path: root/scripts/sphinx-pre-install

#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0-or-later
# Copyright (c) 2017-2025 Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
#
# pylint: disable=C0103,C0114,C0115,C0116,C0301,C0302
# pylint: disable=R0902,R0904,R0911,R0912,R0914,R0915,R1705,R1710,E1121

# Note: this script requires at least Python 3.6 to run.
# Don't add changes not compatible with it, it is meant to report
# incompatible python versions.

"""
Dependency checker for Sphinx documentation Kernel build.

This module provides tools to check for all required dependencies needed to
build documentation using Sphinx, including system packages, Python modules
and LaTeX packages for PDF generation.

It detect packages for a subset of Linux distributions used by Kernel
maintainers, showing hints and missing dependencies.

The main class SphinxDependencyChecker handles the dependency checking logic
and provides recommendations for installing missing packages. It supports both
system package installations and  Python virtual environments. By default,
system pacage install is recommended.
"""

import argparse
import os
import re
import subprocess
import sys
from glob import glob


def parse_version(version):
    """Convert a major.minor.patch version into a tuple"""
    return tuple(int(x) for x in version.split("."))


def ver_str(version):
    """Returns a version tuple as major.minor.patch"""

    return ".".join([str(x) for x in version])


RECOMMENDED_VERSION = parse_version("3.4.3")
MIN_PYTHON_VERSION = parse_version("3.7")


class DepManager:
    """
    Manage package dependencies. There are three types of dependencies:

    - System: dependencies required for docs build;
    - Python: python dependencies for a native distro Sphinx install;
    - PDF: dependencies needed by PDF builds.

    Each dependency can be mandatory or optional. Not installing an optional
    dependency won't break the build, but will cause degradation at the
    docs output.
    """

    # Internal types of dependencies. Don't use them outside DepManager class.
    _SYS_TYPE = 0
    _PHY_TYPE = 1
    _PDF_TYPE = 2

    # Dependencies visible outside the class.
    # The keys are tuple with: (type, is_mandatory flag).
    #
    # Currently we're not using all optional dep types. Yet, we'll keep all
    # possible combinations here. They're not many, and that makes easier
    # if later needed and for the name() method below

    SYSTEM_MANDATORY = (_SYS_TYPE, True)
    PYTHON_MANDATORY = (_PHY_TYPE, True)
    PDF_MANDATORY = (_PDF_TYPE, True)

    SYSTEM_OPTIONAL = (_SYS_TYPE, False)
    PYTHON_OPTIONAL = (_PHY_TYPE, False)
    PDF_OPTIONAL = (_PDF_TYPE, True)

    def __init__(self, pdf):
        """
        Initialize internal vars:

        - missing: missing dependencies list, containing a distro-independent
                   name for a missing dependency and its type.
        - missing_pkg: ancillary dict containing missing dependencies in
                       distro namespace, organized by type.
        - need: total number of needed dependencies. Never cleaned.
        - optional: total number of optional dependencies. Never cleaned.
        - pdf: Is PDF support enabled?
        """
        self.missing = {}
        self.missing_pkg = {}
        self.need = 0
        self.optional = 0
        self.pdf = pdf

    @staticmethod
    def name(dtype):
        """
        Ancillary routine to output a warn/error message reporting
        missing dependencies.
        """
        if dtype[0] == DepManager._SYS_TYPE:
            msg = "build"
        elif dtype[0] == DepManager._PHY_TYPE:
            msg = "Python"
        else:
            msg = "PDF"

        if dtype[1]:
            return f"ERROR: {msg} mandatory deps missing"
        else:
            return f"Warning: {msg} optional deps missing"

    @staticmethod
    def is_optional(dtype):
        """Ancillary routine to report if a dependency is optional"""
        return not dtype[1]

    @staticmethod
    def is_pdf(dtype):
        """Ancillary routine to report if a dependency is for PDF generation"""
        if dtype[0] == DepManager._PDF_TYPE:
            return True

        return False

    def add_package(self, package, dtype):
        """
        Add a package at the self.missing() dictionary.
        Doesn't update missing_pkg.
        """
        is_optional = DepManager.is_optional(dtype)
        self.missing[package] = dtype
        if is_optional:
            self.optional += 1
        else:
            self.need += 1

    def del_package(self, package):
        """
        Remove a package at the self.missing() dictionary.
        Doesn't update missing_pkg.
        """
        if package in self.missing:
            del self.missing[package]

    def clear_deps(self):
        """
        Clear dependencies without changing needed/optional.

        This is an ackward way to have a separate section to recommend
        a package after system main dependencies.

        TODO: rework the logic to prevent needing it.
        """

        self.missing = {}
        self.missing_pkg = {}

    def check_missing(self, progs):
        """
        Update self.missing_pkg, using progs dict to convert from the
        agnostic package name to distro-specific one.

        Returns an string with the packages to be installed, sorted and
        with eventual duplicates removed.
        """

        self.missing_pkg = {}

        for prog, dtype in sorted(self.missing.items()):
            # At least on some LTS distros like CentOS 7, texlive doesn't
            # provide all packages we need. When such distros are
            # detected, we have to disable PDF output.
            #
            # So, we need to ignore the packages that distros would
            # need for LaTeX to work
            if DepManager.is_pdf(dtype) and not self.pdf:
                self.optional -= 1
                continue

            if not dtype in self.missing_pkg:
                self.missing_pkg[dtype] = []

            self.missing_pkg[dtype].append(progs.get(prog, prog))

        install = []
        for dtype, pkgs in self.missing_pkg.items():
            install += pkgs

        return " ".join(sorted(set(install)))

    def warn_install(self):
        """
        Emit warnings/errors related to missing packages.
        """

        output_msg = ""

        for dtype in sorted(self.missing_pkg.keys()):
            progs = " ".join(sorted(set(self.missing_pkg[dtype])))

            try:
                name = DepManager.name(dtype)
                output_msg += f'{name}:\t{progs}\n'
            except KeyError:
                raise KeyError(f"ERROR!!!: invalid dtype for {progs}: {dtype}")

        if output_msg:
            print(f"\n{output_msg}")

class AncillaryMethods:
    """
    Ancillary methods that checks for missing dependencies for different
    types of types, like binaries, python modules, rpm deps, etc.
    """

    @staticmethod
    def which(prog):
        """
        Our own implementation of which(). We could instead use
        shutil.which(), but this function is simple enough.
        Probably faster to use this implementation than to import shutil.
        """
        for path in os.environ.get("PATH", "").split(":"):
            full_path = os.path.join(path, prog)
            if os.access(full_path, os.X_OK):
                return full_path

        return None

    @staticmethod
    def get_python_version(cmd):
        """
        Get python version from a Python binary. As we need to detect if
        are out there newer python binaries, we can't rely on sys.release here.
        """

        result = SphinxDependencyChecker.run([cmd, "--version"],
                                            capture_output=True, text=True)
        version = result.stdout.strip()

        match = re.search(r"(\d+\.\d+\.\d+)", version)
        if match:
            return parse_version(match.group(1))

        print(f"Can't parse version {version}")
        return (0, 0, 0)

    @staticmethod
    def find_python():
        """
        Detect if are out there any python 3.xy version newer than the
        current one.

        Note: this routine is limited to up to 2 digits for python3. We
        may need to update it one day, hopefully on a distant future.
        """
        patterns = [
            "python3.[0-9]",
            "python3.[0-9][0-9]",
        ]

        # Seek for a python binary newer than MIN_PYTHON_VERSION
        for path in os.getenv("PATH", "").split(":"):
            for pattern in patterns:
                for cmd in glob(os.path.join(path, pattern)):
                    if os.path.isfile(cmd) and os.access(cmd, os.X_OK):
                        version = SphinxDependencyChecker.get_python_version(cmd)
                        if version >= MIN_PYTHON_VERSION:
                            return cmd

    @staticmethod
    def check_python():
        """
        Check if the current python binary satisfies our minimal requirement
        for Sphinx build. If not, re-run with a newer version if found.
        """
        cur_ver = sys.version_info[:3]
        if cur_ver >= MIN_PYTHON_VERSION:
            ver = ver_str(cur_ver)
            print(f"Python version: {ver}")

            # This could be useful for debugging purposes
            if SphinxDependencyChecker.which("docutils"):
                result = SphinxDependencyChecker.run(["docutils", "--version"],
                                                    capture_output=True, text=True)
                ver = result.stdout.strip()
                match = re.search(r"(\d+\.\d+\.\d+)", ver)
                if match:
                    ver = match.group(1)

                print(f"Docutils version: {ver}")

            return

        python_ver = ver_str(cur_ver)

        new_python_cmd = SphinxDependencyChecker.find_python()
        if not new_python_cmd:
            print(f"ERROR: Python version {python_ver} is not spported anymore\n")
            print("       Can't find a new version. This script may fail")
            return

        # Restart script using the newer version
        script_path = os.path.abspath(sys.argv[0])
        args = [new_python_cmd, script_path] + sys.argv[1:]

        print(f"Python {python_ver} not supported. Changing to {new_python_cmd}")

        try:
            os.execv(new_python_cmd, args)
        except OSError as e:
            sys.exit(f"Failed to restart with {new_python_cmd}: {e}")

    @staticmethod
    def run(*args, **kwargs):
        """
        Excecute a command, hiding its output by default.
        Preserve comatibility with older Python versions.
        """

        capture_output = kwargs.pop('capture_output', False)

        if capture_output:
            if 'stdout' not in kwargs:
                kwargs['stdout'] = subprocess.PIPE
            if 'stderr' not in kwargs:
                kwargs['stderr'] = subprocess.PIPE
        else:
            if 'stdout' not in kwargs:
                kwargs['stdout'] = subprocess.DEVNULL
            if 'stderr' not in kwargs:
                kwargs['stderr'] = subprocess.DEVNULL

        # Don't break with older Python versions
        if 'text' in kwargs and sys.version_info < (3, 7):
            kwargs['universal_newlines'] = kwargs.pop('text')

        return subprocess.run(*args, **kwargs)

class MissingCheckers(AncillaryMethods):
    """
    Contains some ancillary checkers for different types of binaries and
    package managers.
    """

    def __init__(self, args, texlive):
        """
        Initialize its internal variables
        """
        self.pdf = args.pdf
        self.virtualenv = args.virtualenv
        self.version_check = args.version_check
        self.texlive = texlive

        self.min_version = (0, 0, 0)
        self.cur_version = (0, 0, 0)

        self.deps = DepManager(self.pdf)

        self.need_symlink = 0
        self.need_sphinx = 0

        self.verbose_warn_install = 1

        self.virtenv_dir = ""
        self.install = ""
        self.python_cmd = ""

        self.virtenv_prefix = ["sphinx_", "Sphinx_" ]

    def check_missing_file(self, files, package, dtype):
        """
        Does the file exists? If not, add it to missing dependencies.
        """
        for f in files:
            if os.path.exists(f):
                return
        self.deps.add_package(package, dtype)

    def check_program(self, prog, dtype):
        """
        Does the program exists and it is at the PATH?
        If not, add it to missing dependencies.
        """
        found = self.which(prog)
        if found:
            return found

        self.deps.add_package(prog, dtype)

        return None

    def check_perl_module(self, prog, dtype):
        """
        Does perl have a dependency? Is it available?
        If not, add it to missing dependencies.

        Right now, we still need Perl for doc build, as it is required
        by some tools called at docs or kernel build time, like:

            scripts/documentation-file-ref-check

        Also, checkpatch is on Perl.
        """

        # While testing with lxc download template, one of the
        # distros (Oracle) didn't have perl - nor even an option to install
        # before installing oraclelinux-release-el9 package.
        #
        # Check it before running an error. If perl is not there,
        # add it as a mandatory package, as some parts of the doc builder
        # needs it.
        if not self.which("perl"):
            self.deps.add_package("perl", DepManager.SYSTEM_MANDATORY)
            self.deps.add_package(prog, dtype)
            return

        try:
            self.run(["perl", f"-M{prog}", "-e", "1"], check=True)
        except subprocess.CalledProcessError:
            self.deps.add_package(prog, dtype)

    def check_python_module(self, module, is_optional=False):
        """
        Does a python module exists outside venv? If not, add it to missing
        dependencies.
        """
        if is_optional:
            dtype = DepManager.PYTHON_OPTIONAL
        else:
            dtype = DepManager.PYTHON_MANDATORY

        try:
            self.run([self.python_cmd, "-c", f"import {module}"], check=True)
        except subprocess.CalledProcessError:
            self.deps.add_package(module, dtype)

    def check_rpm_missing(self, pkgs, dtype):
        """
        Does a rpm package exists? If not, add it to missing dependencies.
        """
        for prog in pkgs:
            try:
                self.run(["rpm", "-q", prog], check=True)
            except subprocess.CalledProcessError:
                self.deps.add_package(prog, dtype)

    def check_pacman_missing(self, pkgs, dtype):
        """
        Does a pacman package exists? If not, add it to missing dependencies.
        """
        for prog in pkgs:
            try:
                self.run(["pacman", "-Q", prog], check=True)
            except subprocess.CalledProcessError:
                self.deps.add_package(prog, dtype)

    def check_missing_tex(self, is_optional=False):
        """
        Does a LaTeX package exists? If not, add it to missing dependencies.
        """
        if is_optional:
            dtype = DepManager.PDF_OPTIONAL
        else:
            dtype = DepManager.PDF_MANDATORY

        kpsewhich = self.which("kpsewhich")
        for prog, package in self.texlive.items():

            # If kpsewhich is not there, just add it to deps
            if not kpsewhich:
                self.deps.add_package(package, dtype)
                continue

            # Check if the package is needed
            try:
                result = self.run(
                    [kpsewhich, prog], stdout=subprocess.PIPE, text=True, check=True
                )

                # Didn't find. Add it
                if not result.stdout.strip():
                    self.deps.add_package(package, dtype)

            except subprocess.CalledProcessError:
                # kpsewhich returned an error. Add it, just in case
                self.deps.add_package(package, dtype)

    def get_sphinx_fname(self):
        """
        Gets the binary filename for sphinx-build.
        """
        if "SPHINXBUILD" in os.environ:
            return os.environ["SPHINXBUILD"]

        fname = "sphinx-build"
        if self.which(fname):
            return fname

        fname = "sphinx-build-3"
        if self.which(fname):
            self.need_symlink = 1
            return fname

        return ""

    def get_sphinx_version(self, cmd):
        """
        Gets sphinx-build version.
        """
        try:
            result = self.run([cmd, "--version"],
                              stdout=subprocess.PIPE,
                              stderr=subprocess.STDOUT,
                              text=True, check=True)
        except (subprocess.CalledProcessError, FileNotFoundError):
            return None

        for line in result.stdout.split("\n"):
            match = re.match(r"^sphinx-build\s+([\d\.]+)(?:\+(?:/[\da-f]+)|b\d+)?\s*$", line)
            if match:
                return parse_version(match.group(1))

            match = re.match(r"^Sphinx.*\s+([\d\.]+)\s*$", line)
            if match:
                return parse_version(match.group(1))

    def check_sphinx(self, conf):
        """
        Checks Sphinx minimal requirements
        """
        try:
            with open(conf, "r", encoding="utf-8") as f:
                for line in f:
                    match = re.match(r"^\s*needs_sphinx\s*=\s*[\'\"]([\d\.]+)[\'\"]", line)
                    if match:
                        self.min_version = parse_version(match.group(1))
                        break
        except IOError:
            sys.exit(f"Can't open {conf}")

        if not self.min_version:
            sys.exit(f"Can't get needs_sphinx version from {conf}")

        self.virtenv_dir = self.virtenv_prefix[0] + "latest"

        sphinx = self.get_sphinx_fname()
        if not sphinx:
            self.need_sphinx = 1
            return

        self.cur_version = self.get_sphinx_version(sphinx)
        if not self.cur_version:
            sys.exit(f"{sphinx} didn't return its version")

        if self.cur_version < self.min_version:
            curver = ver_str(self.cur_version)
            minver = ver_str(self.min_version)

            print(f"ERROR: Sphinx version is {curver}. It should be >= {minver}")
            self.need_sphinx = 1
            return

        # On version check mode, just assume Sphinx has all mandatory deps
        if self.version_check and self.cur_version >= RECOMMENDED_VERSION:
            sys.exit(0)

    def catcheck(self, filename):
        """
        Reads a file if it exists, returning as string.
        If not found, returns an empty string.
        """
        if os.path.exists(filename):
            with open(filename, "r", encoding="utf-8") as f:
                return f.read().strip()
        return ""

    def get_system_release(self):
        """
        Determine the system type. There's no unique way that would work
        with all distros with a minimal package install. So, several
        methods are used here.

        By default, it will use lsb_release function. If not available, it will
        fail back to reading the known different places where the distro name
        is stored.

        Several modern distros now have /etc/os-release, which usually have
        a decent coverage.
        """

        system_release = ""

        if self.which("lsb_release"):
            result = self.run(["lsb_release", "-d"], capture_output=True, text=True)
            system_release = result.stdout.replace("Description:", "").strip()

        release_files = [
            "/etc/system-release",
            "/etc/redhat-release",
            "/etc/lsb-release",
            "/etc/gentoo-release",
        ]

        if not system_release:
            for f in release_files:
                system_release = self.catcheck(f)
                if system_release:
                    break

        # This seems more common than LSB these days
        if not system_release:
            os_var = {}
            try:
                with open("/etc/os-release", "r", encoding="utf-8") as f:
                    for line in f:
                        match = re.match(r"^([\w\d\_]+)=\"?([^\"]*)\"?\n", line)
                        if match:
                            os_var[match.group(1)] = match.group(2)

                system_release = os_var.get("NAME", "")
                if "VERSION_ID" in os_var:
                    system_release += " " + os_var["VERSION_ID"]
                elif "VERSION" in os_var:
                    system_release += " " + os_var["VERSION"]
            except IOError:
                pass

        if not system_release:
            system_release = self.catcheck("/etc/issue")

        system_release = system_release.strip()

        return system_release

class SphinxDependencyChecker(MissingCheckers):
    """
    Main class for checking Sphinx documentation build dependencies.

    - Check for missing system packages;
    - Check for missing Python modules;
    - Check for missing LaTeX packages needed by PDF generation;
    - Propose Sphinx install via Python Virtual environment;
    - Propose Sphinx install via distro-specific package install.
    """
    def __init__(self, args):
        """Initialize checker variables"""

        # List of required texlive packages on Fedora and OpenSuse
        texlive = {
            "amsfonts.sty":       "texlive-amsfonts",
            "amsmath.sty":        "texlive-amsmath",
            "amssymb.sty":        "texlive-amsfonts",
            "amsthm.sty":         "texlive-amscls",
            "anyfontsize.sty":    "texlive-anyfontsize",
            "atbegshi.sty":       "texlive-oberdiek",
            "bm.sty":             "texlive-tools",
            "capt-of.sty":        "texlive-capt-of",
            "cmap.sty":           "texlive-cmap",
            "ctexhook.sty":       "texlive-ctex",
            "ecrm1000.tfm":       "texlive-ec",
            "eqparbox.sty":       "texlive-eqparbox",
            "eu1enc.def":         "texlive-euenc",
            "fancybox.sty":       "texlive-fancybox",
            "fancyvrb.sty":       "texlive-fancyvrb",
            "float.sty":          "texlive-float",
            "fncychap.sty":       "texlive-fncychap",
            "footnote.sty":       "texlive-mdwtools",
            "framed.sty":         "texlive-framed",
            "luatex85.sty":       "texlive-luatex85",
            "multirow.sty":       "texlive-multirow",
            "needspace.sty":      "texlive-needspace",
            "palatino.sty":       "texlive-psnfss",
            "parskip.sty":        "texlive-parskip",
            "polyglossia.sty":    "texlive-polyglossia",
            "tabulary.sty":       "texlive-tabulary",
            "threeparttable.sty": "texlive-threeparttable",
            "titlesec.sty":       "texlive-titlesec",
            "ucs.sty":            "texlive-ucs",
            "upquote.sty":        "texlive-upquote",
            "wrapfig.sty":        "texlive-wrapfig",
        }

        super().__init__(args, texlive)

        self.need_pip = False
        self.rec_sphinx_upgrade = 0

        self.system_release = self.get_system_release()
        self.activate_cmd = ""

        # Some distros may not have a Sphinx shipped package compatible with
        # our minimal requirements
        self.package_supported = True

        # Recommend a new python version
        self.recommend_python = None

        # Certain hints are meant to be shown only once
        self.distro_msg = None

        self.latest_avail_ver = (0, 0, 0)
        self.venv_ver = (0, 0, 0)

        prefix = os.environ.get("srctree", ".") + "/"

        self.conf = prefix + "Documentation/conf.py"
        self.requirement_file = prefix + "Documentation/sphinx/requirements.txt"

    def get_install_progs(self, progs, cmd, extra=None):
        """
        Check for missing dependencies using the provided program mapping.

        The actual distro-specific programs are mapped via progs argument.
        """
        install = self.deps.check_missing(progs)

        if self.verbose_warn_install:
            self.deps.warn_install()

        if not install:
            return

        if cmd:
            if self.verbose_warn_install:
                msg = "You should run:"
            else:
                msg = ""

            if extra:
                msg += "\n\t" + extra.replace("\n", "\n\t")

            return(msg + "\n\tsudo " + cmd + " " + install)

        return None

    #
    # Distro-specific hints methods
    #

    def give_debian_hints(self):
        """
        Provide package installation hints for Debian-based distros.
        """
        progs = {
            "Pod::Usage":    "perl-modules",
            "convert":       "imagemagick",
            "dot":           "graphviz",
            "ensurepip":     "python3-venv",
            "python-sphinx": "python3-sphinx",
            "rsvg-convert":  "librsvg2-bin",
            "virtualenv":    "virtualenv",
            "xelatex":       "texlive-xetex",
            "yaml":          "python3-yaml",
        }

        if self.pdf:
            pdf_pkgs = {
                "fonts-dejavu": [
                    "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
                ],
                "fonts-noto-cjk": [
                    "/usr/share/fonts/noto-cjk/NotoSansCJK-Regular.ttc",
                    "/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc",
                    "/usr/share/fonts/opentype/noto/NotoSerifCJK-Regular.ttc",
                ],
                "tex-gyre": [
                    "/usr/share/texmf/tex/latex/tex-gyre/tgtermes.sty"
                ],
                "texlive-fonts-recommended": [
                    "/usr/share/texlive/texmf-dist/fonts/tfm/adobe/zapfding/pzdr.tfm",
                ],
                "texlive-lang-chinese": [
                    "/usr/share/texlive/texmf-dist/tex/latex/ctex/ctexhook.sty",
                ],
            }

            for package, files in pdf_pkgs.items():
                self.check_missing_file(files, package, DepManager.PDF_MANDATORY)

            self.check_program("dvipng", DepManager.PDF_MANDATORY)

        if not self.distro_msg:
            self.distro_msg = \
                "Note: ImageMagick is broken on some distros, affecting PDF output. For more details:\n" \
                "\thttps://askubuntu.com/questions/1158894/imagemagick-still-broken-using-with-usr-bin-convert"

        return self.get_install_progs(progs, "apt-get install")

    def give_redhat_hints(self):
        """
        Provide package installation hints for RedHat-based distros
        (Fedora, RHEL and RHEL-based variants).
        """
        progs = {
            "Pod::Usage":       "perl-Pod-Usage",
            "convert":          "ImageMagick",
            "dot":              "graphviz",
            "python-sphinx":    "python3-sphinx",
            "rsvg-convert":     "librsvg2-tools",
            "virtualenv":       "python3-virtualenv",
            "xelatex":          "texlive-xetex-bin",
            "yaml":             "python3-pyyaml",
        }

        fedora_tex_pkgs = [
            "dejavu-sans-fonts",
            "dejavu-sans-mono-fonts",
            "dejavu-serif-fonts",
            "texlive-collection-fontsrecommended",
            "texlive-collection-latex",
            "texlive-xecjk",
        ]

        fedora = False
        rel = None

        match = re.search(r"(release|Linux)\s+(\d+)", self.system_release)
        if match:
            rel = int(match.group(2))

        if not rel:
            print("Couldn't identify release number")
            noto_sans_redhat = None
            self.pdf = False
        elif re.search("Fedora", self.system_release):
            # Fedora 38 and upper use this CJK font

            noto_sans_redhat = "google-noto-sans-cjk-fonts"
            fedora = True
        else:
            # Almalinux, CentOS, RHEL, ...

            # at least up to version 9 (and Fedora < 38), that's the CJK font
            noto_sans_redhat = "google-noto-sans-cjk-ttc-fonts"

            progs["virtualenv"] = "python-virtualenv"

            if not rel or rel < 8:
                print("ERROR: Distro not supported. Too old?")
                return

            # RHEL 8 uses Python 3.6, which is not compatible with
            # the build system anymore. Suggest Python 3.11
            if rel == 8:
                self.check_program("python3.9", DepManager.SYSTEM_MANDATORY)
                progs["python3.9"] = "python39"
                progs["yaml"] = "python39-pyyaml"

                self.recommend_python = True

                # There's no python39-sphinx package. Only pip is supported
                self.package_supported = False

            if not self.distro_msg:
                self.distro_msg = \
                    "Note: RHEL-based distros typically require extra repositories.\n" \
                    "For most, enabling epel and crb are enough:\n" \
                    "\tsudo dnf install -y epel-release\n" \
                    "\tsudo dnf config-manager --set-enabled crb\n" \
                    "Yet, some may have other required repositories. Those commands could be useful:\n" \
                    "\tsudo dnf repolist all\n" \
                    "\tsudo dnf repoquery --available --info <pkgs>\n" \
                    "\tsudo dnf config-manager --set-enabled '*' # enable all - probably not what you want"

        if self.pdf:
            pdf_pkgs = [
                "/usr/share/fonts/google-noto-cjk/NotoSansCJK-Regular.ttc",
                "/usr/share/fonts/google-noto-sans-cjk-fonts/NotoSansCJK-Regular.ttc",
            ]

            self.check_missing_file(pdf_pkgs, noto_sans_redhat, DepManager.PDF_MANDATORY)

            self.check_rpm_missing(fedora_tex_pkgs, DepManager.PDF_MANDATORY)

            self.check_missing_tex(DepManager.PDF_MANDATORY)

            # There's no texlive-ctex on RHEL 8 repositories. This will
            # likely affect CJK pdf build only.
            if not fedora and rel == 8:
                self.deps.del_package("texlive-ctex")

        return self.get_install_progs(progs, "dnf install")

    def give_opensuse_hints(self):
        """
        Provide package installation hints for openSUSE-based distros
        (Leap and Tumbleweed).
        """
        progs = {
            "Pod::Usage":    "perl-Pod-Usage",
            "convert":       "ImageMagick",
            "dot":           "graphviz",
            "python-sphinx": "python3-sphinx",
            "virtualenv":    "python3-virtualenv",
            "xelatex":       "texlive-xetex-bin texlive-dejavu",
            "yaml":          "python3-pyyaml",
        }

        suse_tex_pkgs = [
            "texlive-babel-english",
            "texlive-caption",
            "texlive-colortbl",
            "texlive-courier",
            "texlive-dvips",
            "texlive-helvetic",
            "texlive-makeindex",
            "texlive-metafont",
            "texlive-metapost",
            "texlive-palatino",
            "texlive-preview",
            "texlive-times",
            "texlive-zapfchan",
            "texlive-zapfding",
        ]

        progs["latexmk"] = "texlive-latexmk-bin"

        match = re.search(r"(Leap)\s+(\d+).(\d)", self.system_release)
        if match:
            rel = int(match.group(2))

            # Leap 15.x uses Python 3.6, which is not compatible with
            # the build system anymore. Suggest Python 3.11
            if rel == 15:
                if not self.which(self.python_cmd):
                    self.check_program("python3.11", DepManager.SYSTEM_MANDATORY)
                    progs["python3.11"] = "python311"
                    self.recommend_python = True

                progs.update({
                    "python-sphinx": "python311-Sphinx python311-Sphinx-latex",
                    "virtualenv":    "python311-virtualenv",
                    "yaml":          "python311-PyYAML",
                })
        else:
            # Tumbleweed defaults to Python 3.11

            progs.update({
                "python-sphinx": "python313-Sphinx python313-Sphinx-latex",
                "virtualenv":    "python313-virtualenv",
                "yaml":          "python313-PyYAML",
            })

        # FIXME: add support for installing CJK fonts
        #
        # I tried hard, but was unable to find a way to install
        # "Noto Sans CJK SC" on openSUSE

        if self.pdf:
            self.check_rpm_missing(suse_tex_pkgs, DepManager.PDF_MANDATORY)
        if self.pdf:
            self.check_missing_tex()

        return self.get_install_progs(progs, "zypper install --no-recommends")

    def give_mageia_hints(self):
        """
        Provide package installation hints for Mageia and OpenMandriva.
        """
        progs = {
            "Pod::Usage":    "perl-Pod-Usage",
            "convert":       "ImageMagick",
            "dot":           "graphviz",
            "python-sphinx": "python3-sphinx",
            "rsvg-convert":  "librsvg2",
            "virtualenv":    "python3-virtualenv",
            "xelatex":       "texlive",
            "yaml":          "python3-yaml",
        }

        tex_pkgs = [
            "texlive-fontsextra",
            "texlive-fonts-asian",
            "fonts-ttf-dejavu",
        ]

        if re.search(r"OpenMandriva", self.system_release):
            packager_cmd = "dnf install"
            noto_sans = "noto-sans-cjk-fonts"
            tex_pkgs = [
                "texlive-collection-basic",
                "texlive-collection-langcjk",
                "texlive-collection-fontsextra",
                "texlive-collection-fontsrecommended"
            ]

            # Tested on OpenMandriva Lx 4.3
            progs["convert"] = "imagemagick"
            progs["yaml"] = "python-pyyaml"
            progs["python-virtualenv"] = "python-virtualenv"
            progs["python-sphinx"] = "python-sphinx"
            progs["xelatex"] = "texlive"

            self.check_program("python-virtualenv", DepManager.PYTHON_MANDATORY)

            # On my tests with openMandriva LX 4.0 docker image, upgraded
            # to 4.3, python-virtualenv package is broken: it is missing
            # ensurepip. Without it, the alternative would be to run:
            # python3 -m venv --without-pip ~/sphinx_latest, but running
            # pip there won't install sphinx at venv.
            #
            # Add a note about that.

            if not self.distro_msg:
                self.distro_msg = \
                    "Notes:\n"\
                    "1. for venv, ensurepip could be broken, preventing its install method.\n" \
                    "2. at least on OpenMandriva LX 4.3, texlive packages seem broken"

        else:
            packager_cmd = "urpmi"
            noto_sans = "google-noto-sans-cjk-ttc-fonts"

        progs["latexmk"] = "texlive-collection-basic"

        if self.pdf:
            pdf_pkgs = [
                "/usr/share/fonts/google-noto-cjk/NotoSansCJK-Regular.ttc",
                "/usr/share/fonts/TTF/NotoSans-Regular.ttf",
            ]

            self.check_missing_file(pdf_pkgs, noto_sans, DepManager.PDF_MANDATORY)
            self.check_rpm_missing(tex_pkgs, DepManager.PDF_MANDATORY)

        return self.get_install_progs(progs, packager_cmd)

    def give_arch_linux_hints(self):
        """
        Provide package installation hints for ArchLinux.
        """
        progs = {
            "convert":      "imagemagick",
            "dot":          "graphviz",
            "latexmk":      "texlive-core",
            "rsvg-convert": "extra/librsvg",
            "virtualenv":   "python-virtualenv",
            "xelatex":      "texlive-xetex",
            "yaml":         "python-yaml",
        }

        archlinux_tex_pkgs = [
            "texlive-basic",
            "texlive-binextra",
            "texlive-core",
            "texlive-fontsrecommended",
            "texlive-langchinese",
            "texlive-langcjk",
            "texlive-latexextra",
            "ttf-dejavu",
        ]

        if self.pdf:
            self.check_pacman_missing(archlinux_tex_pkgs,
                                      DepManager.PDF_MANDATORY)

            self.check_missing_file(["/usr/share/fonts/noto-cjk/NotoSansCJK-Regular.ttc"],
                                    "noto-fonts-cjk",
                                    DepManager.PDF_MANDATORY)


        return self.get_install_progs(progs, "pacman -S")

    def give_gentoo_hints(self):
        """
        Provide package installation hints for Gentoo.
        """
        texlive_deps = [
            "dev-texlive/texlive-fontsrecommended",
            "dev-texlive/texlive-latexextra",
            "dev-texlive/texlive-xetex",
            "media-fonts/dejavu",
        ]

        progs = {
            "convert":       "media-gfx/imagemagick",
            "dot":           "media-gfx/graphviz",
            "rsvg-convert":  "gnome-base/librsvg",
            "virtualenv":    "dev-python/virtualenv",
            "xelatex":       " ".join(texlive_deps),
            "yaml":          "dev-python/pyyaml",
            "python-sphinx": "dev-python/sphinx",
        }

        if self.pdf:
            pdf_pkgs = {
                "media-fonts/dejavu": [
                    "/usr/share/fonts/dejavu/DejaVuSans.ttf",
                ],
                "media-fonts/noto-cjk": [
                    "/usr/share/fonts/noto-cjk/NotoSansCJKsc-Regular.otf",
                    "/usr/share/fonts/noto-cjk/NotoSerifCJK-Regular.ttc",
                ],
            }
            for package, files in pdf_pkgs.items():
                self.check_missing_file(files, package, DepManager.PDF_MANDATORY)

        # Handling dependencies is a nightmare, as Gentoo refuses to emerge
        # some packages if there's no package.use file describing them.
        # To make it worse, compilation flags shall also be present there
        # for some packages. If USE is not perfect, error/warning messages
        #   like those are shown:
        #
        #   !!! The following binary packages have been ignored due to non matching USE:
        #
        #    =media-gfx/graphviz-12.2.1-r1 X pdf -python_single_target_python3_13 qt6 svg
        #    =media-gfx/graphviz-12.2.1-r1 X pdf python_single_target_python3_12 -python_single_target_python3_13 qt6 svg
        #    =media-gfx/graphviz-12.2.1-r1 X pdf qt6 svg
        #    =media-gfx/graphviz-12.2.1-r1 X pdf -python_single_target_python3_10 qt6 svg
        #    =media-gfx/graphviz-12.2.1-r1 X pdf -python_single_target_python3_10 python_single_target_python3_12 -python_single_target_python3_13 qt6 svg
        #    =media-fonts/noto-cjk-20190416 X
        #    =app-text/texlive-core-2024-r1 X cjk -xetex
        #    =app-text/texlive-core-2024-r1 X -xetex
        #    =app-text/texlive-core-2024-r1 -xetex
        #    =dev-libs/zziplib-0.13.79-r1 sdl
        #
        # And will ignore such packages, installing the remaining ones. That
        # affects mostly the image extension and PDF generation.

        # Package dependencies and the minimal needed args:
        portages = {
            "graphviz": "media-gfx/graphviz",
            "imagemagick": "media-gfx/imagemagick",
            "media-libs": "media-libs/harfbuzz icu",
            "media-fonts": "media-fonts/noto-cjk",
            "texlive": "app-text/texlive-core xetex",
            "zziblib": "dev-libs/zziplib sdl",
        }

        extra_cmds = ""
        if not self.distro_msg:
            self.distro_msg = "Note: Gentoo requires package.use to be adjusted before emerging packages"

            use_base = "/etc/portage/package.use"
            files = glob(f"{use_base}/*")

            for fname, portage in portages.items():
                install = False

                while install is False:
                    if not files:
                        # No files under package.usage. Install all
                        install = True
                        break

                    args = portage.split(" ")

                    name = args.pop(0)

                    cmd = ["grep", "-l", "-E", rf"^{name}\b" ] + files
                    result = self.run(cmd, stdout=subprocess.PIPE, text=True)
                    if result.returncode or not result.stdout.strip():
                        # File containing portage name not found
                        install = True
                        break

                    # Ensure that needed USE flags are present
                    if args:
                        match_fname = result.stdout.strip()
                        with open(match_fname, 'r', encoding='utf8',
                                errors='backslashreplace') as fp:
                            for line in fp:
                                for arg in args:
                                    if arg.startswith("-"):
                                        continue

                                if not re.search(rf"\s*{arg}\b", line):
                                    # Needed file argument not found
                                    install = True
                                    break

                    # Everything looks ok, don't install
                    break

                # emit a code to setup missing USE
                if install:
                    extra_cmds += (f"sudo su -c 'echo \"{portage}\" > {use_base}/{fname}'\n")

        # Now, we can use emerge and let it respect USE
        return self.get_install_progs(progs,
                                      "emerge --ask --changed-use --binpkg-respect-use=y",
                                      extra_cmds)

    def get_install(self):
        """
        OS-specific hints logic. Seeks for a hinter. If found, use it to
        provide package-manager specific install commands.

        Otherwise, outputs install instructions for the meta-packages.

        Returns a string with the command to be executed to install the
        the needed packages, if distro found. Otherwise, return just a
        list of packages that require installation.
        """
        os_hints = {
            re.compile("Red Hat Enterprise Linux"):   self.give_redhat_hints,
            re.compile("Fedora"):                     self.give_redhat_hints,
            re.compile("AlmaLinux"):                  self.give_redhat_hints,
            re.compile("Amazon Linux"):               self.give_redhat_hints,
            re.compile("CentOS"):                     self.give_redhat_hints,
            re.compile("openEuler"):                  self.give_redhat_hints,
            re.compile("Oracle Linux Server"):        self.give_redhat_hints,
            re.compile("Rocky Linux"):                self.give_redhat_hints,
            re.compile("Springdale Open Enterprise"): self.give_redhat_hints,

            re.compile("Ubuntu"):                     self.give_debian_hints,
            re.compile("Debian"):                     self.give_debian_hints,
            re.compile("Devuan"):                     self.give_debian_hints,
            re.compile("Kali"):                       self.give_debian_hints,
            re.compile("Mint"):                       self.give_debian_hints,

            re.compile("openSUSE"):                   self.give_opensuse_hints,

            re.compile("Mageia"):                     self.give_mageia_hints,
            re.compile("OpenMandriva"):               self.give_mageia_hints,

            re.compile("Arch Linux"):                 self.give_arch_linux_hints,
            re.compile("Gentoo"):                     self.give_gentoo_hints,
        }

        # If the OS is detected, use per-OS hint logic
        for regex, os_hint in os_hints.items():
            if regex.search(self.system_release):
                return os_hint()

        #
        # Fall-back to generic hint code for other distros
        # That's far from ideal, specially for LaTeX dependencies.
        #
        progs = {"sphinx-build": "sphinx"}
        if self.pdf:
            self.check_missing_tex()

        self.distro_msg = \
            f"I don't know distro {self.system_release}.\n" \
            "So, I can't provide you a hint with the install procedure.\n" \
            "There are likely missing dependencies."

        return self.get_install_progs(progs, None)

    #
    # Common dependencies
    #
    def deactivate_help(self):
        """
        Print a helper message to disable a virtual environment.
        """

        print("\n    If you want to exit the virtualenv, you can use:")
        print("\tdeactivate")

    def get_virtenv(self):
        """
        Give a hint about how to activate an already-existing virtual
        environment containing sphinx-build.

        Returns a tuble with (activate_cmd_path, sphinx_version) with
        the newest available virtual env.
        """

        cwd = os.getcwd()

        activates = []

        # Add all sphinx prefixes with possible version numbers
        for p in self.virtenv_prefix:
            activates += glob(f"{cwd}/{p}[0-9]*/bin/activate")

        activates.sort(reverse=True, key=str.lower)

        # Place sphinx_latest first, if it exists
        for p in self.virtenv_prefix:
            activates = glob(f"{cwd}/{p}*latest/bin/activate") + activates

        ver = (0, 0, 0)
        for f in activates:
            # Discard too old Sphinx virtual environments
            match = re.search(r"(\d+)\.(\d+)\.(\d+)", f)
            if match:
                ver = (int(match.group(1)), int(match.group(2)), int(match.group(3)))

                if ver < self.min_version:
                    continue

            sphinx_cmd = f.replace("activate", "sphinx-build")
            if not os.path.isfile(sphinx_cmd):
                continue

            ver = self.get_sphinx_version(sphinx_cmd)

            if not ver:
                venv_dir = f.replace("/bin/activate", "")
                print(f"Warning: virtual environment {venv_dir} is not working.\n" \
                      "Python version upgrade? Remove it with:\n\n" \
                      "\trm -rf {venv_dir}\n\n")
            else:
                if self.need_sphinx and ver >= self.min_version:
                    return (f, ver)
                elif parse_version(ver) > self.cur_version:
                    return (f, ver)

        return ("", ver)

    def recommend_sphinx_upgrade(self):
        """
        Check if Sphinx needs to be upgraded.

        Returns a tuple with the higest available Sphinx version if found.
        Otherwise, returns None to indicate either that no upgrade is needed
        or no venv was found.
        """

        # Avoid running sphinx-builds from venv if cur_version is good
        if self.cur_version and self.cur_version >= RECOMMENDED_VERSION:
            self.latest_avail_ver = self.cur_version
            return None

        # Get the highest version from sphinx_*/bin/sphinx-build and the
        # corresponding command to activate the venv/virtenv
        self.activate_cmd, self.venv_ver = self.get_virtenv()

        # Store the highest version from Sphinx existing virtualenvs
        if self.activate_cmd and self.venv_ver > self.cur_version:
            self.latest_avail_ver = self.venv_ver
        else:
            if self.cur_version:
                self.latest_avail_ver = self.cur_version
            else:
                self.latest_avail_ver = (0, 0, 0)

        # As we don't know package version of Sphinx, and there's no
        # virtual environments, don't check if upgrades are needed
        if not self.virtualenv:
            if not self.latest_avail_ver:
                return None

            return self.latest_avail_ver

        # Either there are already a virtual env or a new one should be created
        self.need_pip = True

        if not self.latest_avail_ver:
            return None

        # Return if the reason is due to an upgrade or not
        if self.latest_avail_ver != (0, 0, 0):
            if self.latest_avail_ver < RECOMMENDED_VERSION:
                self.rec_sphinx_upgrade = 1

        return self.latest_avail_ver

    def recommend_package(self):
        """
        Recommend installing Sphinx as a distro-specific package.
        """

        print("\n2) As a package with:")

        old_need = self.deps.need
        old_optional = self.deps.optional

        self.pdf = False
        self.deps.optional = 0
        old_verbose = self.verbose_warn_install
        self.verbose_warn_install = 0

        self.deps.clear_deps()

        self.deps.add_package("python-sphinx", DepManager.PYTHON_MANDATORY)

        cmd = self.get_install()
        if cmd:
            print(cmd)

        self.deps.need = old_need
        self.deps.optional = old_optional
        self.verbose_warn_install = old_verbose

    def recommend_sphinx_version(self, virtualenv_cmd):
        """
        Provide recommendations for installing or upgrading Sphinx based
        on current version.

        The logic here is complex, as it have to deal with different versions:

        - minimal supported version;
        - minimal PDF version;
        - recommended version.

        It also needs to work fine with both distro's package and
        venv/virtualenv
        """

        if self.recommend_python:
            cur_ver = sys.version_info[:3]
            if cur_ver < MIN_PYTHON_VERSION:
                print(f"\nPython version {cur_ver} is incompatible with doc build.\n" \
                    "Please upgrade it and re-run.\n")
                return

        # Version is OK. Nothing to do.
        if self.cur_version != (0, 0, 0) and self.cur_version >= RECOMMENDED_VERSION:
            return

        if self.latest_avail_ver:
            latest_avail_ver = ver_str(self.latest_avail_ver)

        if not self.need_sphinx:
            # sphinx-build is present and its version is >= $min_version

            # only recommend enabling a newer virtenv version if makes sense.
            if self.latest_avail_ver and self.latest_avail_ver > self.cur_version:
                print(f"\nYou may also use the newer Sphinx version {latest_avail_ver} with:")
                if f"{self.virtenv_prefix}" in os.getcwd():
                    print("\tdeactivate")
                print(f"\t. {self.activate_cmd}")
                self.deactivate_help()
                return

            if self.latest_avail_ver and self.latest_avail_ver >= RECOMMENDED_VERSION:
                return

        if not self.virtualenv:
            # No sphinx either via package or via virtenv. As we can't
            # Compare the versions here, just return, recommending the
            # user to install it from the package distro.
            if not self.latest_avail_ver or self.latest_avail_ver == (0, 0, 0):
                return

            # User doesn't want a virtenv recommendation, but he already
            # installed one via virtenv with a newer version.
            # So, print commands to enable it
            if self.latest_avail_ver > self.cur_version:
                print(f"\nYou may also use the Sphinx virtualenv version {latest_avail_ver} with:")
                if f"{self.virtenv_prefix}" in os.getcwd():
                    print("\tdeactivate")
                print(f"\t. {self.activate_cmd}")
                self.deactivate_help()
                return
            print("\n")
        else:
            if self.need_sphinx:
                self.deps.need += 1

        # Suggest newer versions if current ones are too old
        if self.latest_avail_ver and self.latest_avail_ver >= self.min_version:
            if self.latest_avail_ver >= RECOMMENDED_VERSION:
                print(f"\nNeed to activate Sphinx (version {latest_avail_ver}) on virtualenv with:")
                print(f"\t. {self.activate_cmd}")
                self.deactivate_help()
                return

            # Version is above the minimal required one, but may be
            # below the recommended one. So, print warnings/notes
            if self.latest_avail_ver < RECOMMENDED_VERSION:
                print(f"Warning: It is recommended at least Sphinx version {RECOMMENDED_VERSION}.")

        # At this point, either it needs Sphinx or upgrade is recommended,
        # both via pip

        if self.rec_sphinx_upgrade:
            if not self.virtualenv:
                print("Instead of install/upgrade Python Sphinx pkg, you could use pip/pypi with:\n\n")
            else:
                print("To upgrade Sphinx, use:\n\n")
        else:
            print("\nSphinx needs to be installed either:\n1) via pip/pypi with:\n")

        if not virtualenv_cmd:
            print("   Currently not possible.\n")
            print("   Please upgrade Python to a newer version and run this script again")
        else:
            print(f"\t{virtualenv_cmd} {self.virtenv_dir}")
            print(f"\t. {self.virtenv_dir}/bin/activate")
            print(f"\tpip install -r {self.requirement_file}")
            self.deactivate_help()

        if self.package_supported:
            self.recommend_package()

        print("\n" \
              "   Please note that Sphinx currentlys produce false-positive\n" \
              "   warnings when the same name is used for more than one type (functions,\n" \
              "   structs, enums,...). This is known Sphinx bug. For more details, see:\n" \
              "\thttps://github.com/sphinx-doc/sphinx/pull/8313")

    def check_needs(self):
        """
        Main method that checks needed dependencies and provides
        recommendations.
        """
        self.python_cmd = sys.executable

        # Check if Sphinx is already accessible from current environment
        self.check_sphinx(self.conf)

        if self.system_release:
            print(f"Detected OS: {self.system_release}.")
        else:
            print("Unknown OS")
        if self.cur_version != (0, 0, 0):
            ver = ver_str(self.cur_version)
            print(f"Sphinx version: {ver}\n")

        # Check the type of virtual env, depending on Python version
        virtualenv_cmd = None

        if sys.version_info < MIN_PYTHON_VERSION:
            min_ver = ver_str(MIN_PYTHON_VERSION)
            print(f"ERROR: at least python {min_ver} is required to build the kernel docs")
            self.need_sphinx = 1

        self.venv_ver = self.recommend_sphinx_upgrade()

        if self.need_pip:
            if sys.version_info < MIN_PYTHON_VERSION:
                self.need_pip = False
                print("Warning: python version is not supported.")
            else:
                virtualenv_cmd = f"{self.python_cmd} -m venv"
                self.check_python_module("ensurepip")

        # Check for needed programs/tools
        self.check_perl_module("Pod::Usage", DepManager.SYSTEM_MANDATORY)

        self.check_program("make", DepManager.SYSTEM_MANDATORY)
        self.check_program("which", DepManager.SYSTEM_MANDATORY)

        self.check_program("dot", DepManager.SYSTEM_OPTIONAL)
        self.check_program("convert", DepManager.SYSTEM_OPTIONAL)

        self.check_python_module("yaml")

        if self.pdf:
            self.check_program("xelatex", DepManager.PDF_MANDATORY)
            self.check_program("rsvg-convert", DepManager.PDF_MANDATORY)
            self.check_program("latexmk", DepManager.PDF_MANDATORY)

        # Do distro-specific checks and output distro-install commands
        cmd = self.get_install()
        if cmd:
            print(cmd)

        # If distro requires some special instructions, print here.
        # Please notice that get_install() needs to be called first.
        if self.distro_msg:
            print("\n" + self.distro_msg)

        if not self.python_cmd:
            if self.need == 1:
                sys.exit("Can't build as 1 mandatory dependency is missing")
            elif self.need:
                sys.exit(f"Can't build as {self.need} mandatory dependencies are missing")

        # Check if sphinx-build is called sphinx-build-3
        if self.need_symlink:
            sphinx_path = self.which("sphinx-build-3")
            if sphinx_path:
                print(f"\tsudo ln -sf {sphinx_path} /usr/bin/sphinx-build\n")

        self.recommend_sphinx_version(virtualenv_cmd)
        print("")

        if not self.deps.optional:
            print("All optional dependencies are met.")

        if self.deps.need == 1:
            sys.exit("Can't build as 1 mandatory dependency is missing")
        elif self.deps.need:
            sys.exit(f"Can't build as {self.deps.need} mandatory dependencies are missing")

        print("Needed package dependencies are met.")

DESCRIPTION = """
Process some flags related to Sphinx installation and documentation build.
"""


def main():
    """Main function"""
    parser = argparse.ArgumentParser(description=DESCRIPTION)

    parser.add_argument(
        "--no-virtualenv",
        action="store_false",
        dest="virtualenv",
        help="Recommend installing Sphinx instead of using a virtualenv",
    )

    parser.add_argument(
        "--no-pdf",
        action="store_false",
        dest="pdf",
        help="Don't check for dependencies required to build PDF docs",
    )

    parser.add_argument(
        "--version-check",
        action="store_true",
        dest="version_check",
        help="If version is compatible, don't check for missing dependencies",
    )

    args = parser.parse_args()

    checker = SphinxDependencyChecker(args)

    checker.check_python()
    checker.check_needs()

# Call main if not used as module
if __name__ == "__main__":
    main()