from __future__ import annotations

import functools
import os
import sys
import warnings
from pathlib import Path
from types import ModuleType
from typing import Callable, TYPE_CHECKING


if TYPE_CHECKING:
    from torch._inductor.runtime.triton_heuristics import CachingAutotuner


def _reload_triton_kernel_in_subproc(
    reload_module: Callable[[], ModuleType], kernel_name: str
) -> CachingAutotuner:
    return _module_to_triton_kernel(reload_module(), kernel_name)


def _module_to_triton_kernel(mod: ModuleType, kernel_name: str) -> CachingAutotuner:
    kernel = getattr(mod, kernel_name)
    kernel._reload_in_subproc = functools.partial(
        _reload_triton_kernel_in_subproc,
        mod._reload_in_subproc,
        kernel_name,
    )
    return kernel


def _reload_python_module_in_subproc(key: str, path: str) -> ModuleType:
    codecache = sys.modules.get("torch._inductor.codecache")
    if codecache:
        return codecache.PyCodeCache.load_by_key_path(key, path)
    else:
        return _reload_python_module(key, path)


def _reload_python_module(key: str, path: str) -> ModuleType:
    with open(path) as f:
        try:
            code = compile(f.read(), path, "exec", dont_inherit=True)
        except Exception as e:
            raise RuntimeError(
                f"Failed to import {path}\n{type(e).__name__}: {e}"
            ) from None
        mod = ModuleType(f"{__name__}.{key}")
        mod.__file__ = path
        mod.key = key  # type: ignore[attr-defined]
        exec(code, mod.__dict__, mod.__dict__)
        sys.modules[mod.__name__] = mod
        return mod


@functools.lru_cache(None)
def _set_triton_ptxas_path() -> None:
    if os.environ.get("TRITON_PTXAS_PATH") is not None:
        return
    ptxas = Path(__file__).absolute().parents[1] / "bin" / "ptxas"
    if not ptxas.exists():
        return
    if ptxas.is_file() and os.access(ptxas, os.X_OK):
        os.environ["TRITON_PTXAS_PATH"] = str(ptxas)
    else:
        warnings.warn(f"{ptxas} exists but is not an executable")


def _worker_compile_triton(
    load_kernel: Callable[[], CachingAutotuner], extra_env: dict[str, str]
) -> None:
    _set_triton_ptxas_path()
    os.environ.update(extra_env)
    load_kernel().precompile(warm_cache_only=True)