#          Copyright (c) 2008 Michael Fellinger m.fellinger@gmail.com
# All files in this distribution are subject to the terms of the Ruby license.

module Ramaze

  # Helper::Redirect actually takes advantage of Helper::Link.link_raw to build the links
  # it redirects to.
  # It doesn't do much else than this:
  #     setting a status-code of 303 and a response['Location'] = link
  # returning some nice text for visitors who insist on ignoring those hints :P
  #
  # Usage:
  #   redirect Rs()
  #   redirect R(MainController)
  #   redirect R(MainController, :foo)
  #   redirect 'foo/bar'
  #   redirect 'foo/bar', :status => 301
  #
  # TODO:
  #   - maybe some more options, like a delay
  #

  module Helper::Redirect

    # render to the browser directly, ignoring any templates
    #
    # Usage:
    #   respond 'Page not found', 404
    #   respond render_template('forbidden.erb'), 403
    #   respond File.open('file.jpg'), 200, 'Content-Type' => 'image/jpeg'

    def respond(*args)
      response.build(*args)
      throw(:respond)
    end

    # Usage:
    #   redirect Rs()
    #   redirect R(MainController)
    #   redirect R(MainController, :foo)
    #   redirect 'foo/bar'
    #   redirect 'foo/bar', :status => 301

    def redirect(target, opts = {})
      target = target.to_s

      unless target =~ %r!^https?://!
        target[0,0] = '/' unless target =~ %r!^/!
        if host = request.env['HTTP_HOST']
          target[0,0] = "http://#{host}"
        end
      end

      raw_redirect(target, opts)
    end

    # Do not perform any mutations on the target like #redirect does.
    # Suitable if you have to redirect to a different subdomain or host.
    def raw_redirect(target, opts = {})
      target = target.to_s
      header = {'Location' => target}
      status = opts[:status] || 302 # Found
      body = %{You are being redirected, please follow <a href="#{target}">this link to: #{target}</a>!}

      Log.info("Redirect to '#{target}'")
      request[:redirected] = true
      throw(:redirect, [body, status, header])
    end

    # Are we being redirected?
    def redirected?
      request[:redirected]
    end

    # Redirect to the location the browser says it's coming from.
    # If the current address is the same as the referrer or no referrer exists
    # yet, we will redirect to +fallback+.
    #
    # NOTE:
    #   * In some cases this may result in a double redirect, given that the
    #     request query parameters may change order. We don't have a nice way
    #     of handling that yet, but it should be very, very rare

    def redirect_referer(fallback = R(:/))
      if referer = request.referer and url = request.url
        referer_uri = URI(referer)
        request_uri = URI(url)

        if referer_uri == request_uri
          redirect fallback
        else
          redirect referer
        end
      else
        redirect fallback
      end
    end
    alias redirect_referrer redirect_referer
  end
end