module CodeRay
module Encoders

  class HTML

    # This module is included in the output String from thew HTML Encoder.
    #
    # It provides methods like wrap, div, page etc.
    #
    # Remember to use #clone instead of #dup to keep the modules the object was
    # extended with.
    #
    # TODO: more doc.
    module Output

      require 'coderay/encoders/html/numerization.rb'

      attr_accessor :css

      class << self

        # This makes Output look like a class.
        #
        # Example:
        #
        #  a = Output.new '<span class="co">Code</span>'
        #  a.wrap! :page
        def new string, css = CSS.new, element = nil
          output = string.clone.extend self
          output.wrapped_in = element
          output.css = css
          output
        end

        # Raises an exception if an object that doesn't respond to to_str is extended by Output,
        # to prevent users from misuse. Use Module#remove_method to disable.
        def extended o
          warn "The Output module is intended to extend instances of String, not #{o.class}." unless o.respond_to? :to_str
        end

        def make_stylesheet css, in_tag = false
          sheet = css.stylesheet
          sheet = <<-CSS if in_tag
<style type="text/css">
#{sheet}
</style>
          CSS
          sheet
        end

        def page_template_for_css css
          sheet = make_stylesheet css
          PAGE.apply 'CSS', sheet
        end

        # Define a new wrapper. This is meta programming.
        def wrapper *wrappers
          wrappers.each do |wrapper|
            define_method wrapper do |*args|
              wrap wrapper, *args
            end
            define_method "#{wrapper}!".to_sym do |*args|
              wrap! wrapper, *args
            end
          end
        end

      end

      wrapper :div, :span, :page

      def wrapped_in? element
        wrapped_in == element
      end

      def wrapped_in
        @wrapped_in ||= nil
      end
      attr_writer :wrapped_in

      def wrap_in template
        clone.wrap_in! template
      end

      def wrap_in! template
        Template.wrap! self, template, 'CONTENT'
        self
      end
      
      def apply_title! title
        self.sub!(/(<title>)(<\/title>)/) { $1 + title + $2 }
        self
      end

      def wrap! element, *args
        return self if not element or element == wrapped_in
        case element
        when :div
          raise "Can't wrap %p in %p" % [wrapped_in, element] unless wrapped_in? nil
          wrap_in! DIV
        when :span
          raise "Can't wrap %p in %p" % [wrapped_in, element] unless wrapped_in? nil
          wrap_in! SPAN
        when :page
          wrap! :div if wrapped_in? nil
          raise "Can't wrap %p in %p" % [wrapped_in, element] unless wrapped_in? :div
          wrap_in! Output.page_template_for_css(@css)
          if args.first.is_a?(Hash) && title = args.first[:title]
            apply_title! title
          end
          self
        when nil
          return self
        else
          raise "Unknown value %p for :wrap" % element
        end
        @wrapped_in = element
        self
      end

      def wrap *args
        clone.wrap!(*args)
      end

      def stylesheet in_tag = false
        Output.make_stylesheet @css, in_tag
      end

      class Template < String

        def self.wrap! str, template, target
          target = Regexp.new(Regexp.escape("<%#{target}%>"))
          if template =~ target
            str[0,0] = $`
            str << $'
          else
            raise "Template target <%%%p%%> not found" % target
          end
        end

        def apply target, replacement
          target = Regexp.new(Regexp.escape("<%#{target}%>"))
          if self =~ target
            Template.new($` + replacement + $')
          else
            raise "Template target <%%%p%%> not found" % target
          end
        end

        module Simple
          def ` str  #` <-- for stupid editors
            Template.new str
          end
        end
      end

      extend Template::Simple

#-- don't include the templates in docu

      SPAN = `<span class="CodeRay"><%CONTENT%></span>`

      DIV = <<-`DIV`
<div class="CodeRay">
  <div class="code"><pre><%CONTENT%></pre></div>
</div>
      DIV

      TABLE = <<-`TABLE`
<table class="CodeRay"><tr>
  <td class="line_numbers" title="click to toggle" onclick="with (this.firstChild.style) { display = (display == '') ? 'none' : '' }"><pre><%LINE_NUMBERS%></pre></td>
  <td class="code"><pre ondblclick="with (this.style) { overflow = (overflow == 'auto' || overflow == '') ? 'visible' : 'auto' }"><%CONTENT%></pre></td>
</tr></table>
      TABLE
      # title="double click to expand"

      LIST = <<-`LIST`
<ol class="CodeRay">
<%CONTENT%>
</ol>
      LIST

      PAGE = <<-`PAGE`
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="de">
<head>
  <meta http-equiv="content-type" content="text/html; charset=utf-8" />
  <title></title>
  <style type="text/css">
<%CSS%>
  </style>
</head>
<body style="background-color: white;">

<%CONTENT%>
</body>
</html>
      PAGE

    end

  end

end
end
