require 'sinatra'
require 'mechanize'

# Find a description from <meta> tags
def meta_description(page)
  description_meta_tag = 
    page.search("meta[property='og:description']")[0] ||
    page.search("meta[property='twitter:description']")[0] ||
    page.search("meta[name='description']")[0]

  description_meta_tag&.attribute("content")&.value
end

# Truncate the text of the first <article>
def article_description(page)
  article = page.search("article")[0]
  article.text[0..500] if article
end


get '/summary' do
  url = params[:url]
  mech = Mechanize.new
  page = mech.get(url)

  title = page.title

  description = meta_description(page) || article_description(page)

  content_type :json
  {url: url, title: title, description: description}.to_json
end