1begin
  2  require 'open3_detach'
  3rescue LoadError
  4  require 'open3'
  5end
  6
  7module GitHub
  8  module Markup
  9    extend self
 10    @@markups = {}
 11    @@deferred_markups = []
 12
 13    def preload!
 14      @@deferred_markups.each do |loader|
 15        loader.call
 16      end
 17      @@deferred_markups = []
 18    end
 19
 20    def render(filename, content = nil)
 21      content ||= File.read(filename)
 22
 23      if proc = renderer(filename)
 24        proc[content]
 25      else
 26        content
 27      end
 28    end
 29
 30    def markup(file, pattern, &block)
 31      loader = proc do
 32        require file.to_s
 33        add_markup(pattern, &block)
 34      end
 35      @@deferred_markups << loader
 36      add_markup pattern do |*args|
 37        @@deferred_markups.delete(loader)
 38        loader.call
 39        block.call(*args)
 40      end
 41      true
 42    rescue LoadError
 43      false
 44    end
 45
 46    def command(command, regexp, &block)
 47      command = command.to_s
 48
 49      if File.exists?(file = File.dirname(__FILE__) + "/commands/#{command}")
 50        command = file
 51      end
 52
 53      add_markup(regexp) do |content|
 54        rendered = execute(command, content)
 55        rendered = rendered.to_s.empty? ? content : rendered
 56
 57        if block && block.arity == 2
 58          # If the block takes two arguments, pass new content and old
 59          # content.
 60          block.call(rendered, content)
 61        elsif block
 62          # One argument is just the new content.
 63          block.call(rendered)
 64        else
 65          # No block? No problem!
 66          rendered
 67        end
 68      end
 69    end
 70
 71    def add_markup(regexp, &block)
 72      @@markups[regexp] = block
 73    end
 74
 75    def can_render?(filename)
 76      !!renderer(filename)
 77    end
 78
 79    def renderer(filename)
 80      @@markups.each do |key, value|
 81        if Regexp.compile("\\.(#{key})$") =~ filename
 82          return value
 83        end
 84      end
 85      nil
 86    end
 87
 88    def renderer_name(filename)
 89      @@markups.each do |key, value|
 90        if Regexp.compile("\\.(#{key})$") =~ filename
 91          return key
 92        end
 93      end
 94      nil
 95    end
 96
 97    def execute(command, target)
 98      out = ''
 99      Open3.popen3(command) do |stdin, stdout, _|
100        stdin.puts target
101        stdin.close
102        out = stdout.read
103      end
104      out.gsub("\r", '')
105    rescue Errno::EPIPE
106      ""
107    rescue Errno::ENOENT
108      ""
109    end
110
111    # Define markups
112    markups_rb = File.dirname(__FILE__) + '/markups.rb'
113    instance_eval File.read(markups_rb), markups_rb
114  end
115end