#!/usr/bin/env python3

# Copyright (c) 2007, 2008 Rocco Rutte <pdmef@gmx.net> and others.
# License: GPLv2

from mercurial import node
from hg2git import setup_repo,load_cache,get_changeset,get_git_sha1
from optparse import OptionParser
import sys
from binascii import hexlify

def heads(ui,repo,start=None,stop=None,max=None):
  # this is copied from mercurial/revlog.py and differs only in
  # accepting a max argument for xrange(startrev+1,...) defaulting
  # to the original repo.changelog.count()
  if start is None:
    start = node.nullid
  if stop is None:
    stop = []
  if max is None:
    max = repo.changelog.count()
  stoprevs = dict.fromkeys([repo.changelog.rev(n) for n in stop])
  startrev = repo.changelog.rev(start)
  reachable = {startrev: 1}
  heads = {startrev: 1}

  parentrevs = repo.changelog.parentrevs
  for r in range(startrev + 1, max):
    for p in parentrevs(r):
      if p in reachable:
        if r not in stoprevs:
          reachable[r] = 1
        heads[r] = 1
      if p in heads and p not in stoprevs:
        del heads[p]

  return [(repo.changelog.node(r), b"%d" % r) for r in heads]

def get_branches(ui,repo,heads_cache,marks_cache,mapping_cache,max):
  h=heads(ui,repo,max=max)
  stale=dict.fromkeys(heads_cache)
  changed=[]
  unchanged=[]
  for node,rev in h:
    _,_,user,(_,_),_,desc,branch,_=get_changeset(ui,repo,rev)
    del stale[branch]
    git_sha1=get_git_sha1(branch)
    cache_sha1=marks_cache.get(b"%d" % (int(rev)+1))
    if git_sha1!=None and git_sha1==cache_sha1:
      unchanged.append([branch,cache_sha1,rev,desc.split(b'\n')[0],user])
    else:
      changed.append([branch,cache_sha1,rev,desc.split(b'\n')[0],user])
  changed.sort()
  unchanged.sort()
  return stale,changed,unchanged

def get_tags(ui,repo,marks_cache,mapping_cache,max):
  l=repo.tagslist()
  good,bad=[],[]
  for tag,node in l:
    if tag==b'tip': continue
    rev=int(mapping_cache[hexlify(node)])
    cache_sha1=marks_cache.get(b"%d" % (int(rev)+1))
    _,_,user,(_,_),_,desc,branch,_=get_changeset(ui,repo,rev)
    if int(rev)>int(max):
      bad.append([tag,branch,cache_sha1,rev,desc.split(b'\n')[0],user])
    else:
      good.append([tag,branch,cache_sha1,rev,desc.split(b'\n')[0],user])
  good.sort()
  bad.sort()
  return good,bad

def mangle_mark(mark):
  return b"%d" % (int(mark)-1)

if __name__=='__main__':
  def bail(parser,opt):
    sys.stderr.write('Error: No option %s given\n' % opt)
    parser.print_help()
    sys.exit(2)

  parser=OptionParser()

  parser.add_option("--marks",dest="marksfile",
      help="File to read git-fast-import's marks from")
  parser.add_option("--mapping",dest="mappingfile",
      help="File to read last run's hg-to-git SHA1 mapping")
  parser.add_option("--heads",dest="headsfile",
      help="File to read last run's git heads from")
  parser.add_option("--status",dest="statusfile",
      help="File to read status from")
  parser.add_option("-r","--repo",dest="repourl",
      help="URL of repo to import")
  parser.add_option("-R","--revision",type=int,dest="revision",
      help="Revision to reset to")

  (options,args)=parser.parse_args()

  if options.marksfile==None: bail(parser,'--marks option')
  if options.mappingfile==None: bail(parser,'--mapping option')
  if options.headsfile==None: bail(parser,'--heads option')
  if options.statusfile==None: bail(parser,'--status option')
  if options.repourl==None: bail(parser,'--repo option')
  if options.revision==None: bail(parser,'-R/--revision')

  heads_cache=load_cache(options.headsfile)
  marks_cache=load_cache(options.marksfile,mangle_mark)
  state_cache=load_cache(options.statusfile)
  mapping_cache = load_cache(options.mappingfile)

  l=int(state_cache.get(b'tip',options.revision))
  if options.revision+1>l:
    sys.stderr.write('Revision is beyond last revision imported: %d>%d\n' % (options.revision,l))
    sys.exit(1)

  ui,repo=setup_repo(options.repourl)

  stale,changed,unchanged=get_branches(ui,repo,heads_cache,marks_cache,mapping_cache,options.revision+1)
  good,bad=get_tags(ui,repo,marks_cache,mapping_cache,options.revision+1)

  print("Possibly stale branches:")
  for b in stale:
    sys.stdout.write('\t%s\n' % b.decode('utf8'))

  print("Possibly stale tags:")
  for b in bad:
    sys.stdout.write(
      '\t%s on %s (r%s)\n'
      % (b[0].decode('utf8'), b[1].decode('utf8'), b[3].decode('utf8'))
    )

  print("Unchanged branches:")
  for b in unchanged:
    sys.stdout.write('\t%s (r%s)\n' % (b[0].decode('utf8'),b[2].decode('utf8')))

  print("Unchanged tags:")
  for b in good:
    sys.stdout.write(
      '\t%s on %s (r%s)\n'
      % (b[0].decode('utf8'), b[1].decode('utf8'), b[3].decode('utf8'))
    )

  print("Reset branches in '%s' to:" % options.headsfile)
  for b in changed:
    sys.stdout.write(
      '\t:%s %s\n\t\t(r%s: %s: %s)\n'
      % (
        b[0].decode('utf8'),
        b[1].decode('utf8'),
        b[2].decode('utf8'),
        b[4].decode('utf8'),
        b[3].decode('utf8'),
      )
    )

  print("Reset ':tip' in '%s' to '%d'" % (options.statusfile,options.revision))