# $Hg$

from mercurial import demandimport
demandimport.enable()

from mercurial.i18n import _
import mercurial.util, re

# name of keyword encode filter:
kwencodefilter = 'hgkwencode'
# look for <Dollar>Hg<Dollar>
kwtrigger = '%sHg$' % '$'

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 (?)
#   absfile = repo.wjoin(f)
#   mercurial.util.copyfile(absfile, absfile+'.kwbak')
    repo.wfile(f, 'w').write(text)

def expandkw(ui, repo, node, cid, candidates, update=False):
    '''Important: returns False on success, True on failure.'''

    # only check files that have hgkwencode assigned as encode filter
    files = []
    for pat, cmd in repo.ui.configitems('encode'):
        if cmd.endswith(kwencodefilter):
            mf = mercurial.util.matcher(repo.root, '', [pat], [], [])[1]
            for candidate in candidates:
                if mf(candidate):
                    # check again that there really are no duplicates
                    # if candidate not in files ???
                    files.append(candidate)

    if not files: # nothing to do
        return False

    user, date = repo.changelog.read(node)[1:3]
    user = mercurial.util.shortuser(user)
    date = mercurial.util.datestr(date=date,
            format=mercurial.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()
        kwrepl = '%sHg: %s,v %s %s %s $' % ('$', f, cid, date, user)

        if update and text.find(kwtrigger) > -1:
            text = text.replace(kwtrigger, kwrepl)
            wwritekw(ui, repo, f, text)
            kwupdates.append(f)
        
        elif not update:
            re_kw = re.compile(r'[$]Hg(: %s,v [a-z0-9]{12} [^$]+? )?\$' % f)
            text, kwct = re_kw.subn(kwrepl, 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')

    return False