contentful.rb

require_relative "helpers"

module Jekyll
  class ContentfulGenerator < Generator
    include Helpers

    priority :high # Execute first
    safe true

    # Generates Jekyll::Collections and Documents from the YAML file written by Contentful's Jekyll
    # plugin. Documents are similar to Pages in Jekyll, but work better for data-driven use case,
    # e.g. by automatically parsing Collection-level frontmatter defaults from _config.yml.
    def generate(site)
      # Select space using id defined in _config/ file
      data = site.data["contentful"]["spaces"][site.config["id"]]

      @sections = {}

      data.fetch("section", []).each do |attributes|
        find_or_generate_section(site, attributes)
      end

      data.fetch("page", []).each do |attributes|
        # Pages within a section render within that section, like /:section/:page/
        section = @sections[attributes["section"]["sys"]["id"]] if attributes.key?("section")

        # Pages without a section go in "orphans" and render at the root level, like /:page/. The
        # orphans collection is defined by _config.yml.
        section ||= site.collections["orphans"]

        generate_page(site, section, attributes)
      end

      if press_releases_section = site.collections["press-releases"]
        data.fetch("pressRelease", []).each do |attributes|
          attributes["date"] = attributes["date"].utc # Undo implicit time zone conversion
          page = generate_page(site, press_releases_section, attributes)
          page.data["breadcrumbs"][-1]["title"] = attributes["date"].strftime("%B %-d, %Y")
          page.data["photo_url"] = attributes["picture"]["url"] if attributes["picture"].present?
          page.data["preview_text"] = attributes["previewText"] if attributes["previewText"].present?
        end
      end
    end

    private

    def find_or_generate_section(site, attributes)
      return @sections[attributes["sys"]["id"]] if @sections.key?(attributes["sys"]["id"])

      label = Utils.slugify(attributes["slug"])
      section = Collection.new(site, label)
      section.metadata["output"] = true
      section.metadata["permalink"] = "/#{label}/:slug/" # Child page URL template

      site.collections[label] = section

      if attributes.key?("parentSection")
        parent = find_or_generate_section(site, attributes["parentSection"])

        # Prepend parent path to this section's child page URL template
        section.metadata["permalink"] = parent.metadata["permalink"].sub(":slug", "#{label}/:slug")
      else
        # Add root-level section pages to default collection (defined in _config.yml)
        parent = site.collections["sections"]
      end

      page = generate_page(site, parent, attributes)
      page.data["docs"] = section.docs
      page.data["layout"] = "section" if page.data["layout"] == "page"

      # Breadcrumbs inherited by child pages (includes parents of this section, if any)
      section.metadata["breadcrumbs"] = page.data["breadcrumbs"]

      @sections[attributes["sys"]["id"]] = section
    end

    def generate_page(site, section, attributes)
      slug = Utils.slugify(attributes["slug"])
      path = section.collection_dir("#{slug}.html")

      doc = Document.new(path, site: site, collection: section)

      # A Page with the same URL as a Section extends the existing section doc
      if existing_doc = site.docs_to_write.find { |existing| existing.url == doc.url }
        doc = existing_doc
        doc.data["contentful_ids"] << attributes["sys"]["id"]
      else
        doc = match_optional_custom_template(section, doc)
        doc.data["contentful_ids"] = [attributes["sys"]["id"]]
        section.docs << doc
      end

      doc.data["title"] = attributes["title"]
      doc.data["slug"] = slug
      doc.data["priority"] = attributes["priority"] if attributes.key?("priority")
      doc.data["date"] = attributes["date"] if attributes.key?("date")
      doc.data["contentful"] = attributes

      # Pass redirects from Contentful to jekyll-redirect-from
      doc.data["redirect_from"] = attributes["redirectFrom"] if attributes["redirectFrom"]

      set_breadcrumbs(doc, section)

      doc
    end

    # If _templates contains a file with the same URL (i.e. path, by default) as the Page, we render
    # that file instead of the default layout.
    def match_optional_custom_template(section, doc)
      templates = section.site.collections["templates"].docs

      if template = templates.find { |template| template.url.sub("/templates", "") == doc.url }
        doc.instance_variable_set(:@path, template.path)
        doc.read
      end

      doc
    end

  end
end