require 'set'
require 'FileUtils'

module StoryTeller
  class Generator
	attr_reader :output, :view_path, :view, :guides_dir

	def initialize(output = nil)
	  @guides_dir = File.join(File.dirname(__FILE__), '..')

	  @output = output || File.join(@guides_dir, "output")

	  unless ENV["ONLY"]
		FileUtils.rm_r(@output) if File.directory?(@output)
		FileUtils.mkdir(@output)
	  end

	  @view_path = File.join(@guides_dir, "content")
	end

	def generate
	  guides = Dir.entries(view_path).find_all {|g| g =~ /textile$/ }

	  if ENV["ONLY"]
		only = ENV["ONLY"].split(",").map{|x| x.strip }.map {|o| "#{o}.textile" }
		guides = guides.find_all {|g| only.include?(g) }
		puts "GENERATING ONLY #{guides.inspect}"
	  end

	  guides.each do |guide|
		generate_guide(guide)
	  end

	  # Copy images and css files to html directory
	  FileUtils.cp_r File.join(guides_dir, 'images'), File.join(output, 'images')
	  FileUtils.cp_r File.join(guides_dir, 'files'), File.join(output, 'files')
	end

	def generate_guide(guide)
	  guide =~ /(.*?)(\.erb)?\.textile/
	  name = $1

	  puts "Generating #{name}"

	  file = File.join(output, "#{name}.html")
	  File.open(file, 'w') do |f|
		@view = ActionView::Base.new(view_path)
		@view.extend(Helpers)

		if guide =~ /\.erb\.textile/
		  result = view.render(:layout => 'layout', :file => name)
		  f.write textile(result)
		else
		  body = File.read(File.join(view_path, guide))
		  body = set_header_section(body, @view)
		  body = set_index(body, @view)

		  result = view.render(:layout => 'layout', :text => textile(body))
		  f.write result
		  warn_about_broken_links(result)
		end
	  end
	end

	def set_header_section(body, view)                     
	  new_body = body.gsub(/(.*?)endprologue\./m, '').strip
	  header = $1
	  header =~ /h2\.(.*)/
	  page_title = $1.strip 

	  header = textile(header)

	  view.content_for(:page_title) { page_title }
	  view.content_for(:header_section) { header }
	  new_body
	end

	def set_index(body, view)
	  index = <<-INDEX
	  <div id="subCol">
		<h3 class="chapter"><img src="images/chapters_icon.gif" alt="" />Chapters</h3>
		<ol class="chapters">
	  INDEX

	  i = Indexer.new(body)
	  i.index

	  # Set index for 2 levels
	  i.level_hash.each do |key, value|
		link = view.content_tag(:a, :href => key[:id]) { textile(key[:title]) }

		children = value.keys.map do |k|
		  l = view.content_tag(:a, :href => k[:id]) { textile(k[:title]) }
		  view.content_tag(:li, l)
		end

		children_ul = view.content_tag(:ul, children)

		index << view.content_tag(:li, link + children_ul)
	  end

	  index << '</ol>'
	  index << '</div>'

	  view.content_for(:index_section) { index }

	  i.result
	end

	def textile(body)
	  # If the issue with notextile is fixed just remove the wrapper.
	  with_workaround_for_notextile(body) do |body|
		t = RedCloth.new(body)
		t.hard_breaks = false
		t.to_html(:notestuff, :plusplus, :code, :tip, :importcode)
	  end
	end

	# For some reason the notextile tag does not always turn off textile. See
	# LH ticket of the security guide (#7). As a temporary workaround we deal
	# with code blocks by hand.
	def with_workaround_for_notextile(body)
	  code_blocks = []
	  body.gsub!(%r{<(yaml|shell|ruby|erb|html|sql|plain)>(.*?)</\1>}m) do |m|
		es = ERB::Util.h($2)
		css_class = ['erb', 'shell'].include?($1) ? 'html' : $1
		code_blocks << %{<div class="code_container"><code class="#{css_class}">#{es}</code></div>}
		"\ndirty_workaround_for_notextile_#{code_blocks.size - 1}\n"
	  end
	  
	  body = yield body
	  
	  body.gsub(%r{<p>dirty_workaround_for_notextile_(\d+)</p>}) do |_|
		code_blocks[$1.to_i]
	  end
	end

	def warn_about_broken_links(html)
	  # Textile generates headers with IDs computed from titles.
	  anchors  = Set.new(html.scan(/<h\d\s+id="([^"]+)/).flatten)
	  # Also, footnotes are rendered as paragraphs this way.
	  anchors += Set.new(html.scan(/<p\s+class="footnote"\s+id="([^"]+)/).flatten)
	  
	  # Check fragment identifiers.
	  html.scan(/<a\s+href="#([^"]+)/).flatten.each do |fragment_identifier|
		next if fragment_identifier == 'mainCol' # in layout, jumps to some DIV
		unless anchors.member?(fragment_identifier)
		  puts "BROKEN LINK: ##{fragment_identifier}"
		end
	  end
	end
  end
end
