import importlib.util
import pathlib
from aoc import exceptions
from typing import Any, Callable
import time


_ANSI_ITALIC: str = "\x1b[3m"
_ANSI_BOLD: str = "\x1b[1m"
_ANSI_RESET: str = "\x1b[0m"


def _pprint_ns(ns: int) -> str:
    if ns >= 1_000_000_000:
        s = ns / 1_000_000_000
        return f"{s:.2f}s"
    elif ns >= 1_000_000:
        ms = ns / 1_000_000
        return f"{ms:.2f}ms"
    elif ns >= 1_000:
        us = ns / 1_000
        return f"{us:.2f}µs"
    else:
        return f"{ns}ns"


def _pprint_result(
    year: int, day: int, part: int | str, result: Any, duration_ns: int
) -> None:
    part = f"{_ANSI_BOLD}{year}/{day:02}/{part}{_ANSI_RESET}"

    if result is None:
        solved = f"{_ANSI_ITALIC}(unsolved){_ANSI_RESET}"
        print(f"{part}: {solved}")
    else:
        if isinstance(result, list) or isinstance(result, tuple):
            result = "\n".join(str(r) for r in result)
        solved = f"{_ANSI_ITALIC}(elapsed: {_pprint_ns(duration_ns)}){_ANSI_RESET}"
        print(f"{part}: {solved}\n{result}")


def _run_func(
    f: Callable[[str], Any], year: int, day: int, part: int | str, input_data: str
) -> None:
    t_1 = time.perf_counter_ns()
    result = f(input_data)
    t_2 = time.perf_counter_ns()

    _pprint_result(year, day, part, result, t_2 - t_1)


def run_day(year: int, day: int, input_data: str, path_base: pathlib.Path) -> None:
    try:
        module_path = path_base / f"year_{year}" / f"day_{day:02}.py"
        spec = importlib.util.spec_from_file_location(
            f"year_{year}.day_{day:02}", module_path
        )
        if spec is None or spec.loader is None:
            raise exceptions.AocError()
        solution_module = importlib.util.module_from_spec(spec)
        spec.loader.exec_module(solution_module)
    except (ModuleNotFoundError, exceptions.AocError) as e:
        raise exceptions.AocError(
            f"solution module for {year}/{day:02} not found: run 'python main.py create --year {year} {day}'"
        ) from e

    p_1 = getattr(solution_module, "part_1", None)
    p_2 = getattr(solution_module, "part_2", None)

    if p_1 is not None and p_2 is not None:
        _run_func(p_1, year, day, 1, input_data)
        _run_func(p_2, year, day, 2, input_data)
        return

    p_1_2 = getattr(solution_module, "part_1_2", None)

    if p_1_2 is not None:
        _run_func(p_1_2, year, day, "1&2", input_data)
        return

    raise exceptions.AocError(
        f"{year}/{day:02} must define part_1 and part_2 or part_1_2"
    )