#!/usr/bin/env python
import sys, re, os, os.path, fnmatch, codecs
from optparse import OptionParser

cwd = os.getcwd()
numfiles = 0
numlines = 0
numchanges = 0
encoding = "UTF-8"

usage = "%prog [options] arg1 arg2"
desc = """Walk the current directory, opening *.text files and replacing
matches for the regex arg1 with arg2. E.g., %prog '@c\s*phone' '@c telephone'.
Unless the option '-m' is used, changes will only be reported and not actually
made."""

def main():
    parser = OptionParser(usage=usage,
    description = desc)
    parser.add_option("-m", "--make_changes",
                      action="store_true", dest="test",
                      help="Actually make changes instead of just reporting them." )
    options, (arg1, arg2) = parser.parse_args()
    walkdir(arg1, arg2, options.test)

def walkdir(arg1, arg2, make_changes=False):
    "%s" % desc
    global numfiles, numlines, numchanges
    change_lines = []
    regex =  re.compile(r'(%s)' % arg1)
    # print("-"*80)
    for path, subdirs, names in os.walk(cwd):
        for name in names:
            if fnmatch.fnmatch(name, '[!.]*.text'):
                numfiles += 1
                changed = False
                f = os.path.join(path,name)
                sf = f[len(cwd)+1:]
                # use the relative path as the key
                fo = codecs.open(f, 'r', encoding)
                lines = fo.readlines()
                fo.close()
                for i in range(len(lines)):
                    numlines += 1
                    m = regex.search(lines[i])
                    if m:
                        numchanges += 1
                        r = "  '%s' => '%s' in line %s of %s" %(arg1, arg2, i+1, sf)
                        if make_changes:
                            lines[i] = regex.sub(arg2, lines[i])
                            changed = True
                        else:
                            line = lines[i]
                        change_lines.append("%s:\n      %s" % (r, lines[i].strip()))
                if changed:
                    fo = codecs.open(f, 'w', encoding)
                    fo.writelines(lines)
                    fo.close()
    if numchanges:
        if make_changes:
            v = "Made"
            w = ""
        else:
            v = "Identified"
            w = "Append '-m' to the command to actually make these changes"
        print("%s %s changes in %s lines from %s files:" %
                (v, numchanges, numlines, numfiles))
        for l in change_lines:
            print(l)
        print(w)
    else:
        print("No changes were found")

if __name__ == '__main__':
    main()