module PdfHelper
  require 'tempfile'

  def self.included(base)
    # Protect from trying to augment modules that appear
    # as the result of adding other gems.
    return if base != ActionController::Base

    base.class_eval do
      alias_method_chain :render, :wicked_pdf
      alias_method_chain :render_to_string, :wicked_pdf
      after_filter :clean_temp_files
    end
  end

  def render_with_wicked_pdf(options = nil, *args, &block)
    if options.is_a?(Hash) && options.key?(:pdf)
      log_pdf_creation
      options[:basic_auth] = set_basic_auth(options)
      make_and_send_pdf(options.delete(:pdf), (WickedPdf.config || {}).merge(options))
    else
      render_without_wicked_pdf(options, *args, &block)
    end
  end

  def render_to_string_with_wicked_pdf(options = nil, *args, &block)
    if options.is_a?(Hash) && options.key?(:pdf)
      log_pdf_creation
      options[:basic_auth] = set_basic_auth(options)
      options.delete :pdf
      make_pdf((WickedPdf.config || {}).merge(options))
    else
      render_to_string_without_wicked_pdf(options, *args, &block)
    end
  end

  private

  def log_pdf_creation
    logger.info '*' * 15 + 'WICKED' + '*' * 15 if logger && logger.respond_to?(:info)
  end

  def set_basic_auth(options = {})
    options[:basic_auth] ||= WickedPdf.config.fetch(:basic_auth) { false }
    return unless options[:basic_auth] && request.env['HTTP_AUTHORIZATION']
    request.env['HTTP_AUTHORIZATION'].split(' ').last
  end

  def clean_temp_files
    return unless defined?(@hf_tempfiles)
    @hf_tempfiles.each(&:close!)
  end

  def make_pdf(options = {})
    render_opts = {
      :template => options[:template],
      :layout => options[:layout],
      :formats => options[:formats],
      :handlers => options[:handlers]
    }
    render_opts[:locals] = options[:locals] if options[:locals]
    render_opts[:file] = options[:file] if options[:file]
    html_string = render_to_string(render_opts)
    options = prerender_header_and_footer(options)
    w = WickedPdf.new(options[:wkhtmltopdf])
    w.pdf_from_string(html_string, options)
  end

  def make_and_send_pdf(pdf_name, options = {})
    options[:wkhtmltopdf] ||= nil
    options[:layout] ||= false
    options[:template] ||= File.join(controller_path, action_name)
    options[:disposition] ||= 'inline'
    if options[:show_as_html]
      render_opts = {
        :template => options[:template],
        :layout => options[:layout],
        :formats => options[:formats],
        :handlers => options[:handlers],
        :content_type => 'text/html'
      }
      render_opts[:locals] = options[:locals] if options[:locals]
      render_opts[:file] = options[:file] if options[:file]
      render(render_opts)
    else
      pdf_content = make_pdf(options)
      File.open(options[:save_to_file], 'wb') { |file| file << pdf_content } if options[:save_to_file]
      send_data(pdf_content, :filename => pdf_name + '.pdf', :type => 'application/pdf', :disposition => options[:disposition]) unless options[:save_only]
    end
  end

  # Given an options hash, prerenders content for the header and footer sections
  # to temp files and return a new options hash including the URLs to these files.
  def prerender_header_and_footer(options)
    [:header, :footer].each do |hf|
      next unless options[hf] && options[hf][:html] && options[hf][:html][:template]
      @hf_tempfiles = [] unless defined?(@hf_tempfiles)
      @hf_tempfiles.push(tf = WickedPdfTempfile.new("wicked_#{hf}_pdf.html"))
      options[hf][:html][:layout] ||= options[:layout]
      render_opts = {
        :template => options[hf][:html][:template],
        :layout => options[hf][:html][:layout],
        :formats => options[hf][:html][:formats],
        :handlers => options[hf][:html][:handlers]
      }
      render_opts[:locals] = options[hf][:html][:locals] if options[hf][:html][:locals]
      render_opts[:file] = options[hf][:html][:file] if options[:file]
      tf.write render_to_string(render_opts)
      tf.flush
      options[hf][:html][:url] = "file:///#{tf.path}"
    end
    options
  end
end