# encoding: utf-8

import ast
import re
from collections import defaultdict
from dataclasses import dataclass, field
from typing import Dict, List, Optional, Set

from .cxxparser import (
    CXXFileParser,
    CXXParseResult,
    Class,
    LiteralVariable,
    Method,
    Variable,
)
from .type import array_base, base_types, is_array_type


"""
42          - dec
0b101010    - bin
052         - oct
0xaa        - hex
0Xaa        - hex
1234u       - suffix
1234ull     - suffix
145'920     - with single quotes
1.0         - double
1.0f        - float

ignore:
5.9604644775390625e-8F16
'123123'

unsuportted:
1e10        - science
1E10        - science
1e+10
1e-10
1E-10
1E+10

"""
cpp_digit_re = re.compile(
    "(0b[01]+|0[0-7]+|0[Xx][0-9a-fA-F]+|[0-9']*[0-9]+)((ull)|(ULL)|(llu)|(LLU)|(ul)|(UL)|(ll)|(LL)|[UuLl])?$"
)

cpp_digit_suffix_types = {
    "u": "unsigned int",
    "l": "long",
    "ul": "usngined long",
    "ll": "long long",
    "ull": "unsigned long long",
    "llu": "unsigned long long",
    "f": "float",
}
cpp_digit_suffix_types.update(
    {k.upper(): v for k, v in cpp_digit_suffix_types.items()}
)


@dataclass
class PreprocessedMethod(Method):
    has_overload: bool = False


@dataclass
class PreprocessedClass(Class):
    functions: Dict[str, List[PreprocessedMethod]] = field(
        default_factory=(lambda: defaultdict(list))
    )
    need_wrap: bool = False  # if need_wrap is true, wrap this to dict
    is_pure_virtual: bool = False  # generator will not assign python constructor for pure virtual


class PreProcessorResult:
    def __init__(self):
        super().__init__()
        self.dict_classes: Set[str] = set()
        self.const_macros: Dict[str, Variable] = {}
        self.classes: Dict[str, PreprocessedClass] = {}


class PreProcessor:
    def __init__(self, parse_result: CXXParseResult):
        self.parser_result = parse_result

    def process(self) -> PreProcessorResult:
        result = PreProcessorResult()

        # all pod struct to dict
        # todo: generator doesn't support dict class currently
        # result.dict_classes = self._find_dict_classes()

        # all error written macros to constant
        result.const_macros = self._pre_process_constant_macros()

        result.classes = self._pre_process_classes(result.dict_classes)
        return result

    def _pre_process_classes(self, dict_classes: Set[str]):
        classes: Dict[str, PreprocessedClass] = {}
        for c in self.parser_result.classes.values():
            gc = PreprocessedClass(**c.__dict__)
            gc.functions = {
                name: [PreprocessedMethod(**m.__dict__) for m in ms]
                for name, ms in gc.functions.items()
            }
            if c.is_polymorphic:
                gc.need_wrap = True
            classes[gc.name] = gc
        for c in classes.values():
            for ms in c.functions.values():

                # check overload
                if len(ms) >= 2:
                    for m in ms:
                        m.has_overload = True

                # check pure virtual
                for m in ms:
                    if m.is_pure_virtual:
                        c.is_pure_virtual = True

        return classes

    def _pre_process_constant_macros(self):
        macros = {}
        for name, definition in self.parser_result.macros.items():
            value = PreProcessor._try_convert_to_constant(definition)
            if value is not None:
                value.name = name
                macros[name] = value
        return macros

    def _find_dict_classes(self):
        dict_classes = set()
        for c in self.parser_result.classes.values():
            if self._can_convert_to_dict(c):
                dict_classes.add(c.name)
        return dict_classes

    def _to_basic_type_combination(self, t: str):
        try:
            return self._to_basic_type_combination(
                self.parser_result.typedefs[t]
            )
        except KeyError:
            return t

    def _is_basic_type(self, t: str):
        basic_combination = self._to_basic_type_combination(t)

        # just a basic type, such as int, char, short, double etc.
        if basic_combination in base_types:
            return True

        # array of basic type, such as int[], char[]
        if (
            is_array_type(basic_combination)
            and array_base(basic_combination) in base_types
        ):
            return True

        print(basic_combination)
        return False

    def _can_convert_to_dict(self, c: Class):
        # first: no functions
        if c.functions:
            return False

        # second: all variables are basic
        for v in c.variables.values():
            if not self._is_basic_type(v.type):
                return False

        return True

    @staticmethod
    def _try_parse_cpp_digit_literal(literal: str):
        m = cpp_digit_re.match(literal)
        if m:
            digit = m.group(1)
            suffix = m.group(2)
            val = ast.literal_eval(digit.replace("'", ""))
            t = "int"
            if suffix:
                t = cpp_digit_suffix_types[suffix]
            return LiteralVariable(
                name="", type=t, default=val, literal=literal
            )
        return None

    @staticmethod
    def _try_convert_to_constant(definition: str) -> Optional[Variable]:
        definition = definition.strip()
        try:
            if definition:
                var = PreProcessor._try_parse_cpp_digit_literal(definition)
                if var:
                    return var
                val = None
                if definition.startswith('"') and definition.endswith('"'):
                    val = ast.literal_eval(definition)
                    return LiteralVariable(
                        name="",
                        type="const char *",
                        default=val,
                        literal=definition,
                    )
                if definition.startswith("'") and definition.endswith("'"):
                    val = CXXFileParser.character_literal_to_int(
                        definition[1:-1]
                    )
                    t = "unsigned int"
                    valid = True
                    if len(definition) >= 6:
                        t = "unsigned long long"
                        valid = False
                    return LiteralVariable(
                        name="",
                        type=t,
                        default=val,
                        literal=definition,
                        literal_valid=valid,
                    )
        except SyntaxError:
            pass
        return None