import logging
import base64
import hashlib
from xml.etree import cElementTree as ET

from sleekxmpp.xmlstream.stanzabase import ElementBase, register_stanza_plugin
from sleekxmpp.plugins import base
from sleekxmpp.xmlstream.handler.callback import Callback
from sleekxmpp.xmlstream.matcher.xpath import MatchXPath
from sleekxmpp.stanza.iq import Iq

from object import Object
from permission import PermissionError

class AliasQuery(ElementBase):
    namespace = 'alias:query'
    name = 'query'
    plugin_attrib = 'alias'
    interfaces = set(('node', 'type', 'content', 'permission', 'key'))
    sub_interfaces = set(('content', 'permission'))

    def addItem(self, node, key, permission = None):
        item = AliasItem(None, self)
        item['node'] = node
        item['key']= key
        if permission is not None:
            item['permission'] = str(permission)

class AliasItem(ElementBase):
    namespace = 'alias:query'
    name = 'item'
    plugin_attrib = 'item'
    interfaces = set(('node', 'permission', 'key' ))

class AliasPlugin(base.base_plugin):

    def plugin_init(self):
        self.description = 'Plugin to handle alias queries'
        register_stanza_plugin(Iq, AliasQuery)
        query_parser = MatchXPath('{{{}}}iq/{{{}}}query'.format(self.xmpp.default_ns,
                                                                AliasQuery.namespace))
        self.xmpp.register_handler(Callback('Alias queries', query_parser,
                                            self.handle_alias_query))

    def post_init(self):
        base.base_plugin.post_init(self)
        self.xmpp.plugin['xep_0030'].add_feature("alias:query")

    def send_permission_error(self, iq, message):
        node = iq['alias']['node']
        iq.reply()
        iq['alias']['type'] = 'error'
        iq['alias']['node'] = node
        iq['alias']['permission'] = message
        iq.send()

    def handle_alias_query(self, iq):
        try:
            callee = base64.b64decode(iq['to'].user)
        except TypeError:
            logging.error("callee field not base64 encoded")
        caller = iq['from'].bare
        node = iq['alias']['node']
        if not node:
            node = hashlib.sha1(callee).hexdigest()
        node = Object(callee, node)
        
        if iq['alias']['type'] == 'items':
            try:
                childs = node.get_child_list(caller)
            except PermissionError:
                self.send_permission_error(iq, 'Permission')
            else:
                iq.reply()
                iq['alias']['type'] = 'items'
                iq['alias']['node'] = node.hash
                for name, perm, key in childs:
                    iq['alias'].addItem(name, key, perm)
                iq.send()

        if iq['alias']['type'] == 'content':
            try:
                content = node.get_content(caller)
                key = node.get_key(caller)
            except PermissionError:
                self.send_permission_error(iq, 'Permission')
            else:
                iq.reply()
                iq['alias']['type'] = 'content'
                iq['alias']['node'] = node.hash
                iq['alias']['content'] = content
                iq['alias']['key'] = key
                iq.send()