from __future__ import annotations

import time
from dataclasses import dataclass, field
from functools import wraps
from inspect import iscoroutinefunction
from typing import Any, Callable, ClassVar, TypeVar

from hibiapi.utils.log import logger

Callable_T = TypeVar("Callable_T", bound=Callable)


class TimerError(Exception):
    """A custom exception used to report errors in use of Timer class"""


@dataclass
class Timer:
    """Time your code using a class, context manager, or decorator"""

    timers: ClassVar[dict[str, float]] = dict()
    name: str | None = None
    text: str = "Elapsed time: {:0.3f} seconds"
    logger_func: Callable[[str], None] | None = print
    _start_time: float | None = field(default=None, init=False, repr=False)

    def __post_init__(self) -> None:
        """Initialization: add timer to dict of timers"""
        if self.name:
            self.timers.setdefault(self.name, 0)

    def start(self) -> None:
        """Start a new timer"""
        if self._start_time is not None:
            raise TimerError("Timer is running. Use .stop() to stop it")

        self._start_time = time.perf_counter()

    def stop(self) -> float:
        """Stop the timer, and report the elapsed time"""
        if self._start_time is None:
            raise TimerError("Timer is not running. Use .start() to start it")

        # Calculate elapsed time
        elapsed_time = time.perf_counter() - self._start_time
        self._start_time = None

        # Report elapsed time
        if self.logger_func:
            self.logger_func(self.text.format(elapsed_time * 1000))
        if self.name:
            self.timers[self.name] += elapsed_time

        return elapsed_time

    def __enter__(self) -> Timer:
        """Start a new timer as a context manager"""
        self.start()
        return self

    def __exit__(self, *exc_info: Any) -> None:
        """Stop the context manager timer"""
        self.stop()

    def _recreate_cm(self) -> Timer:
        return self.__class__(self.name, self.text, self.logger_func)

    def __call__(self, function: Callable_T) -> Callable_T:
        @wraps(function)
        async def async_wrapper(*args: Any, **kwargs: Any):
            self.text = (
                f"<g>Async</g> function <y>{function.__qualname__}</y> "
                "cost <e>{:.3f}ms</e>"
            )

            with self._recreate_cm():
                return await function(*args, **kwargs)

        @wraps(function)
        def sync_wrapper(*args: Any, **kwargs: Any):
            self.text = (
                f"<g>sync</g> function <y>{function.__qualname__}</y> "
                "cost <e>{:.3f}ms</e>"
            )

            with self._recreate_cm():
                return function(*args, **kwargs)

        return (
            async_wrapper if iscoroutinefunction(function) else sync_wrapper
        )  # type:ignore


TimeIt = Timer(logger_func=logger.trace)