#!/usr/bin/env python2
# -*- coding: utf-8 -*-

# SàT plugin for generic data import handling
# Copyright (C) 2009-2016 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from sat.core.i18n import _
from sat.core.constants import Const as C
from sat.core.log import getLogger
log = getLogger(__name__)
from twisted.internet import defer
from sat.core import exceptions
from functools import partial
import collections
import uuid


PLUGIN_INFO = {
    C.PI_NAME: "import",
    C.PI_IMPORT_NAME: "IMPORT",
    C.PI_TYPE: C.PLUG_TYPE_IMPORT,
    C.PI_DEPENDENCIES: [],
    C.PI_MAIN: "ImportPlugin",
    C.PI_HANDLER: "no",
    C.PI_DESCRIPTION: _(u"""Generic import plugin, base for specialized importers""")
}

Importer = collections.namedtuple('Importer', ('callback', 'short_desc', 'long_desc'))


class ImportPlugin(object):

    def __init__(self, host):
        log.info(_("plugin Import initialization"))
        self.host = host

    def initialize(self, import_handler, name):
        """Initialize a specialized import handler

        @param import_handler(object): specialized import handler instance
            must have the following methods:
                - importItem: import a single main item (i.e. prepare data for publishing)
                - importSubitems: import sub items (i.e. items linked to main item, e.g. comments).
                    Must return a dict with kwargs for recursiveImport if items are to be imported recursively.
                    At least "items_import_data", "service" and "node" keys must be provided.
                    if None is returned, no recursion will be done to import subitems, but import can still be done directly by the method.
                - publishItem: actualy publish an item
                - itemFilters: modify item according to options
        @param name(unicode): import handler name
        """
        assert name == name.lower().strip()
        log.info(_(u'initializing {name} import handler').format(name=name))
        import_handler.name = name
        import_handler.register = partial(self.register, import_handler)
        import_handler.unregister = partial(self.unregister, import_handler)
        import_handler.importers = {}
        def _import(name, location, options, pubsub_service, pubsub_node, profile):
            return self._doImport(import_handler, name, location, options, pubsub_service, pubsub_node, profile)
        def _importList():
            return self.listImporters(import_handler)
        def _importDesc(name):
            return self.getDescription(import_handler, name)

        self.host.bridge.addMethod(name + "Import", ".plugin", in_sign='ssa{ss}sss', out_sign='s', method=_import, async=True)
        self.host.bridge.addMethod(name + "ImportList", ".plugin", in_sign='', out_sign='a(ss)', method=_importList)
        self.host.bridge.addMethod(name + "ImportDesc", ".plugin", in_sign='s', out_sign='(ss)', method=_importDesc)

    def getProgress(self, import_handler, progress_id, profile):
        client = self.host.getClient(profile)
        return client._import[import_handler.name][progress_id]

    def listImporters(self, import_handler):
        importers = import_handler.importers.keys()
        importers.sort()
        return [(name, import_handler.importers[name].short_desc) for name in import_handler.importers]

    def getDescription(self, import_handler, name):
        """Return import short and long descriptions

        @param name(unicode): importer name
        @return (tuple[unicode,unicode]): short and long description
        """
        try:
            importer = import_handler.importers[name]
        except KeyError:
            raise exceptions.NotFound(u"{handler_name} importer not found [{name}]".format(
                handler_name = import_handler.name,
                name = name))
        else:
            return importer.short_desc, importer.long_desc

    def _doImport(self, import_handler, name, location, options, pubsub_service='', pubsub_node='', profile=C.PROF_KEY_NONE):
        client = self.host.getClient(profile)
        options = {key: unicode(value) for key, value in options.iteritems()}
        for option in import_handler.BOOL_OPTIONS:
            try:
                options[option] = C.bool(options[option])
            except KeyError:
                pass
        return self.doImport(client, import_handler, unicode(name), unicode(location), options, pubsub_service or None, pubsub_node or None)

    @defer.inlineCallbacks
    def doImport(self, client, import_handler, name, location, options=None, pubsub_service=None, pubsub_node=None):
        """Import data

        @param import_handler(object): instance of the import handler
        @param name(unicode): name of the importer
        @param location(unicode): location of the data to import
            can be an url, a file path, or anything which make sense
            check importer description for more details
        @param options(dict, None): extra options.
        @param pubsub_service(jid.JID, None): jid of the PubSub service where data must be imported
            None to use profile's server
        @param pubsub_node(unicode, None): PubSub node to use
            None to use importer's default node
        @return (unicode): progress id
        """
        if options is None:
            options = {}
        else:
            for opt_name, opt_default in import_handler.OPT_DEFAULTS.iteritems():
                # we want a filled options dict, with all empty or False values removed
                try:
                    value =options[opt_name]
                except KeyError:
                    if opt_default:
                        options[opt_name] = opt_default
                else:
                    if not value:
                        del options[opt_name]

        try:
            importer = import_handler.importers[name]
        except KeyError:
            raise exceptions.NotFound(u"Importer [{}] not found".format(name))
        items_import_data, items_count = yield importer.callback(client, location, options)
        progress_id = unicode(uuid.uuid4())
        try:
            _import = client._import
        except AttributeError:
            _import = client._import = {}
        progress_data = _import.setdefault(import_handler.name, {})
        progress_data[progress_id] = {u'position': '0'}
        if items_count is not None:
            progress_data[progress_id]['size'] = unicode(items_count)
        metadata = {'name': u'{}: {}'.format(name, location),
                    'direction': 'out',
                    'type': import_handler.name.upper() + '_IMPORT'
                   }
        self.host.registerProgressCb(progress_id, partial(self.getProgress, import_handler), metadata, profile=client.profile)
        self.host.bridge.progressStarted(progress_id, metadata, client.profile)
        session = {  # session data, can be used by importers
            u'root_service': pubsub_service,
            u'root_node': pubsub_node
        }
        self.recursiveImport(client, import_handler, items_import_data, progress_id, session, options, None, pubsub_service, pubsub_node)
        defer.returnValue(progress_id)

    @defer.inlineCallbacks
    def recursiveImport(self, client, import_handler, items_import_data, progress_id, session, options, return_data=None, service=None, node=None, depth=0):
        """Do the import recursively

        @param import_handler(object): instance of the import handler
        @param items_import_data(iterable): iterable of data as specified in [register]
        @param progress_id(unicode): id of progression
        @param session(dict): data for this import session
            can be used by importer so store any useful data
            "root_service" and "root_node" are set to the main pubsub service and node of the import
        @param options(dict): import options
        @param return_data(dict): data to return on progressFinished
        @param service(jid.JID, None): PubSub service to use
        @param node(unicode, None): PubSub node to use
        @param depth(int): level of recursion
        """
        if return_data is None:
            return_data = {}
        for idx, item_import_data in enumerate(items_import_data):
            item_data = yield import_handler.importItem(client, item_import_data, session, options, return_data, service, node)
            yield import_handler.itemFilters(client, item_data, session, options)
            recurse_kwargs = yield import_handler.importSubItems(client, item_import_data, item_data, session, options)
            yield import_handler.publishItem(client, item_data, service, node, session)

            if recurse_kwargs is not None:
                recurse_kwargs['client'] = client
                recurse_kwargs['import_handler'] = import_handler
                recurse_kwargs['progress_id'] = progress_id
                recurse_kwargs['session'] = session
                recurse_kwargs.setdefault('options', options)
                recurse_kwargs['return_data'] = return_data
                recurse_kwargs['depth'] = depth + 1
                log.debug(_(u"uploading subitems"))
                yield self.recursiveImport(**recurse_kwargs)

            if depth == 0:
                client._import[import_handler.name][progress_id]['position'] = unicode(idx+1)

        if depth == 0:
            self.host.bridge.progressFinished(progress_id,
                return_data,
                client.profile)
            self.host.removeProgressCb(progress_id, client.profile)
            del client._import[import_handler.name][progress_id]

    def register(self, import_handler, name, callback, short_desc='', long_desc=''):
        """Register an Importer method

        @param name(unicode): unique importer name, should indicate the software it can import and always lowercase
        @param callback(callable): method to call:
            the signature must be (client, location, options) (cf. [doImport])
            the importer must return a tuple with (items_import_data, items_count)
            items_import_data(iterable[dict]) data specific to specialized importer
                cf. importItem docstring of specialized importer for details
            items_count (int, None) indicate the total number of items (without subitems)
                useful to display a progress indicator when the iterator is a generator
                use None if you can't guess the total number of items
        @param short_desc(unicode): one line description of the importer
        @param long_desc(unicode): long description of the importer, its options, etc.
        """
        name = name.lower()
        if name in import_handler.importers:
            raise exceptions.ConflictError(_(u"An {handler_name} importer with the name {name} already exist").format(
                handler_name = import_handler.name,
                name = name))
        import_handler.importers[name] = Importer(callback, short_desc, long_desc)

    def unregister(self, import_handler, name):
        del import_handler.importers[name]