#!/usr/bin/python

# =============================================================================
#
#    gnome-encfs - GNOME keyring and auto-mount integration of EncFS folders.
#    Copyright (C) 2010 Oben Sonne <obensonne@googlemail.com>
#
#    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 3 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, see <http://www.gnu.org/licenses/>.
#
# =============================================================================

import getpass
import os
import os.path
import optparse
import subprocess
import sys

from xdg.DesktopEntry import DesktopEntry as xdg_de
from xdg.BaseDirectory import xdg_config_home as xdg_ch

import gtk # automatically set application name
import gnomekeyring as gk

# =============================================================================
# test mode related
# =============================================================================

TEST = "GNOME_ENCFS_TEST" in os.environ

class preset:
    """Preset user input. Used for non-interactive testing mode."""

    proceed = None
    password = None
    epath = None
    mpoint = None
    amount = None

# =============================================================================
# constants
# =============================================================================

# attributes to detect gnome-encfs items in keyring
GENCFS_ATTR = {"gnome-encfs": TEST and "test" or "" }

KEYRING = gk.get_default_keyring_sync()

ITYPE = gk.ITEM_GENERIC_SECRET

MSG_NO_MATCH = ("No matching EncFS items in keyring.\n"
                "Use option --list to show available items or "
                "option --add to add items.")

USAGE = """Usage: %prog --list
       %prog --mount [ENCFS-PATH-or-MOUNT-POINT]
       %prog --add ENCFS-PATH MOUNT-POINT
       %prog --edit MOUNT-POINT
       %prog --remove MOUNT-POINT"""

DESCRIPTION = """Painlessly mount and manage EncFS folders using GNOME's
keyring."""

EPILOG = """This tool stores EncFS paths,
corresponding mount points as well as passwords in the GNOME keyring and
optionally mounts EncFS paths automatically on login to a GNOME session (works
only if gnome-encfs is installed in the system path, at /usr/bin or
/usr/local/bin).
"""

VERSION="0.1"

# =============================================================================
# helper
# =============================================================================

def _options():
    """Parse command line options."""

    op = optparse.OptionParser(usage=USAGE, version=VERSION,
                               description=DESCRIPTION, epilog=EPILOG)

    op.add_option("-l", "--list", action="store_true", default=False,
                  help="list all EncFS items stored in keyring")
    op.add_option("-m", "--mount", action="store_true", default=False,
                  help="mount all or selected EncFS paths stored in keyring")
    op.add_option("-a", "--add", action="store_true", default=False,
                  help="add a new EncFS item to keyring")
    op.add_option("-e", "--edit", action="store_true", default=False,
                  help="edit an EncFS item in keyring")
    op.add_option("-r", "--remove", action="store_true", default=False,
                  help="remove an EncFS item from keyring")

    og = optparse.OptionGroup(op, "Non-interactive")
    og.add_option("", "--proceed", default=None,
                  help="Input for proceed question")
    og.add_option("", "--password", default=None, metavar="PW",
                  help="Input for password prompt")
    og.add_option("", "--epath", default=None,
                  help="Input for EncFS path edit")
    og.add_option("", "--mpoint", default=None,
                  help="Input for mount point edit")
    og.add_option("", "--amount", default=None,
                  help="Input for auto mount question")
    op.add_option_group(og)

    opts, args = op.parse_args()

    try:
        args.remove("autostart")
        opts.autostart = True
        opts.mount = True
    except ValueError:
        opts.autostart = False

    if opts.list + opts.mount + opts.add + opts.edit + opts.remove != 1:
        op.print_help()
        op.exit(1)

    # normalize paths
    args = [_pathify(a) for a in args]

    opts.p1 = args and args.pop(0) or None
    opts.p2 = args and args.pop(0) or None

    if opts.add and not (opts.p1 and opts.p2):
        op.error("add needs an EncFS path and a moint point")
        op.print_help()
        op.exit(1)

    if opts.remove and not opts.p1:
        op.error("remove needs a moint point")
        op.print_help()
        op.exit(1)

    preset.proceed = opts.proceed
    preset.password = opts.password
    preset.epath = opts.epath
    preset.mpoint = opts.mpoint
    preset.amount = opts.amount

    return opts

def _exit(ec):
    """Exit with additional check if autostart file is still needed."""

    _autostart(_get_items(amount="y"))
    sys.exit(ec)

def _proceed(msg):
    print("Warning: %s" % msg)
    proceed = preset.proceed or raw_input("Proceed [y/N]: ")
    if proceed.strip()[0].lower() != "y":
        _exit(2)

def _pathify(path):

    path = os.path.expanduser(path)
    path = os.path.expandvars(path)
    path = os.path.abspath(path)
    path = os.path.realpath(path)
    return path

def _is_mounted(mpoint):
    """Check of something is mounted at given mount point."""

    p = subprocess.Popen(["mount"], stdout=subprocess.PIPE)
    mount = p.communicate()[0]
    lines = mount.strip('\n').split('\n')
    points = map(lambda line: line.split()[2], lines)
    points = [os.path.abspath(p) for p in points]
    return os.path.abspath(mpoint) in points

def _is_encfs(epath):
    """Check if 'epath' points to an EncFS directory."""

    p = subprocess.Popen(["encfsctl", "info", epath], stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE)
    p.communicate()
    return p.returncode == 0

_items_cached = None

def _get_items(mpoint=None, epath=None, anypath=None, amount=None):
    """Get all EncFS items or those matching given attributes."""

    global _items_cached

    if _items_cached is None:
        try:
            _items_cached = gk.find_items_sync(ITYPE, GENCFS_ATTR)
        except gk.NoMatchError:
            _items_cached = []

    match = []
    for item in _items_cached:
        if mpoint and item.attributes["mount-point"] != mpoint:
            continue
        if epath and item.attributes["encfs-path"] != epath:
            continue
        if anypath and (item.attributes["mount-point"] != anypath and
                        item.attributes["encfs-path"] != anypath):
            continue
        if amount and item.attributes["auto-mount"] != amount:
            continue
        match.append(item)

    return match

def _autostart(enable):
    """Set up XDG autostart file."""

    if TEST:
        fname = os.path.join(os.path.curdir, "autostart.desktop")
    else:
        fname = os.path.join(xdg_ch, "autostart", "gnome-encfs.desktop")

    if not enable:
        if os.path.exists(fname):
            os.remove(fname)
        return

    content = {
        "Exec": "gnome-encfs autostart",
        "Name": "EncFS",
        "Comment": "Mount EncFS folders configured in GNOME's keyring",
        "Icon": "folder",
        "Version": "1.0",
        "X-GNOME-Autostart-enabled": "true"
    }

    de = xdg_de(filename=fname)
    for key, value in content.items():
        de.set(key, value)
    de.validate()
    de.write()

# =============================================================================
# actions
# =============================================================================

def list_items(path=None):
    """List EncFS items in keyring."""

    items = _get_items(anypath=path)

    if not items and path:
        print(MSG_NO_MATCH)
        return False

    for item in items:
        epath = item.attributes["encfs-path"]
        mpoint = item.attributes["mount-point"]
        amount = item.attributes["auto-mount"]
        print("* encfs path     : %s" % epath)
        print("  mount point    : %s" % mpoint)
        print("  mount at login : %s" % (amount == "y" and "yes" or "no"))

    return True

def add_item(epath, mpoint):
    """Add new EncFS item to keyring."""

    if not _is_encfs(epath):
        _proceed("no EncFS at given path")
    if not os.path.isdir(mpoint):
        _proceed("mount point is not a directory")
    if _get_items(mpoint=mpoint):
        _proceed("mount point already in keyring")

    secret = preset.password or getpass.getpass("EncFS password: ")
    amount = preset.amount or raw_input("Mount at login [Y/n]: ") or "y"
    amount = amount.strip()[0].lower() == "y" and "y" or "n"
    attr = {"encfs-path": epath, "mount-point": mpoint, "auto-mount": amount}
    attr.update(GENCFS_ATTR)
    name = "EncFS mount at %s" % mpoint
    gk.item_create_sync(KEYRING, ITYPE, name, attr, secret, False)

    global _items_cached
    _items_cached = None

    return True

def edit_item(mpoint):
    """Edit EncFS item in keyring."""

    items = _get_items()
    edits = _get_items(mpoint=mpoint)

    if not edits:
        print(MSG_NO_MATCH)
        return False

    for item in edits:

        # get item data
        epath = item.attributes["encfs-path"]
        mpoint = item.attributes["mount-point"]
        amount = item.attributes["auto-mount"]
        epath = preset.epath or raw_input("EncFS path [%s]: " % epath) or epath
        mpoint = preset.mpoint or raw_input("Mount point [%s]: " % mpoint) or mpoint
        secret = preset.password or getpass.getpass("Password [**current**]: ") or item.secret
        hint = amount == "y" and "Y/n" or "y/N"
        amount = preset.amount or raw_input("Mount at login [%s]: " % hint) or amount
        amount = amount.strip()[0].lower() == "y" and "y" or "n"
        mpoint = _pathify(mpoint)
        epath = _pathify(epath)

        # check item data
        for other in [i for i in items if i.item_id != item.item_id]:
            if other.attributes["mount-point"] == mpoint:
                _proceed("mount point already in use")
        if not _is_encfs(epath):
            _proceed("no EncFS at given path")
        if not os.path.isdir(mpoint):
            _proceed("mount point is not a directory")

        # update item data
        attributes = GENCFS_ATTR.copy()
        attributes["encfs-path"] = epath
        attributes["mount-point"] = mpoint
        attributes["auto-mount"] = amount
        gk.item_set_attributes_sync(KEYRING, item.item_id, attributes)
        info = gk.item_get_info_sync(KEYRING, item.item_id)
        info.set_secret(secret)
        gk.item_set_info_sync(KEYRING, item.item_id, info)

        global _items_cached
        _items_cached = None

    return True

def remove_item(mpoint):
    """Remove EncFS item from keyring."""

    items = _get_items(mpoint=mpoint)

    if not items:
        print(MSG_NO_MATCH)
        return False

    for item in items:
        gk.item_delete_sync(KEYRING, item.item_id)

    global _items_cached
    _items_cached = None

    return True

def mount_items(path, autostart):
    """Mount selected items.

    If `path` is set, mount only those items where the EncFS path or mount
    point equals `path`. If `autostart` is True, mount only those items where
    auto-mount is set to 'y'.

    """
    items = _get_items(anypath=path, amount=(autostart and "y" or None))

    if not items and path:
        print(MSG_NO_MATCH)
        return False

    rc = True

    for item in items:
        epath = item.attributes["encfs-path"]
        mpoint = item.attributes["mount-point"]
        msg = "Mounting %s at %s: " % (epath, mpoint)
        if _is_mounted(mpoint):
            msg += "mount point already in use"
        elif not os.path.isdir(mpoint):
            msg += "mount point does not exist or is not a directory"
            rc = False
        else:
            cmd = ["encfs", "-o", "nonempty", "-S", epath, mpoint]
            p = subprocess.Popen(cmd, stdin=subprocess.PIPE)
            p.communicate(input="%s\n" % item.secret)
            msg += p.returncode and "FAILED" or "OK"
            rc &= not p.returncode

        print(msg)

    return rc

# =============================================================================
# main
# =============================================================================

def main():

    opts = _options()

    if opts.add:
        ok = add_item(opts.p1, opts.p2)
    elif opts.list:
        ok = list_items(opts.p1)
    elif opts.mount:
        ok = mount_items(opts.p1, opts.autostart)
    elif opts.edit:
        ok = edit_item(opts.p1)
    elif opts.remove:
        ok = remove_item(opts.p1)
    else:
        assert False

    return ok
    
if __name__ == '__main__':

    ret = main()
    _exit(int(not ret))