from __future__ import annotations

import re
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from collections.abc import Sequence, Set

# https://en.cppreference.com/w/c/keyword
_keywords: Set[str] = frozenset({
    'auto',
    'break',
    'case', 'char', 'const', 'continue',
    'default', 'do', 'double',
    'else', 'enum', 'extern',
    'float', 'for',
    'goto',
    'if', 'inline', 'int',
    'long',
    'register', 'restrict', 'return',
    'short', 'signed', 'sizeof', 'static', 'struct', 'switch',
    'typedef',
    'union', 'unsigned',
    'void', 'volatile',
    'while',
    '_Alignas', '_Alignof', '_Atomic',
    '_Bool',
    '_Complex',
    '_Decimal32', '_Decimal64', '_Decimal128',
    '_Generic',
    '_Imaginary',
    '_Noreturn',
    '_Static_assert',
    '_Thread_local',
})  # fmt: skip
# These are only keyword'y when the corresponding headers are included.
# They are used as default value for c_extra_keywords.
_macro_keywords: Set[str] = frozenset({
    'alignas',
    'alignof',
    'bool',
    'complex',
    'imaginary',
    'noreturn',
    'static_assert',
    'thread_local',
})

# these are ordered by precedence
_expression_bin_ops: Sequence[tuple[str, ...]] = [
    ('||', 'or'),
    ('&&', 'and'),
    ('|', 'bitor'),
    ('^', 'xor'),
    ('&', 'bitand'),
    ('==', '!=', 'not_eq'),
    ('<=', '>=', '<', '>'),
    ('<<', '>>'),
    ('+', '-'),
    ('*', '/', '%'),
    ('.*', '->*'),
]
_expression_unary_ops: Sequence[str] = [
    '++',
    '--',
    '*',
    '&',
    '+',
    '-',
    '!',
    'not',
    '~',
    'compl',
]
_expression_assignment_ops: Sequence[str] = [
    '=',
    '*=',
    '/=',
    '%=',
    '+=',
    '-=',
    '>>=',
    '<<=',
    '&=',
    'and_eq',
    '^=',
    'xor_eq',
    '|=',
    'or_eq',
]

_max_id = 1
_id_prefix: Sequence[str] = ('', 'c.', 'Cv2.')
# Ids are used in lookup keys which are used across pickled files,
# so when _max_id changes, make sure to update the ENV_VERSION.

_string_re = re.compile(
    r"[LuU8]?('([^'\\]*(?:\\.[^'\\]*)*)'"
    r'|"([^"\\]*(?:\\.[^"\\]*)*)")',
    re.DOTALL,
)

# bool, complex, and imaginary are macro "keywords", so they are handled separately
_simple_type_specifiers_re = re.compile(
    r"""
    \b(
    void|_Bool
    |signed|unsigned
    |short|long
    |char
    |int
    |__uint128|__int128
    |__int(8|16|32|64|128)  # extension
    |float|double
    |_Decimal(32|64|128)
    |_Complex|_Imaginary
    |__float80|_Float64x|__float128|_Float128|__ibm128  # extension
    |__fp16  # extension
    |_Sat|_Fract|fract|_Accum|accum  # extension
    )\b
    """,
    re.VERBOSE,
)