# Prefixbox.com Feed Generator is a Jekyll plugin that generates a prefixbox.csv file by 
# traversing all of the available posts and pages.
# 
# See readme file for documenation
# 
# Based on the Sitemap generator by Michael Levin
# Site: https://github.com/kinnetica/jekyll-plugins
# 
# Author: Sverrir Sigmundarson
# Site: https://sverrirs.com
# Distributed Under A Creative Commons License
#   - http://creativecommons.org/licenses/by/3.0/
require 'jekyll/document'
require 'csv'

module Jekyll

  class Jekyll::Document
    attr_accessor :name

    def path_to_source
      File.join(*[@name].compact)
    end

    def location_on_server(my_url)
      "#{my_url}#{url}"
    end
  end

  class Page
    attr_accessor :name

    def path_to_source
      File.join(*[@dir, @name].compact)
    end

    def location_on_server(my_url)
      location = "#{my_url}#{url}"
      location.gsub(/index.html$/, "")
    end
  end

  # Recover from strange exception when starting server without --auto
  class PrefixboxFile < StaticFile
    def write(dest)
      true
    end
  end

  class PrefixboxGenerator < Generator
    priority :lowest

    # Config defaults
    PREFIXBOX_FILE_NAME = "/prefixbox.csv"
    EXCLUDE = ["/atom.xml", "/feed.xml", "/feed/index.xml", "/sitemap.xml"]
    #INCLUDE_POSTS = ["/index.html"] 
    INCLUDE_POSTS = [] 
    
    # Goes through pages and posts and generates prefixbox.csv file
    #
    # Returns nothing
    def generate(site)
      # Configuration
      prefixbox_config = site.config['prefixbox'] || {}
      @config = {}
      @config['filename'] = prefixbox_config['filename'] || PREFIXBOX_FILE_NAME
      @config['exclude'] = prefixbox_config['exclude'] || EXCLUDE
      @config['include_posts'] = prefixbox_config['include_posts'] || INCLUDE_POSTS

      # Create destination directory if it doesn't exist yet. Otherwise, we cannot write our file there.
      Dir::mkdir(site.dest) if !File.directory? site.dest
      
      # Create the file name and paths
      filename = @config['filename']
      
      # Write all the data to the file and close it
      CSV.open(File.join(site.dest, filename), "wb") do |csv|
        fill_posts(site, csv)
       #fill_pages(site, csv)
      end
          
      # Keep the prefixbox.csv file from being cleaned by Jekyll
      site.static_files << Jekyll::PrefixboxFile.new(site, site.dest, "/", filename)
    end

    # Create url elements for all the normal pages and find the date of the
    # index to use with the pagination pages
    #
    # Returns last_modified_date of index page
    def fill_pages(site, csv)
      site.pages.each do |page|
        if !excluded?(site, page.path_to_source)
          if File.exists?(page.path)
            url = fill_url(site, page)
            csv <<  [page.title, 100, page.title, url, "", "page"]            
          end
        end
      end
    end
    
    # Create url elements for all the posts and find the date of the latest one
    #
    # Returns last_modified_date of latest post
    def fill_posts(site, csv)
      last_modified_date = nil
      
      site.collections["posts"].docs.each do |post|
        
        # Write the page data
        if !excluded?(site, post.name)
          url = fill_url(site, post)
          title = post.to_liquid['title']
          title = title.length > 80 ? title[0..79] : title
          csv <<  [title, 100, title, url, "", "blog"]
        end

        # Determine the last modified date
        date = File.mtime(post.path)
        last_modified_date = date if last_modified_date == nil or date > last_modified_date
      end

      last_modified_date
    end

    # Fill data of each URL element: location, last modified,
    # change frequency (optional), and priority.
    #
    # Returns url REXML::Element
    def fill_url(site, page_or_post)
      url = 'https:' + site.config['url'] + site.config['baseurl'] + page_or_post.location_on_server(url)
      
      url
    end

    # Is the page or post listed as something we want to exclude?
    #
    # Returns boolean
    def excluded?(site, name)
      @config['exclude'].include? name
    end

    def posts_included?(site, name)
      @config['include_posts'].include? name
    end

  end
end