#!/usr/bin/env python

"""
mtnpatch is a patch tool intended to apply 'mtn diff' patch, including the 
additional cset operations (e.g. add, drop and rename) listed in mtn diff comments.

mtnpatch does not actually apply the patch. It only dumps the list of commands to enter
to actually apply the patch.
To apply the patch, use 'mtnpatch.py file.patch | sh'
"""

import sys, os, string, getopt, re

mtncmd = "mtn"


def usage():
    print "Usage: mtnpatch.py [options] file.patch"
    print "Options:"
    print "  -h  --help         display help message"
    print "  -R  --reverse      apply patch in reverse"
    print "\nTo actually apply the patch, use 'mtnpatch.py file.patch | sh'"

def main(argv = None):
    if argv is None:
        argv = sys.argv
    try:
        opts, list = getopt.getopt(sys.argv[1:], 'h:R', ["--help", "--reverse"])
    except:
        usage()
        sys.exit(2)
    reverse = False
    for o, a in opts:
        if o in ("-h", "--help"):
            usage()
            sys.exit(1)
        if o in ("-R", "--reverse"):
            reverse = True
    if len(list) != 1:
        usage()
        sys.exit(1)
    if os.path.exists(list[0]):
        input = open(list[0], 'r')
        renameFrom = ""
        cmd = ""
        addedFiles = []
        addedDirs = []
        droppedFiles = []
        droppedDirs = []
        renamedFiles = []
        for line in input:
            if len(line) > 0:
                if line[0] == '#':
                    matches = re.search("#\s+(\w+)\s+\"(.*)\"", line)
                    if matches is not None:
                        cmd = matches.group(1)
                        fileName = matches.group(2)
                        isDir = os.path.isdir(fileName)
                        if cmd == "delete":
                            if isDir: droppedDirs.append(fileName)
                            else: droppedFiles.append(fileName)
                        elif cmd == "add" or cmd == "add_file" or cmd == "add_dir":
                            if isDir: addedDirs.append(fileName)
                            else: addedFiles.append(fileName)
                        elif cmd == "rename":
                            renameFrom = fileName
                        elif cmd == "to" and renameFrom != "":
                            renamedFiles.append((renameFrom, fileName))
                            renameFrom = ""
                        else:
                            cmd = ""
        if reverse:
            print "patch -R -p0 < %s" % list[0]
            for f in addedFiles: print "%s drop -e %s" % (mtncmd, f)
            for f in addedDirs: print "%s drop -e %s" % (mtncmd, f)
            for fold,fnew in renamedFiles: print "%s rename -e %s %s" % (mtncmd, fnew, fold)
            for f in droppedDirs: print "%s revert %s" % (mtncmd, f)
            for f in droppedFiles: print "%s revert %s" % (mtncmd, f)
        else:
            print "patch -p0 < %s" % list[0]
            for f in droppedFiles: print "%s drop -e %s" % (mtncmd, f)
            for f in droppedDirs: print "%s drop -e %s" % (mtncmd, f)
            for fold,fnew in renamedFiles: print "%s rename -e %s %s" % (mtncmd, fold, fnew)
            for f in addedDirs: print "%s add %s" % (mtncmd, f)
            for f in addedFiles: print "%s add %s" % (mtncmd, f)

if __name__ == "__main__":
    sys.exit(main())