from mercurial.i18n import _

from mercurial import cmdutil, commands, util

import os.path, re, sys

def pretxnkw(ui, repo, hooktype, **args):

    '''Collects candidates for keyword expansion on commit

    if hooktype != 'pretxncommit':

        # bail out with error

        return True

    # reparse args, opts again as pretxncommit hook is silent about them

    sysargs, globalopts, cmdopts = commands.parse(ui, sys.argv[1:])[2:]

    files, match, anypats = cmdutil.matchpats(repo, sysargs, cmdopts)

    # validity checks should have been done already

    modified, added = repo.status(files=files, match=match)[:2]

    candidates = modified + added

    if not candidates:

        return False

    # only check files that have hgkwencode assigned as encode filter

    files = []

    # python2.4: files = set()

    for pat, opt in repo.ui.configitems('keyword'):

        if opt == 'expand':

            mf = util.matcher(repo.root, '', [pat], [], [])[1]

            for candidate in candidates:

                if mf(candidate) and candidate not in files:

                    files.append(candidate)

                # python2.4:

                # if mf(candidate): files.add(candidate)

    if not files: # nothing to do

        return False

    cid = args['node'][:12]

    user, date = repo.changelog.read(repo.changelog.tip())[1:3]

    user = util.shortuser(user)

    date = util.datestr(date=date, format=util.defaultdateformats[0])

                                               # %Y-%m-%d %H:%M:%S

    re_kw = re.compile(r'\$Hg[^$]*?\$')

    for f in files:

        text = repo.wfile(f).read()

        if not util.binary(text):

            kw = '$Hg: %s,v %s %s %s $' % (

                    os.path.basename(f), cid, date, user)

            text, kwct = re_kw.subn(kw, text)

            if kwct:

                ui.note(_('expanding keywords in %s\n' % f))

                # backup file?

                repo.wfile(f, 'w').write(text)