import t, c
import mbuddy
import string
from stdint import *


class list[T]:
    """堆上动态列表容器，基于 mbuddy 分配器。

    用法:
        mb: mbuddy.MBuddy = mbuddy.MBuddy(arena, arena_size)
        nums: list[int] = list[int](mb)
        nums.append(42)
        x: int = nums.get(0)
    """
    __data__: t.CVoid | t.CPtr
    __count__: t.CSizeT
    __capacity__: t.CSizeT
    __mbuddy__: mbuddy.MBuddy | t.CPtr
    __iter_index__: t.CSizeT

    def __new__(self, mb: mbuddy.MBuddy | t.CPtr):
        # 堆分配 list[T] 对象 (5 字段 × 8 字节 = 40 字节)
        # 避免栈上分配导致返回后 use-after-free
        buf: t.CVoid | t.CPtr = mb.alloc(40)
        return buf

    def __init__(self, mb: mbuddy.MBuddy | t.CPtr):
        self.__mbuddy__ = mb
        self.__count__ = 0
        self.__capacity__ = 8
        self.__data__ = mb.alloc(self.__capacity__ * T.__sizeof__())
        self.__iter_index__ = 0

    def __len__(self) -> t.CSizeT:
        return self.__count__

    def append(self, item: T):
        if self.__count__ >= self.__capacity__:
            new_cap: t.CSizeT = self.__capacity__ * 2
            new_data: t.CVoid | t.CPtr = self.__mbuddy__.alloc(new_cap * T.__sizeof__())
            if new_data == None:
                return
            string.memcpy(new_data, self.__data__, self.__count__ * T.__sizeof__())
            self.__data__ = new_data
            self.__capacity__ = new_cap
        elem_ptr: T | t.CPtr = t.CVoid(t.CUInt64T(self.__data__) + self.__count__ * T.__sizeof__(), t.CPtr)
        elem_ptr[0] = item
        self.__count__ += 1

    def get(self, index: t.CSizeT) -> T:
        elem_ptr: T | t.CPtr = t.CVoid(t.CUInt64T(self.__data__) + index * T.__sizeof__(), t.CPtr)
        return elem_ptr[0]

    def __getitem__(self, index: t.CSizeT) -> T:
        elem_ptr: T | t.CPtr = t.CVoid(t.CUInt64T(self.__data__) + index * T.__sizeof__(), t.CPtr)
        return elem_ptr[0]

    def set(self, index: t.CSizeT, value: T):
        elem_ptr: T | t.CPtr = t.CVoid(t.CUInt64T(self.__data__) + index * T.__sizeof__(), t.CPtr)
        elem_ptr[0] = value

    def __setitem__(self, index: t.CSizeT, value: T):
        elem_ptr: T | t.CPtr = t.CVoid(t.CUInt64T(self.__data__) + index * T.__sizeof__(), t.CPtr)
        elem_ptr[0] = value

    def pop(self) -> T:
        self.__count__ -= 1
        elem_ptr: T | t.CPtr = t.CVoid(t.CUInt64T(self.__data__) + self.__count__ * T.__sizeof__(), t.CPtr)
        return elem_ptr[0]

    def clear(self):
        self.__count__ = 0

    def __iter__(self):
        self.__iter_index__ = 0
        return self

    def __next__(self) -> T:
        if self.__iter_index__ >= self.__count__:
            raise StopIteration
        idx: t.CSizeT = self.__iter_index__
        self.__iter_index__ = idx + 1
        elem_ptr: T | t.CPtr = t.CVoid(t.CUInt64T(self.__data__) + idx * T.__sizeof__(), t.CPtr)
        return elem_ptr[0]