#!/usr/bin/env python3
'''
lltest.py - Example file system for Python-LLFUSE.

This program presents a static file system containing a single file. It is
compatible with both Python 2.x and 3.x. Based on an example from Gerion Entrup.

Copyright © 2015 Nikolaus Rath <Nikolaus.org>
Copyright © 2015 Gerion Entrup.

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
'''


import os
import sys

# If we are running from the Python-LLFUSE source directory, try
# to load the module from there first.
basedir = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), '..'))
if (os.path.exists(os.path.join(basedir, 'setup.py')) and
    os.path.exists(os.path.join(basedir, 'src', 'llfuse.pyx'))):
    sys.path.insert(0, os.path.join(basedir, 'src'))

from argparse import ArgumentParser
import stat
import logging
import errno
import llfuse

try:
    import faulthandler
except ImportError:
    pass
else:
    faulthandler.enable()

log = logging.getLogger(__name__)

class TestFs(llfuse.Operations):
    def __init__(self):
        super().__init__()
        self.hello_name = b"message"
        self.hello_inode = llfuse.ROOT_INODE+1
        self.hello_data = b"hello world\n"

    def getattr(self, inode, ctx=None):
        entry = llfuse.EntryAttributes()
        if inode == llfuse.ROOT_INODE:
            entry.st_mode = (stat.S_IFDIR | 0o755)
            entry.st_size = 0
        elif inode == self.hello_inode:
            entry.st_mode = (stat.S_IFREG | 0o644)
            entry.st_size = len(self.hello_data)
        else:
            raise llfuse.FUSEError(errno.ENOENT)

        stamp = int(1438467123.985654 * 1e9)
        entry.st_atime_ns = stamp
        entry.st_ctime_ns = stamp
        entry.st_mtime_ns = stamp
        entry.st_gid = os.getgid()
        entry.st_uid = os.getuid()
        entry.st_ino = inode

        return entry

    def lookup(self, parent_inode, name, ctx=None):
        if parent_inode != llfuse.ROOT_INODE or name != self.hello_name:
            raise llfuse.FUSEError(errno.ENOENT)
        return self.getattr(self.hello_inode)

    def opendir(self, inode, ctx):
        if inode != llfuse.ROOT_INODE:
            raise llfuse.FUSEError(errno.ENOENT)
        return inode

    def readdir(self, fh, off):
        assert fh == llfuse.ROOT_INODE

        # only one entry
        if off == 0:
            yield (self.hello_name, self.getattr(self.hello_inode), self.hello_inode)

    def statfs(self, ctx):
        stat_ = llfuse.StatvfsData()

        stat_.f_bsize = 512
        stat_.f_frsize = 512

        size = 1024 * stat_.f_frsize
        stat_.f_blocks = size // stat_.f_frsize
        stat_.f_bfree = max(size // stat_.f_frsize, 1024)
        stat_.f_bavail = stat_.f_bfree

        inodes = 100
        stat_.f_files = inodes
        stat_.f_ffree = max(inodes, 100)
        stat_.f_favail = stat_.f_ffree

        return stat_

    def open(self, inode, flags, ctx):
        if inode != self.hello_inode:
            raise llfuse.FUSEError(errno.ENOENT)
        if flags & os.O_RDWR or flags & os.O_WRONLY:
            raise llfuse.FUSEError(errno.EACCES)
        return inode

    def read(self, fh, off, size):
        assert fh == self.hello_inode
        return self.hello_data[off:off+size]

def init_logging(debug=False):
    formatter = logging.Formatter('%(asctime)s.%(msecs)03d %(threadName)s: '
                                  '[%(name)s] %(message)s', datefmt="%Y-%m-%d %H:%M:%S")
    handler = logging.StreamHandler()
    handler.setFormatter(formatter)
    root_logger = logging.getLogger()
    if debug:
        handler.setLevel(logging.DEBUG)
        root_logger.setLevel(logging.DEBUG)
    else:
        handler.setLevel(logging.INFO)
        root_logger.setLevel(logging.INFO)
    root_logger.addHandler(handler)

def parse_args():
    '''Parse command line'''

    parser = ArgumentParser()

    parser.add_argument('mountpoint', type=str,
                        help='Where to mount the file system')
    parser.add_argument('--debug', action='store_true', default=False,
                        help='Enable debugging output')
    parser.add_argument('--debug-fuse', action='store_true', default=False,
                        help='Enable FUSE debugging output')
    return parser.parse_args()


def main():
    options = parse_args()
    init_logging(options.debug)

    testfs = TestFs()
    fuse_options = set(llfuse.default_options)
    fuse_options.add('fsname=lltest')
    if options.debug_fuse:
        fuse_options.add('debug')
    llfuse.init(testfs, options.mountpoint, fuse_options)
    try:
        llfuse.main(workers=1)
    except:
        llfuse.close(unmount=False)
        raise

    llfuse.close()


if __name__ == '__main__':
    main()
