require 'article_json'

# parse the HTML export of a Google Document
article = ArticleJSON::Article.from_google_doc_html(google_doc_html)

# initialize article-json format from storage (JSON string)
article = ArticleJSON::Article.from_json(json_string)

# initialize article-json format from storage (already parsed JSON)
article = ArticleJSON::Article.from_hash(parsed_json)

# export article as HTML
puts article.to_html

# export article as AMP
puts article.to_amp
# get javascript libraries needed for the AMP article
puts article.amp_exporter.amp_libraries

# export article as Facebook Instant Article HTML
puts article.to_facebook_instant_article

# export article as plain text
puts article.to_plain_text

# export article as JSON
puts article.to_json

ArticleJSON.configure do |config|
  # set a custom user agent used for o-embed API calls
  config.oembed_user_agent = 'devex oembed (+https://www.devex.com/)'

  # Register additional html exporters, just make sure that it complies with the
  # interface of other element exporter classes (extend Base, implement #export)
  config.register_element_exporters(
    :html,
    advertisement: ArticleJSON::Export::HTML::Elements::Advertisement
  )

  # You can also overwrite existing exporters:
  config.register_element_exporters(
    :html,
    image: ArticleJSON::Export::HTML::Elements::ScaledImage
  )

  # And you can define multiple custom exporters:
  config.register_element_exporters(
    :html,
    advertisement: ArticleJSON::Export::HTML::Elements::Advertisement,
    image: ArticleJSON::Export::HTML::Elements::ScaledImage
  )

  # It works the same way for custom AMP, FacebookInstantArticle, or
  # PlainText exporters:
  config.register_element_exporters(
    :amp, # Or change this for `:facebook_instant_article` or `:plain_text`
    image: ArticleJSON::Export::AMP::Elements::ScaledImage
  )
end

ArticleJSON.configure do |config|
  config.facebook_token = 'token'
end

# Create your article instance as you normally do
article = ArticleJSON::Article.from_hash(parsed_json)

# Within your code, create additional elements you would like to add
image_advertisement =
  ArticleJSON::Elements::Image.new(source_url: 'https://robohash.org/great-ad',
                                   caption: ArticleJSON::Elements::Text.new(
                                    content: 'Buy more robots!',
                                    href: '/robot-sale'
                                   ))
text_box_similar_articles =
  ArticleJSON::Elements::TextBox.new(content: [
    ArticleJSON::Elements::Heading.new(level: 3, content: 'Read more...'),
    ArticleJSON::Elements::List.new(content: [
      ArticleJSON::Elements::Paragraph(content: [
        ArticleJSON::Elements::Text.new(content: 'Very similar article',
                                        href: '/news/123'),
      ]),
      ArticleJSON::Elements::Paragraph(content: [
        ArticleJSON::Elements::Text.new(content: 'Great article!',
                                        href: '/news/42'),
      ]),
    ]),
  ])

# Add these elements to the article
article.place_additional_elements([image_advertisement,
                                   text_box_similar_articles])

# Export the article to the different formats as you would normally do
article.to_html # this will now include the custom elements

# Define your custom element class
class MyAdvertisement
  attr_reader :url

  def initialize(url:)
    @url = url
  end

  def type
    :my_advertisement
  end
end

# Define an exporter for your class, we only use HTML in this example but this
# would work similarly for AMP or other formats
class MyAdvertisementExporter <
  ArticleJSON::Export::HTML::Elements::Base

  # Needs to implement the `#export` method
  def export
    create_element(:iframe, src: @element.url)
  end
end

# Register your custom exporter for your element type
config.register_element_exporters(
  :html,
  my_advertisement: MyAdvertisementExporter
)

# Create the elements you want to add
ad_1 = MyAdvertisement.new(url: '/my_first_ad')
ad_2 = MyAdvertisement.new(url: '/my_second_ad')
ad_3 = MyAdvertisement.new(url: '/my_last_ad')

# Add them to the article
article.place_additional_elements([ad_1, ad_2, ad_3])

# And again, export the article as you would normally do it
article.to_html

# Create your article instance as you normally do
article = ArticleJSON::Article.from_hash(parsed_json)

# Then simply call `#to_plain_text` on it
article.to_plain_text