#!/usr/bin/perl

use Modern::Perl;

# Авторизация для Дарсана
# Ю. Жиловец, 17.02.2015, 12.05.2023

package darsan_auth;

use Crypt::OpenSSL::RSA;
use Mojo::JSON qw/j/;
use Mojo::UserAgent;
use Convert::Ascii85 qw/ascii85_encode/;
use Time::timegm qw/timegm/;
use POSIX::strptime;
use Data::Dumper;
use Mojo::Promise;

sub error
{
  return $_[0]->{error};
}

sub source_ip
{   
  my $self = shift;
  my $ip = shift;
  $self->{ua}->socket_options({LocalAddr => $ip});
}

sub as_server
{
  my $class = shift;
  my $auth_servers = shift;
  my $name = shift;
  my $private = shift;

  if (ref($private) ne "Crypt::OpenSSL::RSA")
  {
    open(K,$private) or do die "No private key found: $private: $!";
    my $key = do { local($/); <K>};
    close(K);
    $private = Crypt::OpenSSL::RSA->new_private_key($key);
    $private->use_sha256_hash;
    $private->use_pkcs1_oaep_padding;
  }

  my $auth_server = ref $auth_servers ? $auth_servers->[0] : $auth_servers;
  return bless {auth_server=>$auth_server, name=>$name, private=>$private, error=>undef, ua=>new Mojo::UserAgent},$class;
}

sub as_user
{
  my $class = shift;
  my $auth_servers = shift;
  my $login = shift;
  my $password = shift;

  my $auth_server = ref $auth_servers ? $auth_servers->[0] : $auth_servers;
  return bless {auth_server=>$auth_server, login=>$login, password=>$password, error=>undef, ua=>new Mojo::UserAgent},$class;
}

sub set_token
{
  my $self = shift;
  my $token = shift;
  my $exp_stamp = shift;

  $self->{token} = $token;
  $self->{expire} = $exp_stamp;
}

sub token
{
  my $self = shift;
  my $sub = shift;
 
  undef $self->{error};
  return $self->{token} if $self->{token} && $self->{expire}>time();

  my ($err,$token,$expire) = $self->_fetch_token_sync;
  if ($err)
  {
    $self->{error} = $err;
    return undef;
  }

  $self->{token} = $token;
  $self->{expire} = $expire;

  return $token;
}

sub token_p
{
  my $self = shift;

  return Mojo::Promise->resolve($self->{token}) if $self->{token} && $self->{expire}>time();

  $self->_fetch_token_async->then(sub
  {
    my ($token, $expire) = @_;

    $self->{token} = $token;
    $self->{expire} = $expire;
    return $token;
  });
}

sub _token_query
{
  my $self = shift;

  if ($self->{login})
  {
    return ( "$self->{auth_server}/token", {ver=>2, login=>$self->{login}, password=>$self->{password}} );
  }
  else
  {
    my $t = time();
    my $sign = $self->{private}->sign("$self->{name}/$t");
    return ( "$self->{auth_server}/server-token/$self->{name}", {ver=>2, time=>$t, sign=>ascii85_encode($sign)} );
  }
}

sub _fetch_token_sync
{
  my $self = shift;
  my ($url, $form) = $self->_token_query;

  my $tx = $self->{ua}->post($url => form => $form);
  return $self->_parse_reply($tx);
}

sub _fetch_token_async
{
  my $self = shift;
  my $sub = shift;

  my ($url, $form) = $self->_token_query;
  
  $self->{ua}->post_p($url => form => $form)
  ->catch(sub
  {
    my $err = shift;
    die {url=>$url, code=>500, message=>$err, body=>""};
  })
  ->then(sub
  {
    my $tx = shift;
    my ($error, $token, $expires) = $self->_parse_reply($tx);
    die $error if $error;
    return ($token, $expires);
  })
}

sub _parse_reply
{
  my $self = shift;
  my $tx = shift;
  
  my $body = $tx->res->body;
  $body = j($body) if $tx->res->headers->content_type  && $tx->res->headers->content_type =~ m|^application/json|;
      
  if (my $e = $tx->error)
  {
    $e->{code} ||= 500;
    my $err = {url=>$tx->req->url."", code=>$e->{code}, message=>$e->{message}, body=>$tx->res->body};
    return ($err);
  }

  my $token = $body->{token};
  my $expires = $body->{expires};
  my $exp = parse_time($expires);

  return (undef, $token, $exp);
}

sub parse_time {
  no warnings;
  my $s           = shift;
  my $time_format = "%Y-%m-%d %H:%M:%S%z";

  $s =~ /([+-])(\d{4})$/;
  my $tz_sign = $1;
  my $tz      = $2;
  $s =~ s/[+-]\d{4}$//;

  my $time = timegm(POSIX::strptime($s, $time_format));

  if ($tz) {
    my $h      = substr($tz, 0, 2);
    my $s      = substr($tz, 2, 2);
    my $offset = ($h * 60 + $s) * 60;
    $offset    = -$offset if $tz_sign eq "+";
    $time      += $offset;
  }

  return $time;
}

1;