#!/usr/bin/python

############################################################################
#   copyright            : (C) 2001-2004 Marko Grönroos                    #
#   email                : magi@iki.fi                                     #
############################################################################
#                                                                          #
#   This program is free software; you can redistribute it and/or modify   #
#   it under the terms of the GNU General Public License as published by   #
#   the Free Software Foundation; either version 2 of the License, or      #
#   (at your option) any later version.                                    #
#                                                                          #
############################################################################

import os,sys,re

################################################################################
# Print error message
################################################################################
def printError():
    print "Usage: rsed [<options>] '<old>' '<new>' '<file_pattern>'\n\n" \
          "  Replaces a string with a new string from all files that match \n" \
          "  the given file name pattern in and below the current working \n" \
          "  directory, recursively.\n"
    print "  The <old> string is a regular expression to be searched, and \n" \
          "  the <new> string is a replacement that can contain match group \n" \
          "  results indicated with a backslash and the number of the group.\n"
    print "  Options:  -c           Do not recurse into subdirectories."
    print "            -d <path>    Root directory for replacing."
    print "            -q           Quiet.\n"
    print "  Examples: rsed 'foo' 'bar' '*.h'"
    print "            rsed 'f[io]+' 'bar' '*.h'"
    print "            rsed 'f([io]+)' 'bar\1' '*.h'\n"
    sys.exit()

################################################################################
# Handle command line arguments
################################################################################

# Default option values
rootDirectory = "."    # Root directory for find
flagQuiet     = 0      # Be quiet; do not print anything.
findOptions   = ""     # Miscellaneous find options

if len(sys.argv) < 4:
    print "error: too few (%d) arguments.\n" % (len (sys.argv)-1)
    printError ()

# Parse optinal parameters
moreOptions   = 1
while moreOptions:

    # -c: Do not recurse.
    if sys.argv[1] == '-c':
        flagOnlyCurrent = 1
        findOptions = findOptions + " -maxdepth 1 "
        del sys.argv[1]

    # -d: Root directory
    elif sys.argv[1] == '-d':
        if len (sys.argv) < 3:
            print "error: -d requires an argument.\n"
            printError ()
        rootDirectory = sys.argv[2]
        del sys.argv[1:3]

    # -q: Quiet
    elif sys.argv[1] == '-q':
        flagQuiet = 1
        del sys.argv[1]
        
    else:
        moreOptions = 0

if len(sys.argv) != 4:
    print "error: wrong number (%d) of mandatory arguments.\n" % (len (sys.argv))
    printError ()

# Retrieve mandatory parameters
replaced = sys.argv[1]
replacing = sys.argv[2]
include = "-name '%s' " % (sys.argv[3])

################################################################################
# Find files and replace
################################################################################

findCommand = "find %s -type f %s %s -print" % \
              (rootDirectory, include, findOptions)

# Find files to be processed
filesp = os.popen (findCommand, "r")
filenames = map (lambda x: x[:-1], filesp.readlines())
filesp.close ()

# Replace occurrences in each matching file
for filename in filenames:
    
    # To avoid using a temporary file, we first read the file
    # in and then write it.
    
    # Read file in
    filein = open (filename, "r")
    lines = map (lambda x: x[:-1], filein.readlines())
    filein.close()

    # Replace occurrences
    replCount = 0
    for i in xrange(len(lines)):
        if re.search (replaced, lines[i]):
            lines[i] = re.sub (replaced, replacing, lines[i])
            replCount = replCount + 1

    # Write file only if some changes were made.
    if replCount > 0:
	# Write the file
	fileout = open (filename, "w")
	for line in lines:
	    fileout.write (line+"\n")
	fileout.close()

        if not flagQuiet:
            print "%s: %d replaced" % (filename, replCount)