#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
    Blockstack-client
    ~~~~~
    copyright: (c) 2014-2015 by Halfmoon Labs, Inc.
    copyright: (c) 2016 by Blockstack.org

    This file is part of Blockstack-client.

    Blockstack-client 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.

    Blockstack-client 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 Blockstack-client. If not, see <http://www.gnu.org/licenses/>.
"""

import sys
import os
import importlib

from proxy import *
from virtualchain import SPVClient
import storage

from .constants import CONFIG_PATH, VERSION
from .config import get_logger, get_config, semver_match

log = get_logger()

# ancillary storage providers
STORAGE_IMPL = None
ANALYTICS_KEY = None


def session(conf=None, config_path=CONFIG_PATH, server_host=None, server_port=None, wallet_password=None,
            storage_drivers=None, metadata_dir=None, spv_headers_path=None, set_global=False):
    """
    Create a blockstack session:
    * validate the configuration
    * load all storage drivers
    * initialize all storage drivers
    * load an API proxy to blockstack

    conf's fields override specific keyword arguments.

    Returns the API proxy object.
    """

    if conf is None:
        conf = get_config(config_path)
        if conf is None:
            log.error("Failed to read configuration file {}".format(config_path))
            return None 

        conf_version = conf.get('client_version', '')
        if not semver_match(conf_version, VERSION):
            log.error("Failed to use legacy configuration file {}".format(config_path))
            return None

    if conf is not None:
        if server_host is None:
            server_host = conf['server']
        if server_port is None:
            server_port = conf['port']
        if storage_drivers is None:
            storage_drivers = conf['storage_drivers']
        if metadata_dir is None:
            metadata_dir = conf['metadata']
        if spv_headers_path is None:
            spv_headers_path = conf['bitcoind_spv_path']

    if storage_drivers is None:
        msg = ('No storage driver(s) defined in the config file. '
               'Please set "storage=" to a comma-separated list of drivers')
        log.error(msg)
        sys.exit(1)

    # create proxy
    log.debug('Connect to {}:{}'.format(server_host, server_port))
    proxy = BlockstackRPCClient(server_host, server_port)

    # load all storage drivers
    for storage_driver in storage_drivers.split(','):
        storage_impl = load_storage(storage_driver)
        if storage_impl is None:
            log.error('Failed to load storage driver "{}"'.format(storage_driver))
            sys.exit(1)

        rc = register_storage(storage_impl, conf)
        if not rc:
            log.error('Failed to initialize storage driver "{}" ({})'.format(storage_driver, rc))
            sys.exit(1)

    # initialize SPV
    SPVClient.init(spv_headers_path)
    proxy.spv_headers_path = spv_headers_path
    proxy.conf = conf

    if set_global:
        set_default_proxy(proxy)

    return proxy


def load_storage(module_name):
    """
    Load a storage implementation, given its module name.
    """
    try:
        prefix = 'blockstack_client.backend.drivers.{}'
        storage_impl = importlib.import_module(prefix.format(module_name))
        storage_impl.__name__ = module_name
        log.debug('Loaded storage driver "{}"'.format(module_name))
    except ImportError as e:
        msg = ('Failed to import blockstack_client.backend.drivers.{}. '
               'Please verify that it is installed and is accessible via your PYTHONPATH')
        raise Exception(msg.format(module_name))

    return storage_impl


def register_storage(storage_impl, conf):
    """
    Register a storage implementation.
    """
    rc = storage.register_storage(storage_impl)
    if rc:
        rc = storage_impl.storage_init(conf)

    return rc


def get_analytics_key(uuid, proxy=None):
    """
    Get the analytics key from the blockstack server
    """

    key = os.environ.get('BLOCKSTACK_TEST_ANALYTICS_KEY', None)

    if key is not None:
        return key

    try:
        proxy = get_default_proxy() if proxy is None else proxy
        key = proxy.get_analytics_key(uuid)
    except Exception as e:
        log.debug('Failed to get analytics key')
        return

    key = {} if key is None else key
    if 'error' in key:
        log.debug('Failed to fetch analytics key: {}'.format(key['error']))
        return

    key = key.get('analytics_key', None)
    if key is not None:
        return key

    log.debug('No analytics key returned')

    return


def analytics_event(event_type, event_payload, config_path=CONFIG_PATH,
                    proxy=None, analytics_key=None, action_tag='Perform action'):
    """
    Log an analytics event
    Return True if logged
    Return False if not

    The client uses 'Perform action' as its action tag, so we can distinguish
    client events from server events.  The server uses separate action tags.
    """
    global ANALYTICS_KEY

    try:
        import mixpanel
    except:
        log.debug('mixpanel is not installed; no analytics will be reported')
        return False

    conf = get_config(path=config_path)
    if conf is None:
        log.debug('Failed to load config')
        return False

    if not conf['anonymous_statistics']:
        return False

    u = conf['uuid']

    # use the given analytics key, if possible. or fallback.
    analytics_key = ANALYTICS_KEY if analytics_key is None else analytics_key

    # no fallback. so fetch from server.
    if analytics_key is None:
        ANALYTICS_KEY = get_analytics_key(u, proxy=proxy) if ANALYTICS_KEY is None else ANALYTICS_KEY
        analytics_key = ANALYTICS_KEY

        # all attempts failed. nothing more to do.
        if analytics_key is None:
            return False

    # log the event
    log.debug('Track event "{}": {}'.format(event_type, event_payload))
    mp = mixpanel.Mixpanel(analytics_key)
    mp.track(u, event_type, event_payload)
    mp.track(u, action_tag, {})

    return True


def analytics_user_register(u, email, config_path=CONFIG_PATH, proxy=None):
    """
    Register a user with the analytics service
    """
    global ANALYTICS_KEY

    try:
        import mixpanel
    except:
        log.debug('mixpanel is not installed; no analytics will be reported')
        return False

    conf = get_config(path=config_path)
    if conf is None:
        log.debug('Failed to load config')
        return False

    if not conf['anonymous_statistics']:
        return False

    ANALYTICS_KEY = get_analytics_key(u) if ANALYTICS_KEY is None else ANALYTICS_KEY
    if ANALYTICS_KEY is None:
        return False

    # register the user
    log.debug('Register user "{}"'.format(u))
    mp = mixpanel.Mixpanel(ANALYTICS_KEY)
    mp.people_set_once(u, {})

    return True


def analytics_user_update(payload, proxy=None):
    """
    Update a user's info on the analytics service
    """
    global ANALYTICS_KEY

    try:
        import mixpanel
    except:
        log.debug('mixpanel is not installed; no analytics will be reported')
        return False

    conf = get_config(config_path)
    if conf is None:
        log.debug('Failed to load config')
        return False

    if not conf['anonymous_statistics']:
        return False

    u = conf['uuid']
    ANALYTICS_KEY = get_analytics_key(u) if ANALYTICS_KEY is None else ANALYTICS_KEY
    if ANALYTICS_KEY is None:
        return False

    # update the user
    log.debug('Update user "{}"'.format(u))
    mp = mixpanel.Mixpanel(ANALYTICS_KEY)
    mp.people_append(u, payload)

    return True