#!/usr/bin/env python3
# (c) 2015 Taeyeon Mori

from animeimport import transport_path

import argparse
import os
import sys
import errno


def resymlink(target, location, dir, dir_fd):
    try:
       os.unlink(location, dir_fd=dir_fd)
    except FileNotFoundError:
    	pass
    if os.path.isabs(target):
        os.symlink(target, location, dir_fd=dir_fd)
    else:
        os.symlink(transport_path(target, dir, location), location, dir_fd=dir_fd)


def main(argv):
    parser = argparse.ArgumentParser(prog=argv[0], description="""
    Move symbolic link targets (Does not move the files, only changes referencing symlinks)
    """)
    parser.add_argument("source_anchor", help="Old path")
    parser.add_argument("target_anchor", help="New path")

    args = parser.parse_args(argv[1:])

    sa_len = len(args.source_anchor)

    for root, dirs, files, root_fd in os.fwalk():
        print("CHDIR %s" % root)
        for fname in files:
            try:
                target = os.readlink(fname, dir_fd=root_fd)
            except OSError as e:
                if e.errno == errno.EINVAL:
                    continue # not a symlink, don't touch it
                raise
            else:
                if target.startswith(args.source_anchor):
                    newtarget = args.target_anchor + target[sa_len:]
                    print("  LINK '%s' => '%s'" % (fname, newtarget))
                    resymlink(newtarget, fname, root, root_fd)

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