#!/usr/bin/perl

use strict;
use warnings;
use autodie qw(:all);
use feature qw(:5.14);
use LWP::UserAgent;
use LWP::ConnCache;
use JSON;

our $packager = '';
my %pkgmap = ();
my %licenses = ();

my $template = <<'EOF';
# Contributor: [% contributor %]
# Maintainer: [% maintainer %]
pkgname=[% pkgname %]
_pkgreal=[% pkgreal %]
pkgver=[% pkgver %]
pkgrel=0
pkgdesc=[% pkgdesc %]
url="http://packages.python.org/pypi/[% pkgreal %]"
arch="noarch"
license="PSF"
pydepends=""
pymakedepends=""
depends="python $pydepends"
makedepends="python-dev $pymakedepends"
subpackages="$pkgname-doc"
source="[% source %]"
builddir="$srcdir/$_pkgreal-$pkgver"

build() {
	cd "$builddir"
	python setup.py build
}

package() {
	cd "$builddir"
	python setup.py install \
		--prefix=/usr \
		--root="$pkgdir" \
		--single-version-externally-managed
}
EOF

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

sub read_file {
    my ($filename) = @_;
    open my $fh, '<:utf8', $filename;
    local $/;
    my $text = <$fh>;
    return $text;
}

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

    my %temp = (%sline, %mline);

    return \%temp;
}

sub map_pypi_to_apk {
    my ($pypi) = @_;
    return $pkgmap{$pypi} unless !exists($pkgmap{$pypi});
    return 'py-'.lc($pypi);
}

sub map_license {
    my ($license) = @_;

    $license =~ s/ or / /g;

    return $license;
}

sub get_source {
    my ($distdata) = @_;

    for my $url (@{$distdata->{urls}}) {
        return $url->{url} if $url->{python_version} eq 'source'
    }
    die "Unable to locate sources for $distdata->{name}.\n";
}

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

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

    my %repl = (
        packager => $packager,
        pkgname  => map_pypi_to_apk($distdata->{info}{name}),
        pkgreal  => $distdata->{info}{name},
        pkgver   => $distdata->{info}{version},
        source   => get_source($distdata),
        license  => map_license($distdata->{info}{license}),
    );
    $template =~ s/\[% (.*?) %\]/$repl{$1}/g;

    open my $fh, '>:utf8', 'APKBUILD';
    print {$fh} $template;
    close $fh;

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

    return \%repl;
}

sub prepare_tree {
    system('abuild checksum unpack prepare');
}

sub get_data {
    my ($package) = @_;
    my $response = $ua->get("http://pypi.python.org/pypi/$package/json");
    $response->is_success or die $response->status_line;
    my $distdata = $json->decode($response->decoded_content);

    return $distdata;
}

sub get_deps {
    my ($data) = @_;

    chdir "src/$data->{pkgreal}-$data->{pkgver}";
    my $reqs = `python ./setup.py --requires`;

    my @reqs = split /\n/, $reqs;

    foreach my $i (0 .. $#reqs) {
        $reqs[$i] =~ s/(\(|\s+).*$//;
        $reqs[$i] = map_pypi_to_apk($reqs[$i]);
    }

    chdir '../..';

    my $apk = read_file('APKBUILD');

    $reqs = join ' ', @reqs;

    $apk =~ s/pymakedepends=""/pymakedepends="$reqs"/;

    open my $fh, '>:utf8', 'APKBUILD';

    print $fh $apk;

    say "Requires: $reqs";
}

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

sub usage {
    say <<'EOF';
Usage: apkbuild-pypi [create <package> | check | recreate | upgrade | update]

In the repository root:
    create <package>: Creates an APKBUILD for <package>

In the package root:
    check           : Reports current & latest version of the package
    recreate        : Recreates the APKBUILD
    upgrade         : Upgrades to the latest version of the package
    update          : Updates APKBUILD metadata
EOF
}

given ($ARGV[0]) {
    when ('create') {
        my $package = $ARGV[1];
        $package or die usage;

        my $distdata = get_data($package);
        my $apkname = map_pypi_to_apk($package);

        mkdir $apkname;
        chdir $apkname;

        my $data = write_apkbuild($distdata);
        prepare_tree;

        get_deps($data);
    } when ('recreate') {
        my $apkbuild = read_apkbuild;
        my $distdata = get_data($apkbuild->{_pkgreal});

        prepare_tree;
        get_deps;
    } when ('upgrade') {
        my $apkbuild = read_apkbuild;
        my $distdata = get_data($apkbuild->{_pkgreal});

        my $pkgver = $distdata->{info}{version};

        if ($pkgver ne $apkbuild->{pkgver}) {
            say "Upgrading PyPI package from $apkbuild->{pkgver} to $pkgver";

            my $text = read_file('APKBUILD');

            $text =~ s/^(pkgver)=.*$/$1=$pkgver/mg or
                die "Can't find pkgver line in APKBUILD";
            $text =~ s/^(pkgrel)=.*$/$1=0/mg or
                die "Can't find pkgrel line in APKBUILD";

            open my $fh, '>:utf8', 'APKBUILD';
            print $fh $text;
            close $fh;
        } else {
            say "Already up to date with PyPI";
        }
    } when ('check') {
        my $apkbuild = read_apkbuild;
        my $distdata = get_data($apkbuild->{_pkgreal});

        my $pkgver = $distdata->{info}{version};

        say "$apkbuild->{pkgname}: Latest version: $pkgver Packaged version: $apkbuild->{pkgver}";
        if ($pkgver ne $apkbuild->{pkgver}) {
            exit(1);
        }
    } when ('update') {
        prepare_tree;
    } default {
        die usage;
    }
}