module Elsmore
  class Rewriter
    attr_accessor :resource, :emitter

    def initialize resource
      self.resource = resource
    end

    def rewrite
      rewrite_linked_resources
      rewrite_links
    end

    private

    def rewrite_linked_resources
      write_css
      write_js
      write_images
    end

    def write_css
      resource.doc.xpath('//link[@rel="stylesheet"]').each do |element|
        write_element(element, 'href', replace: true)
      end
    end

    def write_images
      resource.doc.xpath('//img').each do |element|
        write_element(element, 'src', replace: false)
      end
    end

    def write_js
      resource.doc.xpath('//script').each do |element|
        write_element(element, 'src', replace: false)
      end
    end

    def write_element element, key, options = {}
      return unless element.attribute(key)
      url = element.attribute(key).value
      _resource = Elsmore::Resource.new(url, resource.url)
      _resource.emitter = emitter
      _resource.write!(options[:replace])

      emitter.log("# Rewriting #{url} => #{_resource.filename}") if url != _resource.filename
      element.attribute(key).value = _resource.filename
    end

    def rewrite_links
      resource.doc.xpath('//a').each do |element|
        return unless element.attribute('href')
        href = element.attribute('href').value

        url = Elsmore::Url.new(href, resource.url)
        if url.valid
          new_url = url.absolute_path_or_external_url
        else
          new_url = href
        end
        emitter.log("# Rewriting #{href} => #{new_url}") if href != new_url
        element.attribute('href').value = new_url
      end
    end
  end
end