import os
import pwd
import time
import select

def __error(errno):
    if errno != 0:
        raise IOError(errno, error_message(errno))

cdef object _string_c2p(char * string):
    if string is NULL:
        return None
    else:
        return string

class ZUid(object):
    """
    A per-transaction unique ID for zephyrs
    """

    def __init__(self):
        self.address = ''
        self.time = 0

cdef void _ZUid_c2p(ZUnique_Id_t * uid, object p_uid) except *:
    p_uid.address = inet_ntoa(uid.zuid_addr)
    p_uid.time = uid.tv.tv_sec + (uid.tv.tv_usec / 100000.0)

cdef void _ZUid_p2c(object uid, ZUnique_Id_t * c_uid) except *:
    inet_aton(uid.address, &c_uid.zuid_addr)
    c_uid.tv.tv_usec = int(uid.time)
    c_uid.tv.tv_usec = int((uid.time - c_uid.tv.tv_usec) * 100000)

cdef char * _string_p2c(object_pool *pool, object string) except *:
    if string is None:
        return NULL
    else:
        object_pool_append(pool, string);
        return string

class ZNotice(object):
    """
    A zephyr message
    """

    def __init__(self, **options):
        self.kind = ACKED
        self.cls = 'message'
        self.instance = 'personal'

        self.uid = ZUid()
        self.time = 0
        self.port = 0
        self.auth = True
        self.recipient = None
        self.sender = None
        self.opcode = None
        self.format = "http://zephyr.1ts.org/wiki/df"
        self.other_fields = []
        self.fields = []
        self._charset = None

        for k, v in options.iteritems():
            setattr(self, k, v)

    def getmessage(self):
        return '\0'.join(self.fields)

    def setmessage(self, newmsg):
        self.fields = newmsg.split('\0')

    message = property(getmessage, setmessage)

    @property
    def charset(self):
        return self._charset

    def send(self):
        cdef object_pool pool
        cdef ZNotice_t notice
        try:
            object_pool_init(&pool)
            _ZNotice_p2c(self, &notice, &pool)

            original_message = self.message

            if self.auth:
                errno = ZSendNotice(&notice, ZAUTH)
            else:
                errno = ZSendNotice(&notice, ZNOAUTH)
            __error(errno)

            _ZNotice_c2p(&notice, self)

            self.message = original_message

            ZFreeNotice(&notice)
        finally:
            object_pool_free(&pool);

cdef void _ZNotice_c2p(ZNotice_t * notice, object p_notice) except *:
    p_notice.kind = notice.z_kind
    _ZUid_c2p(&notice.z_uid, p_notice.uid)
    p_notice.time = notice.z_time.tv_sec + (notice.z_time.tv_usec / 100000.0)
    p_notice.port = int(notice.z_port)
    p_notice.auth = bool(notice.z_auth)

    p_notice.cls = _string_c2p(notice.z_class)
    p_notice.instance = _string_c2p(notice.z_class_inst)
    p_notice.recipient = _string_c2p(notice.z_recipient)
    p_notice.sender = _string_c2p(notice.z_sender)
    p_notice.opcode = _string_c2p(notice.z_opcode)
    p_notice.format = _string_c2p(notice.z_default_format)
    p_notice.other_fields = list()
    for i in range(notice.z_num_other_fields):
        p_notice.other_fields.append(notice.z_other_fields[i])

    if notice.z_message is NULL:
        p_notice.message = None
    else:
        p_notice.message = PyString_FromStringAndSize(notice.z_message, notice.z_message_len)

    p_notice._charset = ZCharsetToString(notice.z_charset)

cdef void _ZNotice_p2c(object notice, ZNotice_t * c_notice, object_pool *pool) except *:
    memset(c_notice, 0, sizeof(ZNotice_t))

    c_notice.z_kind = notice.kind
    _ZUid_p2c(notice.uid, &c_notice.z_uid)
    if notice.time != 0:
        c_notice.z_time.tv_sec = int(notice.time)
        c_notice.z_time.tv_usec = int((notice.time - c_notice.z_time.tv_sec) * 100000)
    if notice.port != 0:
        c_notice.z_port = notice.port
    c_notice.z_auth = int(notice.auth)

    c_notice.z_class = _string_p2c(pool, notice.cls)
    c_notice.z_class_inst = _string_p2c(pool, notice.instance)
    c_notice.z_recipient = _string_p2c(pool, notice.recipient)
    c_notice.z_sender = _string_p2c(pool, notice.sender)
    c_notice.z_opcode = _string_p2c(pool, notice.opcode)
    c_notice.z_default_format = _string_p2c(pool, notice.format)
    c_notice.z_num_other_fields = len(notice.other_fields)
    for i in range(c_notice.z_num_other_fields):
        c_notice.z_other_fields[i] = _string_p2c(pool, notice.other_fields[i])

    cdef unsigned short charset
    if isinstance(notice.message, unicode):
        notice.encoded_message = notice.message.encode('utf-8')
        charset = ZCHARSET_UTF_8
    else:
        notice.encoded_message = notice.message
        charset = ZCHARSET_UNKNOWN

    c_notice.z_message = _string_p2c(pool, notice.encoded_message)
    c_notice.z_message_len = len(notice.encoded_message)
    c_notice.z_charset = charset

def initialize():
    errno = ZInitialize()
    __error(errno)

def openPort():
    cdef unsigned short port

    port = 0

    errno = ZOpenPort(&port)
    __error(errno)

    return port

def getFD():
    return ZGetFD()

def setFD(fd):
    errno = ZSetFD(fd)
    __error(errno)

def sub(cls, instance, recipient):
    cdef ZSubscription_t newsub[1]

    newsub[0].zsub_class = cls
    newsub[0].zsub_classinst = instance
    newsub[0].zsub_recipient = recipient

    errno = ZSubscribeTo(newsub, 1, 0)
    __error(errno)

def subAll(lst):
    cdef ZSubscription_t *newsubs
    cdef unsigned int i

    newsubs = <ZSubscription_t*>calloc(len(lst), sizeof(ZSubscription_t))
    try:
        for 0 <= i < len(lst):
            newsubs[i].zsub_class = lst[i][0]
            newsubs[i].zsub_classinst = lst[i][1]
            newsubs[i].zsub_recipient = lst[i][2]

        errno = ZSubscribeTo(newsubs, len(lst), 0)
        __error(errno)
    finally:
        if newsubs:
            free(newsubs);
    pass

def unsub(cls, instance, recipient):
    cdef ZSubscription_t delsub[1]

    delsub[0].zsub_class = cls
    delsub[0].zsub_classinst = instance
    delsub[0].zsub_recipient = recipient

    errno = ZUnsubscribeTo(delsub, 1, 0)
    __error(errno)

def cancelSubs():
    errno = ZCancelSubscriptions(0)
    __error(errno)

def receive(block=False):
    cdef ZNotice_t notice
    cdef sockaddr_in sender

    while ZPending() == 0:
        if not block:
            return None
        select.select([getFD()], [], [])

    errno = ZReceiveNotice(&notice, &sender)
    __error(errno)

    try:
        if ZCheckAuthentication(&notice, &sender) == ZAUTH_YES:
            notice.z_auth = 1
        else:
            notice.z_auth = 0

        p_notice = ZNotice()
        _ZNotice_c2p(&notice, p_notice)
    finally:
        ZFreeNotice(&notice)
    return p_notice

def sender():
    return ZGetSender()

def realm():
    return ZGetRealm()

def getSubscriptions():
    cdef ZSubscription_t *csubs

    cdef int cnum
    cnum = 0
    errno = ZRetrieveSubscriptions(0, &cnum)
    __error(errno)
    # save the count as a Python variable since ZGetSubscriptions
    # mutates its argument
    num = cnum
    csubs = <ZSubscription_t*>calloc(num, sizeof(ZSubscription_t))
    try:
        errno = ZGetSubscriptions(csubs, &cnum)
        __error(errno)

        subs = []
        for i in range(num):
            subs.append((csubs[i].zsub_class, csubs[i].zsub_classinst, csubs[i].zsub_recipient))
        return subs
    finally:
        ZFlushSubscriptions()
        free(csubs)