# file.py - local file-based back-end for repository storage
#
# Copyright (C) 2015 Arthur de Jong
#
# 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
#
# The files produced as output from the software do not automatically fall
# under the copyright of the software, unless explicitly stated otherwise.

import os


class FileBackend(object):

    def __init__(self, path):
        self.path = path
        # FIXME: check that path exists

    def listdir(self, path):
        """Return the names of all the enties in the directory."""
        try:
            return (
                os.path.join(path, name)
                for name in os.listdir(os.path.join(self.path, path)))
        except:
            return ()

    def exists(self, path):
        return os.path.exists(os.path.join(self.path, path))

    def isdir(self, path):
        return os.path.isdir(os.path.join(self.path, path))

    def remove(self, path, recurse=False):
        # TODO: this only recurses one directory deep and will fail if
        # the directory contains other directories
        if recurse:
            for subpath in self.listdir(path):
                os.remove(os.path.join(self.path, subpath))
            os.rmdir(os.path.join(self.path, path))
        else:
            os.remove(os.path.join(self.path, path))

    def rename(self, old, new):
        if self.exists(new):
            self.remove(new)
        os.rename(os.path.join(self.path, old), os.path.join(self.path, new))

    def put(self, filename, executable=False):
        """Return an open file handle that can be used to write a file
        contents to."""
        path = os.path.join(self.path, filename)
        dirname = os.path.dirname(path)
        if not os.path.isdir(dirname):
            os.makedirs(dirname)
        f = open(path, 'wb')
        if executable:
            os.fchmod(f.fileno(), 0o0755)
        return f

    def get(self, filename):
        """Returns an open file handle that can be used to read from."""
        path = os.path.join(self.path, filename)
        return open(path, 'rb')