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