#!/usr/bin/env ruby
#
# Shows the documentation for a ruby method or class on the command
# line.  Usage:
#
# 1% rubydoc <class>
# 2% rubydoc <class> <method-name>
#
# 1) Prints the entire class's methods
# 2) Prints a specific method from the class
#

require 'open-uri'
require 'cgi'

class Rubydoc

  def initialize

  end

  def real_main(argv)
    if argv.empty?
      print_usage
      return
    end
    cls = argv.shift
    if argv.empty?
      process_class cls
    else
      method = argv.shift
      process_method cls,method
    end
  end

  private

  def process_class(cls)

  end

  def process_method(cls,method)
    url = class_url cls
    txt = open(url).read
    link = nil
    inside_method = false
    contents = ''
    txt.each do |line|
      if link
        if inside_method
          if line.match /<div id=\"method-/
            inside_method = false
          else
            contents += line
          end
        else
          if line.match /<a name="#{link}"><\/a>/
              inside_method = true
          end
        end
      else
        line.scan /<a href="#([^"]+)">#{method}<\/a>&nbsp;/ do |res|
          link = res[0]
        end
      end
    end
    if not link
      STDERR.puts "Couldn't find " + cls + "." + method
      return
    end
    if contents
      puts '========== ' + cls + '.' + method + ' =========='
      puts
      in_pre = false
      contents = CGI.unescapeHTML contents            # escape HTML
      contents.each do |line|
        line.strip!
        line = line.gsub /<br\s?\/?>/, "\n\n"         # add newlines for <br>
        in_pre = true  if line == '<pre>'
        in_pre = false if line == '</pre>'
        line = line.gsub /<\/?pre>/, "\n"             # add newlines for <pre>
        line = line.gsub /<[^>]+>/, ''                # remove HTML tags
        line = line.gsub /^<[^>]*$/, ''               # remove multi-line HTML tags
        line = line.gsub /^[^>]*>$/, ''               # remove multi-line HTML tags
        next if !line or line == ''
        line = line.gsub /<\/p/, "\n"                 # add newlines for <pre>
        print "\t" if in_pre
        puts line
      end
    end
  end

  def class_url(cls)
    return 'http://www.ruby-doc.org/core/classes/' + cls + '.html'
  end

  def print_usage
    def e(s)
      STDERR.puts s
    end
    e 'Usage: ' + File.basename($0) + '<class> [ <method-name> ]'
    e 'where'
    e ' <class>          is a ruby core class'
    e ' <method-name>    is an optional name of a method'
  end

end

def main(argv)
  Rubydoc.new.real_main argv
end

main ARGV