"""Some generic utilities for dealing with classes, urls, and serialization."""

# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.

import logging
import os
import re
import stat
import socket
import sys
import warnings
from signal import signal, SIGINT, SIGABRT, SIGTERM
try:
    from signal import SIGKILL
except ImportError:
    SIGKILL=None
from types import FunctionType

try:
    import cPickle
    pickle = cPickle
except:
    cPickle = None
    import pickle

import zmq
from zmq.log import handlers

from IPython.external.decorator import decorator

from IPython.config.application import Application
from IPython.utils.localinterfaces import localhost, is_public_ip, public_ips
from IPython.utils.py3compat import string_types, iteritems, itervalues
from IPython.kernel.zmq.log import EnginePUBHandler
from IPython.kernel.zmq.serialize import (
    unserialize_object, serialize_object, pack_apply_message, unpack_apply_message
)

#-----------------------------------------------------------------------------
# Classes
#-----------------------------------------------------------------------------

class Namespace(dict):
    """Subclass of dict for attribute access to keys."""
    
    def __getattr__(self, key):
        """getattr aliased to getitem"""
        if key in self:
            return self[key]
        else:
            raise NameError(key)

    def __setattr__(self, key, value):
        """setattr aliased to setitem, with strict"""
        if hasattr(dict, key):
            raise KeyError("Cannot override dict keys %r"%key)
        self[key] = value
    

class ReverseDict(dict):
    """simple double-keyed subset of dict methods."""
    
    def __init__(self, *args, **kwargs):
        dict.__init__(self, *args, **kwargs)
        self._reverse = dict()
        for key, value in iteritems(self):
            self._reverse[value] = key
    
    def __getitem__(self, key):
        try:
            return dict.__getitem__(self, key)
        except KeyError:
            return self._reverse[key]
    
    def __setitem__(self, key, value):
        if key in self._reverse:
            raise KeyError("Can't have key %r on both sides!"%key)
        dict.__setitem__(self, key, value)
        self._reverse[value] = key
    
    def pop(self, key):
        value = dict.pop(self, key)
        self._reverse.pop(value)
        return value
    
    def get(self, key, default=None):
        try:
            return self[key]
        except KeyError:
            return default

#-----------------------------------------------------------------------------
# Functions
#-----------------------------------------------------------------------------

@decorator
def log_errors(f, self, *args, **kwargs):
    """decorator to log unhandled exceptions raised in a method.
    
    For use wrapping on_recv callbacks, so that exceptions
    do not cause the stream to be closed.
    """
    try:
        return f(self, *args, **kwargs)
    except Exception:
        self.log.error("Uncaught exception in %r" % f, exc_info=True)
    

def is_url(url):
    """boolean check for whether a string is a zmq url"""
    if '://' not in url:
        return False
    proto, addr = url.split('://', 1)
    if proto.lower() not in ['tcp','pgm','epgm','ipc','inproc']:
        return False
    return True

def validate_url(url):
    """validate a url for zeromq"""
    if not isinstance(url, string_types):
        raise TypeError("url must be a string, not %r"%type(url))
    url = url.lower()
    
    proto_addr = url.split('://')
    assert len(proto_addr) == 2, 'Invalid url: %r'%url
    proto, addr = proto_addr
    assert proto in ['tcp','pgm','epgm','ipc','inproc'], "Invalid protocol: %r"%proto
    
    # domain pattern adapted from http://www.regexlib.com/REDetails.aspx?regexp_id=391
    # author: Remi Sabourin
    pat = re.compile(r'^([\w\d]([\w\d\-]{0,61}[\w\d])?\.)*[\w\d]([\w\d\-]{0,61}[\w\d])?$')
    
    if proto == 'tcp':
        lis = addr.split(':')
        assert len(lis) == 2, 'Invalid url: %r'%url
        addr,s_port = lis
        try:
            port = int(s_port)
        except ValueError:
            raise AssertionError("Invalid port %r in url: %r"%(port, url))
        
        assert addr == '*' or pat.match(addr) is not None, 'Invalid url: %r'%url
        
    else:
        # only validate tcp urls currently
        pass
    
    return True


def validate_url_container(container):
    """validate a potentially nested collection of urls."""
    if isinstance(container, string_types):
        url = container
        return validate_url(url)
    elif isinstance(container, dict):
        container = itervalues(container)
    
    for element in container:
        validate_url_container(element)


def split_url(url):
    """split a zmq url (tcp://ip:port) into ('tcp','ip','port')."""
    proto_addr = url.split('://')
    assert len(proto_addr) == 2, 'Invalid url: %r'%url
    proto, addr = proto_addr
    lis = addr.split(':')
    assert len(lis) == 2, 'Invalid url: %r'%url
    addr,s_port = lis
    return proto,addr,s_port


def disambiguate_ip_address(ip, location=None):
    """turn multi-ip interfaces '0.0.0.0' and '*' into a connectable address
    
    Explicit IP addresses are returned unmodified.
    
    Parameters
    ----------
    
    ip : IP address
        An IP address, or the special values 0.0.0.0, or *
    location: IP address, optional
        A public IP of the target machine.
        If location is an IP of the current machine,
        localhost will be returned,
        otherwise location will be returned.
    """
    if ip in {'0.0.0.0', '*'}:
        if not location:
            # unspecified location, localhost is the only choice
            ip = localhost()
        elif is_public_ip(location):
            # location is a public IP on this machine, use localhost
            ip = localhost()
        elif not public_ips():
            # this machine's public IPs cannot be determined,
            # assume `location` is not this machine
            warnings.warn("IPython could not determine public IPs", RuntimeWarning)
            ip = location
        else:
            # location is not this machine, do not use loopback
            ip = location
    return ip


def disambiguate_url(url, location=None):
    """turn multi-ip interfaces '0.0.0.0' and '*' into connectable
    ones, based on the location (default interpretation is localhost).
    
    This is for zeromq urls, such as ``tcp://*:10101``.
    """
    try:
        proto,ip,port = split_url(url)
    except AssertionError:
        # probably not tcp url; could be ipc, etc.
        return url
    
    ip = disambiguate_ip_address(ip,location)
    
    return "%s://%s:%s"%(proto,ip,port)


#--------------------------------------------------------------------------
# helpers for implementing old MEC API via view.apply
#--------------------------------------------------------------------------

def interactive(f):
    """decorator for making functions appear as interactively defined.
    This results in the function being linked to the user_ns as globals()
    instead of the module globals().
    """
    
    # build new FunctionType, so it can have the right globals
    # interactive functions never have closures, that's kind of the point
    if isinstance(f, FunctionType):
        mainmod = __import__('__main__')
        f = FunctionType(f.__code__, mainmod.__dict__,
            f.__name__, f.__defaults__,
        )
    # associate with __main__ for uncanning
    f.__module__ = '__main__'
    return f

@interactive
def _push(**ns):
    """helper method for implementing `client.push` via `client.apply`"""
    user_ns = globals()
    tmp = '_IP_PUSH_TMP_'
    while tmp in user_ns:
        tmp = tmp + '_'
    try:
        for name, value in ns.items():
            user_ns[tmp] = value
            exec("%s = %s" % (name, tmp), user_ns)
    finally:
        user_ns.pop(tmp, None)

@interactive
def _pull(keys):
    """helper method for implementing `client.pull` via `client.apply`"""
    if isinstance(keys, (list,tuple, set)):
        return [eval(key, globals()) for key in keys]
    else:
        return eval(keys, globals())

@interactive
def _execute(code):
    """helper method for implementing `client.execute` via `client.apply`"""
    exec(code, globals())

#--------------------------------------------------------------------------
# extra process management utilities
#--------------------------------------------------------------------------

_random_ports = set()

def select_random_ports(n):
    """Selects and return n random ports that are available."""
    ports = []
    for i in range(n):
        sock = socket.socket()
        sock.bind(('', 0))
        while sock.getsockname()[1] in _random_ports:
            sock.close()
            sock = socket.socket()
            sock.bind(('', 0))
        ports.append(sock)
    for i, sock in enumerate(ports):
        port = sock.getsockname()[1]
        sock.close()
        ports[i] = port
        _random_ports.add(port)
    return ports

def signal_children(children):
    """Relay interupt/term signals to children, for more solid process cleanup."""
    def terminate_children(sig, frame):
        log = Application.instance().log
        log.critical("Got signal %i, terminating children..."%sig)
        for child in children:
            child.terminate()
        
        sys.exit(sig != SIGINT)
        # sys.exit(sig)
    for sig in (SIGINT, SIGABRT, SIGTERM):
        signal(sig, terminate_children)

def generate_exec_key(keyfile):
    import uuid
    newkey = str(uuid.uuid4())
    with open(keyfile, 'w') as f:
        # f.write('ipython-key ')
        f.write(newkey+'\n')
    # set user-only RW permissions (0600)
    # this will have no effect on Windows
    os.chmod(keyfile, stat.S_IRUSR|stat.S_IWUSR)


def integer_loglevel(loglevel):
    try:
        loglevel = int(loglevel)
    except ValueError:
        if isinstance(loglevel, str):
            loglevel = getattr(logging, loglevel)
    return loglevel

def connect_logger(logname, context, iface, root="ip", loglevel=logging.DEBUG):
    logger = logging.getLogger(logname)
    if any([isinstance(h, handlers.PUBHandler) for h in logger.handlers]):
        # don't add a second PUBHandler
        return
    loglevel = integer_loglevel(loglevel)
    lsock = context.socket(zmq.PUB)
    lsock.connect(iface)
    handler = handlers.PUBHandler(lsock)
    handler.setLevel(loglevel)
    handler.root_topic = root
    logger.addHandler(handler)
    logger.setLevel(loglevel)

def connect_engine_logger(context, iface, engine, loglevel=logging.DEBUG):
    logger = logging.getLogger()
    if any([isinstance(h, handlers.PUBHandler) for h in logger.handlers]):
        # don't add a second PUBHandler
        return
    loglevel = integer_loglevel(loglevel)
    lsock = context.socket(zmq.PUB)
    lsock.connect(iface)
    handler = EnginePUBHandler(engine, lsock)
    handler.setLevel(loglevel)
    logger.addHandler(handler)
    logger.setLevel(loglevel)
    return logger

def local_logger(logname, loglevel=logging.DEBUG):
    loglevel = integer_loglevel(loglevel)
    logger = logging.getLogger(logname)
    if any([isinstance(h, logging.StreamHandler) for h in logger.handlers]):
        # don't add a second StreamHandler
        return
    handler = logging.StreamHandler()
    handler.setLevel(loglevel)
    formatter = logging.Formatter("%(asctime)s.%(msecs).03d [%(name)s] %(message)s",
                datefmt="%Y-%m-%d %H:%M:%S")
    handler.setFormatter(formatter)

    logger.addHandler(handler)
    logger.setLevel(loglevel)
    return logger

def set_hwm(sock, hwm=0):
    """set zmq High Water Mark on a socket
    
    in a way that always works for various pyzmq / libzmq versions.
    """
    import zmq
    
    for key in ('HWM', 'SNDHWM', 'RCVHWM'):
        opt = getattr(zmq, key, None)
        if opt is None:
            continue
        try:
            sock.setsockopt(opt, hwm)
        except zmq.ZMQError:
            pass

        