# $Hg$

from mercurial.i18n import _

from mercurial import util

import re

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

    '''Important: returns False on success, True on failure.'''

    # name of keyword encode filter:

    kwencodefilter = 'hgkwencode'

    # update only needs string search for encoded keyword

    # as hgkwencode always runs before

    kwstr = '%sHg$' % '$'

    # pretxncommit looks for both encoded and decoded keywords

    kwpat = r'[$]Hg(: %s,v [a-z0-9]{12} [^$]+? )?\$'

    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

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

    user = util.shortuser(user)

    date = util.datestr(date=date, format=util.defaultdateformats[2])

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

    # collect filenames that were changed by hg update

    kwupdates = []

    for f in files:

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

        if not util.binary(text):

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

                re_kw = re.compile(kwpat % f)

                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')