# 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.

"""Windows platform implementation."""

import contextlib
import errno
import functools
import os
import signal
import sys
import time
from collections import namedtuple

from . import _common
from ._common import ENCODING
from ._common import ENCODING_ERRS
from ._common import AccessDenied
from ._common import NoSuchProcess
from ._common import TimeoutExpired
from ._common import conn_tmap
from ._common import conn_to_ntuple
from ._common import debug
from ._common import isfile_strict
from ._common import memoize
from ._common import memoize_when_activated
from ._common import parse_environ_block
from ._common import usage_percent
from ._compat import PY3
from ._compat import long
from ._compat import lru_cache
from ._compat import range
from ._compat import unicode
from ._psutil_windows import ABOVE_NORMAL_PRIORITY_CLASS
from ._psutil_windows import BELOW_NORMAL_PRIORITY_CLASS
from ._psutil_windows import HIGH_PRIORITY_CLASS
from ._psutil_windows import IDLE_PRIORITY_CLASS
from ._psutil_windows import NORMAL_PRIORITY_CLASS
from ._psutil_windows import REALTIME_PRIORITY_CLASS


try:
    from . import _psutil_windows as cext
except ImportError as err:
    if str(err).lower().startswith("dll load failed") and \
            sys.getwindowsversion()[0] < 6:
        # We may get here if:
        # 1) we are on an old Windows version
        # 2) psutil was installed via pip + wheel
        # See: https://github.com/giampaolo/psutil/issues/811
        msg = "this Windows version is too old (< Windows Vista); "
        msg += "psutil 3.4.2 is the latest version which supports Windows "
        msg += "2000, XP and 2003 server"
        raise RuntimeError(msg)
    else:
        raise

if sys.version_info >= (3, 4):
    import enum
else:
    enum = None

# process priority constants, import from __init__.py:
# http://msdn.microsoft.com/en-us/library/ms686219(v=vs.85).aspx
__extra__all__ = [
    "win_service_iter", "win_service_get",
    # Process priority
    "ABOVE_NORMAL_PRIORITY_CLASS", "BELOW_NORMAL_PRIORITY_CLASS",
    "HIGH_PRIORITY_CLASS", "IDLE_PRIORITY_CLASS", "NORMAL_PRIORITY_CLASS",
    "REALTIME_PRIORITY_CLASS",
    # IO priority
    "IOPRIO_VERYLOW", "IOPRIO_LOW", "IOPRIO_NORMAL", "IOPRIO_HIGH",
    # others
    "CONN_DELETE_TCB", "AF_LINK",
]


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

CONN_DELETE_TCB = "DELETE_TCB"
ERROR_PARTIAL_COPY = 299
PYPY = '__pypy__' in sys.builtin_module_names

if enum is None:
    AF_LINK = -1
else:
    AddressFamily = enum.IntEnum('AddressFamily', {'AF_LINK': -1})
    AF_LINK = AddressFamily.AF_LINK

TCP_STATUSES = {
    cext.MIB_TCP_STATE_ESTAB: _common.CONN_ESTABLISHED,
    cext.MIB_TCP_STATE_SYN_SENT: _common.CONN_SYN_SENT,
    cext.MIB_TCP_STATE_SYN_RCVD: _common.CONN_SYN_RECV,
    cext.MIB_TCP_STATE_FIN_WAIT1: _common.CONN_FIN_WAIT1,
    cext.MIB_TCP_STATE_FIN_WAIT2: _common.CONN_FIN_WAIT2,
    cext.MIB_TCP_STATE_TIME_WAIT: _common.CONN_TIME_WAIT,
    cext.MIB_TCP_STATE_CLOSED: _common.CONN_CLOSE,
    cext.MIB_TCP_STATE_CLOSE_WAIT: _common.CONN_CLOSE_WAIT,
    cext.MIB_TCP_STATE_LAST_ACK: _common.CONN_LAST_ACK,
    cext.MIB_TCP_STATE_LISTEN: _common.CONN_LISTEN,
    cext.MIB_TCP_STATE_CLOSING: _common.CONN_CLOSING,
    cext.MIB_TCP_STATE_DELETE_TCB: CONN_DELETE_TCB,
    cext.PSUTIL_CONN_NONE: _common.CONN_NONE,
}

if enum is not None:
    class Priority(enum.IntEnum):
        ABOVE_NORMAL_PRIORITY_CLASS = ABOVE_NORMAL_PRIORITY_CLASS
        BELOW_NORMAL_PRIORITY_CLASS = BELOW_NORMAL_PRIORITY_CLASS
        HIGH_PRIORITY_CLASS = HIGH_PRIORITY_CLASS
        IDLE_PRIORITY_CLASS = IDLE_PRIORITY_CLASS
        NORMAL_PRIORITY_CLASS = NORMAL_PRIORITY_CLASS
        REALTIME_PRIORITY_CLASS = REALTIME_PRIORITY_CLASS

    globals().update(Priority.__members__)

if enum is None:
    IOPRIO_VERYLOW = 0
    IOPRIO_LOW = 1
    IOPRIO_NORMAL = 2
    IOPRIO_HIGH = 3
else:
    class IOPriority(enum.IntEnum):
        IOPRIO_VERYLOW = 0
        IOPRIO_LOW = 1
        IOPRIO_NORMAL = 2
        IOPRIO_HIGH = 3
    globals().update(IOPriority.__members__)

pinfo_map = dict(
    num_handles=0,
    ctx_switches=1,
    user_time=2,
    kernel_time=3,
    create_time=4,
    num_threads=5,
    io_rcount=6,
    io_wcount=7,
    io_rbytes=8,
    io_wbytes=9,
    io_count_others=10,
    io_bytes_others=11,
    num_page_faults=12,
    peak_wset=13,
    wset=14,
    peak_paged_pool=15,
    paged_pool=16,
    peak_non_paged_pool=17,
    non_paged_pool=18,
    pagefile=19,
    peak_pagefile=20,
    mem_private=21,
)


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


# psutil.cpu_times()
scputimes = namedtuple('scputimes',
                       ['user', 'system', 'idle', 'interrupt', 'dpc'])
# psutil.virtual_memory()
svmem = namedtuple('svmem', ['total', 'available', 'percent', 'used', 'free'])
# psutil.Process.memory_info()
pmem = namedtuple(
    'pmem', ['rss', 'vms',
             'num_page_faults', 'peak_wset', 'wset', 'peak_paged_pool',
             'paged_pool', 'peak_nonpaged_pool', 'nonpaged_pool',
             'pagefile', 'peak_pagefile', 'private'])
# psutil.Process.memory_full_info()
pfullmem = namedtuple('pfullmem', pmem._fields + ('uss', ))
# psutil.Process.memory_maps(grouped=True)
pmmap_grouped = namedtuple('pmmap_grouped', ['path', 'rss'])
# psutil.Process.memory_maps(grouped=False)
pmmap_ext = namedtuple(
    'pmmap_ext', 'addr perms ' + ' '.join(pmmap_grouped._fields))
# psutil.Process.io_counters()
pio = namedtuple('pio', ['read_count', 'write_count',
                         'read_bytes', 'write_bytes',
                         'other_count', 'other_bytes'])


# =====================================================================
# --- utils
# =====================================================================


@lru_cache(maxsize=512)
def convert_dos_path(s):
    r"""Convert paths using native DOS format like:
        "\Device\HarddiskVolume1\Windows\systemew\file.txt"
    into:
        "C:\Windows\systemew\file.txt"
    """
    rawdrive = '\\'.join(s.split('\\')[:3])
    driveletter = cext.QueryDosDevice(rawdrive)
    remainder = s[len(rawdrive):]
    return os.path.join(driveletter, remainder)


def py2_strencode(s):
    """Encode a unicode string to a byte string by using the default fs
    encoding + "replace" error handler.
    """
    if PY3:
        return s
    else:
        if isinstance(s, str):
            return s
        else:
            return s.encode(ENCODING, ENCODING_ERRS)


@memoize
def getpagesize():
    return cext.getpagesize()


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


def virtual_memory():
    """System virtual memory as a namedtuple."""
    mem = cext.virtual_mem()
    totphys, availphys, totsys, availsys = mem
    #
    total = totphys
    avail = availphys
    free = availphys
    used = total - avail
    percent = usage_percent((total - avail), total, round_=1)
    return svmem(total, avail, percent, used, free)


def swap_memory():
    """Swap system memory as a (total, used, free, sin, sout) tuple."""
    mem = cext.virtual_mem()

    total_phys = mem[0]
    free_phys = mem[1]
    total_system = mem[2]
    free_system = mem[3]

    # system memory (commit total/limit) is the sum of physical and swap
    # thus physical memory values need to be substracted to get swap values
    total = total_system - total_phys
    free = min(total, free_system - free_phys)
    used = total - free
    percent = usage_percent(used, total, round_=1)
    return _common.sswap(total, used, free, percent, 0, 0)


# =====================================================================
# --- disk
# =====================================================================


disk_io_counters = cext.disk_io_counters


def disk_usage(path):
    """Return disk usage associated with path."""
    if PY3 and isinstance(path, bytes):
        # XXX: do we want to use "strict"? Probably yes, in order
        # to fail immediately. After all we are accepting input here...
        path = path.decode(ENCODING, errors="strict")
    total, free = cext.disk_usage(path)
    used = total - free
    percent = usage_percent(used, total, round_=1)
    return _common.sdiskusage(total, used, free, percent)


def disk_partitions(all):
    """Return disk partitions."""
    rawlist = cext.disk_partitions(all)
    return [_common.sdiskpart(*x) for x in rawlist]


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


def cpu_times():
    """Return system CPU times as a named tuple."""
    user, system, idle = cext.cpu_times()
    # Internally, GetSystemTimes() is used, and it doesn't return
    # interrupt and dpc times. cext.per_cpu_times() does, so we
    # rely on it to get those only.
    percpu_summed = scputimes(*[sum(n) for n in zip(*cext.per_cpu_times())])
    return scputimes(user, system, idle,
                     percpu_summed.interrupt, percpu_summed.dpc)


def per_cpu_times():
    """Return system per-CPU times as a list of named tuples."""
    ret = []
    for user, system, idle, interrupt, dpc in cext.per_cpu_times():
        item = scputimes(user, system, idle, interrupt, dpc)
        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_cores():
    """Return the number of CPU cores in the system."""
    return cext.cpu_count_cores()


def cpu_stats():
    """Return CPU statistics."""
    ctx_switches, interrupts, dpcs, syscalls = cext.cpu_stats()
    soft_interrupts = 0
    return _common.scpustats(ctx_switches, interrupts, soft_interrupts,
                             syscalls)


def cpu_freq():
    """Return CPU frequency.
    On Windows per-cpu frequency is not supported.
    """
    curr, max_ = cext.cpu_freq()
    min_ = 0.0
    return [_common.scpufreq(float(curr), min_, float(max_))]


_loadavg_inititialized = False


def getloadavg():
    """Return the number of processes in the system run queue averaged
    over the last 1, 5, and 15 minutes respectively as a tuple"""
    global _loadavg_inititialized