#!/usr/bin/perl
# SPDX-License-Identifier: GPL-2.0-or-later
use strict;

# Copyright (c) 2017 Mauro Carvalho Chehab <mchehab@kernel.org>
#

my $conf = "Documentation/conf.py";
my $requirement_file = "Documentation/sphinx/requirements.txt";

#
# Static vars
#

my %missing;
my $system_release;
my $need = 0;
my $optional = 0;
my $need_symlink = 0;
my $need_sphinx = 0;
my $rec_sphinx_upgrade = 0;
my $install = "";
my $virtenv_dir = "sphinx_";

#
# Command line arguments
#

my $pdf = 1;
my $virtualenv = 1;

#
# List of required texlive packages on Fedora and OpenSuse
#

my %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',
	'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',
);

#
# Subroutines that checks if a feature exists
#

sub check_missing(%)
{
	my %map = %{$_[0]};

	foreach my $prog (sort keys %missing) {
		my $is_optional = $missing{$prog};

		# 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 ($is_optional == 2 && !$pdf) {
			$optional--;
			next;
		}

		if ($is_optional) {
			print "Warning: better to also install \"$prog\".\n";
		} else {
			print "ERROR: please install \"$prog\", otherwise, build won't work.\n";
		}
		if (defined($map{$prog})) {
			$install .= " " . $map{$prog};
		} else {
			$install .= " " . $prog;
		}
	}

	$install =~ s/^\s//;
}

sub add_package($$)
{
	my $package = shift;
	my $is_optional = shift;

	$missing{$package} = $is_optional;
	if ($is_optional) {
		$optional++;
	} else {
		$need++;
	}
}

sub check_missing_file($$$)
{
	my $file = shift;
	my $package = shift;
	my $is_optional = shift;

	return if(-e $file);

	add_package($package, $is_optional);
}

sub findprog($)
{
	foreach(split(/:/, $ENV{PATH})) {
		return "$_/$_[0]" if(-x "$_/$_[0]");
	}
}

sub check_program($$)
{
	my $prog = shift;
	my $is_optional = shift;

	return if findprog($prog);

	add_package($prog, $is_optional);
}

sub check_perl_module($$)
{
	my $prog = shift;
	my $is_optional = shift;

	my $err = system("perl -M$prog -e 1 2>/dev/null /dev/null");
	return if ($err == 0);

	add_package($prog, $is_optional);
}

sub check_python_module($$)
{
	my $prog = shift;
	my $is_optional = shift;

	my $err = system("python3 -c 'import $prog' 2>/dev/null /dev/null");
	return if ($err == 0);
	my $err = system("python -c 'import $prog' 2>/dev/null /dev/null");
	return if ($err == 0);

	add_package($prog, $is_optional);
}

sub check_rpm_missing($$)
{
	my @pkgs = @{$_[0]};
	my $is_optional = $_[1];

	foreach my $prog(@pkgs) {
		my $err = system("rpm -q '$prog' 2>/dev/null >/dev/null");
		add_package($prog, $is_optional) if ($err);
	}
}

sub check_pacman_missing($$)
{
	my @pkgs = @{$_[0]};
	my $is_optional = $_[1];

	foreach my $prog(@pkgs) {
		my $err = system("pacman -Q '$prog' 2>/dev/null >/dev/null");
		add_package($prog, $is_optional) if ($err);
	}
}

sub check_missing_tex($)
{
	my $is_optional = shift;
	my $kpsewhich = findprog("kpsewhich");

	foreach my $prog(keys %texlive) {
		my $package = $texlive{$prog};
		if (!$kpsewhich) {
			add_package($package, $is_optional);
			next;
		}
		my $file = qx($kpsewhich $prog);
		add_package($package, $is_optional) if ($file =~ /^\s*$/);
	}
}

sub get_sphinx_fname()
{
	my $fname = "sphinx-build";
	return $fname if findprog($fname);

	$fname = "sphinx-build-3";
	if (findprog($fname)) {
		$need_symlink = 1;
		return $fname;
	}

	if ($virtualenv) {
		my $prog = findprog("virtualenv-3");
		$prog = findprog("virtualenv-3.5") if (!$prog);

		check_program("virtualenv", 0) if (!$prog);
		$need_sphinx = 1;
	} else {
		add_package("python-sphinx", 0);
	}

	return "";
}

sub check_sphinx()
{
	my $min_version;
	my $rec_version;
	my $cur_version;

	open IN, $conf or die "Can't open $conf";
	while (<IN>) {
		if (m/^\s*needs_sphinx\s*=\s*[\'\"]([\d\.]+)[\'\"]/) {
			$min_version=$1;
			last;
		}
	}
	close IN;

	die "Can't get needs_sphinx version from $conf" if (!$min_version);

	open IN, $requirement_file or die "Can't open $requirement_file";
	while (<IN>) {
		if (m/^\s*Sphinx\s*==\s*([\d\.]+)$/) {
			$rec_version=$1;
			last;
		}
	}
	close IN;

	die "Can't get recommended sphinx version from $requirement_file" if (!$min_version);

	$virtenv_dir .= $rec_version;

	my $sphinx = get_sphinx_fname();
	return if ($sphinx eq "");

	open IN, "$sphinx --version 2>&1 |" or die "$sphinx returned an error";
	while (<IN>) {
		if (m/^\s*sphinx-build\s+([\d\.]+)$/) {
			$cur_version=$1;
			last;
		}
		# Sphinx 1.2.x uses a different format
		if (m/^\s*Sphinx.*\s+([\d\.]+)$/) {
			$cur_version=$1;
			last;
		}
	}
	close IN;

	die "$sphinx didn't return its version" if (!$cur_version);

	printf "Sphinx version %s (minimal: %s, recommended >= %s)\n",
		$cur_version, $min_version, $rec_version;

	if ($cur_version lt $min_version) {
		print "Warning: Sphinx version should be >= $min_version\n\n";
		$need_sphinx = 1;
		return;
	}

	if ($cur_version lt $rec_version) {
		print "Warning: It is recommended at least Sphinx version $rec_version.\n";
		print "         To upgrade, use:\n\n";
		$rec_sphinx_upgrade = 1;
	}
}

#
# Ancillary subroutines
#

sub catcheck($)
{
  my $res = "";
  $res = qx(cat $_[0]) if (-r $_[0]);
  return $res;
}

sub which($)
{
	my $file = shift;
	my @path = split ":", $ENV{PATH};

	foreach my $dir(@path) {
		my $name = $dir.'/'.$file;
		return $name if (-x $name );
	}
	return undef;
}

#
# Subroutines that check distro-specific hints
#

sub give_debian_hints()
{
	my %map = (
		"python-sphinx"		=> "python3-sphinx",
		"sphinx_rtd_theme"	=> "python3-sphinx-rtd-theme",
		"virtualenv"		=> "virtualenv",
		"dot"			=> "graphviz",
		"convert"		=> "imagemagick",
		"Pod::Usage"		=> "perl-modules",
		"xelatex"		=> "texlive-xetex",
		"rsvg-convert"		=> "librsvg2-bin",
	);

	if ($pdf) {
		check_missing_file("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
				   "fonts-dejavu", 2);
	}

	check_program("dvipng", 2) if ($pdf);
	check_missing(\%map);

	return if (!$need && !$optional);
	printf("You should run:\n\n\tsudo apt-get install $install\n");
}

sub give_redhat_hints()
{
	my %map = (
		"python-sphinx"		=> "python3-sphinx",
		"sphinx_rtd_theme"	=> "python3-sphinx_rtd_theme",
		"virtualenv"		=> "python3-virtualenv",
		"dot"			=> "graphviz",
		"convert"		=> "ImageMagick",
		"Pod::Usage"		=> "perl-Pod-Usage",
		"xelatex"		=> "texlive-xetex-bin",
		"rsvg-convert"		=> "librsvg2-tools",
	);

	my @fedora26_opt_pkgs = (
		"graphviz-gd",		# Fedora 26: needed for PDF support
	);

	my @fedora_tex_pkgs = (
		"texlive-collection-fontsrecommended",
		"texlive-collection-latex",
		"dejavu-sans-fonts",
		"dejavu-serif-fonts",
		"dejavu-sans-mono-fonts",
	);

	#
	# Checks valid for RHEL/CentOS version 7.x.
	#
	my $old = 0;
	my $rel;
	$rel = $1 if ($system_release =~ /release\s+(\d+)/);

	if (!($system_release =~ /Fedora/)) {
		$map{"virtualenv"} = "python-virtualenv";

		if ($rel && $rel < 8) {
			$old = 1;
			$pdf = 0;

			printf("Note: texlive packages on RHEL/CENTOS <= 7 are incomplete. Can't support PDF output\n");
			printf("If you want to build PDF, please read:\n");
			printf("\thttps://www.systutorials.com/241660/how-to-install-tex-live-on-centos-7-linux/\n");
		}
	} else {
		if ($rel && $rel < 26) {
			$old = 1;
		}
	}
	if (!$rel) {
		printf("Couldn't identify release number\n");
		$old = 1;
		$pdf = 0;
	}

	check_rpm_missing(\@fedora26_opt_pkgs, 2) if ($pdf && !$old);
	check_rpm_missing(\@fedora_tex_pkgs, 2) if ($pdf);
	check_missing_tex(2) if ($pdf);
	check_missing(\%map);

	return if (!$need && !$optional);

	if (!$old) {
		# dnf, for Fedora 18+
		printf("You should run:\n\n\tsudo dnf install -y $install\n");
	} else {
		# yum, for RHEL (and clones) or Fedora version < 18
		printf("You should run:\n\n\tsudo yum install -y $install\n");
	}
}

sub give_opensuse_hints()
{
	my %map = (
		"python-sphinx"		=> "python3-sphinx",
		"sphinx_rtd_theme"	=> "python3-sphinx_rtd_theme",
		"virtualenv"		=> "python3-virtualenv",
		"dot"			=> "graphviz",
		"convert"		=> "ImageMagick",
		"Pod::Usage"		=> "perl-Pod-Usage",
		"xelatex"		=> "texlive-xetex-bin",
		"rsvg-convert"		=> "rsvg-view",
	);

	my @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",
	);

	$map{"latexmk"} = "texlive-latexmk-bin";

	check_rpm_missing(\@suse_tex_pkgs, 2) if ($pdf);
	check_missing_tex(2) if ($pdf);
	check_missing(\%map);

	return if (!$need && !$optional);
	printf("You should run:\n\n\tsudo zypper install --no-recommends $install\n");
}

sub give_mageia_hints()
{
	my %map = (
		"python-sphinx"		=> "python3-sphinx",
		"sphinx_rtd_theme"	=> "python3-sphinx_rtd_theme",
		"virtualenv"		=> "python3-virtualenv",
		"dot"			=> "graphviz",
		"convert"		=> "ImageMagick",
		"Pod::Usage"		=> "perl-Pod-Usage",
		"xelatex"		=> "texlive",
		"rsvg-convert"		=> "librsvg2-tools",
	);

	my @tex_pkgs = (
		"texlive-fontsextra",
	);

	$map{"latexmk"} = "texlive-collection-basic";

	check_rpm_missing(\@tex_pkgs, 2) if ($pdf);
	check_missing(\%map);

	return if (!$need && !$optional);
	printf("You should run:\n\n\tsudo urpmi $install\n");
}

sub give_arch_linux_hints()
{
	my %map = (
		"sphinx_rtd_theme"	=> "python-sphinx_rtd_theme",
		"virtualenv"		=> "python-virtualenv",
		"dot"			=> "graphviz",
		"convert"		=> "imagemagick",
		"xelatex"		=> "texlive-bin",
		"rsvg-convert"		=> "extra/librsvg",
	);

	my @archlinux_tex_pkgs = (
		"texlive-core",
		"texlive-latexextra",
		"ttf-dejavu",
	);
	check_pacman_missing(\@archlinux_tex_pkgs, 2) if ($pdf);

	check_missing(\%map);

	return if (!$need && !$optional);
	printf("You should run:\n\n\tsudo pacman -S $install\n");
}

sub give_gentoo_hints()
{
	my %map = (
		"sphinx_rtd_theme"	=> "dev-python/sphinx_rtd_theme",
		"virtualenv"		=> "dev-python/virtualenv",
		"dot"			=> "media-gfx/graphviz",
		"convert"		=> "media-gfx/imagemagick",
		"xelatex"		=> "dev-texlive/texlive-xetex media-fonts/dejavu",
		"rsvg-convert"		=> "gnome-base/librsvg",
	);

	check_missing_file("/usr/share/fonts/dejavu/DejaVuSans.ttf",
			   "media-fonts/dejavu", 2) if ($pdf);

	check_missing(\%map);

	return if (!$need && !$optional);

	printf("You should run:\n\n");
	printf("\tsudo su -c 'echo \"media-gfx/imagemagick svg png\" > /etc/portage/package.use/imagemagick'\n");
	printf("\tsudo su -c 'echo \"media-gfx/graphviz cairo pdf\" > /etc/portage/package.use/graphviz'\n");
	printf("\tsudo emerge --ask $install\n");

}

sub check_distros()
{
	# Distro-specific hints
	if ($system_release =~ /Red Hat Enterprise Linux/) {
		give_redhat_hints;
		return;
	}
	if ($system_release =~ /CentOS/) {
		give_redhat_hints;
		return;
	}
	if ($system_release =~ /Scientific Linux/) {
		give_redhat_hints;
		return;
	}
	if ($system_release =~ /Oracle Linux Server/) {
		give_redhat_hints;
		return;
	}
	if ($system_release =~ /Fedora/) {
		give_redhat_hints;
		return;
	}
	if ($system_release =~ /Ubuntu/) {
		give_debian_hints;
		return;
	}
	if ($system_release =~ /Debian/) {
		give_debian_hints;
		return;
	}
	if ($system_release =~ /openSUSE/) {
		give_opensuse_hints;
		return;
	}
	if ($system_release =~ /Mageia/) {
		give_mageia_hints;
		return;
	}
	if ($system_release =~ /Arch Linux/) {
		give_arch_linux_hints;
		return;
	}
	if ($system_release =~ /Gentoo/) {
		give_gentoo_hints;
		return;
	}

	#
	# Fall-back to generic hint code for other distros
	# That's far from ideal, specially for LaTeX dependencies.
	#
	my %map = (
		"sphinx-build" => "sphinx"
	);
	check_missing_tex(2) if ($pdf);
	check_missing(\%map);
	print "I don't know distro $system_release.\n";
	print "So, I can't provide you a hint with the install procedure.\n";
	print "There are likely missing dependencies.\n";
}

#
# Common dependencies
#

sub check_needs()
{
	if ($system_release) {
		print "Detected OS: $system_release.\n";
	} else {
		print "Unknown OS\n";
	}

	# RHEL 7.x and clones have Sphinx version 1.1.x and incomplete texlive
	if (($system_release =~ /Red Hat Enterprise Linux/) ||
	    ($system_release =~ /CentOS/) ||
	    ($system_release =~ /Scientific Linux/) ||
	    ($system_release =~ /Oracle Linux Server/)) {
		$virtualenv = 1;
		$pdf = 0;

		printf("NOTE: On this distro, Sphinx and TexLive shipped versions are incompatible\n");
		printf("with doc build. So, use Sphinx via a Python virtual environment.\n\n");
		printf("This script can't install a TexLive version that would provide PDF.\n");
	}

	# Check for needed programs/tools
	check_sphinx();
	check_perl_module("Pod::Usage", 0);
	check_program("make", 0);
	check_program("gcc", 0);
	check_python_module("sphinx_rtd_theme", 1) if (!$virtualenv);
	check_program("dot", 1);
	check_program("convert", 1);

	# Extra PDF files - should use 2 for is_optional
	check_program("xelatex", 2) if ($pdf);
	check_program("rsvg-convert", 2) if ($pdf);
	check_program("latexmk", 2) if ($pdf);

	check_distros();

	if ($need_symlink) {
		printf "\tsudo ln -sf %s /usr/bin/sphinx-build\n\n",
		       which("sphinx-build-3");
	}
	if ($need_sphinx || $rec_sphinx_upgrade) {
		my $activate = "$virtenv_dir/bin/activate";
		if (-e "$ENV{'PWD'}/$activate") {
			printf "\nNeed to activate virtualenv with:\n";
			printf "\t. $activate\n";
		} else {
			my $virtualenv = findprog("virtualenv-3");
			$virtualenv = findprog("virtualenv-3.5") if (!$virtualenv);
			$virtualenv = findprog("virtualenv") if (!$virtualenv);
			$virtualenv = "virtualenv" if (!$virtualenv);

			printf "\t$virtualenv $virtenv_dir\n";
			printf "\t. $activate\n";
			printf "\tpip install -r $requirement_file\n";

			$need++ if (!$rec_sphinx_upgrade);
		}
	}
	printf "\n";

	print "All optional dependenties are met.\n" if (!$optional);

	if ($need == 1) {
		die "Can't build as $need mandatory dependency is missing";
	} elsif ($need) {
		die "Can't build as $need mandatory dependencies are missing";
	}

	print "Needed package dependencies are met.\n";
}

#
# Main
#

while (@ARGV) {
	my $arg = shift(@ARGV);

	if ($arg eq "--no-virtualenv") {
		$virtualenv = 0;
	} elsif ($arg eq "--no-pdf"){
		$pdf = 0;
	} else {
		print "Usage:\n\t$0 <--no-virtualenv> <--no-pdf>\n\n";
		exit -1;
	}
}

#
# Determine the system type. There's no standard 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
#

$system_release = qx(lsb_release -d) if which("lsb_release");
$system_release =~ s/Description:\s*// if ($system_release);
$system_release = catcheck("/etc/system-release") if !$system_release;
$system_release = catcheck("/etc/redhat-release") if !$system_release;
$system_release = catcheck("/etc/lsb-release") if !$system_release;
$system_release = catcheck("/etc/gentoo-release") if !$system_release;
$system_release = catcheck("/etc/issue") if !$system_release;
$system_release =~ s/\s+$//;

check_needs;