from __future__ import unicode_literals

import re

__DECIMAL_RE = r'(?:[1-9][0-9]*)|0'
__OCTAL_RE = r'0[0-7]+'
__HEXADECIMAL_RE = r'0[xX][0-9a-fA-F]+'
__ESC_UNICODE_RE = r'u[0-9a-fA-F]{4}'
__ESC_HEX_RE = r'x[0-9a-fA-F]{2}'


# NOTE order is fixed due to regex matching, does not represent any precedence
_punctuations = ['{', '}', '(', ')', '[', ']', '.', ';', ',', '?', ':']
_logical_operator = ['||', '&&']
_unary_operator = ['++', '--', '!', '~', 'delete', 'void', 'typeof']
_relation = ['===', '!==', '==', '!=', '<=', '>=', '<', '>']
_operator = ['|', '^', '&', '>>>', '>>', '<<', '-', '+', '%', '/', '*']
_assign_operator = [op + '=' for op in _operator]
_assign_operator.append('=')

# XXX add support for unicode chars
_NAME_RE = r'[a-zA-Z_$][a-zA-Z_$0-9]*'

# non-escape char also can be escaped, but line continuation and quotes has to be
# XXX unicode and hexadecimal escape sequences should be validated
_SINGLE_QUOTED_RE = r"""'(?:(?:\\'|\n)|[^'\n])*'"""
_DOUBLE_QUOTED_RE = r'''"(?:(?:\\"|\n)|[^"\n])*"'''
_STRING_RE = r'(?:%s)|(?:%s)' % (_SINGLE_QUOTED_RE, _DOUBLE_QUOTED_RE)

_INTEGER_RE = r'(?:%(hex)s)|(?:%(dec)s)|(?:%(oct)s)' % {'hex': __HEXADECIMAL_RE, 'dec': __DECIMAL_RE, 'oct': __OCTAL_RE}
_FLOAT_RE = r'(?:(?:%(dec)s\.[0-9]*)|(?:\.[0-9]+))(?:[eE][+-]?[0-9]+)?' % {'dec': __DECIMAL_RE}

_BOOL_RE = r'true|false'
_NULL_RE = r'null'

# XXX early validation might needed
# r'''/(?!\*)
#     (?:(?:\\(?:[tnvfr0.\\+*?^$\[\]{}()|/]|[0-7]{3}|x[0-9A-Fa-f]{2}|u[0-9A-Fa-f]{4}|c[A-Z]|))|[^/\n])*
#     /(?:(?![gimy]*(?P<flag>[gimy])[gimy]*(?P=flag))[gimy]{0,4}\b|\s|$)'''
_REGEX_FLAGS_RE = r'(?![gimy]*(?P<reflag>[gimy])[gimy]*(?P=reflag))(?P<reflags>[gimy]{0,4}\b)'
_REGEX_RE = r'/(?!\*)(?P<rebody>(?:[^/\n]|(?:\\/))*)/(?:(?:%s)|(?:\s|$))' % _REGEX_FLAGS_RE

_TOKENS = [
    ('null', _NULL_RE),
    ('bool', _BOOL_RE),
    ('id', _NAME_RE),
    ('str', _STRING_RE),
    ('int', _INTEGER_RE),
    ('float', _FLOAT_RE),
    ('regex', _REGEX_RE)
]

COMMENT_RE = r'(?P<comment>/\*(?:(?!\*/)(?:\n|.))*\*/)'
TOKENS_RE = r'|'.join('(?P<%(id)s>%(value)s)' % {'id': name, 'value': value}
                      for name, value in _TOKENS)

PUNCTUATIONS_RE = r'(?P<punc>%s)' % r'|'.join(re.escape(value) for value in _punctuations)
LOGICAL_OPERATORS_RE = r'(?P<lop>%s)' % r'|'.join(re.escape(value) for value in _logical_operator)
UNARY_OPERATORS_RE = r'(?P<uop>%s)' % r'|'.join(re.escape(value) for value in _unary_operator)
RELATIONS_RE = r'(?P<rel>%s)' % r'|'.join(re.escape(value) for value in _relation)
OPERATORS_RE = r'(?P<op>%s)' % r'|'.join(re.escape(value) for value in _operator)
ASSIGN_OPERATORS_RE = r'(?P<aop>%s)' % r'|'.join(re.escape(value) for value in _assign_operator)