# Jekyll plugin for generating an rss 2.0 feed for posts
#
# Based on https://github.com/kikoval/jekyll-rss/ but heavily modified
#
# Usage: place this file in the _plugins directory and set the required configuration
#        attributes in the _config.yml file
#
# Uses the following attributes in _config.yml:
#   title           - the title of the site
#   url            - the url of the site
#   description    - (optional) a description for the feed (if not specified will be generated from title)
#   author         - (optional) the author of the site (if not specified will be left blank)
#   copyright      - (optional) the copyright of the feed (if not specified will be left blank)
#   rss_path       - (optional) the path to the feed (if not specified "/" will be used)
#   rss_name       - (optional) the name of the rss file (if not specified "rss.xml" will be used)
#   rss_post_limit - (optional) the number of posts in the feed
#
# Author: Assaf Gelber <assaf.gelber@gmail.com>
# Site: http://agelber.com
# Source: http://github.com/agelber/jekyll-rss
#
# Distributed under the MIT license
# Copyright Assaf Gelber 2013

require "jekyll"
require "rss"

module RssFeed
  class Page < Jekyll::Page; end

  class Generator < Jekyll::Generator
    priority :low
    safe true

    attr_reader :site, :rss_content
    # Generates an rss 2.0 feed
    #
    # site - the site
    #
    # Returns nothing
    def generate(site)

      @site = site
      feed_items = []
      # collect Data
      @rss_content = RSS::Maker.make('2.0') do |maker|
        maker.channel.title = @site.config['title']
        maker.channel.link = @site.config['url']
        maker.channel.description = @site.config['description'] || "RSS feed for #{site.config['title']}"
        maker.channel.author = @site.config['author']
        maker.channel.updated = @site.posts.docs.map { |p| p.date }.max
        maker.channel.copyright = @site.config['copyright']

        @site.collections.each do |name, meta|
          Jekyll.logger.info "muhh Feed:", "Adding #{name} to global feed"
          feed_items

          site.posts.docs.reverse[0..post_limit].each do |post|
            maker.items.new_item do |item|
              item.title = post.data["title"]
              item.link = "#{@site.config['url']}#{post.url}"
              item.description = post.data["excerpt"]
              item.updated = post.date
            end
          end
        end
      end

      create_file

      # Add the feed page to the site pages
      site.pages << RssFeed::Page.new(site, site.dest, rss_path, rss_name)
    end

    private

    def rss_path
      ensure_slashes(@site.config['rss_path'] || "/")
    end

    def rss_name
      @site.config['rss_name'] || "rss.xml"
    end

    def create_file
      full_path = File.join(@site.dest, rss_path)
      ensure_dir(full_path)
      File.open("#{full_path}#{rss_name}", "w") { |f| f.write(@rss_content) }
    end
    # Ensures the given path has leading and trailing slashes
    #
    # path - the string path
    #
    # Return the path with leading and trailing slashes
    def ensure_slashes(path)
      ensure_leading_slash(ensure_trailing_slash(path))
    end

    # Ensures the given path has a leading slash
    #
    # path - the string path
    #
    # Returns the path with a leading slash
    def ensure_leading_slash(path)
      path[0] == "/" ? path : "/#{path}"
    end

    # Ensures the given path has a trailing slash
    #
    # path - the string path
    #
    # Returns the path with a trailing slash
    def ensure_trailing_slash(path)
      path[-1] == "/" ? path : "#{path}/"
    end

    # Ensures the given directory exists
    #
    # path - the string path of the directory
    #
    # Returns nothing
    def ensure_dir(path)
      FileUtils.mkdir_p(path)
    end

    def post_limit
      @site.config['rss_post_limit'] - 1 rescue @site.posts.count
    end
  end
end