from __future__ import annotations

import codecs
import datetime
import functools
import keyword
import logging
import operator
import os
import os.path
import re
import sys
import warnings
from collections.abc import Iterable, MutableSequence
from io import StringIO
from itertools import zip_longest
from pathlib import Path

logger = logging.getLogger('tatsu')
logger.setLevel(logging.DEBUG)
ch = logging.StreamHandler()
formatter = logging.Formatter('%(message)s')
ch.setFormatter(formatter)
logger.addHandler(ch)


ESCAPE_SEQUENCE_RE = re.compile(
    r"""
    ( \\U........      # 8-digit Unicode escapes
    | \\u....          # 4-digit Unicode escapes
    | \\x..            # 2-digit Unicode escapes
    | \\[0-7]{1,3}     # Octal character escapes
    | \\N\{[^}]+\}     # Unicode characters by name
    | \\[\\'"abfnrtv]  # Single-character escapes
    )""",
    re.UNICODE | re.VERBOSE,
)


def program_name():
    import __main__ as main
    if package := main.__package__:
        return package
    return Path(main.__file__).name


def is_posix():
    return os.name == 'posix'


def _prints(*args, **kwargs):
    with StringIO() as f:
        kwargs['file'] = f
        kwargs['end'] = ''
        print(*args, **kwargs)
        return f.getvalue()


def info(*args, **kwargs):
    logger.info(_prints(*args, **kwargs))


def debug(*args, **kwargs):
    logger.debug(_prints(*args, **kwargs))


def warning(*args, **kwargs):
    logger.warning(_prints(*args, **kwargs))


def error(*args, **kwargs):
    logger.error(_prints(*args, **kwargs))


def identity(*args):
    if len(args) == 1:
        return args[0]
    return args


def is_list(o):
    return type(o) is list


def to_list(o):
    if o is None:
        return []
    elif isinstance(o, list):
        return o
    else:
        return [o]


def is_namedtuple(obj) -> bool:
    return (
        len(type(obj).__bases__) == 1
        and isinstance(obj, tuple)
        and hasattr(obj, '_asdict')
        and hasattr(obj, '_fields')
        and all(isinstance(f, str) for f in getattr(obj, '_fields', ()))
    )


def simplify_list(x):
    if isinstance(x, list) and len(x) == 1:
        return simplify_list(x[0])
    return x


def extend_list(x, n, default=None):
    def _null():
        pass

    default = default or _null

    missing = max(0, 1 + n - len(x))
    x.extend(default() for _ in range(missing))


def contains_sublist(lst, sublst):
    n = len(sublst)
    return any(sublst == lst[i: i + n] for i in range(1 + len(lst) - n))


def join_lists(lists):
    return functools.reduce(operator.iadd, lists, [])


def flatten(o):
    if not isinstance(o, MutableSequence):
        yield o
        return

    for item in o:
        yield from flatten(item)


def compress_seq(seq):
    seen = set()
    result = []
    for x in seq:
        if x not in seen:
            result.append(x)
            seen.add(x)
    return result


def eval_escapes(s):
    """
    Given a string, evaluate escape sequences starting with backslashes as
    they would be evaluated in Python source code. For a list of these
    sequences, see: https://docs.python.org/3/reference/lexical_analysis.html

    This is not the same as decoding the whole string with the 'unicode-escape'
    codec, because that provides no way to handle non-ASCII characters that are
    literally present in the string.
    """
    # by Rob Speer

    def decode_match(match):
        return codecs.decode(match.group(0), 'unicode-escape')

    return ESCAPE_SEQUENCE_RE.sub(decode_match, s)


def isiter(value):
    return isinstance(value, Iterable) and not isinstance(
        value, str | bytes | bytearray,
    )


def trim(text, tabwidth=4):
    """
    Trim text of common, leading whitespace.

    Based on the trim algorithm of PEP 257:
        http://www.python.org/dev/peps/pep-0257/
    """
    if not text:
        return ''
    lines = text.expandtabs(tabwidth).splitlines()
    maxindent = len(text)
    indent = maxindent
    for line in lines[1:]:
        stripped = line.lstrip()
        if stripped:
            indent = min(indent, len(line) - len(stripped))
    trimmed = [lines[0].strip()] + [
        line[indent:].rstrip() for line in lines[1:]
    ]
    i = 0
    while i < len(trimmed) and not trimmed[i]:
        i += 1
    return '\n'.join(trimmed[i:])


def indent(text, indent=1, multiplier=4):
    """Indent the given block of text by indent*4 spaces"""
    if text is None:
        return ''
    text = str(text)
    if indent >= 0:
        sindent = ' ' * multiplier * indent
        text = '\n'.join((sindent + t).rstrip() for t in text.splitlines())
    return text


def format_if(fmt, values):
    return fmt % values if values else ''


def notnone(value, default=None):
    return value if value is not None else default


def timestamp():
    return '.'.join(
        '%2.2d' % t for t in datetime.datetime.utcnow().utctimetuple()[:-2]
    )


def prune_dict(d, predicate):
    """Remove all items x where predicate(x, d[x])"""

    keys = [k for k, v in d.items() if predicate(k, v)]
    for k in keys:
        del d[k]


def safe_name(name):
    if keyword.iskeyword(name):
        return name + '_'
    return name


def chunks(iterable, size, fillvalue=None):
    return zip_longest(*[iter(iterable)] * size, fillvalue=fillvalue)


def generic_main(custom_main, parser_class, name='Unknown'):
    import argparse

    class ListRules(argparse.Action):
        def __call__(self, parser, namespace, values, option_string=None):
            print('Rules:')
            for r in parser_class.rule_list():
                print(r)
            print()
            sys.exit(0)

    argp = argparse.ArgumentParser(description=f'Simple parser for {name}.')
    addarg = argp.add_argument

    addarg(
        '-c',
        '--color',
        help='use color in traces (requires the colorama library)',
        action='store_true',
    )
    addarg(
        '-l',
        '--list',
        action=ListRules,
        nargs=0,
        help='list all rules and exit',
    )
    addarg(
        '-n',
        '--no-nameguard',
        action='store_true',
        dest='no_nameguard',
        help="disable the 'nameguard' feature",
    )
    addarg(
        '-t', '--trace', action='store_true', help='output trace information',
    )
    addarg(
        '-w',
        '--whitespace',
        type=str,
        default=None,
        help='whitespace specification',
    )
    addarg(
        'file',
        metavar='FILE',
        help="the input file to parse or '-' for standard input",
        nargs='?',
        default='-',
    )
    addarg(
        'startrule',
        metavar='STARTRULE',
        nargs='?',
        help='the start rule for parsing',
        default=None,
    )

    args = argp.parse_args()
    try:
        return custom_main(
            args.file,
            start=args.startrule,
            trace=args.trace,
            whitespace=args.whitespace,
            nameguard=not args.no_nameguard,
            colorize=args.color,
        )
    except KeyboardInterrupt:
        pass


# decorator
def deprecated(fun):
    @functools.wraps(fun)
    def wrapper(*args, **kwargs):
        warnings.filterwarnings('default', category=DeprecationWarning)
        msg = 'Call to deprecated function {}.'
        warnings.warn(
            msg.format(fun.__name__), category=DeprecationWarning, stacklevel=2,
        )
        return fun(*args, **kwargs)

    return wrapper


def left_assoc(elements):
    if not elements:
        return ()

    it = iter(elements)
    expre = next(it)
    for e in it:
        op = e
        expre = (op, expre, next(it))
    return expre


def right_assoc(elements):
    if not elements:
        return ()

    def assoc(it):
        left = next(it)
        try:
            op = next(it)
        except StopIteration:
            return left
        else:
            return (op, left, assoc(it))

    return assoc(iter(elements))


try:
    import psutil
except ImportError:

    def memory_use():
        return 0

else:

    def memory_use():
        process = psutil.Process(os.getpid())
        return process.memory_info().rss


def try_read(filename):
    if isinstance(filename, Path):
        filename = str(filename)
    for e in ['utf-16', 'utf-8', 'latin-1', 'cp1252', 'ascii']:
        try:
            with Path(filename).open(encoding=e) as f:
                return f.read()
        except UnicodeError:
            pass
    raise UnicodeDecodeError(f"cannot find the encoding for '{filename}'")


def filelist_from_patterns(patterns, ignore=None, base='.', sizesort=False):
    base = Path(base or '.').expanduser()

    filenames = set()
    for pattern in patterns or []:
        path = base / pattern
        if path.is_file():
            filenames.add(path)
            continue

        if path.is_dir():
            path += '/*'

        parts = path.parts[1:] if path.is_absolute() else path.parts
        joined_pattern = str(Path().joinpath(*parts))
        filenames.update(
            p for p in Path(path.root).glob(joined_pattern) if not p.is_dir()
        )

    filenames = list(filenames)

    def excluded(path):
        if any(path.match(ex) for ex in ignore):
            return True

        return any(
            any(Path(part).match(ex) for ex in ignore) for part in path.parts
        )

    if ignore:
        filenames = [path for path in filenames if not excluded(path)]
    if sizesort:
        filenames.sort(key=lambda f: f.stat().st_size)

    return filenames


def short_relative_path(path, base='.'):
    path = Path(path)
    base = Path(base)
    common = Path(os.path.commonpath([base.resolve(), path.resolve()]))

    if common == path.root:
        return path
    elif common == Path.home():
        up = Path('~')
    elif common == base:
        up = Path()
    else:
        n = len(base.parts) - len(common.parts)
        up = Path('../' * n)

    rel = str(up / path.resolve().relative_to(common))
    if len(rel) < len(str(path)):
        return rel
    else:
        return str(path)