module ArticleCrux

# File lib/article_crux.rb, line 9
def self.fetch(url, user_agent="ArticleCrux(https://github.com/amitsaxena/article_crux)")
  url = (url =~ /^(http|https):\/\/(.)*/i) ? url : "http://#{url}"
  probe = HTTParty.head(url, headers: {"User-Agent" => user_agent})
  if(probe.content_type && probe.content_type.split('/')[0] == "image")
    return {:image => url, :title => nil, :tags => []}
  end
  
  begin
    res = HTTParty.get(url, headers: {"User-Agent" => user_agent})
    raise "Unable to crawl URL" if res.code != 200
    doc = Nokogiri::HTML(res)
  rescue
    doc = Nokogiri::HTML(open(url, "User-Agent" => user_agent))
  end
  
  og_url = doc.search("//meta[@property='og:url' or @name='og:url']")
  if (!og_url.empty? && !str_blank?(og_url[0]["content"]) && (og_url[0]["content"] =~ /^(http|https):\/\/(.)*/i) && (url != og_url[0]["content"]))
    begin
      res = HTTParty.get(og_url[0]["content"], headers: {"User-Agent" => user_agent})
      raise "Unable to crawl URL" if res.code != 200
      doc = Nokogiri::HTML(res)
    rescue
      # If the og:url is faulty or doesn't return a 200 response, use the original url for meta data scraping
    end
  end
  
  og_image = doc.search("//meta[@property='og:image' or @name='og:image']")
  og_images = []
  if !og_image.empty?
    og_image.each do |ogi|
      if !str_blank?(ogi["content"])
        image = ogi["content"]
        if (image =~ /^\/\/(.)*/)
          uri = URI.parse(url)
          image = "#{uri.scheme}:#{image}"
        elsif (image =~ /^\/(.)*/)
          uri = URI.parse(url)
          image = File.join("#{uri.scheme}://#{uri.host}", image)
        end
        og_images << image
      end
    end
  end

  # Try to get the best image based on heuristics
  image = get_best_image(og_images)

  # If og:image is an invalid image (or extremely small), fall back to <img> tags
  og_size = FastImage.size(Addressable::URI.escape(image)) if !str_blank?(image)
  if (str_blank?(image) || og_size.nil? || (og_size[0] < 100 && og_size[1] < 100))
    image = nil # reset image so that it doesn't show up in response
    image_paths = []
    page_images = doc.search("//img")
    page_images.each do |page_image|
      next if (str_blank?(page_image["src"]))
      clip_image = page_image["src"]
      if (clip_image && !(clip_image =~ /^(http|https):\/\/(.)*/i))
        base = doc.search("//base")[0]
        base_url = base["href"] if (!base.nil? && !str_blank?(base["href"]))
        uri = URI.parse(url)
        if (clip_image =~ /^\/(.)*/)
          base_url = "#{uri.scheme}://#{uri.host}" if str_blank?(base_url)
        else
          base_url = "#{uri.scheme}://#{uri.host}#{uri.path[%r{^(.*[\/])}]}" if str_blank?(base_url)
        end
        clip_image = File.join(base_url, clip_image)
      end
      image_paths << clip_image
    end
  end

  og_title = doc.search("//meta[@property='og:title' or @name='og:title']")
  if (!og_title.empty? && !str_blank?(og_title[0]["content"]))
    clip_title = og_title[0]["content"]
  else
    page_title = doc.search("//title")[0]
    clip_title = page_title.text if !page_title.nil?
  end

  tags = []
  possible_tags = doc.xpath('//meta[contains(@name, "tag") or contains(@name, "keyword") or contains(@property, "tag") or contains(@property, "keyword")]')
  possible_tags.each{|e| tags << e["content"].split(',') if !str_blank?(e["content"])}
  tags = tags.flatten.map(&:strip).uniq

  res = {:image => image, :title => clip_title, :tags => tags}
end

# File lib/article_crux.rb, line 96
def self.get_best_image(images)
  return nil if images.empty?
  return images[0] if (images.size == 1)
  # reject logo or similar images
  refined_images = images.reject{|i| i =~ /logo|fallback/i}
  return refined_images[0] if (refined_images.size == 1)
  refined_images = images if refined_images.empty?
  dimensions = []
  refined_images.each do |i|
    type = FastImage.type(Addressable::URI.escape(i))
    size = FastImage.size(Addressable::URI.escape(i))
    return i if((type == :gif) && (size && size[0] > 299 && size[1] > 199))
    dimensions << {:x => size[0], :y => size[1], :image => i} if !size.nil?
  end
  image = dimensions.empty? ? nil : dimensions.max_by{|d| d[:x]}[:image]
  return image
end

# File lib/article_crux.rb, line 114
def self.str_blank?(str)
  str.nil? || str.empty?
end