# Copyright (C) 2006 - Marco Barisione <marco@barisione.org>
#
# This is a small extension for Mercurial (http://www.selenic.com/mercurial)
# that removes files not known to mercurial
#
# This program was inspired by the "cvspurge" script contained in CVS utilities
# (http://www.red-bean.com/cvsutils/).
#
# To enable the "purge" extension put these lines in your ~/.hgrc:
#  [extensions]
#  hgext.purge =
#
# For help on the usage of "hg purge" use:
#  hg help purge
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

from mercurial import hg, util, commands
from mercurial.i18n import _
import os

def dopurge(ui, repo, dirs=None, act=True, ignored=False,
            abort_on_err=False, eol='\n',
            force=False, include=None, exclude=None):
    def error(msg):
        if abort_on_err:
            raise util.Abort(msg)
        else:
            ui.warn(_('warning: %s\n') % msg)

    def remove(remove_func, name):
        if act:
            try:
                remove_func(os.path.join(repo.root, name))
            except OSError, e:
                error(_('%s cannot be removed') % name)
        else:
            ui.write('%s%s' % (name, eol))

    directories = []
    files = []
    missing = []
    roots, match, anypats = util.cmdmatcher(repo.root, repo.getcwd(), dirs,
                                            include, exclude)
    for src, f, st in repo.dirstate.statwalk(files=roots, match=match,
                                             ignored=ignored, directories=True):
        if src == 'd':
            directories.append(f)
        elif src == 'm':
            missing.append(f)
        elif src == 'f' and f not in repo.dirstate:
            files.append(f)

    _check_missing(ui, repo, missing, force)

    directories.sort()

    for f in files:
        if f not in repo.dirstate:
            ui.note(_('Removing file %s\n') % f)
            remove(os.remove, f)

    for f in directories[::-1]:
        if match(f) and not os.listdir(repo.wjoin(f)):
            ui.note(_('Removing directory %s\n') % f)
            remove(os.rmdir, f)

def _check_missing(ui, repo, missing, force=False):
    """Abort if there is the chance of having problems with name-mangling fs

    In a name mangling filesystem (e.g. a case insensitive one)
    dirstate.walk() can yield filenames different from the ones
    stored in the dirstate. This already confuses the status and
    add commands, but with purge this may cause data loss.

    To prevent this, _check_missing will abort if there are missing
    files. The force option will let the user skip the check if he
    knows it is safe.

    Even with the force option this function will check if any of the
    missing files is still available in the working dir: if so there
    may be some problem with the underlying filesystem, so it
    aborts unconditionally."""

    found = [f for f in missing if util.lexists(repo.wjoin(f))]

    if found:
        if not ui.quiet:
            ui.warn(_("The following tracked files weren't listed by the "
                      "filesystem, but could still be found:\n"))
            for f in found:
                ui.warn("%s\n" % f)
            if util.checkfolding(repo.path):
                ui.warn(_("This is probably due to a case-insensitive "
                          "filesystem\n"))
        raise util.Abort(_("purging on name mangling filesystems is not "
                           "yet fully supported"))

    if missing and not force:
        raise util.Abort(_("there are missing files in the working dir and "
                           "purge still has problems with them due to name "
                           "mangling filesystems. "
                           "Use --force if you know what you are doing"))


def purge(ui, repo, *dirs, **opts):
    '''removes files not tracked by mercurial

    Delete files not known to mercurial, this is useful to test local and
    uncommitted changes in the otherwise clean source tree.

    This means that purge will delete:
     - Unknown files: files marked with "?" by "hg status"
     - Ignored files: files usually ignored by Mercurial because they match
       a pattern in a ".hgignore" file
     - Empty directories: in fact Mercurial ignores directories unless they
       contain files under source control managment
    But it will leave untouched:
     - Unmodified tracked files
     - Modified tracked files
     - New files added to the repository (with "hg add")

    If directories are given on the command line, only files in these
    directories are considered.

    Be careful with purge, you could irreversibly delete some files you
    forgot to add to the repository. If you only want to print the list of
    files that this program would delete use the --print option.
    '''
    act = not opts['print']
    ignored = bool(opts['all'])
    abort_on_err = bool(opts['abort_on_err'])
    eol = opts['print0'] and '\0' or '\n'
    if eol == '\0':
        # --print0 implies --print
        act = False
    force = bool(opts['force'])
    include = opts['include']
    exclude = opts['exclude']
    dopurge(ui, repo, dirs, act, ignored, abort_on_err,
            eol, force, include, exclude)


cmdtable = {
    'purge|clean':
        (purge,
         [('a', 'abort-on-err', None, _('abort if an error occurs')),
          ('',  'all', None, _('purge ignored files too')),
          ('f', 'force', None, _('purge even when missing files are detected')),
          ('p', 'print', None, _('print the file names instead of deleting them')),
          ('0', 'print0', None, _('end filenames with NUL, for use with xargs'
                                  ' (implies -p)')),
         ] + commands.walkopts,
         _('hg purge [OPTION]... [DIR]...'))
}