require 'action_mailer/adv_attr_accessor'
require 'action_mailer/part'
require 'action_mailer/part_container'
require 'action_mailer/utils'
require 'tmail/net'

module ActionMailer #:nodoc:
  # ActionMailer allows you to send email from your application using a mailer model and views.
  #
  #
  # = Mailer Models
  #
  # To use ActionMailer, you need to create a mailer model.
  #   
  #   $ script/generate mailer Notifier
  #
  # The generated model inherits from ActionMailer::Base. Emails are defined by creating methods within the model which are then 
  # used to set variables to be used in the mail template, to change options on the mail, or 
  # to add attachments.
  #
  # Examples:
  #
  #  class Notifier < ActionMailer::Base
  #    def signup_notification(recipient)
  #      recipients recipient.email_address_with_name
  #      from       "system@example.com"
  #      subject    "New account information"
  #      body       :account => recipient
  #    end
  #  end
  #
  # Mailer methods have the following configuration methods available.
  #
  # * <tt>recipients</tt> - Takes one or more email addresses. These addresses are where your email will be delivered to. Sets the <tt>To:</tt> header.
  # * <tt>subject</tt> - The subject of your email. Sets the <tt>Subject:</tt> header.
  # * <tt>from</tt> - Who the email you are sending is from. Sets the <tt>From:</tt> header.
  # * <tt>cc</tt> - Takes one or more email addresses. These addresses will receive a carbon copy of your email. Sets the <tt>Cc:</tt> header.
  # * <tt>bcc</tt> - Takes one or more email address. These addresses will receive a blind carbon copy of your email. Sets the <tt>Bcc</tt> header.
  # * <tt>sent_on</tt> - The date on which the message was sent. If not set, the header wil be set by the delivery agent.
  # * <tt>content_type</tt> - Specify the content type of the message. Defaults to <tt>text/plain</tt>.
  # * <tt>headers</tt> - Specify additional headers to be set for the message, e.g. <tt>headers 'X-Mail-Count' => 107370</tt>.
  #
  # The <tt>body</tt> method has special behavior. It takes a hash which generates an instance variable
  # named after each key in the hash containing the value that that key points to.
  #
  # So, for example, <tt>body "account" => recipient</tt> would result
  # in an instance variable <tt>@account</tt> with the value of <tt>recipient</tt> being accessible in the 
  # view.
  #
  #
  # = Mailer views
  #
  # Like ActionController, each mailer class has a corresponding view directory
  # in which each method of the class looks for a template with its name.
  # To define a template to be used with a mailing, create an <tt>.erb</tt> file with the same name as the method
  # in your mailer model. For example, in the mailer defined above, the template at 
  # <tt>app/views/notifier/signup_notification.erb</tt> would be used to generate the email.
  #
  # Variables defined in the model are accessible as instance variables in the view.
  #
  # Emails by default are sent in plain text, so a sample view for our model example might look like this:
  #
  #   Hi <%= @account.name %>,
  #   Thanks for joining our service! Please check back often.
  #
  # You can even use Action Pack helpers in these views. For example:
  #
  #   You got a new note!
  #   <%= truncate(note.body, 25) %>
  # 
  #
  # = Generating URLs for mailer views
  #
  # If your view includes URLs from the application, you need to use url_for in the mailing method instead of the view.
  # Unlike controllers from Action Pack, the mailer instance doesn't have any context about the incoming request. That's
  # why you need to jump this little hoop and supply all the details needed for the URL. Example:
  #
  #    def signup_notification(recipient)
  #      recipients recipient.email_address_with_name
  #      from       "system@example.com"
  #      subject    "New account information"
  #      body       :account => recipient,
  #                 :home_page => url_for(:host => "example.com", :controller => "welcome", :action => "greeting")
  #    end
  #
  # You can now access @home_page in the template and get http://example.com/welcome/greeting.
  #
  # = Sending mail
  #
  # Once a mailer action and template are defined, you can deliver your message or create it and save it 
  # for delivery later:
  #
  #   Notifier.deliver_signup_notification(david) # sends the email
  #   mail = Notifier.create_signup_notification(david)  # => a tmail object
  #   Notifier.deliver(mail)
  # 
  # You never instantiate your mailer class. Rather, your delivery instance
  # methods are automatically wrapped in class methods that start with the word
  # <tt>deliver_</tt> followed by the name of the mailer method that you would
  # like to deliver. The <tt>signup_notification</tt> method defined above is
  # delivered by invoking <tt>Notifier.deliver_signup_notification</tt>.
  #
  #
  # = HTML email
  #
  # To send mail as HTML, make sure your view (the <tt>.erb</tt> file) generates HTML and
  # set the content type to html.
  #
  #   class MyMailer < ActionMailer::Base
  #     def signup_notification(recipient)
  #       recipients recipient.email_address_with_name
  #       subject    "New account information"
  #       body       "account" => recipient
  #       from       "system@example.com"
  #       content_type "text/html"   #    Here's where the magic happens
  #     end
  #   end  
  #
  #
  # = Multipart email
  #
  # You can explicitly specify multipart messages:
  #
  #   class ApplicationMailer < ActionMailer::Base
  #     def signup_notification(recipient)
  #       recipients      recipient.email_address_with_name
  #       subject         "New account information"
  #       from            "system@example.com"
  #
  #       part :content_type => "text/html",
  #         :body => render_message("signup-as-html", :account => recipient)
  #
  #       part "text/plain" do |p|
  #         p.body = render_message("signup-as-plain", :account => recipient)
  #         p.transfer_encoding = "base64"
  #       end
  #     end
  #   end
  #  
  # Multipart messages can also be used implicitly because ActionMailer will automatically
  # detect and use multipart templates, where each template is named after the name of the action, followed
  # by the content type. Each such detected template will be added as separate part to the message.
  # 
  # For example, if the following templates existed:
  # * signup_notification.text.plain.erb
  # * signup_notification.text.html.erb
  # * signup_notification.text.xml.builder
  # * signup_notification.text.x-yaml.erb
  #  
  # Each would be rendered and added as a separate part to the message,
  # with the corresponding content type. The same body hash is passed to
  # each template.
  #
  #
  # = Attachments
  #
  # Attachments can be added by using the +attachment+ method.
  #
  # Example:
  #
  #   class ApplicationMailer < ActionMailer::Base
  #     # attachments
  #     def signup_notification(recipient)
  #       recipients      recipient.email_address_with_name
  #       subject         "New account information"
  #       from            "system@example.com"
  #
  #       attachment :content_type => "image/jpeg",
  #         :body => File.read("an-image.jpg")
  #
  #       attachment "application/pdf" do |a|
  #         a.body = generate_your_pdf_here()
  #       end
  #     end
  #   end 
  #
  #
  # = Configuration options
  #
  # These options are specified on the class level, like <tt>ActionMailer::Base.template_root = "/my/templates"</tt>
  #
  # * <tt>template_root</tt> - template root determines the base from which template references will be made.
  #
  # * <tt>logger</tt> - the logger is used for generating information on the mailing run if available.
  #   Can be set to nil for no logging. Compatible with both Ruby's own Logger and Log4r loggers.
  #
  # * <tt>smtp_settings</tt> -  Allows detailed configuration for :smtp delivery method:
  #   * <tt>:address</tt> Allows you to use a remote mail server. Just change it from its default "localhost" setting.
  #   * <tt>:port</tt> On the off chance that your mail server doesn't run on port 25, you can change it.
  #   * <tt>:domain</tt> If you need to specify a HELO domain, you can do it here.
  #   * <tt>:user_name</tt> If your mail server requires authentication, set the username in this setting.
  #   * <tt>:password</tt> If your mail server requires authentication, set the password in this setting.
  #   * <tt>:authentication</tt> If your mail server requires authentication, you need to specify the authentication type here. 
  #     This is a symbol and one of :plain, :login, :cram_md5
  #
  # * <tt>sendmail_settings</tt> - Allows you to override options for the :sendmail delivery method
  #   * <tt>:location</tt> The location of the sendmail executable, defaults to "/usr/sbin/sendmail"
  #   * <tt>:arguments</tt> The command line arguments
  # * <tt>raise_delivery_errors</tt> - whether or not errors should be raised if the email fails to be delivered.
  #
  # * <tt>delivery_method</tt> - Defines a delivery method. Possible values are :smtp (default), :sendmail, and :test.
  #
  # * <tt>perform_deliveries</tt> - Determines whether deliver_* methods are actually carried out. By default they are,
  #   but this can be turned off to help functional testing.
  #
  # * <tt>deliveries</tt> - Keeps an array of all the emails sent out through the Action Mailer with delivery_method :test. Most useful
  #   for unit and functional testing.
  #
  # * <tt>default_charset</tt> - The default charset used for the body and to encode the subject. Defaults to UTF-8. You can also 
  #   pick a different charset from inside a method with <tt>@charset</tt>.
  # * <tt>default_content_type</tt> - The default content type used for the main part of the message. Defaults to "text/plain". You
  #   can also pick a different content type from inside a method with <tt>@content_type</tt>. 
  # * <tt>default_mime_version</tt> - The default mime version used for the message. Defaults to "1.0". You
  #   can also pick a different value from inside a method with <tt>@mime_version</tt>.
  # * <tt>default_implicit_parts_order</tt> - When a message is built implicitly (i.e. multiple parts are assembled from templates
  #   which specify the content type in their filenames) this variable controls how the parts are ordered. Defaults to
  #   ["text/html", "text/enriched", "text/plain"]. Items that appear first in the array have higher priority in the mail client
  #   and appear last in the mime encoded message. You can also pick a different order from inside a method with
  #   <tt>@implicit_parts_order</tt>.
  class Base
    include AdvAttrAccessor, PartContainer
    include ActionController::UrlWriter if Object.const_defined?(:ActionController)

    private_class_method :new #:nodoc:

    class_inheritable_accessor :template_root
    cattr_accessor :logger

    cattr_accessor :template_extensions
    @@template_extensions = ['erb', 'builder', 'rhtml', 'rxml']

    @@smtp_settings = { 
      :address        => "localhost", 
      :port           => 25, 
      :domain         => 'localhost.localdomain', 
      :user_name      => nil, 
      :password       => nil, 
      :authentication => nil
    }
    cattr_accessor :smtp_settings
    
    @@sendmail_settings = {
      :location       => '/usr/sbin/sendmail',
      :arguments      => '-i -t'
    }
    cattr_accessor :sendmail_settings

    @@raise_delivery_errors = true
    cattr_accessor :raise_delivery_errors

    @@delivery_method = :smtp
    cattr_accessor :delivery_method
    
    @@perform_deliveries = true
    cattr_accessor :perform_deliveries
    
    @@deliveries = []
    cattr_accessor :deliveries

    @@default_charset = "utf-8"
    cattr_accessor :default_charset

    @@default_content_type = "text/plain"
    cattr_accessor :default_content_type
    
    @@default_mime_version = "1.0"
    cattr_accessor :default_mime_version

    @@default_implicit_parts_order = [ "text/html", "text/enriched", "text/plain" ]
    cattr_accessor :default_implicit_parts_order

    # Specify the BCC addresses for the message
    adv_attr_accessor :bcc
    
    # Define the body of the message. This is either a Hash (in which case it
    # specifies the variables to pass to the template when it is rendered),
    # or a string, in which case it specifies the actual text of the message.
    adv_attr_accessor :body
    
    # Specify the CC addresses for the message.
    adv_attr_accessor :cc
    
    # Specify the charset to use for the message. This defaults to the
    # +default_charset+ specified for ActionMailer::Base.
    adv_attr_accessor :charset
    
    # Specify the content type for the message. This defaults to <tt>text/plain</tt>
    # in most cases, but can be automatically set in some situations.
    adv_attr_accessor :content_type
    
    # Specify the from address for the message.
    adv_attr_accessor :from
    
    # Specify additional headers to be added to the message.
    adv_attr_accessor :headers
    
    # Specify the order in which parts should be sorted, based on content-type.
    # This defaults to the value for the +default_implicit_parts_order+.
    adv_attr_accessor :implicit_parts_order
    
    # Override the mailer name, which defaults to an inflected version of the
    # mailer's class name. If you want to use a template in a non-standard
    # location, you can use this to specify that location.
    adv_attr_accessor :mailer_name
    
    # Defaults to "1.0", but may be explicitly given if needed.
    adv_attr_accessor :mime_version
    
    # The recipient addresses for the message, either as a string (for a single
    # address) or an array (for multiple addresses).
    adv_attr_accessor :recipients
    
    # The date on which the message was sent. If not set (the default), the
    # header will be set by the delivery agent.
    adv_attr_accessor :sent_on
    
    # Specify the subject of the message.
    adv_attr_accessor :subject
    
    # Specify the template name to use for current message. This is the "base"
    # template name, without the extension or directory, and may be used to
    # have multiple mailer methods share the same template.
    adv_attr_accessor :template

    # The mail object instance referenced by this mailer.
    attr_reader :mail

    class << self
      def method_missing(method_symbol, *parameters)#:nodoc:
        case method_symbol.id2name
          when /^create_([_a-z]\w*)/  then new($1, *parameters).mail
          when /^deliver_([_a-z]\w*)/ then new($1, *parameters).deliver!
          when "new" then nil
          else super
        end
      end

      # Receives a raw email, parses it into an email object, decodes it,
      # instantiates a new mailer, and passes the email object to the mailer
      # object's #receive method. If you want your mailer to be able to
      # process incoming messages, you'll need to implement a #receive
      # method that accepts the email object as a parameter:
      #
      #   class MyMailer < ActionMailer::Base
      #     def receive(mail)
      #       ...
      #     end
      #   end
      def receive(raw_email)
        logger.info "Received mail:\n #{raw_email}" unless logger.nil?
        mail = TMail::Mail.parse(raw_email)
        mail.base64_decode
        new.receive(mail)
      end

      # Deliver the given mail object directly. This can be used to deliver
      # a preconstructed mail object, like:
      #
      #   email = MyMailer.create_some_mail(parameters)
      #   email.set_some_obscure_header "frobnicate"
      #   MyMailer.deliver(email)
      def deliver(mail)
        new.deliver!(mail)
      end

      # Register a template extension so mailer templates written in a
      # templating language other than rhtml or rxml are supported.
      # To use this, include in your template-language plugin's init
      # code or on a per-application basis, this can be invoked from
      # config/environment.rb:
      #
      #   ActionMailer::Base.register_template_extension('haml')
      def register_template_extension(extension)
        template_extensions << extension
      end
    end

    # Instantiate a new mailer object. If +method_name+ is not +nil+, the mailer
    # will be initialized according to the named method. If not, the mailer will
    # remain uninitialized (useful when you only need to invoke the "receive"
    # method, for instance).
    def initialize(method_name=nil, *parameters) #:nodoc:
      create!(method_name, *parameters) if method_name 
    end

    # Initialize the mailer via the given +method_name+. The body will be
    # rendered and a new TMail::Mail object created.
    def create!(method_name, *parameters) #:nodoc:
      initialize_defaults(method_name)
      __send__(method_name, *parameters)

      # If an explicit, textual body has not been set, we check assumptions.
      unless String === @body
        # First, we look to see if there are any likely templates that match,
        # which include the content-type in their file name (i.e.,
        # "the_template_file.text.html.erb", etc.). Only do this if parts
        # have not already been specified manually.
        if @parts.empty?
          templates = Dir.glob("#{template_path}/#{@template}.*")
          templates.each do |path|
            basename = File.basename(path)
            template_regex = Regexp.new("^([^\\\.]+)\\\.([^\\\.]+\\\.[^\\\.]+)\\\.(" + template_extensions.join('|') + ")$")
            next unless md = template_regex.match(basename)
            template_name = basename
            content_type = md.captures[1].gsub('.', '/')
            @parts << Part.new(:content_type => content_type,
              :disposition => "inline", :charset => charset,
              :body => render_message(template_name, @body))
          end
          unless @parts.empty?
            @content_type = "multipart/alternative"
            @parts = sort_parts(@parts, @implicit_parts_order)
          end
        end

        # Then, if there were such templates, we check to see if we ought to
        # also render a "normal" template (without the content type). If a
        # normal template exists (or if there were no implicit parts) we render
        # it.
        template_exists = @parts.empty?
        template_exists ||= Dir.glob("#{template_path}/#{@template}.*").any? { |i| File.basename(i).split(".").length == 2 }
        @body = render_message(@template, @body) if template_exists

        # Finally, if there are other message parts and a textual body exists,
        # we shift it onto the front of the parts and set the body to nil (so
        # that create_mail doesn't try to render it in addition to the parts).
        if !@parts.empty? && String === @body
          @parts.unshift Part.new(:charset => charset, :body => @body)
          @body = nil
        end
      end

      # If this is a multipart e-mail add the mime_version if it is not
      # already set.
      @mime_version ||= "1.0" if !@parts.empty?

      # build the mail object itself
      @mail = create_mail
    end

    # Delivers a TMail::Mail object. By default, it delivers the cached mail
    # object (from the #create! method). If no cached mail object exists, and
    # no alternate has been given as the parameter, this will fail.
    def deliver!(mail = @mail)
      raise "no mail object available for delivery!" unless mail
      logger.info "Sent mail:\n #{mail.encoded}" unless logger.nil?

      begin
        __send__("perform_delivery_#{delivery_method}", mail) if perform_deliveries
      rescue Exception => e  # Net::SMTP errors or sendmail pipe errors
        raise e if raise_delivery_errors
      end

      return mail
    end

    private
      # Set up the default values for the various instance variables of this
      # mailer. Subclasses may override this method to provide different
      # defaults.
      def initialize_defaults(method_name)
        @charset ||= @@default_charset.dup
        @content_type ||= @@default_content_type.dup
        @implicit_parts_order ||= @@default_implicit_parts_order.dup
        @template ||= method_name
        @mailer_name ||= Inflector.underscore(self.class.name)
        @parts ||= []
        @headers ||= {}
        @body ||= {}
        @mime_version = @@default_mime_version.dup if @@default_mime_version
      end

      def render_message(method_name, body)
        render :file => method_name, :body => body
      end

      def render(opts)
        body = opts.delete(:body)
        initialize_template_class(body).render(opts)
      end

      def template_path
        "#{template_root}/#{mailer_name}"
      end

      def initialize_template_class(assigns)
        ActionView::Base.new(template_path, assigns, self)
      end

      def sort_parts(parts, order = [])
        order = order.collect { |s| s.downcase }

        parts = parts.sort do |a, b|
          a_ct = a.content_type.downcase
          b_ct = b.content_type.downcase

          a_in = order.include? a_ct
          b_in = order.include? b_ct

          s = case
          when a_in && b_in
            order.index(a_ct) <=> order.index(b_ct)
          when a_in
            -1
          when b_in
            1
          else
            a_ct <=> b_ct
          end

          # reverse the ordering because parts that come last are displayed
          # first in mail clients
          (s * -1)
        end

        parts
      end

      def create_mail
        m = TMail::Mail.new

        m.subject, = quote_any_if_necessary(charset, subject)
        m.to, m.from = quote_any_address_if_necessary(charset, recipients, from)
        m.bcc = quote_address_if_necessary(bcc, charset) unless bcc.nil?
        m.cc  = quote_address_if_necessary(cc, charset) unless cc.nil?

        m.mime_version = mime_version unless mime_version.nil?
        m.date = sent_on.to_time rescue sent_on if sent_on
        headers.each { |k, v| m[k] = v }

        real_content_type, ctype_attrs = parse_content_type

        if @parts.empty?
          m.set_content_type(real_content_type, nil, ctype_attrs)
          m.body = Utils.normalize_new_lines(body)
        else
          if String === body
            part = TMail::Mail.new
            part.body = Utils.normalize_new_lines(body)
            part.set_content_type(real_content_type, nil, ctype_attrs)
            part.set_content_disposition "inline"
            m.parts << part
          end

          @parts.each do |p|
            part = (TMail::Mail === p ? p : p.to_mail(self))
            m.parts << part
          end
          
          if real_content_type =~ /multipart/
            ctype_attrs.delete "charset"
            m.set_content_type(real_content_type, nil, ctype_attrs)
          end
        end

        @mail = m
      end

      def perform_delivery_smtp(mail)
        destinations = mail.destinations
        mail.ready_to_send

        Net::SMTP.start(smtp_settings[:address], smtp_settings[:port], smtp_settings[:domain], 
            smtp_settings[:user_name], smtp_settings[:password], smtp_settings[:authentication]) do |smtp|
          smtp.sendmail(mail.encoded, mail.from, destinations)
        end
      end

      def perform_delivery_sendmail(mail)
        IO.popen("#{sendmail_settings[:location]} #{sendmail_settings[:arguments]}","w+") do |sm|
          sm.print(mail.encoded.gsub(/\r/, ''))
          sm.flush
        end
      end

      def perform_delivery_test(mail)
        deliveries << mail
      end
  end
end