#!/usr/bin/perl
#
# based on http://www.perlmonks.org/?node_id=582781 by Justin Hawkins
# and http://poe.perl.org/?POE_Cookbook/Web_Server_With_Forking

###
# modules and constants and variables, oh my
###

use warnings;
use strict;

use constant DEBUG         => 1;       # Enable much runtime information.
use constant MAX_PROCESSES => 10;      # Total server process count.
use constant SERVER_PORT   => 8080;    # Server port.
use constant TESTING_CHURN => 0;       # Randomly test process respawning.

use POE 1.2;                     # Base features.
use POE::Filter::HTTPD;          # For serving HTTP content.
use POE::Wheel::ReadWrite;       # For socket I/O.
use POE::Wheel::SocketFactory;   # For serving socket connections.

use XMLRPC::Transport::HTTP; #SOAP::Transport::HTTP;
use XMLRPC::Lite; # for XMLRPC::Serializer

use FS::Daemon qw( daemonize1 drop_root logfile daemonize2 );
use FS::UID qw( adminsuidsetup forksuidsetup dbh );
use FS::Conf;
use FS::ClientAPI qw( load_clientapi_modules );
use FS::ClientAPI_XMLRPC; #FS::SelfService::XMLRPC;
use FS::TicketSystem;

#freeside
my $FREESIDE_LOG = "%%%FREESIDE_LOG%%%";
my $FREESIDE_LOCK = "%%%FREESIDE_LOCK%%%";
my $lock_file = "$FREESIDE_LOCK/selfservice-xmlrpcd.writelock";

#freeside xmlrpc.cgi
my %typelookup = (
#not utf-8 safe#  base64 => [10, sub {$_[0] =~ /[^\x09\x0a\x0d\x20-\x7f]/}, 'as_base64'],
  dateTime => [35, sub {$_[0] =~ /^\d{8}T\d\d:\d\d:\d\d$/}, 'as_dateTime'],
  string => [40, sub {1}, 'as_string'],
);

###
# freeside init
###

my $user = shift or die &usage;

$FS::Daemon::NOSIG = 1;
$FS::Daemon::PID_NEWSTYLE = 1;
daemonize1('selfservice-xmlrpcd');

POE::Kernel->has_forked(); #daemonize forks...

drop_root();

adminsuidsetup($user);

load_clientapi_modules;

logfile("$FREESIDE_LOG/selfservice-xmlrpcd.log");

daemonize2();

FS::ClientAPI::Signup::clear_cache();

my $conf = new FS::Conf;

die "not running; selfservice-xmlrpc conf option is off\n"
  unless $conf->exists('selfservice-xmlrpc');

#parent doesn't need to hold a DB connection open
dbh->disconnect;
undef $FS::UID::dbh;

###
# the main loop
###

server_spawn(MAX_PROCESSES);
POE::Kernel->run();
exit;

###
# the subroutines
###

### Spawn the main server.  This will run as the parent process.

sub server_spawn {
    my ($max_processes) = @_;

    POE::Session->create(
      inline_states => {
        _start         => \&server_start,
        _stop          => \&server_stop,
        do_fork        => \&server_do_fork,
        got_error      => \&server_got_error,
        got_sig_int    => \&server_got_sig_int,
        got_sig_child  => \&server_got_sig_child,
        got_connection => \&server_got_connection,
        _child         => sub { undef },
      },
      heap => { max_processes => MAX_PROCESSES },
    );
}

### The main server session has started.  Set up the server socket and
### bookkeeping information, then fork the initial child processes.

sub server_start {
    my ( $kernel, $heap ) = @_[ KERNEL, HEAP ];

    $heap->{server} = POE::Wheel::SocketFactory->new
      ( BindPort => SERVER_PORT,
        SuccessEvent => "got_connection",
        FailureEvent => "got_error",
        Reuse        => "yes",
      );

    $kernel->sig( INT  => "got_sig_int" );
    $kernel->sig( TERM => "got_sig_int" ); #huh

    $heap->{children}   = {};
    $heap->{is_a_child} = 0;

    warn "Server $$ has begun listening on port ", SERVER_PORT, "\n";

    $kernel->yield("do_fork");
}

### The server session has shut down.  If this process has any
### children, signal them to shutdown too.

sub server_stop {
    my $heap = $_[HEAP];
    DEBUG and warn "Server $$ stopped.\n";

    if ( my @children = keys %{ $heap->{children} } ) {
        DEBUG and warn "Server $$ is signaling children to stop.\n";
        kill INT => @children;
    }
}

### The server session has encountered an error.  Shut it down.

sub server_got_error {
    my ( $heap, $syscall, $errno, $error ) = @_[ HEAP, ARG0 .. ARG2 ];
      warn( "Server $$ got $syscall error $errno: $error\n",
        "Server $$ is shutting down.\n",
      );
    delete $heap->{server};
}

### The server has a need to fork off more children.  Only honor that
### request form the parent, otherwise we would surely "forkbomb".
### Fork off as many child processes as we need.

sub server_do_fork {
    my ( $kernel, $heap ) = @_[ KERNEL, HEAP ];

    return if $heap->{is_a_child};

    #my $current_children = keys %{ $heap->{children} };
    #for ( $current_children + 2 .. $heap->{max_processes} ) {
    while (scalar(keys %{$heap->{children}}) < $heap->{max_processes}) {

        DEBUG and warn "Server $$ is attempting to fork.\n";

        my $pid = fork();

        unless ( defined($pid) ) {
            DEBUG and
              warn( "Server $$ fork failed: $!\n",
                "Server $$ will retry fork shortly.\n",
              );
            $kernel->delay( do_fork => 1 );
            return;
        }

        # Parent.  Add the child process to its list.
        if ($pid) {
            $heap->{children}->{$pid} = 1;
            $kernel->sig_child($pid, "got_sig_child");
            next;
        }

        # Child.  Clear the child process list.
        $kernel->has_forked();
        DEBUG and warn "Server $$ forked successfully.\n";
        $heap->{is_a_child} = 1;
        $heap->{children}   = {};

        #freeside db connection, etc.
        forksuidsetup($user);

        #why isn't this needed ala freeside-selfservice-server??
        #FS::TicketSystem->init();

        return;
    }
}

### The server session received SIGINT.  Don't handle the signal,
### which in turn will trigger the process to exit gracefully.

sub server_got_sig_int {
    my ( $kernel, $heap ) = @_[ KERNEL, HEAP ];
    DEBUG and warn "Server $$ received SIGINT/TERM.\n";

    if ( my @children = keys %{ $heap->{children} } ) {
        DEBUG and warn "Server $$ is signaling children to stop.\n";
        kill INT => @children;
    }

    delete $heap->{server};
    $kernel->sig_handled();
}

### The server session received a SIGCHLD, indicating that some child
### server has gone away.  Remove the child's process ID from our
### list, and trigger more fork() calls to spawn new children.

sub server_got_sig_child {
    my ( $kernel, $heap, $child_pid ) = @_[ KERNEL, HEAP, ARG1 ];

    return unless delete $heap->{children}->{$child_pid};

   DEBUG and warn "Server $$ reaped child $child_pid.\n";
   $kernel->yield("do_fork") if exists $_[HEAP]->{server};
}

### The server session received a connection request.  Spawn off a
### client handler session to parse the request and respond to it.

sub server_got_connection {
    my ( $heap, $socket, $peer_addr, $peer_port ) = @_[ HEAP, ARG0, ARG1, ARG2 ];

    DEBUG and warn "Server $$ received a connection.\n";

    POE::Session->create(
      inline_states => {
        _start      => \&client_start,
        _stop       => \&client_stop,
        got_request => \&client_got_request,
        got_flush   => \&client_flushed_request,
        got_error   => \&client_got_error,
        _parent     => sub { 0 },
      },
      heap => {
        socket    => $socket,
        peer_addr => $peer_addr,
        peer_port => $peer_port,
      },
    );

    # Gracefully exit if testing process churn.
    delete $heap->{server}
      if TESTING_CHURN and $heap->{is_a_child} and ( rand() < 0.1 );
}

### The client handler has started.  Wrap its socket in a ReadWrite
### wheel to begin interacting with it.

sub client_start {
    my $heap = $_[HEAP];

    $heap->{client} = POE::Wheel::ReadWrite->new
      ( Handle => $heap->{socket},
        Filter       => POE::Filter::HTTPD->new(),
        InputEvent   => "got_request",
        ErrorEvent   => "got_error",
        FlushedEvent => "got_flush",
      );

    DEBUG and warn "Client handler $$/", $_[SESSION]->ID, " started.\n";
}

### The client handler has stopped.  Log that fact.

sub client_stop {
    DEBUG and warn "Client handler $$/", $_[SESSION]->ID, " stopped.\n";
}

### The client handler has received a request.  If it's an
### HTTP::Response object, it means some error has occurred while
### parsing the request.  Send that back and return immediately.
### Otherwise parse and process the request, generating and sending an
### HTTP::Response object in response.

sub client_got_request {
    my ( $heap, $request ) = @_[ HEAP, ARG0 ];

    forksuidsetup($user) unless dbh && dbh->ping;

    my $serializer = new XMLRPC::Serializer(typelookup => \%typelookup);

    #my $soap = SOAP::Transport::HTTP::Server
    my $soap = XMLRPC::Transport::HTTP::Server
               -> new
               -> dispatch_to('FS::ClientAPI_XMLRPC')
               -> serializer($serializer);

    DEBUG and
      warn "Client handler $$/", $_[SESSION]->ID, " is handling a request.\n";

    if ( $request->isa("HTTP::Response") ) {
        $heap->{client}->put($request);
        return;
    }

    $soap->request($request);
    $soap->handle;
    my $response = $soap->response;

    $heap->{client}->put($response);
}

### The client handler received an error.  Stop the ReadWrite wheel,
### which also closes the socket.

sub client_got_error {
    my ( $heap, $operation, $errnum, $errstr ) = @_[ HEAP, ARG0, ARG1, ARG2 ];
    DEBUG and
      warn( "Client handler $$/", $_[SESSION]->ID,
        " got $operation error $errnum: $errstr\n",
        "Client handler $$/", $_[SESSION]->ID, " is shutting down.\n"
      );
    delete $heap->{client};
}

### The client handler has flushed its response to the socket.  We're
### done with the client connection, so stop the ReadWrite wheel.

sub client_flushed_request {
    my $heap = $_[HEAP];
    DEBUG and
      warn( "Client handler $$/", $_[SESSION]->ID,
        " flushed its response.\n",
        "Client handler $$/", $_[SESSION]->ID, " is shutting down.\n"
      );
    delete $heap->{client};
}

sub usage {
  die "Usage:\n\n  freeside-selfservice-xmlrpcd user\n";
}

###
# the end
###

1;