#! /usr/bin/python
#
## Copyright (C) 2007 Mark Wooding
##   Do with this as you will; attribution would be nice but is not
##   essential.  There is no warranty, not even of any kind.

import sys as SYS
import os as OS
import subprocess as PROC
import errno as E

left, base, right = SYS.argv[1:]
if left !=  OS.path.abspath('.hgtags'):
  next = OS.environ.get('HGMERGE_TAGS_NEXT', 'hgmerge')
  OS.execvp(next, [next] + SYS.argv[1:])

tagmap = {}
def read(f, s):
  try:
    for line in file(f):
      if line.endswith('\n'): line = line[:-1]
      rev, name = line.split(None, 1)
      tagmap.setdefault(name, [None, None, None])[s] = rev
  except OSError, err:
    if err.errno != E.ENOENT:
      raise
read(left, 0)
read(base, 1)
read(right, 2)

seq = 1
while True:
  outname = left + '.' + str(seq)
  if not OS.path.exists(outname):
    break
  seq += 1
out = file(outname, 'w')
confl = []
for name, val in tagmap.iteritems():
  if val[0] == val[2]:
    merge = val[0]
  elif val[0] == val[1]:
    merge = val[2]
  elif val[2] == val[1]:
    merge = val[0]
  else:
    confl.append((name, val))
    merge = None
  if merge is not None:
    out.write('%s %s\n' % (merge, name))
if not confl:
  out.close()
else:
  out.write('*** CONFLICTS ***\n')
  for sep, f, i in ('<', left, 0), ('=', base, 1), ('=', right, 2):
    out.write(sep * 6 + ' ' + f + '\n')
    for name, val in confl:
      out.write('%s %s\n' % (name, val[i]))
  out.write('>' * 6 + ' ' + '\n')
  out.close()
  qn = "'" + ''.join((ch == "'" and "'\\''" or ch for ch in outname)) + "'"
  ed = OS.environ.get('VISUAL', OS.environ.get('EDITOR', 'vi'))
  editor = PROC.Popen(['sh', '-c', '%s %s' % (ed, qn)])
  stat = editor.wait()
  if stat != 0:
    SYS.stderr.write('hgmerge-tags: editor failed (status = %d)' % stat)
    OS.unlink(outname)
    SYS.exit(1)
  for i in file(outname):
    if len(i) and i[0] in '*<=>':
      SYS.stderr.write('hgmerge-tags: user couldn\'t fix the merge')
      OS.unlink(outname)
      SYS.exit(1)
OS.rename(outname, left)
SYS.exit(0)