require "erector/xml_widget"

module Erector

  # A Widget is the center of the Erector universe.
  #
  # To create a widget, extend Erector::Widget and implement the +content+
  # method. Inside this method you may call any of the tag methods like +span+
  # or +p+ to emit HTML/XML tags.
  #
  # You can also define a widget on the fly by passing a block to +new+. This
  # block will get executed when the widget's +content+ method is called. See
  # the userguide for important details about the scope of this block when run --
  # http://erector.rubyforge.org/userguide.html#blocks
  #
  # To render a widget from the outside, instantiate it and call its +to_html+
  # method.
  #
  # A widget's +new+ method optionally accepts an options hash. Entries in
  # this hash are converted to instance variables.
  #
  # You can add runtime input checking via the +needs+ macro. See #needs.
  # This mechanism is meant to ameliorate development-time confusion about
  # exactly what parameters are supported by a given widget, avoiding
  # confusing runtime NilClass errors.
  #
  # To call one widget from another, inside the parent widget's +content+
  # method, instantiate the child widget and call the +widget+ method. This
  # assures that the same output stream is used, which gives better
  # performance than using +capture+ or +to_html+. It also preserves the
  # indentation and helpers of the enclosing class.
  #
  # In this documentation we've tried to keep the distinction clear between
  # methods that *emit* text and those that *return* text. "Emit" means that
  # it writes to the output stream; "return" means that it returns a string
  # like a normal method and leaves it up to the caller to emit that string if
  # it wants.
  #
  # This class extends AbstractWidget and includes several modules,
  # so be sure to check all of those places for API documentation for the
  # various methods of Widget:
  #
  # * AbstractWidget
  # * Element
  # * Attributes
  # * Text
  # * Needs
  # * Caching
  # * Externals
  # * AfterInitialize
  #
  # * HTML
  # * Convenience
  # * JQuery
  # * Sass
  #
  # Also read the API Cheatsheet in the user guide
  # at http://erector.rubyforge.org/userguide#apicheatsheet
  class HTMLWidget < Erector::XMLWidget

    include Erector::HTML
    include Erector::Convenience
    include Erector::JQuery
    include Erector::Sass if Object.const_defined?(:Sass)

    tag 'area', :self_closing
    tag 'base', :self_closing
    tag 'br', :self_closing
    tag 'col', :self_closing
    tag 'embed', :self_closing
    tag 'frame', :self_closing
    tag 'hr', :self_closing
    tag 'img', :self_closing, :inline
    tag 'input', :self_closing, :inline
    tag 'link', :self_closing
    tag 'meta', :self_closing
    tag 'param', :self_closing

    tag 'a', :inline
    tag 'abbr'
    tag 'acronym'
    tag 'address'
    tag 'article'
    tag 'aside'
    tag 'audio'

    tag 'b', :inline
    tag 'bdo'
    tag 'big'
    tag 'blockquote'
    tag 'body'
    tag 'button', :inline

    tag 'canvas'
    tag 'caption'
    tag 'center'
    tag 'cite'
    tag 'code'
    tag 'colgroup'
    tag 'command'

    tag 'datalist'
    tag 'dd'
    tag 'del'
    tag 'details'
    tag 'dfn'
    tag 'dialog'
    tag 'div'
    tag 'dl'
    tag 'dt'

    tag 'em'

    tag 'fieldset'
    tag 'figure'
    tag 'footer'
    tag 'form'
    tag 'frameset'

    tag 'h1'
    tag 'h2'
    tag 'h3'
    tag 'h4'
    tag 'h5'
    tag 'h6'
    tag 'head'
    tag 'header'
    tag 'hgroup'
    tag 'html'
    tag 'i', :inline

    tag 'iframe'
    tag 'ins'
    tag 'keygen'
    tag 'kbd'
    tag 'label'
    tag 'legend'
    tag 'li'

    tag 'map'
    tag 'mark'
    tag 'meter'

    tag 'nav'
    tag 'noframes'
    tag 'noscript'

    tag 'object'
    tag 'ol'
    tag 'optgroup'
    tag 'option'

    tag 'p'
    tag 'pre'
    tag 'progress'

    tag 'q'
    tag 'ruby'
    tag 'rt'
    tag 'rp'
    tag 's'

    tag 'samp'
    tag 'script'
    tag 'section'
    tag 'select', :inline
    tag 'small', :inline
    tag 'source'
    tag 'span', :inline
    tag 'strike'

    tag 'strong'
    tag 'style'
    tag 'sub'
    tag 'sup'

    tag 'table'
    tag 'tbody'
    tag 'td'
    tag 'textarea', :inline
    tag 'tfoot'

    tag 'th'
    tag 'thead'
    tag 'time'
    tag 'title'
    tag 'tr'
    tag 'tt'

    tag 'u'
    tag 'ul'

    tag 'var'
    tag 'video'


    # Emits a javascript block inside a +script+ tag, wrapped in CDATA
    # doohickeys like all the cool JS kids do.
    def javascript(value = nil, attributes = {})
      if value.is_a?(Hash)
        attributes = value
        value      = nil
      elsif block_given? && value
        raise ArgumentError, "You can't pass both a block and a value to javascript -- please choose one."
      end

      script(attributes.merge(:type => "text/javascript")) do
        # Shouldn't this be a "cdata" HtmlPart?
        # (maybe, but the syntax is specific to javascript; it isn't
        # really a generic XML CDATA section.  Specifically,
        # ]]> within value is not treated as ending the
        # CDATA section by Firefox2 when parsing text/html,
        # although I guess we could refuse to generate ]]>
        # there, for the benefit of XML/XHTML parsers).
        output << raw("\n// <![CDATA[\n")
        if block_given?
          yield
        else
          output << raw(value)
        end
        output << raw("\n// ]]>")
        output.append_newline # this forces a newline even if we're not in pretty mode
      end

      output << raw("\n")
    end



    # alias for AbstractWidget#render
    def to_html(options = {})
      raise "Erector::Widget#to_html takes an options hash, not a symbol. Try calling \"to_html(:content_method_name=> :#{options})\"" if options.is_a? Symbol
      _render(options).to_s
    end

    # alias for #to_html
    # @deprecated Please use {#to_html} instead
    def to_s(*args)
      unless defined? @@already_warned_to_s
        $stderr.puts "Erector::Widget#to_s is deprecated. Please use #to_html instead. Called from #{caller.first}"
        @@already_warned_to_s = true
      end
      to_html(*args)
    end


    # Emits an XML instruction, which looks like this: <?xml version=\"1.0\" encoding=\"UTF-8\"?>
    def instruct(attributes={:version => "1.0", :encoding => "UTF-8"})
      output << raw("<?xml#{format_sorted(sort_for_xml_declaration(attributes))}?>")
    end

    # Emits an XML/HTML comment (&lt;!-- ... --&gt;) surrounding +text+ and/or
    # the output of +block+. see
    # http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4
    #
    # If +text+ is an Internet Explorer conditional comment condition such as
    # "[if IE]", the output includes the opening condition and closing
    # "[endif]". See http://www.quirksmode.org/css/condcom.html
    #
    # Since "Authors should avoid putting two or more adjacent hyphens inside
    # comments," we emit a warning if you do that.
    def comment(text = '')
      puts "Warning: Authors should avoid putting two or more adjacent hyphens inside comments." if text =~ /--/

      conditional = text =~ /\[if .*\]/

      rawtext "<!--"
      rawtext text
      rawtext ">" if conditional

      if block_given?
        rawtext "\n"
        yield
        rawtext "\n"
      end

      rawtext "<![endif]" if conditional
      rawtext "-->\n"
    end

    protected

    def sort_for_xml_declaration(attributes)
      # correct order is "version, encoding, standalone" (XML 1.0 section 2.8).
      # But we only try to put version before encoding for now.
      stringized = []
      attributes.each do |key, value|
        stringized << [key.to_s, value]
      end
      stringized.sort{|a, b| b <=> a}
    end

  end

  public

  # Alias to make it easier to spell
  HtmlWidget = HTMLWidget

end