# -*- coding: utf-8 -*-
#
# Copyright (C) 2009 GazpachoKing <chase.sterling@gmail.com>
# Copyright (C) 2011 Pedro Algarvio <pedro@algarvio.me>
#
# Basic plugin template created by:
# Copyright (C) 2008 Martijn Voncken <mvoncken@gmail.com>
# Copyright (C) 2007-2009 Andrew Resch <andrewresch@gmail.com>
# Copyright (C) 2009 Damien Churchill <damoxc@gmail.com>
#
# This file is part of Deluge and is licensed under GNU General Public License 3.0, or later, with
# the additional special exception to link portions of this program with the OpenSSL library.
# See LICENSE for more details.
#

from __future__ import unicode_literals

import logging
import os
import shutil
from base64 import b64encode

from twisted.internet import reactor
from twisted.internet.task import LoopingCall, deferLater

import deluge.component as component
import deluge.configmanager
from deluge._libtorrent import lt
from deluge.common import AUTH_LEVEL_ADMIN, is_magnet
from deluge.core.rpcserver import export
from deluge.error import AddTorrentError
from deluge.event import DelugeEvent
from deluge.plugins.pluginbase import CorePluginBase

log = logging.getLogger(__name__)


DEFAULT_PREFS = {'watchdirs': {}, 'next_id': 1}


OPTIONS_AVAILABLE = {  # option: builtin
    'enabled': False,
    'path': False,
    'append_extension': False,
    'copy_torrent': False,
    'delete_copy_torrent_toggle': False,
    'abspath': False,
    'download_location': True,
    'max_download_speed': True,
    'max_upload_speed': True,
    'max_connections': True,
    'max_upload_slots': True,
    'prioritize_first_last': True,
    'auto_managed': True,
    'stop_at_ratio': True,
    'stop_ratio': True,
    'remove_at_ratio': True,
    'move_completed': True,
    'move_completed_path': True,
    'label': False,
    'add_paused': True,
    'queue_to_top': False,
    'owner': True,
    'seed_mode': True,
}

MAX_NUM_ATTEMPTS = 10


class AutoaddOptionsChangedEvent(DelugeEvent):
    """Emitted when the options for the plugin are changed."""

    def __init__(self):
        pass


def check_input(cond, message):
    if not cond:
        raise Exception(message)


class Core(CorePluginBase):
    def enable(self):

        # reduce typing, assigning some values to self...
        self.config = deluge.configmanager.ConfigManager('autoadd.conf', DEFAULT_PREFS)
        self.config.run_converter((0, 1), 2, self.__migrate_config_1_to_2)
        self.config.save()
        self.watchdirs = self.config['watchdirs']

        self.rpcserver = component.get('RPCServer')
        component.get('EventManager').register_event_handler(
            'PreTorrentRemovedEvent', self.__on_pre_torrent_removed
        )

        # Dict of Filename:Attempts
        self.invalid_torrents = {}
        # Loopingcall timers for each enabled watchdir
        self.update_timers = {}
        deferLater(reactor, 5, self.enable_looping)

    def enable_looping(self):
        # Enable all looping calls for enabled watchdirs here
        for watchdir_id, watchdir in self.watchdirs.items():
            if watchdir['enabled']:
                self.enable_watchdir(watchdir_id)

    def disable(self):
        # disable all running looping calls
        component.get('EventManager').deregister_event_handler(
            'PreTorrentRemovedEvent', self.__on_pre_torrent_removed
        )
        for loopingcall in self.update_timers.values():
            loopingcall.stop()
        self.config.save()

    def update(self):
        pass

    @export
    def set_options(self, watchdir_id, options):
        """Update the options for a watch folder."""
        watchdir_id = str(watchdir_id)
        options = self._make_unicode(options)
        check_input(watchdir_id in self.watchdirs, _('Watch folder does not exist.'))
        if 'path' in options:
            options['abspath'] = os.path.abspath(options['path'])
            check_input(os.path.isdir(options['abspath']), _('Path does not exist.'))
            for w_id, w in self.watchdirs.items():
                if options['abspath'] == w['abspath'] and watchdir_id != w_id:
                    raise Exception('Path is already being watched.')
        for key in options:
            if key not in OPTIONS_AVAILABLE:
                if key not in [key2 + '_toggle' for key2 in OPTIONS_AVAILABLE]:
                    raise Exception('autoadd: Invalid options key:%s' % key)
        # disable the watch loop if it was active
        if watchdir_id in self.update_timers:
            self.disable_watchdir(watchdir_id)

        self.watchdirs[watchdir_id].update(options)
        # re-enable watch loop if appropriate
        if self.watchdirs[watchdir_id]['enabled']:
            self.enable_watchdir(watchdir_id)
        self.config.save()
        component.get('EventManager').emit(AutoaddOptionsChangedEvent())

    def load_torrent(self, filename, magnet):
        log.debug('Attempting to open %s for add.', filename)
        file_mode = 'r' if magnet else 'rb'
        try:
            with open(filename, file_mode) as _file:
                filedump = _file.read()
        except IOError as ex:
            log.warning('Unable to open %s: %s', filename, ex)
            raise ex

        if not filedump:
            raise EOFError('Torrent is 0 bytes!')

        # Get the info to see if any exceptions are raised
        if not magnet:
            lt.torrent_info(lt.bdecode(filedump))

        return filedump

    def split_magnets(self, filename):
        log.debug('Attempting to open %s for splitting magnets.', filename)
        magnets = []
        try:
            with open(filename, 'r') as _file:
                magnets = list(filter(len, _file.read().splitlines()))
        except IOError as ex:
            log.warning('Unable to open %s: %s', filename, ex)

        if len(magnets) < 2:
            return []

        path = filename.rsplit(os.sep, 1)[0]
        for magnet in magnets:
            if not is_magnet(magnet):
                log.warning('Found line which is not a magnet: %s', magnet)
                continue

            for part in magnet.split('&'):
                if part.startswith('dn='):
                    name = part[3:].strip()
                    if name:
                        mname = os.sep.join([path, name + '.magnet'])
                        break
            else:
                short_hash = magnet.split('btih:')[1][:8]
                mname = '.'.join([os.path.splitext(filename)[0], short_hash, 'magnet'])

            try:
                with open(mname, 'w') as _mfile:
                    _mfile.write(magnet)
            except IOError as ex:
                log.warning('Unable to open %s: %s', mname, ex)
        return magnets

    def update_watchdir(self, watchdir_id):
        """Check the watch folder for new torrents to add."""
        log.trace('Updating watchdir id: %s', watchdir_id)
        watchdir_id = str(watchdir_id)
        watchdir = self.watchdirs[watchdir_id]
        if not watchdir['enabled']:
            # We shouldn't be updating because this watchdir is not enabled
            log.debug('Watchdir id %s is not enabled. Disabling it.', watchdir_id)
            self.disable_watchdir(watchdir_id)
            return

        if not os.path.isdir(watchdir['abspath']):
            log.warning('Invalid AutoAdd folder: %s', watchdir['abspath'])
            self.disable_watchdir(watchdir_id)
            return

        # Generate options dict for watchdir
        options = {}
        if 'stop_at_ratio_toggle' in watchdir:
            watchdir['stop_ratio_toggle'] = watchdir['stop_at_ratio_toggle']
        # We default to True when reading _toggle values, so a config
        # without them is valid, and applies all its settings.
        for option, value in watchdir.items():
            if OPTIONS_AVAILABLE.get(option):
                if watchdir.get(option + '_toggle', True) or option in [
                    'owner',
                    'seed_mode',
                ]:
                    options[option] = value

        # Check for .magnet files containing multiple magnet links and
        # create a new .magnet file for each of them.
        for filename in os.listdir(watchdir['abspath']):
            try:
                filepath = os.path.join(watchdir['abspath'], filename)
            except UnicodeDecodeError as ex:
                log.error(
                    'Unable to auto add torrent due to improper filename encoding: %s',
                    ex,
                )
                continue
            if os.path.isdir(filepath):
                # Skip directories
                continue
            elif os.path.splitext(filename)[1] == '.magnet' and self.split_magnets(
                filepath
            ):
                os.remove(filepath)

        for filename in os.listdir(watchdir['abspath']):
            try:
                filepath = os.path.join(watchdir['abspath'], filename)
            except UnicodeDecodeError as ex:
                log.error(
                    'Unable to auto add torrent due to improper filename encoding: %s',
                    ex,
                )
                continue

            if os.path.isdir(filepath):
                # Skip directories
                continue

            ext = os.path.splitext(filename)[1].lower()
            magnet = ext == '.magnet'
            if not magnet and not ext == '.torrent':
                log.debug('File checked for auto-loading is invalid: %s', filename)
                continue

            try:
                filedump = self.load_torrent(filepath, magnet)
            except (IOError, EOFError) as ex:
                # If torrent is invalid, keep track of it so can try again on the next pass.
                # This catches torrent files that may not be fully saved to disk at load time.
                log.debug('Torrent is invalid: %s', ex)
                if filename in self.invalid_torrents:
                    self.invalid_torrents[filename] += 1
                    if self.invalid_torrents[filename] >= MAX_NUM_ATTEMPTS:
                        log.warning(
                            'Maximum attempts reached while trying to add the '
                            'torrent file with the path %s',
                            filepath,
                        )
                        os.rename(filepath, filepath + '.invalid')
                        del self.invalid_torrents[filename]
                else:
                    self.invalid_torrents[filename] = 1
                continue

            def on_torrent_added(torrent_id, filename, filepath):
                if 'Label' in component.get('CorePluginManager').get_enabled_plugins():
                    if watchdir.get('label_toggle', True) and watchdir.get('label'):
                        label = component.get('CorePlugin.Label')
                        if not watchdir['label'] in label.get_labels():
                            label.add(watchdir['label'])
                        try:
                            label.set_torrent(torrent_id, watchdir['label'])
                        except Exception as ex:
                            log.error('Unable to set label: %s', ex)

                if (
                    watchdir.get('queue_to_top_toggle', True)
                    and 'queue_to_top' in watchdir
                ):
                    if watchdir['queue_to_top']:
                        component.get('TorrentManager').queue_top(torrent_id)
                    else:
                        component.get('TorrentManager').queue_bottom(torrent_id)

                # Rename, copy or delete the torrent once added to deluge.
                if watchdir.get('append_extension_toggle'):
                    if not watchdir.get('append_extension'):
                        watchdir['append_extension'] = '.added'
                    os.rename(filepath, filepath + watchdir['append_extension'])
                elif watchdir.get('copy_torrent_toggle'):
                    copy_torrent_path = watchdir['copy_torrent']
                    copy_torrent_file = os.path.join(copy_torrent_path, filename)
                    log.debug(
                        'Moving added torrent file "%s" to "%s"',
                        os.path.basename(filepath),
                        copy_torrent_path,
                    )
                    shutil.move(filepath, copy_torrent_file)
                else:
                    os.remove(filepath)

            def fail_torrent_add(err_msg, filepath, magnet):
                # torrent handle is invalid and so is the magnet link
                log.error(
                    'Cannot Autoadd %s: %s: %s',
                    'magnet' if magnet else 'torrent file',
                    filepath,
                    err_msg,
                )
                os.rename(filepath, filepath + '.invalid')

            try:
                # The torrent looks good, so lets add it to the session.
                if magnet:
                    d = component.get('Core').add_torrent_magnet(
                        filedump.strip(), options
                    )
                else:
                    d = component.get('Core').add_torrent_file_async(
                        filename, b64encode(filedump), options
                    )
                d.addCallback(on_torrent_added, filename, filepath)
                d.addErrback(fail_torrent_add, filepath, magnet)
            except AddTorrentError as ex:
                fail_torrent_add(str(ex), filepath, magnet)

    def on_update_watchdir_error(self, failure, watchdir_id):
        """Disables any watch folders with un-handled exceptions."""
        self.disable_watchdir(watchdir_id)
        log.error(
            'Disabling "%s", error during update: %s',
            self.watchdirs[watchdir_id]['path'],
            failure,
        )

    @export
    def enable_watchdir(self, watchdir_id):
        w_id = str(watchdir_id)
        # Enable the looping call
        if w_id not in self.update_timers or not self.update_timers[w_id].running:
            self.update_timers[w_id] = LoopingCall(self.update_watchdir, w_id)
            self.update_timers[w_id].start(5).addErrback(
                self.on_update_watchdir_error, w_id
            )
        # Update the config
        if not self.watchdirs[w_id]['enabled']:
            self.watchdirs[w_id]['enabled'] = True
            self.config.save()
            component.get('EventManager').emit(AutoaddOptionsChangedEvent())

    @export
    def disable_watchdir(self, watchdir_id):
        w_id = str(watchdir_id)
        # Disable the looping call
        if w_id in self.update_timers:
            if self.update_timers[w_id].running:
                self.update_timers[w_id].stop()
            del self.update_timers[w_id]
        # Update the config
        if self.watchdirs[w_id]['enabled']:
            self.watchdirs[w_id]['enabled'] = False
            self.config.save()
            component.get('EventManager').emit(AutoaddOptionsChangedEvent())

    @export
    def set_config(self, config):
        """Sets the config dictionary."""
        config = self._make_unicode(config)
        for key in config:
            self.config[key] = config[key]
        self.config.save()
        component.get('EventManager').emit(AutoaddOptionsChangedEvent())

    @export
    def get_config(self):
        """Returns the config dictionary."""
        return self.config.config

    @export
    def get_watchdirs(self):
        session_user = self.rpcserver.get_session_user()
        session_auth_level = self.rpcserver.get_session_auth_level()
        if session_auth_level == AUTH_LEVEL_ADMIN:
            log.debug(
                'Current logged in user %s is an ADMIN, send all ' 'watchdirs',
                session_user,
            )
            return self.watchdirs

        watchdirs = {}
        for watchdir_id, watchdir in self.watchdirs.items():
            if watchdir.get('owner', 'localclient') == session_user:
                watchdirs[watchdir_id] = watchdir

        log.debug(
            'Current logged in user %s is not an ADMIN, send only '
            'their watchdirs: %s',
            session_user,
            list(watchdirs),
        )
        return watchdirs

    def _make_unicode(self, options):
        opts = {}
        for key in options:
            if isinstance(options[key], bytes):
                options[key] = options[key].decode('utf8')
            opts[key] = options[key]
        return opts

    @export
    def add(self, options=None):
        """Add a watch folder."""
        if options is None:
            options = {}
        options = self._make_unicode(options)
        abswatchdir = os.path.abspath(options['path'])
        check_input(os.path.isdir(abswatchdir), _('Path does not exist.'))
        check_input(
            os.access(abswatchdir, os.R_OK | os.W_OK),
            'You must have read and write access to watch folder.',
        )
        if abswatchdir in [wd['abspath'] for wd in self.watchdirs.values()]:
            raise Exception('Path is already being watched.')
        options.setdefault('enabled', False)
        options['abspath'] = abswatchdir
        watchdir_id = self.config['next_id']
        self.watchdirs[str(watchdir_id)] = options
        if options.get('enabled'):
            self.enable_watchdir(watchdir_id)
        self.config['next_id'] = watchdir_id + 1
        self.config.save()
        component.get('EventManager').emit(AutoaddOptionsChangedEvent())
        return watchdir_id

    @export
    def remove(self, watchdir_id):
        """Remove a watch folder."""
        watchdir_id = str(watchdir_id)
        check_input(
            watchdir_id in self.watchdirs, 'Unknown Watchdir: %s' % self.watchdirs
        )
        if self.watchdirs[watchdir_id]['enabled']:
            self.disable_watchdir(watchdir_id)
        del self.watchdirs[watchdir_id]
        self.config.save()
        component.get('EventManager').emit(AutoaddOptionsChangedEvent())

    def __migrate_config_1_to_2(self, config):
        for watchdir_id in config['watchdirs']:
            config['watchdirs'][watchdir_id]['owner'] = 'localclient'
        return config

    def __on_pre_torrent_removed(self, torrent_id):
        try:
            torrent = component.get('TorrentManager')[torrent_id]
        except KeyError:
            log.warning(
                'Unable to remove torrent file for torrent id %s. It'
                'was already deleted from the TorrentManager',
                torrent_id,
            )
            return
        torrent_fname = torrent.filename
        for watchdir in self.watchdirs.values():
            if not watchdir.get('copy_torrent_toggle', False):
                # This watchlist does copy torrents
                continue
            elif not watchdir.get('delete_copy_torrent_toggle', False):
                # This watchlist is not set to delete finished torrents
                continue
            copy_torrent_path = watchdir['copy_torrent']
            torrent_fname_path = os.path.join(copy_torrent_path, torrent_fname)
            if os.path.isfile(torrent_fname_path):
                try:
                    os.remove(torrent_fname_path)
                    log.info(
                        'Removed torrent file "%s" from "%s"',
                        torrent_fname,
                        copy_torrent_path,
                    )
                    break
                except OSError as ex:
                    log.info(
                        'Failed to removed torrent file "%s" from "%s": %s',
                        torrent_fname,
                        copy_torrent_path,
                        ex,
                    )

    @export
    def is_admin_level(self):
        return self.rpcserver.get_session_auth_level() == deluge.common.AUTH_LEVEL_ADMIN

    @export
    def get_auth_user(self):
        return self.rpcserver.get_session_user()