require File.join(Rails.root, 'lib/hcard')
require File.join(Rails.root, 'lib/webfinger_profile')

class EMWebfinger
  TIMEOUT = 5
  def initialize(account)
    @account = account.strip.gsub('acct:','').to_s
    @callbacks = []
    # Raise an error if identifier has a port number 
    raise "Identifier is invalid" if(@account.strip.match(/\:\d+$/))
    # Raise an error if identifier is not a valid email (generous regexp)
    raise "Identifier is invalid" if !(@account=~ /\A.*\@.*\..*\Z/)
  end
  
  def fetch
    raise 'you need to set a callback before calling fetch' if @callbacks.empty?
    person = Person.by_account_identifier(@account)
    if person
      process_callbacks person
    else
      get_xrd
    end
  end

  def on_person(&block)
    @callbacks << block
    self.fetch
  end

  private

  def get_xrd
    http = EventMachine::HttpRequest.new(xrd_url).get :timeout => TIMEOUT
    http.callback { get_webfinger_profile(webfinger_profile_url(http.response)) }
    http.errback { process_callbacks "there was an error getting the xrd at #{xrd_url}" }
  end


  def get_webfinger_profile(profile_url)
     http = EventMachine::HttpRequest.new(profile_url).get :timeout => TIMEOUT
     http.callback{ make_person_from_webfinger(http.response) }
     http.errback{ process_callbacks "failed to fetch webfinger profile for #{profile_url}"}
  end

  def make_person_from_webfinger(webfinger_profile)
    unless webfinger_profile.strip == ""
      
      wf_profile = WebfingerProfile.new(@account, webfinger_profile)
      
      http = EventMachine::HttpRequest.new(wf_profile.hcard).get :timeout => TIMEOUT
      http.callback{
        hcard = HCard.build http.response
        p = Person.build_from_webfinger(wf_profile, hcard)
        process_callbacks(p)
      }
      http.errback{process_callbacks "there was a problem fetching the hcard for #{@account}"}
    end
  end


  def process_callbacks(person)
    @callbacks.each { |c| c.call(person) }
  end


  ##helpers
  private
  def webfinger_profile_url(xrd_response)
    doc = Nokogiri::XML::Document.parse(xrd_response)  
    swizzle doc.at('Link[rel=lrdd]').attribute('template').value
  end

  def xrd_url(ssl = false)
    domain = @account.split('@')[1]
    "http#{'s' if ssl}://#{domain}/.well-known/host-meta"
  end
  
  def swizzle(template)
    template.gsub '{uri}', @account
  end

end