module SmallCage::Commands
  #
  # 'smc update' command
  #
  class Update
    include SmallCage

    def self.execute(opts)
      new(opts).execute
    end

    def initialize(opts)
      @opts = opts
    end

    def execute
      start = Time.now
      target = Pathname.new(@opts[:path])

      fail 'target directory or file does not exist.: ' + target.to_s unless target.exist?

      @loader   = Loader.new(target)
      @renderer = Renderer.new(@loader)
      @list     = UpdateList.create(@loader.root, target)
      STDERR.puts 'WARN: Can\'t load tmp/list.yml file.' if @list.load_error

      render_smc_files
      expire_old_files @list.expire
      @list.save

      count = @list.update_count
      elapsed  = Time.now - start
      puts "-- #{count} files.  #{sprintf('%.3f', elapsed)} sec." +
        "  #{sprintf('%.3f', count == 0 ? 0 : elapsed / count)} sec/file." unless @opts[:quiet]
    end

    def expire_old_files(uris)
      root = @loader.root
      uris.each do |uri|
        file = root + uri[1..-1]
        if file.exist?
          puts "D #{uri}" unless @opts[:quiet]
          file.delete
        end
      end
    end
    private :expire_old_files

    def render_smc_files
      if @opts[:fast]
        @loader.each_smc_obj_using_target_template(@list) do |obj|
          render_smc_obj(obj)
        end
      else
        @loader.each_smc_obj do |obj|
          render_smc_obj(obj)
        end
      end
    end
    private :render_smc_files

    def render_smc_obj(obj)
      uris = @renderer.render(obj['template'] + '.uri', obj)
      if uris
        render_multi(obj, uris.split(/\r\n|\r|\n/))
      else
        render_single(obj)
      end
    end
    private :render_smc_obj

    def render_single(obj, mtime = nil)
      mark = obj['path'].exist? ? 'U ' : 'A '
      mtime ||= obj['path'].smc.stat.mtime.to_i

      # Do not skip if the target is file.
      if @opts[:fast] && @loader.dir_target && !@loader.target_template
        last_mtime = @list.mtime(obj['uri'].smc)
        if mtime == last_mtime
          @list.update(obj['uri'].smc, mtime, String.new(obj['uri']), obj['template'])
          return
        end
      end

      result = @renderer.render(obj['template'], obj)
      result = after_rendering_filters(obj, result)
      output_result(obj, result)
      puts mark + obj['uri'] unless @opts[:quiet]

      # create new uri String to remove smc instance-specific method.
      @list.update(obj['uri'].smc, mtime, String.new(obj['uri']), obj['template'])
    end
    private :render_single

    def render_multi(obj, uris)
      obj['uris'] ||= uris
      uris    = uris.map { |uri| uri.strip }
      smcuri  = obj['uri'].smc
      smcpath = obj['path'].smc
      base    = obj['path'].parent
      mtime   = smcpath.stat.mtime.to_i
      uris.each_with_index do |uri, index|
        next if uri.empty?
        docpath = DocumentPath.create_with_uri(@loader.root, uri, base)
        next if docpath.path.directory?
        FileUtils.mkpath(docpath.path.parent)
        obj['uri']    = DocumentPath.add_smc_method(docpath.uri, smcuri)
        obj['path']   = DocumentPath.add_smc_method(docpath.path, smcpath)
        obj['cursor'] = index
        render_single(obj, mtime)
      end
    end
    private :render_multi

    def after_rendering_filters(obj, result)
      filters = @loader.filters('after_rendering_filters')
      filters.each do |f|
        result = f.after_rendering_filter(obj, result)
      end
      result
    end
    private :after_rendering_filters

    def output_result(obj, str)
      open(obj['path'], 'w') do |io|
        io << str
      end
    end
    private :output_result
  end
end