# Copyright 2014 Open Source Robotics Foundation, Inc.
#
# 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 argparse
import os
import re
import sys
from multiprocessing import cpu_count

from .common import wide_log
from .execution import job_server


def add_context_args(parser):
    """Add common workspace and profile args to an argparse parser.

    :param parser: The python argparse parser object (or subparser)
    :type parser: ArgumentParser
    """

    add = parser.add_argument
    add_workspace_arg(parser)
    add('--profile', default=None,
        help='The name of a config profile to use (default: active profile)')


def add_workspace_arg(parser):
    """Add common workspace arg to an argparse parser.

    :param parser: The python argparse parser object (or subparser)
    :type parser: ArgumentParser
    """

    add = parser.add_argument
    add('--workspace', '-w', default=None,
        help='The path to the catkin_tools workspace or a directory contained within it (default: ".")')


def add_cmake_and_make_and_catkin_make_args(parser):
    """Add common make and cmake args to an argparse parser.

    :param parser: The python argparse parser object (or subparser)
    :type parser: ArgumentParser
    """

    add = parser.add_argument
    add('-j', '--jobs', default=None, type=int,
        help='Maximum number of build jobs to be distributed across active packages. (default is cpu count)')
    add('-p', '--parallel-packages', metavar='PACKAGE_JOBS', dest='parallel_jobs', default=None, type=int,
        help='Maximum number of packages allowed to be built in parallel (default is cpu count)')
    add('-l', '--load-average', default=None, type=float,
        help='Maximum load average before no new build jobs are scheduled')
    # Deprecated flags kept for compatibility
    add('--parallel-jobs', '--parallel', action='store_true', dest='parallel_jobs', help=argparse.SUPPRESS)

    add = parser.add_mutually_exclusive_group().add_argument
    add('--jobserver', dest='use_internal_make_jobserver', default=None, action='store_true',
        help='Use the internal GNU Make job server which will limit the number '
             'of Make jobs across all active packages.')
    add('--no-jobserver', dest='use_internal_make_jobserver', default=None, action='store_false',
        help='Disable the internal GNU Make job server, and use an external one (like distcc, for example).')

    add = parser.add_mutually_exclusive_group().add_argument
    add('--env-cache', dest='use_env_cache', default=None, action='store_true',
        help='Re-use cached environment variables when re-sourcing a resultspace that has been '
             'loaded at a different stage in the task.')
    add('--no-env-cache', dest='use_env_cache', default=None, action='store_false',
        help='Don\'t cache environment variables when re-sourcing the same resultspace.')

    add = parser.add_mutually_exclusive_group().add_argument
    add('--cmake-args', metavar='ARG', dest='cmake_args', nargs='+', required=False, type=str, default=None,
        help='Arbitrary arguments which are passed to CMake. '
             'It collects all of following arguments until a "--" is read.')
    add('--no-cmake-args', dest='cmake_args', action='store_const', const=[], default=None,
        help='Pass no additional arguments to CMake.')

    add = parser.add_mutually_exclusive_group().add_argument
    add('--make-args', metavar='ARG', dest='make_args', nargs='+', required=False, type=str, default=None,
        help='Arbitrary arguments which are passed to make. '
             'It collects all of following arguments until a "--" is read.')
    add('--no-make-args', dest='make_args', action='store_const', const=[], default=None,
        help='Pass no additional arguments to make (does not affect --catkin-make-args).')

    add = parser.add_mutually_exclusive_group().add_argument
    add('--catkin-make-args', metavar='ARG', dest='catkin_make_args',
        nargs='+', required=False, type=str, default=None,
        help='Arbitrary arguments which are passed to make but only for catkin packages. '
             'It collects all of following arguments until a "--" is read.')
    add('--no-catkin-make-args', dest='catkin_make_args', action='store_const', const=[], default=None,
        help='Pass no additional arguments to make for catkin packages (does not affect --make-args).')


def split_arguments(args, splitter_name=None, splitter_index=None):
    """Split list of args into (other, split_args, other) between splitter_name/index and `--`

    :param args: list of all arguments
    :type args: list of str
    :param splitter_name: optional argument used to split out specific args
    :type splitter_name: str
    :param splitter_index: specific index at which to split
    :type splitter_index: int

    :returns: tuple (other, split_args)
    """

    if splitter_index is None:
        if splitter_name not in args:
            return args, []
        splitter_index = args.index(splitter_name)

    start_index = splitter_index + 1
    end_index = args.index('--', start_index) if '--' in args[start_index:] else None

    if end_index:
        return (
            args[0:splitter_index],
            args[start_index:end_index],
            args[(end_index + 1):]
        )
    else:
        return (
            args[0:splitter_index],
            args[start_index:],
            []
        )


def _extract_cmake_and_make_arguments(args, extract_catkin_make):
    """Extract arguments which are meant to be passed to CMake and GNU Make
    through the catkin_tools command line interface.

    :param args: system arguments from which special arguments need to be extracted
    :type args: list
    :returns: tuple of separate args, cmake_args, make args, and catkin make args
    :rtype: tuple
    """

    cmake_args = []
    make_args = []
    catkin_make_args = []

    arg_types = {}

    if '--no-cmake-args' not in args:
        arg_types['--cmake-args'] = cmake_args
    if '--no-make-args' not in args:
        arg_types['--make-args'] = make_args
    if '--no-catkin_make_args' not in args and extract_catkin_make:
        arg_types['--catkin-make-args'] = catkin_make_args

    # Get the splitter indexes for each type (multiples allowed) starting at the end
    ordered_splitters = reversed([
        (i, t)
        for i, t in enumerate(args)
        if t in arg_types
    ])
    # Extract explicit specific args
    head_args = args
    tail_args = []
    for index, name in ordered_splitters:
        # Update whole args list, get specific args
        head_args, specific, tail = split_arguments(head_args, splitter_index=index)
        tail_args.extend(tail)
        arg_types[name][0:0] = specific

    args = head_args + tail_args

    # classify -D* and -G* arguments as cmake specific arguments
    if '--cmake-args' in arg_types:
        implicit_cmake_args = [a for a in args if a.startswith('-D') or a.startswith('-G')]
        args = [a for a in args if a not in implicit_cmake_args]
        cmake_args = implicit_cmake_args + cmake_args

    if '--no-cmake-args' not in args and len(cmake_args) == 0:
        cmake_args = None
    if '--no-make-args' not in args and len(make_args) == 0:
        make_args = None
    if '--no-catkin-make-args' not in args and len(catkin_make_args) == 0 and extract_catkin_make:
        catkin_make_args = None

    return args, cmake_args, make_args, catkin_make_args


def extract_cmake_and_make_and_catkin_make_arguments(args):
    """Extracts cmake, make, and catkin specific make arguments from given system arguments

    :param args: system arguments from which special arguments need to be extracted
    :type args: list
    :returns: tuple of separate args, cmake_args, make args, and catkin make args
    :rtype: tuple
    """
    return _extract_cmake_and_make_arguments(args, extract_catkin_make=True)


def extract_cmake_and_make_arguments(args):
    """Extracts cmake and make arguments from the given system arguments

    :param args: system arguments from which special arguments need to be extracted
    :type args: list
    :returns: tuple of separate args, cmake_args, and make_args
    :rtype: tuple
    """
    args, cmake_args, make_args, _ = _extract_cmake_and_make_arguments(args, extract_catkin_make=False)
    return args, cmake_args, make_args


def extract_jobs_flags_values(mflags):
    """Gets the values of the make jobs flags

    :param mflags: string of space separated make arguments
    :type mflags: str
    :returns: dictionary mapping jobs flags to jobs flags values
    :rtype: dict
    """
    jobs_dict = {'jobs': None, 'load-average': None}

    # These regular expressions use (?P<name>...) for named capture groups
    # (^|\s) and (?=$|\s) make sure that the flag is surrounded by whitespace

    regex = r'(^|\s)(-j\s*|--jobs(=|\s+))(?P<jobs>\d*)(?=$|\s)'
    for m in re.finditer(regex, mflags):
        if m.group('jobs'):
            jobs_dict['jobs'] = int(m.group('jobs'))

    regex = r'(^|\s)(-l\s*|--load-average(=|\s+))(?P<load>\d*\.?\d*)(?=$|\s)'
    for m in re.finditer(regex, mflags):
        if m.group('load'):
            jobs_dict['load-average'] = float(m.group('load'))

    return jobs_dict


def extract_jobs_flags(mflags):
    """Extracts make job flags from a list of other make flags, i.e. -j8 -l8

    :param mflags: string of space separated make arguments
    :type mflags: str
    :returns: list of make jobs flags
    :rtype: list
    """
    if not mflags:
        return None

    # Each line matches a flag type, i.e. -j, -l, --jobs, --load-average
    # (?:^|\s) and (?=$|\s) make sure that the flag is surrounded by whitespace
    # (?:...) is just a group that will not be captured, this is necessary because the whole flag should be captured
    # The upper two expressions are simple, they just match the flag, optional whitespace and an optional number
    # The bottom two expressions are more complicated because the long flag may be # followed by '=' and a number,
    # whitespace and a number or nothing
    regex = r'(?:^|\s)(-j\s*\d*)(?=$|\s)|' + \
            r'(?:^|\s)(-l\s*\d*\.?\d*)(?=$|\s)|' + \
            r'(?:^|\s)(--jobs(?:(?:=|\s+)\d+)?)(?=$|\s)|' + \
            r'(?:^|\s)(--load-average(?:(?:=|\s+)\d*\.?\d+)?)(?=$|\s)'

    filtered_flags = []
    for match in re.findall(regex, mflags):
        filtered_flags.extend([m.strip() for m in match if m])

    return filtered_flags or None


def handle_make_arguments(
        input_make_args,
        force_single_threaded_when_running_tests=False):
    """Special handling for make arguments.

    If force_single_threaded_when_running_tests is True, jobs flags are
    replaced with -j1, because tests cannot handle parallelization.

    If no job flags are present and there are none in the MAKEFLAGS environment
    variable, then make flags are set to the cpu_count, e.g. -j4 -l4.

    :param input_make_args: list of make arguments to be handled
    :type input_make_args: list
    :param force_single_threaded_when_running_tests: self explanatory
    :type force_single_threaded_when_running_tests: bool
    :returns: copied list of make arguments, potentially with some modifications
    :rtype: list
    """
    make_args = list(input_make_args)

    # Get the values for the jobs flags which may be in the make args
    jobs_dict = extract_jobs_flags_values(' '.join(make_args))
    jobs_args = extract_jobs_flags(' '.join(make_args))
    if jobs_args:
        # Remove jobs flags from cli args if they're present
        make_args = re.sub(' '.join(jobs_args), '', ' '.join(make_args)).split()

    if force_single_threaded_when_running_tests:
        # force single threaded execution when running test since rostest does not support multiple parallel runs
        run_tests = [a for a in make_args if a.startswith('run_tests')]
        if run_tests:
            wide_log('Forcing "-j1" for running unit tests.')
            jobs_dict['jobs'] = 1

    if job_server.gnu_make_enabled():
        make_args.extend(job_server.gnu_make_args())
    else:
        if 'jobs' in jobs_dict:
            make_args.append('-j{0}'.format(jobs_dict['jobs']))
        if 'load-average' in jobs_dict:
            make_args.append('-l{0}'.format(jobs_dict['load-average']))

    return make_args


def configure_make_args(make_args, jobs_args, use_internal_make_jobserver):
    """Initialize the internal GNU Make jobserver or configure it as a pass-through

    :param make_args: arguments to be passed to GNU Make
    :type make_args: list
    :param jobs_args: job arguments overriding make flags
    :type jobs_args: list
    :param use_internal_make_jobserver: if true, use the internal jobserver
    :type make_args: bool
    :rtype: tuple (final make_args, using makeflags, using cliflags, using jobserver)
    """

    # Configure default jobs options: use all CPUs in each package
    try:
        # NOTE: this will yield greater than 100% CPU utilization
        n_cpus = cpu_count()
        jobs_flags = {
            'jobs': n_cpus,
            'load-average': n_cpus + 1}
    except NotImplementedError:
        # If the number of cores cannot be determined, limit to one job
        jobs_flags = {
            'jobs': 1,
            'load-average': 1}

    # Get MAKEFLAGS from environment
    makeflags_jobs_flags = extract_jobs_flags(os.environ.get('MAKEFLAGS', ''))
    using_makeflags_jobs_flags = makeflags_jobs_flags is not None
    if using_makeflags_jobs_flags:
        makeflags_jobs_flags_dict = extract_jobs_flags_values(' '.join(makeflags_jobs_flags))
        jobs_flags.update(makeflags_jobs_flags_dict)

    # Extract make jobs flags (these override MAKEFLAGS)
    cli_jobs_flags = jobs_args
    using_cli_flags = len(cli_jobs_flags) > 0
    if cli_jobs_flags:
        jobs_flags.update(extract_jobs_flags_values(' '.join(cli_jobs_flags)))
        # Remove jobs flags from cli args if they're present
        make_args = re.sub(' '.join(cli_jobs_flags), '', ' '.join(make_args)).split()

    # Instantiate the jobserver
    job_server.initialize(
        max_jobs=jobs_flags.get('jobs', None),
        max_load=jobs_flags.get('load-average', None),
        gnu_make_enabled=use_internal_make_jobserver)

    # If the jobserver is supported
    if job_server.gnu_make_enabled():
        jobs_args = []
    else:
        jobs_args = cli_jobs_flags

    return make_args + jobs_args, using_makeflags_jobs_flags, using_cli_flags, job_server.gnu_make_enabled()


def argument_preprocessor(args):
    """Perform processing of argument patterns which are not captured by
    argparse, before being passed to argparse

    :param args: system arguments from which special arguments need to be extracted
    :type args: list
    :returns: a tuple containing a list of the arguments which can be handled
    by argparse and a dict of the extra arguments which this function has
    extracted
    :rtype: tuple
    """
    # CMake/make pass-through flags collect dashed options. They require special
    # handling or argparse will complain about unrecognized options.
    # NOTE: http://bugs.python.org/issue9334
    args = sys.argv[1:] if args is None else args
    extract_make_args = extract_cmake_and_make_and_catkin_make_arguments
    args, cmake_args, make_args, catkin_make_args = extract_make_args(args)

    # Extract make jobs flags (these override MAKEFLAGS later on)
    jobs_args = extract_jobs_flags(' '.join(args))
    if jobs_args:
        # Remove jobs flags from cli args if they're present
        args = [arg for arg in args if arg not in jobs_args]
    elif make_args is not None:
        jobs_args = extract_jobs_flags(' '.join(make_args))
        if jobs_args:
            # Remove jobs flags from cli args if they're present
            make_args = [arg for arg in make_args if arg not in jobs_args]

    extras = {
        'cmake_args': cmake_args,
        'make_args': make_args,
        'jobs_args': jobs_args,
        'catkin_make_args': catkin_make_args,
    }

    return args, extras
