from __future__ import annotations

import contextlib
import os
import re
import subprocess
import sys
import sysconfig

from pathlib import Path
from subprocess import CalledProcessError
from typing import TYPE_CHECKING
from typing import Any

from virtualenv.seed.wheels.embed import get_embed_wheel

from poetry.utils._compat import decode
from poetry.utils._compat import encode
from poetry.utils.env.exceptions import EnvCommandError
from poetry.utils.env.site_packages import SitePackages
from poetry.utils.helpers import get_real_windows_path


if TYPE_CHECKING:
    from packaging.tags import Tag
    from poetry.core.constraints.version import Version
    from poetry.core.version.markers import BaseMarker
    from virtualenv.seed.wheels.util import Wheel

    from poetry.utils.env.generic_env import GenericEnv


class Env:
    """
    An abstract Python environment.
    """

    def __init__(self, path: Path, base: Path | None = None) -> None:
        self._is_windows = sys.platform == "win32"
        self._is_mingw = sysconfig.get_platform().startswith("mingw")
        self._is_conda = bool(os.environ.get("CONDA_DEFAULT_ENV"))

        if self._is_windows:
            path = get_real_windows_path(path)
            base = get_real_windows_path(base) if base else None

        bin_dir = "bin" if not self._is_windows or self._is_mingw else "Scripts"
        self._path = path
        self._bin_dir = self._path / bin_dir

        self._executable = "python"
        self._pip_executable = "pip"

        self.find_executables()

        self._base = base or path

        self._marker_env: dict[str, Any] | None = None
        self._pip_version: Version | None = None
        self._site_packages: SitePackages | None = None
        self._paths: dict[str, str] | None = None
        self._supported_tags: list[Tag] | None = None
        self._purelib: Path | None = None
        self._platlib: Path | None = None
        self._script_dirs: list[Path] | None = None

        self._embedded_pip_path: Path | None = None

    @property
    def path(self) -> Path:
        return self._path

    @property
    def base(self) -> Path:
        return self._base

    @property
    def version_info(self) -> tuple[int, int, int, str, int]:
        version_info: tuple[int, int, int, str, int] = self.marker_env["version_info"]
        return version_info

    @property
    def python_implementation(self) -> str:
        implementation: str = self.marker_env["platform_python_implementation"]
        return implementation

    @property
    def python(self) -> Path:
        """
        Path to current python executable
        """
        return Path(self._bin(self._executable))

    @property
    def marker_env(self) -> dict[str, Any]:
        if self._marker_env is None:
            self._marker_env = self.get_marker_env()

        return self._marker_env

    @property
    def parent_env(self) -> GenericEnv:
        from poetry.utils.env.generic_env import GenericEnv

        return GenericEnv(self.base, child_env=self)

    def _find_python_executable(self) -> None:
        bin_dir = self._bin_dir

        if self._is_windows and self._is_conda:
            bin_dir = self._path

        python_executables = sorted(
            p.name
            for p in bin_dir.glob("python*")
            if re.match(r"python(?:\d+(?:\.\d+)?)?(?:\.exe)?$", p.name)
        )
        if python_executables:
            executable = python_executables[0]
            if executable.endswith(".exe"):
                executable = executable[:-4]

            self._executable = executable

    def _find_pip_executable(self) -> None:
        pip_executables = sorted(
            p.name
            for p in self._bin_dir.glob("pip*")
            if re.match(r"pip(?:\d+(?:\.\d+)?)?(?:\.exe)?$", p.name)
        )
        if pip_executables:
            pip_executable = pip_executables[0]
            if pip_executable.endswith(".exe"):
                pip_executable = pip_executable[:-4]

            self._pip_executable = pip_executable

    def find_executables(self) -> None:
        self._find_python_executable()
        self._find_pip_executable()

    def get_embedded_wheel(self, distribution: str) -> Path:
        wheel: Wheel = get_embed_wheel(
            distribution, f"{self.version_info[0]}.{self.version_info[1]}"
        )
        path: Path = wheel.path
        return path

    @property
    def pip_embedded(self) -> Path:
        if self._embedded_pip_path is None:
            self._embedded_pip_path = self.get_embedded_wheel("pip") / "pip"
        return self._embedded_pip_path

    @property
    def pip(self) -> Path:
        """
        Path to current pip executable
        """
        # we do not use as_posix() here due to issues with windows pathlib2
        # implementation
        path = Path(self._bin(self._pip_executable))
        if not path.exists():
            return self.pip_embedded
        return path

    @property
    def platform(self) -> str:
        return sys.platform

    @property
    def os(self) -> str:
        return os.name

    @property
    def pip_version(self) -> Version:
        if self._pip_version is None:
            self._pip_version = self.get_pip_version()

        return self._pip_version

    @property
    def site_packages(self) -> SitePackages:
        if self._site_packages is None:
            # we disable write checks if no user site exist
            fallbacks = [self.usersite] if self.usersite else []
            self._site_packages = SitePackages(
                self.purelib,
                self.platlib,
                fallbacks,
                skip_write_checks=not fallbacks,
            )
        return self._site_packages

    @property
    def usersite(self) -> Path | None:
        if "usersite" in self.paths:
            return Path(self.paths["usersite"])
        return None

    @property
    def userbase(self) -> Path | None:
        if "userbase" in self.paths:
            return Path(self.paths["userbase"])
        return None

    @property
    def purelib(self) -> Path:
        if self._purelib is None:
            self._purelib = Path(self.paths["purelib"])

        return self._purelib

    @property
    def platlib(self) -> Path:
        if self._platlib is None:
            if "platlib" in self.paths:
                self._platlib = Path(self.paths["platlib"])
            else:
                self._platlib = self.purelib

        return self._platlib

    def is_path_relative_to_lib(self, path: Path) -> bool:
        for lib_path in [self.purelib, self.platlib]:
            with contextlib.suppress(ValueError):
                path.relative_to(lib_path)
                return True

        return False

    @property
    def sys_path(self) -> list[str]:
        raise NotImplementedError()

    @property
    def paths(self) -> dict[str, str]:
        if self._paths is None:
            self._paths = self.get_paths()

            if self.is_venv():
                # We copy pip's logic here for the `include` path
                self._paths["include"] = str(
                    self.path.joinpath(
                        "include",
                        "site",
                        f"python{self.version_info[0]}.{self.version_info[1]}",
                    )
                )

        return self._paths

    @property
    def supported_tags(self) -> list[Tag]:
        if self._supported_tags is None:
            self._supported_tags = self.get_supported_tags()

        return self._supported_tags

    @classmethod
    def get_base_prefix(cls) -> Path:
        real_prefix = getattr(sys, "real_prefix", None)
        if real_prefix is not None:
            return Path(real_prefix)

        base_prefix = getattr(sys, "base_prefix", None)
        if base_prefix is not None:
            return Path(base_prefix)

        return Path(sys.prefix)

    def get_version_info(self) -> tuple[Any, ...]:
        raise NotImplementedError()

    def get_python_implementation(self) -> str:
        raise NotImplementedError()

    def get_marker_env(self) -> dict[str, Any]:
        raise NotImplementedError()

    def get_pip_command(self, embedded: bool = False) -> list[str]:
        if embedded or not Path(self._bin(self._pip_executable)).exists():
            return [str(self.python), str(self.pip_embedded)]
        # run as module so that pip can update itself on Windows
        return [str(self.python), "-m", "pip"]

    def get_supported_tags(self) -> list[Tag]:
        raise NotImplementedError()

    def get_pip_version(self) -> Version:
        raise NotImplementedError()

    def get_paths(self) -> dict[str, str]:
        raise NotImplementedError()

    def is_valid_for_marker(self, marker: BaseMarker) -> bool:
        valid: bool = marker.validate(self.marker_env)
        return valid

    def is_sane(self) -> bool:
        """
        Checks whether the current environment is sane or not.
        """
        return True

    def get_command_from_bin(self, bin: str) -> list[str]:
        if bin == "pip":
            # when pip is required we need to ensure that we fall back to
            # embedded pip when pip is not available in the environment
            return self.get_pip_command()

        return [self._bin(bin)]

    def run(self, bin: str, *args: str, **kwargs: Any) -> str:
        cmd = self.get_command_from_bin(bin) + list(args)
        return self._run(cmd, **kwargs)

    def run_pip(self, *args: str, **kwargs: Any) -> str:
        pip = self.get_pip_command()
        cmd = pip + list(args)
        return self._run(cmd, **kwargs)

    def run_python_script(self, content: str, **kwargs: Any) -> str:
        return self.run(
            self._executable,
            "-I",
            "-W",
            "ignore",
            "-",
            input_=content,
            stderr=subprocess.PIPE,
            **kwargs,
        )

    def _run(self, cmd: list[str], **kwargs: Any) -> str:
        """
        Run a command inside the Python environment.
        """
        call = kwargs.pop("call", False)
        input_ = kwargs.pop("input_", None)
        env = kwargs.pop("env", dict(os.environ))
        stderr = kwargs.pop("stderr", subprocess.STDOUT)

        try:
            if input_:
                output = subprocess.run(
                    cmd,
                    stdout=subprocess.PIPE,
                    stderr=stderr,
                    input=encode(input_),
                    check=True,
                    env=env,
                    **kwargs,
                ).stdout
            elif call:
                assert stderr != subprocess.PIPE
                subprocess.check_call(cmd, stderr=stderr, env=env, **kwargs)
                output = ""
            else:
                output = subprocess.check_output(cmd, stderr=stderr, env=env, **kwargs)
        except CalledProcessError as e:
            raise EnvCommandError(e, input=input_)

        return decode(output)

    def execute(self, bin: str, *args: str, **kwargs: Any) -> int:
        command = self.get_command_from_bin(bin) + list(args)
        env = kwargs.pop("env", dict(os.environ))

        if not self._is_windows:
            return os.execvpe(command[0], command, env=env)

        kwargs["shell"] = True
        exe = subprocess.Popen(command, env=env, **kwargs)
        exe.communicate()
        return exe.returncode

    def is_venv(self) -> bool:
        raise NotImplementedError()

    @property
    def script_dirs(self) -> list[Path]:
        if self._script_dirs is None:
            scripts = self.paths.get("scripts")
            self._script_dirs = [
                Path(scripts) if scripts is not None else self._bin_dir
            ]
            if self.userbase:
                self._script_dirs.append(self.userbase / self._script_dirs[0].name)
        return self._script_dirs

    def _bin(self, bin: str) -> str:
        """
        Return path to the given executable.
        """
        if self._is_windows and not bin.endswith(".exe"):
            bin_path = self._bin_dir / (bin + ".exe")
        else:
            bin_path = self._bin_dir / bin

        if not bin_path.exists():
            # On Windows, some executables can be in the base path
            # This is especially true when installing Python with
            # the official installer, where python.exe will be at
            # the root of the env path.
            if self._is_windows:
                if not bin.endswith(".exe"):
                    bin_path = self._path / (bin + ".exe")
                else:
                    bin_path = self._path / bin

                if bin_path.exists():
                    return str(bin_path)

            return bin

        return str(bin_path)

    def __eq__(self, other: object) -> bool:
        if not isinstance(other, Env):
            return False

        return other.__class__ == self.__class__ and other.path == self.path

    def __repr__(self) -> str:
        return f'{self.__class__.__name__}("{self._path}")'
