#!/usr/bin/env ruby
# CodeRay Executable
#
# Version: 0.1
# Author: murphy

def err msg
  $stderr.puts msg
end

begin
  require 'coderay'

  if ARGV.empty?
    puts <<-USAGE
CodeRay #{CodeRay::VERSION} (http://rd.cYcnus.de/coderay)
Usage:
  coderay -<lang> [-<format>] < file > output
  coderay file [-<format>]
Example:
  coderay -ruby -statistic < foo.rb
  coderay codegen.c  # generates codegen.c.html
    USAGE
  end

  first, second = ARGV

  if first
    if first[/-(\w+)/] == first
      lang = $1.to_sym
      input = $stdin.read
      tokens = :scan
    elsif first == '-'
      lang = $1.to_sym
      input = $stdin.read
      tokens = :scan
    else
      file = first
      tokens = CodeRay.scan_file file
      output_filename, output_ext = file, /#{Regexp.escape(File.extname(file))}$/
    end
  else
    puts 'No lang/file given.'
    exit 1
  end

  if second
    if second[/-(\w+)/] == second
      format = $1.to_sym
    else
      raise 'Invalid format (must be -xxx).'
    end
  else
    $stderr.puts 'No format given; setting to default (HTML Page)'
    format = :page
  end
  
  # TODO: allow streaming
  if tokens == :scan
    output = CodeRay::Duo[lang => format].highlight input  #, :stream => true
  else
    output = tokens.encode format
  end
  out = $stdout
  if output_filename
    output_filename += '.' + CodeRay::Encoders[format]::FILE_EXTENSION
    if File.exist? output_filename
      err 'File %s already exists.' % output_filename
      exit
    else
      out = File.open output_filename, 'w'
    end
  end
  out.print output

rescue => boom
  err "Error: #{boom.message}\n"
  err boom.backtrace
  err '-' * 50
  err ARGV
  exit 1
end