# Copyright (c) 2009, Giampaolo Rodola'. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""OSX platform implementation."""

import errno
import functools
import os
from collections import namedtuple

from . import _common
from . import _psposix
from . import _psutil_osx as cext
from . import _psutil_posix as cext_posix
from ._common import conn_tmap
from ._common import isfile_strict
from ._common import parse_environ_block
from ._common import sockfam_to_enum
from ._common import socktype_to_enum
from ._common import usage_percent


__extra__all__ = []

# --- constants

PAGESIZE = os.sysconf("SC_PAGE_SIZE")
AF_LINK = cext_posix.AF_LINK

# http://students.mimuw.edu.pl/lxr/source/include/net/tcp_states.h
TCP_STATUSES = {
    cext.TCPS_ESTABLISHED: _common.CONN_ESTABLISHED,
    cext.TCPS_SYN_SENT: _common.CONN_SYN_SENT,
    cext.TCPS_SYN_RECEIVED: _common.CONN_SYN_RECV,
    cext.TCPS_FIN_WAIT_1: _common.CONN_FIN_WAIT1,
    cext.TCPS_FIN_WAIT_2: _common.CONN_FIN_WAIT2,
    cext.TCPS_TIME_WAIT: _common.CONN_TIME_WAIT,
    cext.TCPS_CLOSED: _common.CONN_CLOSE,
    cext.TCPS_CLOSE_WAIT: _common.CONN_CLOSE_WAIT,
    cext.TCPS_LAST_ACK: _common.CONN_LAST_ACK,
    cext.TCPS_LISTEN: _common.CONN_LISTEN,
    cext.TCPS_CLOSING: _common.CONN_CLOSING,
    cext.PSUTIL_CONN_NONE: _common.CONN_NONE,
}

PROC_STATUSES = {
    cext.SIDL: _common.STATUS_IDLE,
    cext.SRUN: _common.STATUS_RUNNING,
    cext.SSLEEP: _common.STATUS_SLEEPING,
    cext.SSTOP: _common.STATUS_STOPPED,
    cext.SZOMB: _common.STATUS_ZOMBIE,
}

scputimes = namedtuple('scputimes', ['user', 'nice', 'system', 'idle'])

svmem = namedtuple(
    'svmem', ['total', 'available', 'percent', 'used', 'free',
              'active', 'inactive', 'wired'])

pmem = namedtuple('pmem', ['rss', 'vms', 'pfaults', 'pageins'])
pfullmem = namedtuple('pfullmem', pmem._fields + ('uss', ))

pmmap_grouped = namedtuple(
    'pmmap_grouped',
    'path rss private swapped dirtied ref_count shadow_depth')

pmmap_ext = namedtuple(
    'pmmap_ext', 'addr perms ' + ' '.join(pmmap_grouped._fields))

# set later from __init__.py
NoSuchProcess = None
ZombieProcess = None
AccessDenied = None
TimeoutExpired = None


# --- functions

def virtual_memory():
    """System virtual memory as a namedtuple."""
    total, active, inactive, wired, free = cext.virtual_mem()
    avail = inactive + free
    used = active + inactive + wired
    percent = usage_percent((total - avail), total, _round=1)
    return svmem(total, avail, percent, used, free,
                 active, inactive, wired)


def swap_memory():
    """Swap system memory as a (total, used, free, sin, sout) tuple."""
    total, used, free, sin, sout = cext.swap_mem()
    percent = usage_percent(used, total, _round=1)
    return _common.sswap(total, used, free, percent, sin, sout)


def cpu_times():
    """Return system CPU times as a namedtuple."""
    user, nice, system, idle = cext.cpu_times()
    return scputimes(user, nice, system, idle)


def per_cpu_times():
    """Return system CPU times as a named tuple"""
    ret = []
    for cpu_t in cext.per_cpu_times():
        user, nice, system, idle = cpu_t
        item = scputimes(user, nice, system, idle)
        ret.append(item)
    return ret


def cpu_count_logical():
    """Return the number of logical CPUs in the system."""
    return cext.cpu_count_logical()


def cpu_count_physical():
    """Return the number of physical CPUs in the system."""
    return cext.cpu_count_phys()


def cpu_stats():
    ctx_switches, interrupts, soft_interrupts, syscalls, traps = \
        cext.cpu_stats()
    return _common.scpustats(
        ctx_switches, interrupts, soft_interrupts, syscalls)


def boot_time():
    """The system boot time expressed in seconds since the epoch."""
    return cext.boot_time()


def disk_partitions(all=False):
    retlist = []
    partitions = cext.disk_partitions()
    for partition in partitions:
        device, mountpoint, fstype, opts = partition
        if device == 'none':
            device = ''
        if not all:
            if not os.path.isabs(device) or not os.path.exists(device):
                continue
        ntuple = _common.sdiskpart(device, mountpoint, fstype, opts)
        retlist.append(ntuple)
    return retlist


def users():
    retlist = []
    rawlist = cext.users()
    for item in rawlist:
        user, tty, hostname, tstamp = item
        if tty == '~':
            continue  # reboot or shutdown
        if not tstamp:
            continue
        nt = _common.suser(user, tty or None, hostname or None, tstamp)
        retlist.append(nt)
    return retlist


def net_connections(kind='inet'):
    # Note: on OSX this will fail with AccessDenied unless
    # the process is owned by root.
    ret = []
    for pid in pids():
        try:
            cons = Process(pid).connections(kind)
        except NoSuchProcess:
            continue
        else:
            if cons:
                for c in cons:
                    c = list(c) + [pid]
                    ret.append(_common.sconn(*c))
    return ret


def net_if_stats():
    """Get NIC stats (isup, duplex, speed, mtu)."""
    names = net_io_counters().keys()
    ret = {}
    for name in names:
        isup, duplex, speed, mtu = cext_posix.net_if_stats(name)
        if hasattr(_common, 'NicDuplex'):
            duplex = _common.NicDuplex(duplex)
        ret[name] = _common.snicstats(isup, duplex, speed, mtu)
    return ret


pids = cext.pids
pid_exists = _psposix.pid_exists
disk_usage = _psposix.disk_usage
net_io_counters = cext.net_io_counters
disk_io_counters = cext.disk_io_counters
net_if_addrs = cext_posix.net_if_addrs


def wrap_exceptions(fun):
    """Decorator which translates bare OSError exceptions into
    NoSuchProcess and AccessDenied.
    """
    @functools.wraps(fun)
    def wrapper(self, *args, **kwargs):
        try:
            return fun(self, *args, **kwargs)
        except OSError as err:
            if err.errno == errno.ESRCH:
                if not pid_exists(self.pid):
                    raise NoSuchProcess(self.pid, self._name)
                else:
                    raise ZombieProcess(self.pid, self._name, self._ppid)
            if err.errno in (errno.EPERM, errno.EACCES):
                raise AccessDenied(self.pid, self._name)
            raise
    return wrapper


class Process(object):
    """Wrapper class around underlying C implementation."""

    __slots__ = ["pid", "_name", "_ppid"]

    def __init__(self, pid):
        self.pid = pid
        self._name = None
        self._ppid = None

    @wrap_exceptions
    def name(self):
        return cext.proc_name(self.pid)

    @wrap_exceptions
    def exe(self):
        return cext.proc_exe(self.pid)

    @wrap_exceptions
    def cmdline(self):
        if not pid_exists(self.pid):
            raise NoSuchProcess(self.pid, self._name)
        return cext.proc_cmdline(self.pid)

    @wrap_exceptions
    def environ(self):
        if not pid_exists(self.pid):
            raise NoSuchProcess(self.pid, self._name)
        return parse_environ_block(cext.proc_environ(self.pid))

    @wrap_exceptions
    def ppid(self):
        return cext.proc_ppid(self.pid)

    @wrap_exceptions
    def cwd(self):
        return cext.proc_cwd(self.pid)

    @wrap_exceptions
    def uids(self):
        real, effective, saved = cext.proc_uids(self.pid)
        return _common.puids(real, effective, saved)

    @wrap_exceptions
    def gids(self):
        real, effective, saved = cext.proc_gids(self.pid)
        return _common.pgids(real, effective, saved)

    @wrap_exceptions
    def terminal(self):
        tty_nr = cext.proc_tty_nr(self.pid)
        tmap = _psposix._get_terminal_map()
        try:
            return tmap[tty_nr]
        except KeyError:
            return None

    @wrap_exceptions
    def memory_info(self):
        rss, vms, pfaults, pageins = cext.proc_memory_info(self.pid)
        return pmem(rss, vms, pfaults, pageins)

    @wrap_exceptions
    def memory_full_info(self):
        basic_mem = self.memory_info()
        uss = cext.proc_memory_uss(self.pid)
        return pfullmem(*basic_mem + (uss, ))

    @wrap_exceptions
    def cpu_times(self):
        user, system = cext.proc_cpu_times(self.pid)
        # Children user/system times are not retrievable (set to 0).
        return _common.pcputimes(user, system, 0, 0)

    @wrap_exceptions
    def create_time(self):
        return cext.proc_create_time(self.pid)

    @wrap_exceptions
    def num_ctx_switches(self):
        return _common.pctxsw(*cext.proc_num_ctx_switches(self.pid))

    @wrap_exceptions
    def num_threads(self):
        return cext.proc_num_threads(self.pid)

    @wrap_exceptions
    def open_files(self):
        if self.pid == 0:
            return []
        files = []
        rawlist = cext.proc_open_files(self.pid)
        for path, fd in rawlist:
            if isfile_strict(path):
                ntuple = _common.popenfile(path, fd)
                files.append(ntuple)
        return files

    @wrap_exceptions
    def connections(self, kind='inet'):
        if kind not in conn_tmap:
            raise ValueError("invalid %r kind argument; choose between %s"
                             % (kind, ', '.join([repr(x) for x in conn_tmap])))
        families, types = conn_tmap[kind]
        rawlist = cext.proc_connections(self.pid, families, types)
        ret = []
        for item in rawlist:
            fd, fam, type, laddr, raddr, status = item
            status = TCP_STATUSES[status]
            fam = sockfam_to_enum(fam)
            type = socktype_to_enum(type)
            nt = _common.pconn(fd, fam, type, laddr, raddr, status)
            ret.append(nt)
        return ret

    @wrap_exceptions
    def num_fds(self):
        if self.pid == 0:
            return 0
        return cext.proc_num_fds(self.pid)

    @wrap_exceptions
    def wait(self, timeout=None):
        try:
            return _psposix.wait_pid(self.pid, timeout)
        except _psposix.TimeoutExpired:
            raise TimeoutExpired(timeout, self.pid, self._name)

    @wrap_exceptions
    def nice_get(self):
        return cext_posix.getpriority(self.pid)

    @wrap_exceptions
    def nice_set(self, value):
        return cext_posix.setpriority(self.pid, value)

    @wrap_exceptions
    def status(self):
        code = cext.proc_status(self.pid)
        # XXX is '?' legit? (we're not supposed to return it anyway)
        return PROC_STATUSES.get(code, '?')

    @wrap_exceptions
    def threads(self):
        rawlist = cext.proc_threads(self.pid)
        retlist = []
        for thread_id, utime, stime in rawlist:
            ntuple = _common.pthread(thread_id, utime, stime)
            retlist.append(ntuple)
        return retlist

    @wrap_exceptions
    def memory_maps(self):
        return cext.proc_memory_maps(self.pid)
