## -*- Ruby -*-
## filesed -s <pattern> -r <string> <file 1> [ <more files> ]
## Replace pattern by string in all given files.
## Testversion: parses commandline but doesn't change files

def using
	print <<-'ENDE'
Usage: filesed -s <pattern> -r <string> <file 1> [ <more files> ]
	ENDE
	exit 1
end

def filesed!(pattern, replaceString, filename)
  regexPattern = Regexp.compile(pattern)
  count = 0 
  tmpFilename = "#{filename}.#{Time.now.usec}"
  tmpFile = File.new(tmpFilename, "w")
  srcFile = File.open(filename)
  srcFile.each_line do
    |line|
    tmpFile.print line.gsub(regexPattern) {
      |match|
      count += 1
      replaceString
    }
  end
  tmpFile.close
  srcFile .close
#~  File.rename(tmpFilename, filename)
  return count
end

pattern = nil
replacer = nil
optionsArt = nil
files = Array.new
$*.each do
  | argument |
  if (/^-.*/ =~ argument) != nil  # option
    if (/^-[rs]/ =~ argument) == nil then using end
    optionsArt = argument[1]  # expect option parameter
  else
    case optionsArt
    when 's'[0] then pattern = argument
    when 'r'[0] then replacer = argument
    else files.push(argument)
    end
    optionsArt = nil
  end
end
using unless pattern && replacer && !files.empty?
counter = 0
files.each { |filename|
  counter += filesed!(pattern, replacer, filename) }
print "Replaced: #{counter.to_s}\n"