#!/usr/bin/env python3

import argparse
import contextlib
import logging
import os
import subprocess
import sys
import tempfile
import time
from collections.abc import Iterator
from pathlib import Path


logging.basicConfig(
    level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s"
)
logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)

ROOT_PATH = Path(__file__).absolute().parent.parent.parent
SETUP_PY_PATH = ROOT_PATH / "setup.py"
REQUIREMENTS_PATH = ROOT_PATH / "requirements.txt"


def run_cmd(
    cmd: list[str], capture_output: bool = False
) -> subprocess.CompletedProcess[bytes]:
    logger.debug("Running command: %s", " ".join(cmd))
    return subprocess.run(
        cmd,
        # Give the parent environment to the subprocess
        env={**os.environ},
        capture_output=capture_output,
        check=True,
    )


def interpreter_version(interpreter: str) -> str:
    version_string = (
        run_cmd([interpreter, "--version"], capture_output=True)
        .stdout.decode("utf-8")
        .strip()
    )
    return str(version_string.split(" ")[1])


@contextlib.contextmanager
def venv(interpreter: str) -> Iterator[str]:
    # Should this use EnvBuilder? Probably, maybe a good todo in the future
    python_version = interpreter_version(interpreter)
    with tempfile.TemporaryDirectory(
        suffix=f"_pytorch_builder_{python_version}"
    ) as tmp_dir:
        logger.info(
            "Creating virtual environment (Python %s) at %s",
            python_version,
            tmp_dir,
        )
        run_cmd([interpreter, "-m", "venv", tmp_dir])
        yield str(Path(tmp_dir) / "bin" / "python3")


class Builder:
    # The python interpreter that we should be using
    interpreter: str

    def __init__(self, interpreter: str) -> None:
        self.interpreter = interpreter

    def setup_py(self, cmd_args: list[str]) -> bool:
        return (
            run_cmd([self.interpreter, str(SETUP_PY_PATH), *cmd_args]).returncode == 0
        )

    def bdist_wheel(self, destination: str) -> bool:
        logger.info("Running bdist_wheel -d %s", destination)
        return self.setup_py(["bdist_wheel", "-d", destination])

    def clean(self) -> bool:
        logger.info("Running clean")
        return self.setup_py(["clean"])

    def install_requirements(self) -> None:
        logger.info("Installing requirements")
        run_cmd(
            [self.interpreter, "-m", "pip", "install", "-r", str(REQUIREMENTS_PATH)]
        )


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "-p",
        "--python",
        action="append",
        type=str,
        help=(
            "Python interpreters to build packages for, can be set multiple times,"
            " should ideally be full paths, (default: %(default)s)"
        ),
    )
    parser.add_argument(
        "-d",
        "--destination",
        default="dist/",
        type=str,
        help="Destination to put the compiled binaries",
    )
    return parser.parse_args()


def main() -> None:
    args = parse_args()
    pythons = args.python or [sys.executable]
    build_times: dict[str, float] = dict()

    if len(pythons) > 1 and args.destination == "dist/":
        logger.warning(
            "dest is 'dist/' while multiple python versions specified, output will be overwritten"
        )

    for interpreter in pythons:
        with venv(interpreter) as venv_interpreter:
            builder = Builder(venv_interpreter)
            # clean actually requires setuptools so we need to ensure we
            # install requirements before
            builder.install_requirements()
            builder.clean()

            start_time = time.time()

            builder.bdist_wheel(args.destination)

            end_time = time.time()

            build_times[interpreter_version(venv_interpreter)] = end_time - start_time
    for version, build_time in build_times.items():
        logger.info("Build time (%s): %fs", version, build_time)


if __name__ == "__main__":
    main()