$tab_size = 2
$tab_string = " "

# indent regexp tests

$indent_expression = [
  /^module\b/,
  /(=\s*|^)if\b/,
  /(=\s*|^)until\b/,
  /(=\s*|^)for\b/,
  /(=\s*|^)unless\b/,
  /(=\s*|^)while\b/,
  /(=\s*|^)begin\b/,
  /(=\s*|^)case\b/,
  /\bthen\b/,
  /^class\b/,
  /^rescue\b/,
  /^def\b/,
  /\bdo\b/,
  /^else\b/,
  /^elsif\b/,
  /^ensure\b/,
  /\bwhen\b/,
  /\{[^\}]*$/,
  /\[[^\]]*$/
]

# outdent regexp tests

$outdent_expression = [
  /^rescue\b/,
  /^ensure\b/,
  /^elsif\b/,
  /^end\b/,
  /^else\b/,
  /\bwhen\b/,
  /^[^\{]*\}/,
  /^[^\[]*\]/
]

def make_tab(tab)
  # If the tab is negative, don't do anything
  return (tab < 0) ? "" : $tab_string * $tab_size * tab
end

def add_line line, tab
  line.strip!
  line = make_tab(tab) + line if line.length > 0
  return line + "\n"
end

def format_ruby
  comment_block = false
  multi_line_array = Array.new
  multi_line_string = ""
  tab = 0
  ############
  #filename entered on command line as argument gets passed in Ruby's
  #special argument array ARGV. The ARGV[0] zeroth element has the filename
  ############
  filename = ARGV[0]

  # Open the file for reading
  source = File.new(filename,'r').read
  new_file = ""

  # Read each line
  source.split("\n").each do |line|
    # SKIPPING THIS FOR NOW.  NOT SURE WHY I'D NEED TO DO THIS YET.
    #   Says: if it's not a comment line and has a \ (plus spaces)
    # combine continuing lines
    if(!(line =~ /^\s*#/) && line =~ /[^\\]\\\s*$/)
      multi_line_array.push line
      multi_line_string += line.sub(/^(.*)\\\s*$/,"\\1")
      next
    end

    # THIS GOES WITH THE PREVIOUS IF STATEMENT; SKIP FOR NOW.
    # add final line
    if(multi_line_string.length > 0)
      multi_line_array.push line
      multi_line_string += line.sub(/^(.*)\\\s*$/,"\\1")
    end

    # tab_line is really just the line to check
    tab_line = ((multi_line_string.length > 0) ? multi_line_string : line).strip

    # HE SKIPS CHECKING OF COMMENT BLOCKS; LET'S GO AHEAD AND CHECK THEM
    if(tab_line =~ /^=begin/)
      comment_block = true
    end

    if(comment_block)
      # add the line unchanged
      new_file += line + "\n"
    # THIS IS WHERE THE MAGIC STARTS
    else
      commentab_line = (tab_line =~ /^#/)

      # 
      if(!commentab_line)
        # throw out sequences that will
        # only sow confusion
        tab_line.gsub!(/\/.*?\//,"")  # Subs anything / stuff / with ""
        tab_line.gsub!(/%r\{.*?\}/,"")
        tab_line.gsub!(/%r(.).*?\1/,"")
        tab_line.gsub!(/\\\"/,"'")
        tab_line.gsub!(/".*?"/,"\"\"")
        tab_line.gsub!(/'.*?'/,"''")
        tab_line.gsub!(/#\{.*?\}/,"")

        $outdent_expression.each do |re|
          # Search each line for an outdent keyword
          # If the line contains one of the keywords, it's indented too far
          #   so set it to be out 1 level
          if(tab_line =~ re)
            tab -= 1
            break
          end
        end
      end

      if (multi_line_array.length > 0)
        # This will:
        #   Set lines with indent keywords to not change their indenting.
        #   Set lines without indent keywords to not change their indenting
        #     since tab is still 0.
        multi_line_array.each do |ml|
          # He adds the line; I'd compare actual vs. proper.
          dest += add_line(ml,tab)
        end
        multi_line_array.clear
        multi_line_string = ""
      else
        dest += add_line(line,tab)
      end

      if(!commentab_line)
        # Check the line to see if it contains one of the indent keywords
        $indent_expression.each do |re|
          # If it does contain one of the keywords and doesn't contain the 
          #   'end' keywords
          if(tab_line =~ re && !(tab_line =~ /\s+end\s*$/))
            # Bump the level up 1
            tab += 1
            break
          end
        end
      end
    end

    if(tab_line =~ /^=end/)
      comment_block = false
    end
  end

  #STDOUT.write(dest)
  #File.open(filename, 'w') {|fw| fw.write(dest)}
  puts "File #{ARGV[0]} has been formatted."

  # uncomment this to complain about mismatched blocks
  if(tab != 0)
    STDERR.puts "Indentation error: #{tab}"
  end
end

format_ruby