# Copyright 2016 Cisco Systems, Inc.  All rights reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

import errno
import fcntl
from functools import wraps
import json
from log import LOG
from math import isnan
import os
import re
import signal
import subprocess


class TimeoutError(Exception):
    pass


def timeout(seconds=10, error_message=os.strerror(errno.ETIME)):
    def decorator(func):
        def _handle_timeout(signum, frame):
            raise TimeoutError(error_message)

        def wrapper(*args, **kwargs):
            signal.signal(signal.SIGALRM, _handle_timeout)
            signal.alarm(seconds)
            try:
                result = func(*args, **kwargs)
            finally:
                signal.alarm(0)
            return result

        return wraps(func)(wrapper)

    return decorator


def save_json_result(result, json_file, std_json_path, service_chain, service_chain_count,
                     flow_count, frame_sizes):
    """Save results in json format file."""
    filepaths = []
    if json_file:
        filepaths.append(json_file)
    if std_json_path:
        name_parts = [service_chain, str(service_chain_count), str(flow_count)] + list(frame_sizes)
        filename = '-'.join(name_parts) + '.json'
        filepaths.append(os.path.join(std_json_path, filename))

    if filepaths:
        for file_path in filepaths:
            LOG.info('Saving results in json file: ' + file_path + "...")
            with open(file_path, 'w') as jfp:
                json.dump(result,
                          jfp,
                          indent=4,
                          sort_keys=True,
                          separators=(',', ': '),
                          default=lambda obj: obj.to_json())


def byteify(data, ignore_dicts=False):
    # if this is a unicode string, return its string representation
    if isinstance(data, unicode):
        return data.encode('utf-8')
    # if this is a list of values, return list of byteified values
    if isinstance(data, list):
        return [byteify(item, ignore_dicts=ignore_dicts) for item in data]
    # if this is a dictionary, return dictionary of byteified keys and values
    # but only if we haven't already byteified it
    if isinstance(data, dict) and not ignore_dicts:
        return {byteify(key, ignore_dicts=ignore_dicts): byteify(value, ignore_dicts=ignore_dicts)
                for key, value in data.iteritems()}
    # if it's anything else, return it in its original form
    return data


def dict_to_json_dict(record):
    return json.loads(json.dumps(record, default=lambda obj: obj.to_json()))


def get_intel_pci(nic_ports):
    """Returns the first two PCI addresses of sorted PCI list for Intel NIC (i40e, ixgbe)"""
    hx = r'[0-9a-fA-F]'
    regex = r'{hx}{{4}}:({hx}{{2}}:{hx}{{2}}\.{hx}{{1}}).*(drv={driver}|.*unused=.*{driver})'

    try:
        trex_base_dir = '/opt/trex'
        contents = os.listdir(trex_base_dir)
        trex_dir = os.path.join(trex_base_dir, contents[0])
        process = subprocess.Popen(['python', 'dpdk_setup_ports.py', '-s'],
                                   cwd=trex_dir,
                                   stdout=subprocess.PIPE,
                                   stderr=subprocess.PIPE)
        devices, _ = process.communicate()
    except Exception:
        devices = ''

    for driver in ['i40e', 'ixgbe']:
        matches = re.findall(regex.format(hx=hx, driver=driver), devices)
        if matches:
            pcis = map(lambda x: x[0], matches)
            if len(pcis) < 2:
                continue
            pcis.sort()
            return [pcis[port_index] for port_index in nic_ports]

    return []


multiplier_map = {
    'K': 1000,
    'M': 1000000,
    'G': 1000000000
}


def parse_flow_count(flow_count):
    flow_count = str(flow_count)
    input_fc = flow_count
    multiplier = 1
    if flow_count[-1].upper() in multiplier_map:
        multiplier = multiplier_map[flow_count[-1].upper()]
        flow_count = flow_count[:-1]

    try:
        flow_count = int(flow_count)
    except ValueError:
        raise Exception("Unknown flow count format '{}'".format(input_fc))

    return flow_count * multiplier


def cast_integer(value):
    return int(value) if not isnan(value) else value


class RunLock(object):
    """
    Attempts to lock file and run current instance of NFVbench as the first,
    otherwise raises exception.
    """

    def __init__(self, path='/tmp/nfvbench.lock'):
        self._path = path
        self._fd = None

    def __enter__(self):
        try:
            self._fd = os.open(self._path, os.O_CREAT)
            fcntl.flock(self._fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
        except (OSError, IOError):
            raise Exception('Other NFVbench process is running. Please wait')

    def __exit__(self, *args):
        fcntl.flock(self._fd, fcntl.LOCK_UN)
        os.close(self._fd)
        self._fd = None

        # Try to remove the lock file, but don't try too hard because it is unnecessary.
        try:
            os.unlink(self._path)
        except (OSError, IOError):
            pass