from mercurial.i18n import _

from mercurial import util

import os.path, re

def expandkw(ui, repo, rev, cid, candidates, update=False):

    '''Expands logged <Dollar>Hg<Dollar> in working directory.'''

    # name of keyword encode filter:

    kwencodefilter = 'hgkwencode'

    # update only needs string search for encoded keyword

    # as hgkwencode always runs before

    kwstr = '$Hg$'

    # pretxncommit looks for both encoded and decoded keywords

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

    def wwritekw(ui, repo, f, text):

        '''Writes text with kwupdates keywords to f in working directory.'''

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

        # backup file, at least when commiting (?)

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

    # only check files that have hgkwencode assigned as encode filter

#    files = []

    # python2.4: files = set()

#    for pat, cmd in repo.ui.configitems('encode'):

#        if cmd.endswith(kwencodefilter):

#            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

    files = candidates

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

    user = util.shortuser(user)

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

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

    # collect filenames that were changed by hg update

    kwupdates = []

    for f in files:

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

        if not util.binary(text):

            # TODO for update:

            # walk back through file history onto last add/modify

            # like "hg log -l1 f"

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

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

            if update and text.find(kwstr) > -1:

                text = text.replace(kwstr, kw)

                wwritekw(ui, repo, f, text)

                kwupdates.append(f)

            elif not update:

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

                if kwct:

                    wwritekw(ui, repo, f, text)

    if kwupdates:

        # cheat hg to believe that updated files were not modified

        repo.dirstate.update(kwupdates, 'n')