require 'jsduck/logger'
require 'jsduck/json_duck'
require 'jsduck/null_object'
require 'jsduck/logger'
require 'jsduck/grouped_asset'
require 'fileutils'

module JsDuck

  # Reads in guides and converts them to JsonP files
  class Guides < GroupedAsset
    # Creates Guides object from filename and formatter
    def self.create(filename, formatter)
      if filename
        Guides.new(filename, formatter)
      else
        NullObject.new(:to_array => [], :to_html => "", :[] => nil)
      end
    end

    # Parses guides config file
    def initialize(filename, formatter)
      @path = File.dirname(filename)
      @groups = JsonDuck.read(filename)
      build_map_by_name("Two guides have the same name")
      @formatter = formatter
    end

    # Writes all guides to given dir in JsonP format
    def write(dir)
      FileUtils.mkdir(dir) unless File.exists?(dir)
      each_item {|guide| write_guide(guide, dir) }
      # Write the JSON to output dir, so it's available in released
      # version of docs and people can use it with JSDuck by themselves.
      JsonDuck.write_json(dir+"/guides.json", @groups)
    end

    def write_guide(guide, dir)
      guide_dir = @path + "/guides/" + guide["name"]
      tutorial_dir = @path + "/tutorials/" + guide["name"]
      out_dir = dir + "/" + guide["name"]

      if File.exists?(guide_dir)
        in_dir = guide_dir
      elsif File.exists?(tutorial_dir)
        in_dir = tutorial_dir
      else
        return Logger.instance.warn(:guide, "Guide #{guide_dir} / #{tutorial_dir} not found")
      end

      guide_file = in_dir + "/README.md"
      return Logger.instance.warn(:guide, "README.md not found in #{in_dir}") unless File.exists?(guide_file)

      Logger.instance.log("Writing guide", out_dir)
      # Copy the whole guide dir over
      FileUtils.cp_r(in_dir, out_dir)

      @formatter.doc_context = {:filename => guide_file, :linenr => 0}
      name = File.basename(in_dir)
      @formatter.img_path = "guides/#{name}"
      html = add_toc(guide, @formatter.format(IO.read(guide_file)))

      JsonDuck.write_jsonp(out_dir+"/README.js", name, {:guide => html, :title => guide["title"]})
    end

    # Creates table of contents at the top of guide by looking for <h2> elements in HTML.
    def add_toc(guide, html)
      toc = [
        "<div class='toc'>\n",
        "<p><strong>Contents</strong></p>\n",
        "<ol>\n",
      ]
      new_html = []
      i = 0
      html.each_line do |line|
        if line =~ /^<h2>(.*)<\/h2>$/
          i += 1
          toc << "<li><a href='#!/guide/#{guide['name']}-section-#{i}'>#{$1}</a></li>\n"
          new_html << "<h2 id='#{guide['name']}-section-#{i}'>#{$1}</h2>\n"
        else
          new_html << line
        end
      end
      toc << "</ol>\n"
      toc << "</div>\n"
      # Inject TOC at below first heading if at least 2 items in TOC
      if i >= 2
        new_html.insert(1, toc)
        new_html.flatten.join
      else
        html
      end
    end

    # Returns HTML listing of guides
    def to_html
      html = @groups.map do |group|
        [
          "<h3>#{group['title']}</h3>",
          "<ul>",
          group["items"].map {|g| "<li><a href='#!/guide/#{g['name']}'>#{g['title']}</a></li>" },
          "</ul>",
        ]
      end.flatten.join("\n")

      return <<-EOHTML
        <div id='guides-content' style='display:none'>
            #{html}
        </div>
      EOHTML
    end

    # Extracts guide icon URL from guide hash
    def icon_url(guide)
      "guides/" + guide["name"] + "/icon-lg.png"
    end

  end

end