#!/usr/bin/env python3

import argparse
import datetime
import importlib.util
from itertools import chain
import logging
import os
import os.path
import sys
import tempfile
import time

# If the cvise modules cannot be found
# add the known install location to the path
destdir = os.getenv('DESTDIR', '')
if importlib.util.find_spec('cvise') is None:
    sys.path.append('@CMAKE_INSTALL_FULL_DATADIR@')
    sys.path.append(destdir + '@CMAKE_INSTALL_FULL_DATADIR@')

import chardet  # noqa: E402
from cvise.cvise import CVise  # noqa: E402
from cvise.passes.abstract import AbstractPass  # noqa: E402
from cvise.utils import misc, statistics, testing  # noqa: E402
from cvise.utils.error import CViseError  # noqa: E402
from cvise.utils.error import MissingPassGroupsError  # noqa: E402
from cvise.utils.externalprograms import find_external_programs  # noqa: E402
import psutil  # noqa: E402


class DeltaTimeFormatter(logging.Formatter):
    def format(self, record):  # noqa: A003
        record.delta = str(datetime.timedelta(seconds=int(record.relativeCreated / 1000)))
        # pad with one more zero
        if record.delta[1] == ':':
            record.delta = '0' + record.delta
        return super().format(record)


script_path = os.path.dirname(os.path.realpath(__file__))


def get_share_dir():
    # Test all known locations for the cvise directory
    share_dirs = [
        os.path.join('@CMAKE_INSTALL_FULL_DATADIR@', '@cvise_PACKAGE@'),
        destdir + os.path.join('@CMAKE_INSTALL_FULL_DATADIR@', '@cvise_PACKAGE@'),
        os.path.join(script_path, 'cvise'),
    ]

    for d in share_dirs:
        if os.path.isdir(d):
            return d

    raise CViseError('Cannot find cvise module directory!')


def get_pass_group_path(name):
    return os.path.join(get_share_dir(), 'pass_groups', name + '.json')


def get_available_pass_groups():
    pass_group_dir = os.path.join(get_share_dir(), 'pass_groups')

    if not os.path.isdir(pass_group_dir):
        raise MissingPassGroupsError()

    group_names = []

    for entry in os.listdir(pass_group_dir):
        path = os.path.join(pass_group_dir, entry)

        if not os.path.isfile(path):
            continue

        try:
            pass_group_dict = CVise.load_pass_group_file(path)
            CVise.parse_pass_group_dict(pass_group_dict, set(), None, None, None, None, None, None)
        except MissingPassGroupsError:
            logging.warning(f'Skipping file {path}. Not valid pass group.')
        else:
            (name, _) = os.path.splitext(entry)
            group_names.append(name)

    return group_names


def get_available_cores():
    try:
        # try to detect only physical cores, ignore HyperThreading
        # in order to speed up parallel execution
        core_count = psutil.cpu_count(logical=False)
        if not core_count:
            core_count = psutil.cpu_count(logical=True)
        # respect affinity
        try:
            affinity = len(psutil.Process().cpu_affinity())
            assert affinity >= 1
        except AttributeError:
            return core_count

        if core_count:
            core_count = min(core_count, affinity)
        else:
            core_count = affinity
        return core_count
    except NotImplementedError:
        return 1


EPILOG_TEXT = f"""
available shortcuts:
  S - skip execution of the current pass
  D - toggle --print-diff option

For bug reporting instructions, please use:
{CVise.Info.PACKAGE_URL}
"""

if __name__ == '__main__':
    parser = argparse.ArgumentParser(
        description='C-Vise',
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog=EPILOG_TEXT,
    )
    parser.add_argument(
        '--n',
        '-n',
        type=int,
        default=get_available_cores(),
        help='Number of cores to use; C-Vise tries to automatically pick a good setting but its choice may be too low or high for your situation',
    )
    parser.add_argument(
        '--tidy',
        action='store_true',
        help='Do not make a backup copy of each file to reduce as file.orig',
    )
    parser.add_argument(
        '--shaddap',
        action='store_true',
        help='Suppress output about non-fatal internal errors',
    )
    parser.add_argument(
        '--die-on-pass-bug',
        action='store_true',
        help='Terminate C-Vise if a pass encounters an otherwise non-fatal problem',
    )
    parser.add_argument(
        '--sllooww',
        action='store_true',
        help='Try harder to reduce, but perhaps take a long time to do so',
    )
    parser.add_argument(
        '--also-interesting',
        metavar='EXIT_CODE',
        type=int,
        help='A process exit code (somewhere in the range 64-113 would be usual) that, when returned by the interestingness test, will cause C-Vise to save a copy of the variant',
    )
    parser.add_argument(
        '--debug',
        action='store_true',
        help='Print debug information (alias for --log-level=DEBUG)',
    )
    parser.add_argument(
        '--log-level',
        type=str,
        choices=['INFO', 'DEBUG', 'WARNING', 'ERROR'],
        default='INFO',
        help='Define the verbosity of the logged events',
    )
    parser.add_argument(
        '--log-file',
        type=str,
        help='Log events into LOG_FILE instead of stderr. New events are appended to the end of the file',
    )
    parser.add_argument(
        '--no-give-up',
        action='store_true',
        help=f"Don't give up on a pass that hasn't made progress for {testing.TestManager.GIVEUP_CONSTANT} iterations",
    )
    parser.add_argument(
        '--print-diff',
        action='store_true',
        help='Show changes made by transformations, for debugging',
    )
    parser.add_argument(
        '--save-temps',
        action='store_true',
        help="Don't delete /tmp/cvise-xxxxxx directories on termination",
    )
    parser.add_argument(
        '--skip-initial-passes',
        action='store_true',
        help='Skip initial passes (useful if input is already partially reduced)',
    )
    parser.add_argument(
        '--skip-interestingness-test-check',
        '-s',
        action='store_true',
        help='Skip initial interestingness test check',
    )
    parser.add_argument(
        '--remove-pass',
        help='Remove all instances of the specified passes from the schedule (comma-separated)',
    )
    parser.add_argument('--start-with-pass', help='Start with the specified pass')
    parser.add_argument(
        '--no-timing',
        action='store_true',
        help='Do not print timestamps about reduction progress',
    )
    parser.add_argument(
        '--timestamp',
        action='store_true',
        help='Print timestamps instead of relative time from a reduction start',
    )
    parser.add_argument(
        '--timeout',
        type=int,
        nargs='?',
        default=300,
        help='Interestingness test timeout in seconds',
    )
    parser.add_argument('--no-cache', action='store_true', help="Don't cache behavior of passes")
    parser.add_argument(
        '--skip-key-off',
        action='store_true',
        help="Disable skipping the rest of the current pass when 's' is pressed",
    )
    parser.add_argument(
        '--max-improvement',
        metavar='BYTES',
        type=int,
        help='Largest improvement in file size from a single transformation that C-Vise should accept (useful only to slow C-Vise down)',
    )
    passes_group = parser.add_mutually_exclusive_group()
    passes_group.add_argument(
        '--pass-group',
        type=str,
        choices=get_available_pass_groups(),
        help='Set of passes used during the reduction',
    )
    passes_group.add_argument('--pass-group-file', type=str, help='JSON file defining a custom pass group')
    parser.add_argument(
        '--clang-delta-std',
        type=str,
        choices=['c++98', 'c++11', 'c++14', 'c++17', 'c++20', 'c++2b'],
        help='Specify clang_delta C++ standard, it can rapidly speed up all clang_delta passes',
    )
    parser.add_argument(
        '--clang-delta-preserve-routine',
        type=str,
        help='Preserve the given function in replace-function-def-with-decl clang delta pass',
    )
    parser.add_argument(
        '--not-c',
        action='store_true',
        help="Don't run passes that are specific to C and C++, use this mode for reducing other languages",
    )
    parser.add_argument(
        '--renaming',
        action='store_true',
        help='Enable all renaming passes (that are disabled by default)',
    )
    parser.add_argument('--list-passes', action='store_true', help='Print all available passes and exit')
    parser.add_argument(
        '--version',
        action='version',
        version=CVise.Info.PACKAGE_STRING
        + (f' ({CVise.Info.GIT_VERSION})' if CVise.Info.GIT_VERSION != 'unknown' else ''),
    )
    parser.add_argument(
        '--commands',
        '-c',
        help='Use shell commands instead of an interestingness test case',
    )
    parser.add_argument('--shell', default='bash', help='Use selected shell for the --commands option')
    parser.add_argument(
        '--to-utf8',
        action='store_true',
        help='Convert any non-UTF-8 encoded input file to UTF-8',
    )
    parser.add_argument(
        '--skip-after-n-transforms',
        type=int,
        help='Skip each pass after N successful transformations',
    )
    parser.add_argument(
        'interestingness_test',
        metavar='INTERESTINGNESS_TEST',
        nargs='?',
        help='Executable to check interestingness of test cases',
    )
    parser.add_argument('test_cases', metavar='TEST_CASE', nargs='+', help='Test cases')
    parser.add_argument(
        '--stopping-threshold',
        default=1.0,
        type=float,
        help='CVise will stop reducing a test case once it has reduced by this fraction of its original size.  Between 0.0 and 1.0.',
    )

    args = parser.parse_args()

    log_config = {}

    log_format = '%(levelname)s %(message)s'
    if not args.no_timing:
        if args.timestamp:
            log_format = '%(asctime)s ' + log_format
        else:
            log_format = '%(delta)s ' + log_format

    if args.debug:
        log_config['level'] = logging.DEBUG
    else:
        log_config['level'] = getattr(logging, args.log_level.upper())

    logging.getLogger().setLevel(log_config['level'])
    formatter = DeltaTimeFormatter(log_format)
    root_logger = logging.getLogger()

    if args.log_file is not None:
        file_handler = logging.FileHandler(args.log_file)
        file_handler.setFormatter(formatter)
        root_logger.addHandler(file_handler)
    else:
        syslog = logging.StreamHandler()
        syslog.setFormatter(formatter)
        root_logger.addHandler(syslog)

    pass_options = set()

    if sys.platform == 'win32':
        pass_options.add(AbstractPass.Option.windows)

    if args.sllooww:
        pass_options.add(AbstractPass.Option.slow)

    if args.pass_group is not None:
        pass_group_file = get_pass_group_path(args.pass_group)
    elif args.pass_group_file is not None:
        pass_group_file = args.pass_group_file
    else:
        pass_group_file = get_pass_group_path('all')

    external_programs = find_external_programs()

    pass_group_dict = CVise.load_pass_group_file(pass_group_file)
    pass_group = CVise.parse_pass_group_dict(
        pass_group_dict,
        pass_options,
        external_programs,
        args.remove_pass,
        args.clang_delta_std,
        args.clang_delta_preserve_routine,
        args.not_c,
        args.renaming,
    )
    if args.list_passes:
        logging.info('Available passes:')
        logging.info('INITIAL PASSES')
        for p in pass_group['first']:
            logging.info(str(p))
        logging.info('MAIN PASSES')
        for p in pass_group['main']:
            logging.info(str(p))
        logging.info('CLEANUP PASSES')
        for p in pass_group['last']:
            logging.info(str(p))
        sys.exit(0)

    pass_statistic = statistics.PassStatistic()

    if args.start_with_pass:
        pass_names = [str(p) for p in chain(*pass_group.values())]
        if args.start_with_pass not in pass_names:
            print(
                f'Cannot find pass called "{args.start_with_pass}". '
                'Please use --list-passes to get a list of available passes.'
            )
            sys.exit(1)

    if not args.interestingness_test and not args.commands:
        print('Either INTERESTINGNESS_TEST or --commands must be used!')
        sys.exit(1)

    # shift interestingness_test if --commands is used
    if args.interestingness_test and args.commands:
        args.test_cases.insert(0, args.interestingness_test)
        args.interestingness_test = None

    if args.to_utf8:
        for test_case in args.test_cases:
            with open(test_case, 'rb') as fd:
                encoding = chardet.detect(fd.read())['encoding']
                if encoding not in ('ascii', 'utf-8'):
                    logging.info(f'Converting {test_case} file ({encoding} encoding) to UTF-8')
                    data = open(test_case, encoding=encoding).read()
                    with open(test_case, 'w') as w:
                        w.write(data)

    script = None
    if args.commands:
        with tempfile.NamedTemporaryFile(mode='w', delete=False, suffix='.sh') as script:
            script.write(f'#!/usr/bin/env {args.shell}\n\n')
            script.write(args.commands + '\n')
        os.chmod(script.name, 0o744)
        logging.info(f'Using temporary interestingness test: {script.name}')
        args.interestingness_test = script.name

    test_manager = testing.TestManager(
        pass_statistic,
        args.interestingness_test,
        args.timeout,
        args.save_temps,
        args.test_cases,
        args.n,
        args.no_cache,
        args.skip_key_off,
        args.shaddap,
        args.die_on_pass_bug,
        args.print_diff,
        args.max_improvement,
        args.no_give_up,
        args.also_interesting,
        args.start_with_pass,
        args.skip_after_n_transforms,
        args.stopping_threshold,
    )

    reducer = CVise(test_manager, args.skip_interestingness_test_check)

    reducer.tidy = args.tidy

    # Track runtime
    time_start = time.monotonic()

    try:
        reducer.reduce(pass_group, skip_initial=args.skip_initial_passes)
    except CViseError as err:
        time_stop = time.monotonic()
        print(err)
    else:
        time_stop = time.monotonic()
        with open(args.log_file, 'a') if args.log_file else sys.stderr as fs:
            fs.write('===< PASS statistics >===\n')
            fs.write(
                '  %-60s %8s %8s %8s %8s %15s\n'
                % (
                    'pass name',
                    'time (s)',
                    'time (%)',
                    'worked',
                    'failed',
                    'total executed',
                )
            )

            for pass_name, pass_data in pass_statistic.sorted_results:
                fs.write(
                    '  %-60s %8.2f %8.2f %8d %8d %15d\n'
                    % (
                        pass_name,
                        pass_data.total_seconds,
                        100.0 * pass_data.total_seconds / (time_stop - time_start),
                        pass_data.worked,
                        pass_data.failed,
                        pass_data.totally_executed,
                    )
                )
            fs.write('\n')

            if not args.no_timing:
                fs.write(f'Runtime: {round(time_stop - time_start)} seconds\n')

            fs.write('Reduced test-cases:\n\n')
            for test_case in sorted(test_manager.test_cases):
                if misc.is_readable_file(test_case):
                    print(f'--- {test_case} ---')
                    with open(test_case) as test_case_file:
                        fs.write(test_case_file.read() + '\n')
            if script:
                os.unlink(script.name)

    logging.shutdown()