import os

import dbus


class MountException(Exception):
    pass


class MountManager:
    instance = None

    def __init__(self):
        self.bus = dbus.SystemBus()
        self.manager = self.bus.get_object('org.freedesktop.UDisks2', '/org/freedesktop/UDisks2/Manager')
        self.manager_interface = dbus.Interface(self.manager, 'org.freedesktop.UDisks2.Manager')
        self.interfaces = {}

    @classmethod
    def get(cls):
        if not cls.instance:
            cls.instance = cls()

        return cls.instance

    def mount(self, source):
        f = os.open(source, os.O_RDWR)
        path = self.manager_interface.LoopSetup(f, {
            'read-only': ('b', False)
        })

        device = self.bus.get_object('org.freedesktop.UDisks2', path)
        self.interfaces[source] = dbus.Interface(device, 'org.freedesktop.UDisks2.Filesystem')

        self.interfaces[source].Mount({'options': 'rw'})
        dbus.Interface(device, 'org.freedesktop.UDisks2.Loop').SetAutoclear(True, [])
        mount_point = self.interfaces[source].proxy_object.Get(
            'org.freedesktop.UDisks2.Filesystem', 'MountPoints', dbus_interface='org.freedesktop.DBus.Properties'
        )[0]
        mount_point = ''.join([str(v) for v in mount_point])
        return mount_point.rstrip(chr(0))

    def dispose_all(self):
        """
        Run this on program closing if you care about your os state to be clean and beautiful
        :return:
        """
        for s in self.interfaces:
            if self.is_mounted(s):
                self.interfaces[s].Unmount([])
            else:
                dbus.Interface(self.interfaces[s].proxy_object, 'org.freedesktop.UDisks2.Loop').Delete([])
        self.interfaces.clear()

    def is_mounted(self, source):
        return source in self.interfaces and bool(
            self.interfaces[source].proxy_object.Get(
                'org.freedesktop.UDisks2.Filesystem', 'MountPoints', dbus_interface='org.freedesktop.DBus.Properties'
            )
        )

    def unmount(self, source):
        self.interfaces[source].Unmount([])
        del self.interfaces[source]