# Copyright (c) 2009, Giampaolo Rodola'
# Copyright (c) 2017, Arnon Yaari
# All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""AIX platform implementation."""

import functools
import glob
import os
import re
import subprocess
import sys
from collections import namedtuple

from . import _common
from . import _psposix
from . import _psutil_aix as cext
from . import _psutil_posix as cext_posix
from ._common import NIC_DUPLEX_FULL
from ._common import NIC_DUPLEX_HALF
from ._common import NIC_DUPLEX_UNKNOWN
from ._common import AccessDenied
from ._common import NoSuchProcess
from ._common import ZombieProcess
from ._common import conn_to_ntuple
from ._common import get_procfs_path
from ._common import memoize_when_activated
from ._common import usage_percent
from ._compat import PY3
from ._compat import FileNotFoundError
from ._compat import PermissionError
from ._compat import ProcessLookupError


__extra__all__ = ["PROCFS_PATH"]


# =====================================================================
# --- globals
# =====================================================================


HAS_THREADS = hasattr(cext, "proc_threads")
HAS_NET_IO_COUNTERS = hasattr(cext, "net_io_counters")
HAS_PROC_IO_COUNTERS = hasattr(cext, "proc_io_counters")

PAGE_SIZE = cext_posix.getpagesize()
AF_LINK = cext_posix.AF_LINK

PROC_STATUSES = {
    cext.SIDL: _common.STATUS_IDLE,
    cext.SZOMB: _common.STATUS_ZOMBIE,
    cext.SACTIVE: _common.STATUS_RUNNING,
    cext.SSWAP: _common.STATUS_RUNNING,      # TODO what status is this?
    cext.SSTOP: _common.STATUS_STOPPED,
}

TCP_STATUSES = {
    cext.TCPS_ESTABLISHED: _common.CONN_ESTABLISHED,
    cext.TCPS_SYN_SENT: _common.CONN_SYN_SENT,
    cext.TCPS_SYN_RCVD: _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_info_map = dict(
    ppid=0,
    rss=1,
    vms=2,
    create_time=3,
    nice=4,
    num_threads=5,
    status=6,
    ttynr=7)


# =====================================================================
# --- named tuples
# =====================================================================


# psutil.Process.memory_info()
pmem = namedtuple('pmem', ['rss', 'vms'])
# psutil.Process.memory_full_info()
pfullmem = pmem
# psutil.Process.cpu_times()
scputimes = namedtuple('scputimes', ['user', 'system', 'idle', 'iowait'])
# psutil.virtual_memory()
svmem = namedtuple('svmem', ['total', 'available', 'percent', 'used', 'free'])


# =====================================================================
# --- memory
# =====================================================================


def virtual_memory():
    total, avail, free, pinned, inuse = cext.virtual_mem()
    percent = usage_percent((total - avail), total, round_=1)
    return svmem(total, avail, percent, inuse, free)


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


# =====================================================================
# --- CPU
# =====================================================================


def cpu_times():
    """Return system-wide CPU times as a named tuple"""
    ret = cext.per_cpu_times()
    return scputimes(*[sum(x) for x in zip(*ret)])


def per_cpu_times():
    """Return system per-CPU times as a list of named tuples"""
    ret = cext.per_cpu_times()
    return [scputimes(*x) for x in ret]


def cpu_count_logical():
    """Return the number of logical CPUs in the system."""
    try:
        return os.sysconf("SC_NPROCESSORS_ONLN")
    except ValueError:
        # mimic os.cpu_count() behavior
        return None


def cpu_count_cores():
    cmd = "lsdev -Cc processor"
    p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE)
    stdout, stderr = p.communicate()
    if PY3:
        stdout, stderr = [x.decode(sys.stdout.encoding)
                          for x in (stdout, stderr)]
    if p.returncode != 0:
        raise RuntimeError("%r command error\n%s" % (cmd, stderr))
    processors = stdout.strip().splitlines()
    return len(processors) or None


def cpu_stats():
    """Return various CPU stats as a named tuple."""
    ctx_switches, interrupts, soft_interrupts, syscalls = cext.cpu_stats()
    return _common.scpustats(
        ctx_switches, interrupts, soft_interrupts, syscalls)


# =====================================================================
# --- disks
# =====================================================================


disk_io_counters = cext.disk_io_counters
disk_usage = _psposix.disk_usage


def disk_partitions(all=False):
    """Return system disk partitions."""
    # TODO - the filtering logic should be better checked so that
    # it tries to reflect 'df' as much as possible
    retlist = []
    partitions = cext.disk_partitions()
    for partition in partitions:
        device, mountpoint, fstype, opts = partition
        if device == 'none':
            device = ''
        if not all:
            # Differently from, say, Linux, we don't have a list of
            # common fs types so the best we can do, AFAIK, is to
            # filter by filesystem having a total size > 0.
            if not disk_usage(mountpoint).total:
                continue
        maxfile = maxpath = None  # set later
        ntuple = _common.sdiskpart(device, mountpoint, fstype, opts,
                                   maxfile, maxpath)
        retlist.append(ntuple)
    return retlist


# =====================================================================
# --- network
# =====================================================================


net_if_addrs = cext_posix.net_if_addrs

if HAS_NET_IO_COUNTERS:
    net_io_counters = cext.net_io_counters


def net_connections(kind, _pid=-1):
    """Return socket connections.  If pid == -1 return system-wide
    connections (as opposed to connections opened by one process only).
    """
    cmap = _common.conn_tmap
    if kind not in cmap:
        raise ValueError("invalid %r kind argument; choose between %s"
                         % (kind, ', '.join([repr(x) for x in cmap])))
    families, types = _common.conn_tmap[kind]
    rawlist = cext.net_connections(_pid)
    ret = []
    for item in rawlist:
        fd, fam, type_, laddr, raddr, status, pid = item
        if fam not in families:
            continue
        if type_ not in types:
            continue
        nt = conn_to_ntuple(fd, fam, type_, laddr, raddr, status,
                            TCP_STATUSES, pid=pid if _pid == -1 else None)
        ret.append(nt)
    return ret


def net_if_stats():
    """Get NIC stats (isup, duplex, speed, mtu)."""
    duplex_map = {"Full": NIC_DUPLEX_FULL,
                  "Half": NIC_DUPLEX_HALF}
    names = set([x[0] for x in net_if_addrs()])
    ret = {}
    for name in names:
        mtu = cext_posix.net_if_mtu(name)
        flags = cext_posix.net_if_flags(name)

        # try to get speed and duplex
        # TODO: rewrite this in C (entstat forks, so use truss -f to follow.
        # looks like it is using an undocumented ioctl?)
        duplex = ""
        speed = 0
        p = subprocess.Popen(["/usr/bin/entstat", "-d", name],
                             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        stdout, stderr = p.communicate()
        if PY3:
            stdout, stderr = [x.decode(sys.stdout.encoding)
                              for x in (stdout, stderr)]
        if p.returncode == 0:
            re_result = re.search(
                r"Running: (\d+) Mbps.*?(\w+) Duplex", stdout)
            if re_result is not None:
                speed = int(re_result.group(1))
                duplex = re_result.group(2)

        output_flags = ','.join(flags)
        isup = 'running' in flags
        duplex = duplex_map.get(duplex, NIC_DUPLEX_UNKNOWN)
        ret[name] = _common.snicstats(isup, duplex, speed, mtu, output_flags)
    return ret


# =====================================================================
# --- other system functions
# =====================================================================


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


def users():
    """Return currently connected users as a list of namedtuples."""
    retlist = []
    rawlist = cext.users()
    localhost = (':0.0', ':0')
    for item in rawlist:
        user, tty, hostname, tstamp, user_process, pid = item
        # note: the underlying C function includes entries about
        # system boot, run level and others.  We might want
        # to use them in the future.
        if not user_process:
            continue
        if hostname in localhost:
            hostname = 'localhost'
        nt = _common.suser(user, tty, hostname, tstamp, pid)
        retlist.append(nt)
    return retlist


# =====================================================================
# --- processes
# =====================================================================


def pids():
    """Returns a list of PIDs currently running on the system."""
    return [int(x) for x in os.listdir(get_procfs_path()) if x.isdigit()]


def pid_exists(pid):
    """Check for the existence of a unix pid."""
    return os.path.exists(os.path.join(get_procfs_path(), str(pid), "psinfo"))


def wrap_exceptions(fun):
    """Call callable into a try/except clause and translate ENOENT,
    EACCES and EPERM in NoSuchProcess or AccessDenied exceptions.
    """
    @functools.wraps(fun)
    def wrapper(self, *args, **kwargs):
        try:
            return fun(self, *args, **kwargs)
        except (FileNotFoundError, ProcessLookupError):
            # ENOENT (no such file or directory) gets raised on open().
            # ESRCH (no such process) can get raised on read() if
            # process is gone in meantime.
            if not pid_exists(self.pid):
                raise NoSuchProcess(self.pid, self._name)
            else:
                raise ZombieProcess(self.pid, self._name, self._ppid)
        except PermissionError:
            raise AccessDenied(self.pid, self._name)
    return wrapper


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

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

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

    def oneshot_enter(self):
        self._proc_basic_info.cache_activate(self)