#     Copyright 2022, Kay Hayen, mailto:kay.hayen@gmail.com
#
#     Part of "Nuitka", an optimizing Python compiler that is compatible and
#     integrates with CPython, but also works on its own.
#
#     Licensed under the Apache License, Version 2.0 (the "License");
#     you may not use this file except in compliance with the License.
#     You may obtain a copy of the License at
#
#        http://www.apache.org/licenses/LICENSE-2.0
#
#     Unless required by applicable law or agreed to in writing, software
#     distributed under the License is distributed on an "AS IS" BASIS,
#     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#     See the License for the specific language governing permissions and
#     limitations under the License.
#
""" Provide installed Pythons with module availability checks. """

import os
import sys

from nuitka.__past__ import WindowsError  # pylint: disable=I0021,redefined-builtin
from nuitka.containers.OrderedSets import OrderedSet
from nuitka.PythonVersions import python_version_str

from .Execution import (
    NuitkaCalledProcessError,
    check_output,
    getExecutablePath,
)
from .FileOperations import getDirectoryRealPath
from .Utils import isWin32Windows


class InstalledPython(object):
    def __init__(self, python_exe, python_version):
        self.python_exe = python_exe
        self.python_version = python_version

    def __repr__(self):
        return "<InstalledPython '%s' version '%s'>" % (
            self.python_exe,
            self.python_version,
        )

    def getPythonExe(self):
        return self.python_exe

    def getPythonVersion(self):
        return "%d.%d" % (self.python_version // 256, (self.python_version // 16) % 16)

    # Necessary for Python 2.7, otherwise SyntaxError is given on exec.
    @staticmethod
    def _exec(code, context):
        # We can trust our own code there, pylint: disable=exec-used
        exec(code.replace("print", "catch_print"), context)

    def checkUsability(self, module_name, module_version):
        # very many cases and return driven
        # pylint: disable=too-many-branches,too-many-return-statements

        if module_name is None:
            return True

        test_code = "import %s" % module_name

        if module_version is not None:
            test_code += ";print(%s.__version__)" % module_name

        test_code += ";print('OK')"

        if self.python_exe != sys.executable:
            try:
                output = check_output([self.python_exe, "-c", test_code])
            except NuitkaCalledProcessError:
                return False
            except OSError:
                return False

            output = output.splitlines()
        else:
            output = []

            def catch_print(value):
                output.append(value)

            try:
                self._exec(code=test_code, context={"catch_print": catch_print})
            except ImportError:
                return False

            if str is not bytes:
                output = [line.encode("utf8") for line in output]

        if output[-1] != b"OK":
            return False

        if module_version is not None:
            detected_version = output[-2].split(b".")

            if str is not bytes:
                module_version = module_version.encode("utf8")

            for detected_part, wanted_part in zip(
                detected_version, module_version.split(b".")
            ):
                if int(detected_part) < int(wanted_part):
                    return False

        return True


_installed_pythons = {}


def getInstalledPythonRegistryPaths(python_version):
    """Yield all Pythons as found in the Windows registry."""
    # Windows only code, pylint: disable=I0021,import-error,undefined-variable
    if str is bytes:
        import _winreg as winreg  # pylint: disable=I0021,import-error,no-name-in-module
    else:
        import winreg  # pylint: disable=I0021,import-error,no-name-in-module

    for hkey_branch in (winreg.HKEY_LOCAL_MACHINE, winreg.HKEY_CURRENT_USER):
        for arch_key in (0, winreg.KEY_WOW64_32KEY, winreg.KEY_WOW64_64KEY):
            for suffix in "", "-32", "-arm64":
                try:
                    key = winreg.OpenKey(
                        hkey_branch,
                        r"SOFTWARE\Python\PythonCore\%s%s\InstallPath"
                        % (python_version, suffix),
                        0,
                        winreg.KEY_READ | arch_key,
                    )

                    install_dir = os.path.normpath(winreg.QueryValue(key, ""))
                except WindowsError:
                    pass
                else:
                    candidate = os.path.normpath(
                        os.path.join(install_dir, "python.exe")
                    )

                    if os.path.exists(candidate):
                        yield candidate


def _getPythonInstallPathsWindows(python_version):
    """Find Python installation on Windows.

    Find a Python installation, first try a few
    guesses for their paths, then look into registry for user or system wide
    installations.
    """
    seen = set()

    # Shortcuts for the default installation directories, to avoid going to
    # registry at all unless necessary. Any Python2 will do for Scons, so it
    # might be avoided entirely.

    candidate = r"c:\python%s\python.exe" % python_version.replace(".", "")

    if os.path.isfile(candidate):
        candidate = os.path.join(
            getDirectoryRealPath(os.path.dirname(candidate)),
            os.path.basename(candidate),
        )

        yield candidate

        seen.add(candidate)

    for candidate in getInstalledPythonRegistryPaths(python_version=python_version):
        if candidate not in seen:
            seen.add(candidate)
            yield candidate


def findPythons(python_version):
    """Find all Python installations for a specific version."""
    result = OrderedSet()

    if python_version == python_version_str:
        result.add(
            InstalledPython(python_exe=sys.executable, python_version=python_version)
        )

    if isWin32Windows():
        result.update(
            InstalledPython(python_exe=python_exe, python_version=python_version)
            for python_exe in _getPythonInstallPathsWindows(python_version)
        )

    candidate = getExecutablePath("python" + python_version)
    if candidate is not None:
        result.add(InstalledPython(python_exe=candidate, python_version=python_version))

    return result


def findInstalledPython(python_versions, module_name, module_version):
    python_versions = list(python_versions)
    python_versions.sort(
        key=lambda python_version: python_version != python_version_str
    )

    # Make sure the current Python version is scanned for if acceptable.
    if (
        python_version_str in python_versions
        and python_version_str not in _installed_pythons
    ):
        _installed_pythons[python_version_str] = findPythons(python_version_str)

    # Attempt to prefer scanned versions.
    for python_version in python_versions:
        for candidate in _installed_pythons.get(python_version, ()):
            if module_name is None or candidate.checkUsability(
                module_name=module_name, module_version=module_version
            ):
                return candidate

    # Attempt to find so far not scanned versions.
    for python_version in python_versions:
        if python_version not in _installed_pythons:
            _installed_pythons[python_version] = findPythons(python_version)

            for candidate in _installed_pythons.get(python_version, ()):
                if module_name is None or candidate.checkUsability(
                    module_name=module_name, module_version=module_version
                ):
                    return candidate

    return None
