["blocks"].map { |subblock_hash| BlockFactory.build(subblock_hash) }
+    end
+  end
+end

app/models/block/two_column_layout.rb

@@ -0,0 +1,26 @@
+module Block
+  class TwoColumnLayout < Block::LayoutBase
+    attr_reader :left, :right, :theme
+    alias_method :columns, :blocks
+
+    def initialize(block_hash)
+      super(block_hash)
+
+      @left = columns[0]
+      @right = columns[1]
+      @theme = data["theme"]
+    end
+
+    def left_column_size
+      theme == "two_thirds_one_third" ? 2 : 1
+    end
+
+    def right_column_size
+      theme == "one_third_two_thirds" ? 2 : 1
+    end
+
+    def total_columns
+      left_column_size + right_column_size
+    end
+  end
+end

app/models/block_factory.rb

@@ -0,0 +1,12 @@
+class BlockFactory
+  def self.build(block_hash)
+    block_class(block_hash["type"]).new(block_hash)
+  end
+
+  def self.block_class(type)
+    klass = "Block::#{type.camelize}".constantize
+    klass.ancestors.include?(Block::Base) ? klass : Block::Base
+  rescue StandardError
+    Block::Base
+  end
+end

app/models/content_item_factory.rb

@@ -1,9 +1,12 @@
 class ContentItemFactory
   def self.build(content_hash)
-    content_item_class(content_hash).new(content_hash)
+    content_item_class(content_hash["document_type"]).new(content_hash)
   end
 
-  def self.content_item_class(_content_hash)
+  def self.content_item_class(document_type)
+    klass = document_type.camelize.constantize
+    klass.superclass == ContentItem ? klass : ContentItem
+  rescue StandardError
     ContentItem
   end
 end

app/models/landing_page.rb

@@ -0,0 +1,25 @@
+class LandingPage < ContentItem
+  attr_reader :blocks
+
+  def initialize(content_store_response)
+    if content_store_response.dig("details", "blocks")
+      super(content_store_response)
+    else
+      super(content_store_response.deep_merge(load_additional_content(content_store_response["base_path"])))
+    end
+
+    @blocks = (@content_store_response.dig("details", "blocks") || []).map { |block_hash| BlockFactory.build(block_hash) }
+  end
+
+private
+
+  # SCAFFOLDING: can be removed (and reference above) when full content items
+  # including block details are available from content-store
+  def load_additional_content(base_path)
+    file_slug = base_path.split("/").last.gsub("-", "_")
+    filename = Rails.root.join("lib/data/landing_page_content_items/#{file_slug}.yaml")
+    return { "details" => {} } unless File.exist?(filename)
+
+    { "details" => YAML.load(File.read(filename)) }
+  end
+end

app/views/landing_page/blocks/_big_number.html.erb

@@ -0,0 +1,4 @@
+<%= render "govuk_publishing_components/components/big_number", {
+  number: block.data["number"],
+  label: block.data["label"],
+} %>

app/views/landing_page/blocks/_columns_layout.html.erb

@@ -0,0 +1,5 @@
+<div class="govuk-grid-row">
+  <% block.columns.each do |column| %>
+    <div class="<%= column_class_for_equal_columns(block.columns.count) %>"><%= render "landing_page/blocks/#{column.type}", block: column %></div>
+  <% end %>
+</div>

app/views/landing_page/blocks/_govspeak.html.erb

@@ -0,0 +1,4 @@
+<%= render "govuk_publishing_components/components/govspeak", {
+} do %>
+  <%= block.data["content"].html_safe %>
+<% end %>

app/views/landing_page/blocks/_tabs.html.erb

@@ -0,0 +1,3 @@
+<%= render "govuk_publishing_components/components/tabs", {
+  tabs: tab_items_to_component_format(block.data["tab_items"]),
+} %>

app/views/landing_page/blocks/_two_column_layout.html.erb

@@ -0,0 +1,8 @@
+<div class="govuk-grid-row">
+  <div class="<%= column_class_for_assymetric_columns(block.total_columns, block.left_column_size) %>">
+    <%= render "landing_page/blocks/#{block.left.type}", block: block.left %>
+  </div>
+  <div class="<%= column_class_for_assymetric_columns(block.total_columns, block.right_column_size) %>">
+    <%= render "landing_page/blocks/#{block.right.type}", block: block.right %>
+  </div>
+</div>

app/views/landing_page/show.html.erb

@@ -0,0 +1,9 @@
+
+<div class="landing-page">
+  <% @content_item.blocks.each do |block| %>
+    <%= render "landing_page/blocks/#{block.type}", block: %>
+  <% end %>
+  <% if @content_item.blocks.empty? %>
+    Warning: No blocks specified for this page
+  <% end %>
+</div>

config/routes.rb

@@ -29,6 +29,15 @@
 
   get "/foreign-travel-advice", to: "travel_advice#index", as: :travel_advice
 
+  scope "/landing-page" do
+    get "/", to: "landing_page#show"
+    get "/*any", to: "landing_page#show"
+  end
+
+  constraints FormatRoutingConstraint.new("landing_page") do
+    get ":slug", to: "landing_page#show"
+  end
+
   # Accounts
   get "/sign-in", to: "help#sign_in"
   get "/sign-in/redirect", to: "sessions#create"

lib/data/landing_page_content_items/landing_page.yaml

@@ -0,0 +1,43 @@
+blocks:
+- type: govspeak
+  content: |
+    <h2>Here's a heading</h2>
+    <p>Here's some content!</p>
+    <p>Here's some more content</p>
+    <ul>
+      <li>What?</li>
+      <li>When?</li>
+    </ul>
+    <a href="/landing-page/sub-page-1">Visit sub-page 1</a>
+- type: tabs
+  id: landing-pages-item-selector
+  tab_items:
+  - id: tab-1
+    label: Item 1
+    content: Here's the content for item one
+  - id: tab-2
+    label: Item 2
+    content: Here's the content for item two
+- type: govspeak
+  content: <p>Here's some more content!</p>
+- type: two_column_layout
+  theme: two_thirds_one_third
+  blocks:
+  - type: govspeak
+    content: <p>Left content!</p>
+  - type: govspeak
+    content: <p>Right content!</p>
+- type: govspeak
+  content: <h2>Statistics</h2>
+- type: columns_layout
+  blocks:
+  - type: big_number
+    number: £75m
+    label: amount of money that looks big
+  - type: big_number
+    number: 100%
+    label: increase in the number of big_number components added to the columns at this point
+  - type: big_number
+    number: £43
+    label: Cost of a cup of coffee in Covent Garden
+

lib/data/landing_page_content_items/sub_page_1.yaml

@@ -0,0 +1,5 @@
+blocks:
+- type: govspeak
+  content: |
+    <h2>Sub Page 1</h2>
+    <a href="/landing-page">Back to main landing page</a>