# -*- encoding: utf-8 -*-
# couchdb.py
# Copyright (C) 2013 LEAP
#
# 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/>.


"""
Classes for working with CouchDB or BigCouch instances which store email alias
maps, user UUIDs, and GPG keyIDs.
"""


from paisley import client
from twisted.internet import defer
from twisted.python import log
from leap.soledad.common.couch import CouchDatabase


class ConnectedCouchDB(client.CouchDB):
    """
    Connect to a CouchDB instance.

    CouchDB document for testing is '_design', and the view is simply
    a preconfigured set of mapped responses.
    """

    def __init__(self, host, port=5984, dbName=None, username=None,
                 password=None, *args, **kwargs):
        """
        Connect to a CouchDB instance.

        :param host: A hostname string for the CouchDB server.
        :type host: str
        :param port: The port of the CouchDB server.
        :type port: int
        :param dbName: (optional) The default database to bind queries to.
        :type dbName: str
        :param username: (optional) The username for authorization.
        :type username: str
        :param str password: (optional) The password for authorization.
        :type password: str
        """
        self._mail_couch_url = "http://%s:%s@%s:%s" % (username,
                                                       password,
                                                       host,
                                                       port)
        client.CouchDB.__init__(self,
                                host,
                                port=port,
                                dbName=dbName,
                                username=username,
                                password=password,
                                *args, **kwargs)
        self._cache = {}

    def createDB(self, dbName):
        """
        Overrides ``paisley.client.CouchDB.createDB``.
        """
        pass

    def deleteDB(self, dbName):
        """
        Overrides ``paisley.client.CouchDB.deleteDB``.
        """
        pass

    def getUuidAndPubkey(self, address):
        """
        Query couch and return a deferred that will fire with the uuid and pgp
        public key for address.

        :param address: A string representing the email or alias to check.
        :type address: str
        :return: A deferred that will fire with the user's uuid and pgp public
                 key.
        :rtype twisted.defer.Deferred
        """
        # TODO: Cache results
        d = self.openView(docId="Identity",
                          viewId="by_address/",
                          key=address,
                          reduce=False,
                          include_docs=True)

        def _get_uuid_and_pubkey_cbk(result):
            uuid = None
            pubkey = None
            if result["rows"]:
                doc = result["rows"][0]["doc"]
                if doc["enabled"]:
                    uuid = doc["user_id"]
                    if "keys" in doc:
                        pubkey = doc["keys"]["pgp"]
            return uuid, pubkey

        d.addCallback(_get_uuid_and_pubkey_cbk)
        return d

    def getPubkey(self, uuid):
        """
        Query couch and return a deferred that will fire with the pgp public
        key for user with given uuid.

        :param uuid: The uuid of a user
        :type uuid: str

        :return: A deferred that will fire with the pgp public key for
                 the user.
        :rtype: Deferred
        """
        d = self.openView(docId="Identity",
                          viewId="by_user_id/",
                          key=uuid,
                          reduce=False,
                          include_docs=True)

        def _get_pubkey_cbk(result):
            pubkey = None
            try:
                doc = result["rows"][0]["doc"]
                pubkey = doc["keys"]["pgp"]
            except (KeyError, IndexError):
                pass
            return pubkey

        d.addCallbacks(_get_pubkey_cbk, log.err)
        return d

    def getCertExpiry(self, fingerprint):
        """
        Query couch and return a deferred that will fire with the expiration
        date for the cert with the given fingerprint.

        :param fingerprint: The cert fingerprint
        :type fingerprint: str

        :return: A deferred that will fire with the cert expiration date as a
                 str.
        :rtype: Deferred
        """
        d = self.openView(docId="Identity",
                          viewId="cert_expiry_by_fingerprint/",
                          key=fingerprint,
                          reduce=False,
                          include_docs=True)

        def _get_cert_expiry_cbk(result):
            try:
                expiry = result["rows"][0]["value"]
            except (KeyError, IndexError):
                expiry = None
            return expiry

        d.addCallback(_get_cert_expiry_cbk)
        return d

    def put_doc(self, uuid, doc):
        """
        Update a document.

        If the document currently has conflicts, put will fail.
        If the database specifies a maximum document size and the document
        exceeds it, put will fail and raise a DocumentTooBig exception.

        :param uuid: The uuid of a user
        :type uuid: str
        :param doc: A Document with new content.
        :type doc: leap.soledad.common.couch.CouchDocument

        :return: A deferred which fires with the new revision identifier for
                 the document if the Document object has being updated, or
                 which fails with CouchDBError if there was any error.
        """
        # TODO: that should be implemented with paisley
        url = self._mail_couch_url + "/user-%s" % (uuid,)
        try:
            db = CouchDatabase.open_database(url, create=False)
            return defer.succeed(db.put_doc(doc))
        except Exception as e:
            return defer.fail(CouchDBError(e.message))


class CouchDBError(Exception):
    pass