from dataclasses import dataclass
import re
from typing import Any, Optional
import logging

from isledecomp.cvdump.symbols import SymbolsEntry
from isledecomp.types import SymbolType
from isledecomp.compare import Compare as IsleCompare
from isledecomp.compare.db import MatchInfo

logger = logging.getLogger(__file__)


@dataclass
class CppStackOrRegisterSymbol:
    name: str
    data_type: str


@dataclass
class CppStackSymbol(CppStackOrRegisterSymbol):
    stack_offset: int
    """Should have a value iff `symbol_type=='S_BPREL32'."""


@dataclass
class CppRegisterSymbol(CppStackOrRegisterSymbol):
    register: str
    """Should have a value iff `symbol_type=='S_REGISTER'.` Should always be set/converted to lowercase."""


@dataclass
class FunctionSignature:
    call_type: str
    arglist: list[str]
    return_type: str
    class_type: Optional[str]
    stack_symbols: list[CppStackOrRegisterSymbol]


class PdbFunctionExtractor:
    """
    Extracts all information on a given function from the parsed PDB
    and prepares the data for the import in Ghidra.
    """

    def __init__(self, compare: IsleCompare):
        self.compare = compare

    scalar_type_regex = re.compile(r"t_(?P<typename>\w+)(?:\((?P<type_id>\d+)\))?")

    _call_type_map = {
        "ThisCall": "__thiscall",
        "C Near": "__thiscall",
        "STD Near": "__stdcall",
    }

    def _get_cvdump_type(self, type_name: Optional[str]) -> Optional[dict[str, Any]]:
        return (
            None
            if type_name is None
            else self.compare.cv.types.keys.get(type_name.lower())
        )

    def get_func_signature(self, fn: SymbolsEntry) -> Optional[FunctionSignature]:
        function_type_str = fn.func_type
        if function_type_str == "T_NOTYPE(0000)":
            logger.debug(
                "Skipping a NOTYPE (synthetic or template + synthetic): %s", fn.name
            )
            return None

        # get corresponding function type

        function_type = self.compare.cv.types.keys.get(function_type_str.lower())
        if function_type is None:
            logger.error(
                "Could not find function type %s for function %s", fn.func_type, fn.name
            )
            return None

        class_type = function_type.get("class_type")

        arg_list_type = self._get_cvdump_type(function_type.get("arg_list_type"))
        assert arg_list_type is not None
        arg_list_pdb_types = arg_list_type.get("args", [])
        assert arg_list_type["argcount"] == len(arg_list_pdb_types)

        stack_symbols: list[CppStackOrRegisterSymbol] = []
        for symbol in fn.stack_symbols:
            if symbol.symbol_type == "S_REGISTER":
                stack_symbols.append(
                    CppRegisterSymbol(
                        symbol.name,
                        symbol.data_type,
                        symbol.location,
                    )
                )
            elif symbol.symbol_type == "S_BPREL32":
                stack_offset = int(symbol.location[1:-1], 16)
                stack_symbols.append(
                    CppStackSymbol(
                        symbol.name,
                        symbol.data_type,
                        stack_offset,
                    )
                )

        call_type = self._call_type_map[function_type["call_type"]]

        return FunctionSignature(
            call_type=call_type,
            arglist=arg_list_pdb_types,
            return_type=function_type["return_type"],
            class_type=class_type,
            stack_symbols=stack_symbols,
        )

    def get_function_list(self) -> list[tuple[MatchInfo, FunctionSignature]]:
        handled = (
            self.handle_matched_function(match)
            for match in self.compare.get_functions()
        )
        return [signature for signature in handled if signature is not None]

    def handle_matched_function(
        self, match_info: MatchInfo
    ) -> Optional[tuple[MatchInfo, FunctionSignature]]:
        assert match_info.orig_addr is not None
        match_options = self.compare.db.get_match_options(match_info.orig_addr)
        assert match_options is not None
        if match_options.get("skip", False) or match_options.get("stub", False):
            return None

        function_data = next(
            (
                y
                for y in self.compare.cvdump_analysis.nodes
                if y.addr == match_info.recomp_addr
            ),
            None,
        )
        if not function_data:
            logger.error(
                "Did not find function in nodes, skipping: %s", match_info.name
            )
            return None

        function_symbol = function_data.symbol_entry
        if function_symbol is None:
            logger.debug(
                "Could not find function symbol (likely a PUBLICS entry): %s",
                match_info.name,
            )
            return None

        function_signature = self.get_func_signature(function_symbol)
        if function_signature is None:
            return None

        return match_info, function_signature