from mercurial.i18n import _

from mercurial import util

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

    # pretxncommit looks for both encoded and decoded keywords

    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

    # python2.4: files = set()

                # python2.4:

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

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

    user = util.shortuser(user)

    # 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"

            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')