#!/usr/bin/env perl

use strict;
use warnings;

my $version = '2014-05-22-0628-41ad571';

my $base_url = 'http://get.pmb.io';
my $os       = $^O;
my $bits     = `uname -m`;
my $local    = "$ENV{HOME}/.pmb";

my $os_bits_to_name = {
    darwin => { x86_64 => 'pmb_darwin_amd64', },
    linux  => { x86_64 => 'pmb_linux_amd64', },
};

chomp($bits);

DEBUG("OS: $os\n");
DEBUG("BITS: $bits\n");
DEBUG("VER: $version\n");
DEBUG("LOCAL: $local\n");

my $binary = $os_bits_to_name->{$os}{$bits}
    || die "Unknown os/bits combination $os/$bits\n";
my $sum = get_sum($binary);

if ( !-e $local || !check_sum( $local, $sum ) ) {
    fetch( "${base_url}/${version}/$binary", $local );
    chmod 0755, $local;
}

if ( !check_sum( $local, $sum ) ) {
    die "Downloaded file doesn't match checksum.\n";
}

DEBUG("Running ${local}\n");
exec $local, @ARGV;

sub fetch {
    my ( $remote_path, $local_path ) = @_;

    INFO("Fetching $remote_path\n");
    if ( bin_exists('wget') ) {
        system("wget -q $remote_path -O $local_path");
    }
    elsif ( bin_exists('curl') ) {
        system("curl -s $remote_path $local_path");
    }
    my $rc = $? >> 8;
    DEBUG("RC: $rc\n");
    if ( $rc > 0 ) {
        unlink($local_path);
        die "Unable to fetch $remote_path\n";
    }
}

sub bin_exists {
    my $prog = shift;

    return scalar grep {defined}
        map { -x $_ } map {"$_/$prog"} split( /:/, $ENV{PATH} );
}

sub get_sum {
    my $binary_name = shift;

    foreach my $sum_info (<DATA>) {
        chomp($sum_info);
        my ( $sum, $name ) = split( /\s+/, $sum_info );
        if ( $name eq $binary_name ) {
            return $sum;
        }
    }
}

sub check_sum {
    my ( $local_path, $sum ) = @_;

    my $file_sum;
    if ( bin_exists('openssl') ) {
        my $output = `openssl md5 $local_path`;
        $file_sum = ( split( /\s+/, $output ) )[1];
    }
    elsif ( bin_exists('md5sum') ) {
        my $output = `md5sum $local_path`;
        ($file_sum) = split( /\s+/, $output );
    }
    elsif ( bin_exists('gmd5sum') ) {
        my $output = `gmd5sum $local_path`;
        ($file_sum) = split( /\s+/, $output );
    }
    else {
        die "Unable to check file sum.";
    }

    DEBUG("downloaded: $file_sum\n");
    DEBUG("checked: $sum\n");

    return $file_sum eq $sum;
}

sub DEBUG {
    if ( $ENV{PMB_BOOTSTRAP_DEBUG} ) {
        print @_;
    }
}

sub INFO {
    print @_;
}

__END__
35b268469807b98fd77380231913202f  pmb_darwin_amd64
dca0ed27b683870a6c03f16ffb36ad52  pmb_linux_amd64