#!/usr/bin/perl
# apk add perl-libwww perl-json

use strict;
use warnings;
use 5.016;
use feature "switch";
no if $] >= 5.018, warnings => "experimental::smartmatch";

use LWP::UserAgent;
use LWP::ConnCache;
use CPAN::Meta;
use Module::CoreList;
use JSON;
use Text::Wrap qw(wrap $columns);
use List::Util qw (uniq);

my $license_mappings = {
    "perl_5"     => "GPL-1.0-or-later OR Artistic-1.0-Perl",
    "artistic_2" => "Artistic-2.0",
    "gpl_2"      => "GPL-2.0-only",
    "gpl_3"      => "GPL-3.0-only",
    "mit"        => "MIT",
    "apache_2_0" => "Apache-2.0",
};

my $package_mappings = {
    "LWP"         => "perl-libwww",
    "libwww-perl" => "perl-libwww",
    "TermReadKey" => "perl-term-readkey",
    "perl-ldap"   => "perl-ldap",
    "PerlIO-gzip" => "perl-io-gzip",
};
our $packager = "";
my $template = <<'EOF';
# Automatically generated by apkbuild-cpan, template 3
[% authors %]
pkgname=[% pkgname %]
#_pkgreal is used by apkbuild-cpan to find modules at MetaCpan
_pkgreal=[% pkgreal %]
pkgver=[% pkgver %]
pkgrel=[% pkgrel %]
pkgdesc="Perl module for [% pkgreal %]"
provides="[% provides %]"
replaces="[% replaces %]"
url="https://metacpan.org/release/[% pkgreal %]/"
arch="noarch"
license="GPL-1.0-or-later OR Artistic-1.0-Perl"
depends="perl"
makedepends=""
checkdepends=""
subpackages="$pkgname-doc"
source="[% source %]"
builddir="[% builddir %]"

build() {
	:
}

check() {
	:
}

package() {
	:
}

EOF

our $ua   = LWP::UserAgent->new();
our $json = JSON->new;
$ua->env_proxy;
$ua->conn_cache( LWP::ConnCache->new() );

sub read_file {
    my ($filename) = @_;
    local $/;
    open my $fh, "<", $filename or die "could not open $filename: $!";
    return <$fh>;
}

sub read_assignments_from_file {
    my ($filename) = @_;
    return () if ( !-e $filename );
    my $text  = read_file($filename);
    my %sline = $text =~ /^(\w+)\s*=\s*([^\"\n]*)$/mg;
    my %mline = $text =~ /^(\w+)\s*=\s*\"([^\"]*)\"$/mg;
    my %hash  = ( %sline, %mline );

    my $authors = join( "\n",
        $text =~ /^# Contributor: .*$/mg,
        $text =~ /^# Maintainer: .*$/mg );
    $hash{'authors'} = $authors if length($authors) > 1;

    my $provides = $text =~ m/^provides=\"(.*)\"".*$/mg;
    $hash{'provides'} = $1 if length($provides) >= 1;

    my $requires = $text =~ m/^requires=\"(.*)\"".*$/mg;
    $hash{'requires'} = $1 if length($requires) >= 1;

    return \%hash;
}

sub map_cpan_to_apk {
    my ($cpan_distrib) = @_;
    return $package_mappings->{$cpan_distrib}
      if exists $package_mappings->{$cpan_distrib};

    # most packages are named according to the
    # distribution name
    return 'perl-' . lc $cpan_distrib;
}

sub read_apkbuild {
    return read_assignments_from_file("APKBUILD");
}

sub write_apkbuild {
    my ( $distdata, $apkbuild, $moddata ) = @_;

    my $cpanid = $distdata->{id};
    $cpanid =
      substr( $cpanid, 0, 1 ) . "/" . substr( $cpanid, 0, 2 ) . "/$cpanid";

    my $authors  = undef;
    my $replaces = undef;
    my $provides = undef;
    my $pkgrel   = 0;
    if ( defined $apkbuild ) {
        $authors  = $apkbuild->{authors};
        $provides = $apkbuild->{provides};
        $replaces = $apkbuild->{replaces};
        $pkgrel   = $apkbuild->{pkgrel};
        if ( $apkbuild->{pkgver} eq $moddata->{version} ) {
            $pkgrel++;
        }
    }

    my $builddir;

    my $pkgver = $moddata->{version} =~ s/^[^0-9]+//r;
    if ( $pkgver ne $moddata->{version} ) {

        # Appears to only be needed for Class::DBI
        $builddir = "\$srcdir/\$_pkgreal-" . $moddata->{version};
    }
    else {
        $builddir = "\$srcdir/\$_pkgreal-\$pkgver";
    }

    my %repl = (
        authors => (
            $authors
              or "# Contributor: $packager\n# Maintainer: $packager"
        ),
        pkgname  => map_cpan_to_apk( $moddata->{distribution} ),
        pkgreal  => $moddata->{distribution},
        pkgver   => $moddata->{version} =~ s/^[^0-9]+//r,
        pkgrel   => $pkgrel,
        source   => $moddata->{download_url},
        pkgdesc  => $distdata->{abstract},
        provides => ( $provides or '' ),
        replaces => ( $replaces or '' ),
        builddir => $builddir,
    );
    $repl{source} =~ s/-$repl{pkgver}/-\$pkgver/g;
    $template =~ s/\[% (.*?) %\]/$repl{$1}/g;

    open my $fh, '>', "APKBUILD" or die;
    print $fh $template;
    close $fh;

    say "Wrote $repl{pkgname}/APKBUILD";
}

sub parse_deps {
    my ($reqs) = @_;
    my $distfiles = {};
    my $response;
    my $deps       = "";
    my $reqmodlist = "";

    #Get list of unique required modules from all parameters
    foreach $reqs (@_) {
        for my $module ( $reqs->required_modules ) {
            $reqmodlist .= "$module " unless $reqmodlist =~ m/^$module$/;
        }
    }

    # Check add the require module to $dep if not part of core perl
    foreach my $module ( split " ", $reqmodlist ) {
        next if $module eq 'perl';
        if ( Module::CoreList->is_core($module) ) {
            my $perlver = Module::CoreList->first_release($module);
            say "    $module is part of core perl since $perlver.";
            next;
        }

        # map module name to package name
        $response = $ua->get("https://fastapi.metacpan.org/module/$module");
        $response->is_success or die $response->status_line;
        my $moddata = $json->decode( $response->decoded_content );
        $moddata->{error}
          and die "Error trying to locate $module: $moddata->{error}\n";
        $distfiles->{$module} = $moddata->{distribution};
    }

    # map package names to alpine packages
    foreach ( keys %{$distfiles} ) {
        $response = $ua->get("https://fastapi.metacpan.org/module/$_");
        $response->is_success or die $response->status_line;
        my $distdata = $json->decode( $response->decoded_content );
        $distdata->{error}
          and die "Error trying to locate $_: $distdata->{error}\n";

        my $pkgname = map_cpan_to_apk( $distdata->{distribution} );
        $deps .= "$pkgname " unless $deps =~ m/^$pkgname$/;
    }
    $deps =~ s/\h+/ /g;
    $deps =~ s/ $//;
    return $deps;

}

sub prepare_tree {
    system("abuild checksum unpack prepare") == 0
      or die "abuild checksum failed";
}

sub update_functions {
    my $apkbuild = read_apkbuild;
    my $metaprefix =
      "src/" . $apkbuild->{'_pkgreal'} . "-" . $apkbuild->{'pkgver'} . "/";
    my $build_func;
    my $check_func;
    my $package_func;

    my $text = read_file "APKBUILD";
    if ( -e "$metaprefix/Build.PL" ) {
        $build_func = <<'EOF';
build() {
	export CFLAGS=$(perl -MConfig -E 'say $Config{ccflags}')
	perl Build.PL --installdirs=vendor
	./Build
}
EOF
        $package_func = <<'EOF';
package() {
	./Build install --destdir="$pkgdir"
	find "$pkgdir" \( -name perllocal.pod -o -name .packlist \) -delete
}
EOF
        $check_func = <<'EOF';
check() {
	./Build test
}
EOF
    }
    else {
        $build_func = <<'EOF';
build() {
	export CFLAGS=$(perl -MConfig -E 'say $Config{ccflags}')
	PERL_MM_USE_DEFAULT=1 perl -I. Makefile.PL INSTALLDIRS=vendor
	make
}
EOF
        $package_func = <<'EOF';
package() {
	make DESTDIR="$pkgdir" install
	find "$pkgdir" \( -name perllocal.pod -o -name .packlist \) -delete
}
EOF
        $check_func = <<'EOF';
check() {
	export CFLAGS=$(perl -MConfig -E 'say $Config{ccflags}')
	make test
}
EOF
    }

    $text =~ s/^build\(\) \{.*?^\}\n/$build_func/smg
      or die "Can't replace build function APKBUILD";
    $text =~ s/^package\(\) \{.*?^\}\n/$package_func/smg
      or die "Can't replace package function APKBUILD";
    $text =~ s/^check\(\) \{.*?^\}\n/$check_func/smg
      or die "Can't replace check function APKBUILD";

    open my $fh, '>', "APKBUILD" or die;
    print $fh $text;
    close $fh;
}

sub sort_pkgs_by_orig {
    my $sort_order    = shift;
    my @array_to_sort = split / /, shift;

    s/[\t\n\r\f]/ /g
      for $sort_order;    # remove embedded new lines from sort order
    s/\h+/ /g for $sort_order;    # remove embedded spaces from sort order

    my @sort_order = split / /, $sort_order;

    #get order of order by string
    my $count = 0;
    my %position_of;
    $position_of{$_} = $count++ for @sort_order;

    my %sorted;                   # holds the position of array to sort

    foreach (@array_to_sort) {
        my $pos = $position_of{$_};
        if ( !defined $pos ) {

            # not found in sort order so add to the end
            $sorted{$_} = $count;
            $count++;
        }
        else {
            $sorted{$_} = $pos;
        }
    }

    my @tmp;    # hold array of sorted in position order

    foreach my $name ( sort { $sorted{$a} <=> $sorted{$b} } keys %sorted ) {
        push @tmp, $name;
    }

    # remove any duplicates
    uniq @tmp;

    return join( " ", @tmp );
}

sub format_depends {
    my $deps = shift;

    $columns = 102;

    $deps =~ s/ {2,}/ /g;
    $deps =~ s/^\s//g;
    $deps =~ s/\s$//g;

    if ( length($deps) >= $columns ) {
        $deps = wrap( "\t", "\t", $deps );
    }
    $deps =~ s/\s$//g;

    if ( length($deps) >= $columns ) {
        $deps = "\n" . $deps . "\n\t";
    }
    return $deps;
}

sub do_depends {
    my $modver      = shift;
    my $oldapkbuild = shift;
    my $apkbuild    = read_apkbuild;

    $modver = defined($modver) ? $modver : $apkbuild->{'pkgver'};
    my $metaprefix = '';
    if ( exists $apkbuild->{'_realname'} ) {
        $metaprefix = "src/" . $apkbuild->{'_realname'} . "-" . $modver . "/";
    }
    elsif ( exists $apkbuild->{'_pkgreal'} ) {
        $metaprefix = "src/" . $apkbuild->{'_pkgreal'} . "-" . $modver . "/";
    }
    elsif ( exists $apkbuild->{'_pkgname'} ) {
        $metaprefix = "src/" . $apkbuild->{'_pkgname'} . "-" . $modver . "/";
    }
    elsif ( exists $apkbuild->{'_name'} ) {
        $metaprefix = "src/" . $apkbuild->{'_name'} . "-" . $modver . "/";
    }
    elsif ( exists $apkbuild->{'_realpkgname'} ) {
        $metaprefix =
          "src/" . $apkbuild->{'_realpkgname'} . "-" . $modver . "/";
    }
    elsif ( exists $apkbuild->{'_pkg_real'} ) {
        $metaprefix = "src/" . $apkbuild->{'_pkg_real'} . "-" . $modver . "/";
    }
    else {
        die
"Unable to find meta file directory - check APKBUILD Perl Module Name";
    }

    $metaprefix =~ s/-\$pkgver//g;
    print "\nMetaprefix: $metaprefix\n";

    my $meta;

    foreach
      my $metafile ( "MYMETA.json", "META.json", "MYMETA.yml", "META.yml" )
    {
        if ( -e "$metaprefix$metafile" ) {
            say "Using meta information from $metafile";
            $meta = CPAN::Meta->load_file("$metaprefix$metafile");
            last;
        }
    }
    die "No dependency meta file found" unless $meta;

    my $abstract = $meta->abstract;
    say "Abstract: $abstract";

    my $license = join " OR ",
      map { $license_mappings->{$_} or $_ } $meta->license;
    say "License: $license";

    my $deps = parse_deps(
        $meta->effective_prereqs->requirements_for( 'runtime', 'requires' ) );

    if ( defined $oldapkbuild->{'depends'} ) {
        if ( defined $oldapkbuild->{'cpandepends'} ) {
            $oldapkbuild->{'depends'} =~
              s/\$cpandepends/$oldapkbuild->{'cpandepends'}/g;
        }
        my $libs = $oldapkbuild->{'depends'};
        $libs =~ s/perl\-\w+[-\w+]+//g;
        $libs =~ s/perl//g;
        if ( $libs ne '' ) {
            $deps = $deps . " " . $libs;
        }
        $deps = sort_pkgs_by_orig( $oldapkbuild->{'depends'}, $deps );
    }

    if ( $deps eq '' ) {
        $deps = "perl";
    }
    else {
        $deps = format_depends( "perl " . $deps );

    }

    say "CPAN runtime Required: $deps";
    say "CPAN runtime Recommended: "
      . parse_deps(
        $meta->effective_prereqs->requirements_for( 'runtime', 'recommends' ) );

    my $makedeps = parse_deps(
        $meta->effective_prereqs->requirements_for( 'configure', 'requires' ),
        $meta->effective_prereqs->requirements_for( 'configure', 'recommends' ),
        $meta->effective_prereqs->requirements_for( 'build',     'requires' ),
        $meta->effective_prereqs->requirements_for( 'build',     'recommends' )
    );

    if ( -e "$metaprefix/Build.PL" ) {
        $makedeps = "$makedeps perl-module-build"
          unless $makedeps =~ m/^perl-module-build$/;
    }

    if ( defined $oldapkbuild->{'makedepends'} ) {
        if ( defined $oldapkbuild->{'cpanmakedepends'} ) {
            $oldapkbuild->{'makedepends'} =~
              s/\$cpanmakedepends/$oldapkbuild->{'cpanmakedepends'}/g;
        }
        my $libs = $oldapkbuild->{'makedepends'};
        $libs =~ s/perl\-\w+[-\w+]+//g;
        $makedeps = $makedeps . " " . $libs;
        $makedeps =
          sort_pkgs_by_orig( $oldapkbuild->{'makedepends'}, $makedeps );
    }

    if ( $makedeps eq '' ) {
        $makedeps = "perl-dev";
    }
    else {
        $makedeps = format_depends( "perl-dev " . $makedeps );
    }
    $makedeps =~ s/ +$//g;

    say "CPAN build deps: $makedeps";
    say "    CPAN build requires: "
      . parse_deps(
        $meta->effective_prereqs->requirements_for( 'configure', 'requires' ),
        $meta->effective_prereqs->requirements_for( 'build',     'requires' )
      );
    say "    CPAN build recommends: "
      . parse_deps(
        $meta->effective_prereqs->requirements_for( 'configure', 'recommends' ),
        $meta->effective_prereqs->requirements_for( 'build',     'recommends' )
      );

    my $checkdeps = parse_deps(
        $meta->effective_prereqs->requirements_for( 'test', 'requires' ),
        $meta->effective_prereqs->requirements_for( 'test', 'recommends' )
    );

    if ( defined $oldapkbuild->{'checkdepends'} ) {
        if ( defined $oldapkbuild->{'cpancheckdepends'} ) {
            $oldapkbuild->{'checkdepends'} =~
              s/\$cpancheckdepends/$oldapkbuild->{'cpancheckdepends'}/g;
        }
        my $libs = $oldapkbuild->{'checkdepends'};
        $libs =~ s/perl\-\w+[-\w+]+//g;
        if ( $libs ne "" ) {
            $checkdeps = $checkdeps . " " . $libs;
        }
        $checkdeps =
          sort_pkgs_by_orig( $oldapkbuild->{'checkdepends'}, $checkdeps );
    }

    $checkdeps = format_depends($checkdeps);
    say "CPAN check deps: $checkdeps";

    my $text = read_file "APKBUILD";
    if ( $abstract && $abstract ne 'unknown' ) {
        $text =~ s/^pkgdesc=\"([^\"]*)\"$/pkgdesc=\"$abstract\"/mg
          or die "Can't find pkgdesc line in APKBUILD";
    }
    if ( length(`find $metaprefix -name '*.xs'`) ) {
        if ( !exists $oldapkbuild->{'arch'} ) {
            $text =~ s/^arch=\"([^\"]*)\"$/arch="all"/mg
              or die "Can't find arch line in APKBUILD";
        }
    }
    if ( $license ne 'unknown' ) {
        $text =~ s/^license=\"([^\"]*)\"$/license=\"$license\"/mg
          or die "Can't find license line in APKBUILD";
    }
    $text =~ s/^depends=\"([^\"]*)\"$/depends=\"$deps\"/mg
      or $text =~ s/(license=.*\n)/$1depends=\"$deps\"/gm
      or die "Can't insert depends line in APKBUILD";

    $text =~ s/^makedepends=\"([^\"]*)\"$/makedepends=\"$makedeps\"/mg
      or $text =~ s/(depends=.*\n)/$1makedepends=\"$makedeps\"/gm
      or die "Can't insert makedepends line in APKBUILD";

    $text =~ s/^checkdepends=\"([^\"]*)\"$/checkdepends=\"$checkdeps\"/mg
      or $text =~ s/(makedepends=.*\n)/$1checkdepends=\"$checkdeps\"/gm
      or die "Can't insert checkdepends line in APKBUILD";

    # remove empty variables
    $text =~ s/.*=""\n//g;

    open my $fh, '>', "APKBUILD" or die;
    print $fh $text;
    close $fh;
}

sub get_data {
    my $apkbuild = read_apkbuild;
    my $pkgreal  = '';

    if ( exists $apkbuild->{_realname} ) {
        $pkgreal = $apkbuild->{_realname};
    }
    elsif ( exists $apkbuild->{_pkgreal} ) {
        $pkgreal = $apkbuild->{_pkgreal};
    }
    elsif ( exists $apkbuild->{_pkgname} ) {
        $pkgreal = $apkbuild->{_pkgname};
    }
    elsif ( exists $apkbuild->{_name} ) {
        $pkgreal = $apkbuild->{_name};
    }
    elsif ( exists $apkbuild->{_realpkgname} ) {
        $pkgreal = $apkbuild->{_realpkgname};
    }
    elsif ( exists $apkbuild->{_pkg_real} ) {
        $pkgreal = $apkbuild->{_pkg_real};
    }
    else {
        my $module       = '';
        my $distribution = '';
        while ( ( my $key, my $value ) = each(%$apkbuild) ) {

            # Do not parse any depends lines to not find incorrect module
            if ( $key =~ m/.*depends.*/ ) {
                next;
            }

            # Try to find a perl module name in APKBUILD
            if ( $value =~ m/((\w+::)+\w+)/g ) {

                # Match Perl Module names containing ::
                $module .= "$1 " unless $module =~ m/$1/;
            }
            elsif ( $value =~ m/(([A-Z]\w+-)+\w+)/ ) {

                # Match possible distribution names with -
                $distribution .= "$1 " unless $distribution =~ m/ *$1 /;
            }
            elsif ( $value =~ m/.*release\/([A-Z]\w+).*/ ) {

                # Match Single Word Perl Module Name after release in URL?
                $distribution .= "$1 " unless $distribution =~ m/ *$1 /;
            }
        }

        # Want to try the traditional Module::Name first
        my $list = $module . $distribution;
        foreach ( split / /, $list ) {
            my $type = '';
            if ( $_ =~ m/::/ ) {
                $type = 'module';
            }
            else {
                $type = 'release';
            }

            my $response = $ua->get("https://fastapi.metacpan.org/$type/$_");
            $response->is_success or next;

            my $moddata = $json->decode( $response->decoded_content );
            $moddata->{error} and next;

            $pkgreal = $moddata->{distribution};
            last;
        }
    }

    $pkgreal =~ s/-\$pkgver//g;

    my $response = $ua->get("https://fastapi.metacpan.org/release/$pkgreal");
    $response->is_success
      or die $response->status_line
      . " unable to find $pkgreal verify Perl Module name in APKBUILD\n";
    my $distdata = $json->decode( $response->decoded_content );
    $distdata->{error}
      and die "Error trying to locate $pkgreal: $distdata->{error}\n";

    $response =
      $ua->get("https://fastapi.metacpan.org/module/$distdata->{main_module}");
    $response->is_success or die $response->status_line;
    my $moddata = $json->decode( $response->decoded_content );
    $moddata->{error}
      and die
      "Error trying to locate $distdata->{main_module}: $moddata->{error}\n";

    return ( $apkbuild, $distdata, $moddata );
}

my $abuild_conf = read_assignments_from_file("/etc/abuild.conf");
$packager = $abuild_conf->{PACKAGER} if $abuild_conf->{PACKAGER};

my $user_abuild_conf =
  read_assignments_from_file( $ENV{"HOME"} . "/.abuild/abuild.conf" );
$packager = $user_abuild_conf->{PACKAGER} if $user_abuild_conf->{PACKAGER};

my $command = $ARGV[0];

if ( $command eq "create" ) {
    my $module = $ARGV[1];
    $module or die "Module name is a mandatory argument";

    my $response = $ua->get("https://fastapi.metacpan.org/module/$module");
    $response->is_success or die $response->status_line;
    my $moddata = $json->decode( $response->decoded_content );
    $moddata->{error}
      and die "Error trying to locate $module: $moddata->{error}\n";

    $response =
      $ua->get("https://fastapi.metacpan.org/release/$moddata->{distribution}");
    $response->is_success or die $response->status_line;
    my $distdata = $json->decode( $response->decoded_content );
    $distdata->{error}
      and die "Error trying to locate $module: $distdata->{error}\n";

    my $apkname = map_cpan_to_apk $distdata->{metadata}{name};
    mkdir $apkname;
    chdir $apkname;
    write_apkbuild( $distdata, undef, $moddata );
    prepare_tree;
    update_functions;
    do_depends $moddata->{version};
}
elsif ( $command eq "recreate" ) {

    #TODO: likely should keep pkgrel the same on recreate
    my ( $apkbuild, $distdata, $moddata ) = get_data;
    my $pkgver = $moddata->{version} =~ s/^[^0-9]+//r;
    if ( $pkgver ne $apkbuild->{pkgver} ) {

        #Reset pkgrel on upgrade on recreate
        say "Upgrading CPAN module from $apkbuild->{pkgver} to $pkgver";
        $apkbuild->{pkgrel} = 0;
    }
    write_apkbuild( $distdata, $apkbuild, $moddata );
    prepare_tree;
    update_functions;
    do_depends( $moddata->{version}, $apkbuild );
}
elsif ( $command eq "upgrade" ) {
    my ( $apkbuild, $distdata, $moddata ) = get_data;

    my $pkgver = $moddata->{version} =~ s/^[^0-9]+//r;
    if ( $pkgver ne $apkbuild->{pkgver} ) {
        say "Upgrading CPAN module from $apkbuild->{pkgver} to $pkgver";

        my $text = read_file "APKBUILD";
        $text =~ s/^pkgver=(.*)$/pkgver=$pkgver/mg
          or die "Can't find pkgver line in APKBUILD";
        $text =~ s/^pkgrel=(.*)$/pkgrel=0/mg;

        #FIXME: review whether this works over time
        #       It deletes the blank line before the checksum
        #       So prepare_tree does not insert extra blank line
        $text =~ s/\n^(.*sums=.*\n)/$1/mg;
        open my $fh, '>', "APKBUILD" or die;
        say $fh $text;
        close $fh;
        prepare_tree;
        do_depends( $moddata->{version}, $apkbuild );
    }
    else {
        say "Up-to-date with CPAN";
    }
}
elsif ( $command eq "check" ) {
    my ( $apkbuild, $distdata, $moddata ) = get_data;
    my $pkgver = $moddata->{version} =~ s/^[^0-9]+//r;
    say
"$apkbuild->{pkgname}: Latest version: $pkgver Packaged version: $apkbuild->{pkgver}";
    if ( $pkgver ne $apkbuild->{pkgver} ) {
        exit(1);
    }
}
elsif ( $command eq "update" ) {
    prepare_tree;
    do_depends;
}
else {
    say
"Usage: apkbuild-cpan [create <Module::Name> | check | recreate | update | upgrade]";
    exit;
}
