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

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

use warnings;
use strict;

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

use POE;                         # 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 FS::UID qw(adminsuidsetup);
#use FS::SelfService::XMLRPC;
use FS::ClientAPI qw( load_clientapi_modules );
use FS::ClientAPI_XMLRPC;


#sub DEBUG ()         { 0 }       # Enable a lot of runtime information.
#sub MAX_PROCESSES () { 10 }      # Total number of server processes.
#sub SERVER_PORT ()   { 8092 }    # Server port to listen on.
sub DEBUG ()         { 0 }       # Enable a lot of runtime information.
sub MAX_PROCESSES () { 32 }      # Total number of server processes.
sub SERVER_PORT ()   { 8080 }    # Server port to listen on.

sub TESTING_CHURN () { 0 }       # Randomly shutdown children to test respawn.

#xmlrpc.cgi
my %typelookup = (
  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'],
);

# These are HTTP::Request headers that have methods.
my @method_headers =
  qw( authorization authorization_basic
  content content_encoding content_language content_length content_type
  date expires from if_modified_since if_unmodified_since last_modified
  method protocol proxy_authorization proxy_authorization_basic referer
  server title url user_agent www_authenticate
);

# These are HTTP::Request headers that do not have methods.
my @header_headers =
  qw( username opaque stale algorithm realm uri qop auth nonce cnonce
  nc response
);

###
# init
###

my $user = shift or die &usage;

#FS::ClientAPI
load_clientapi_modules;

###
# the main loop
###

# Spawn up to MAX_PROCESSES server processes, and then run them.  Exit
# when they are done.

server_spawn(MAX_PROCESSES);
$poe_kernel->run();

#XXX we probably want to sleep a bit and then try all over again...
exit 0;

###
# 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_chld   => \&server_got_sig_chld,
            got_connection => \&server_got_connection,

            _child => sub { 0 },
          },
        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( CHLD => "got_sig_chld" );
    $kernel->sig( INT  => "got_sig_int" );

    $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} ) {

        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;
            next;
        }

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

        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 {
    DEBUG and warn "Server $$ received SIGINT.\n";
    return 0;
}

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

    if ( delete $heap->{children}->{$child_pid} ) {
        DEBUG and warn "Server $$ received SIGCHLD.\n";
        $kernel->yield("do_fork");
    }
    return 0;
}

### 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,
          },
      );

    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 ];

    freeside_kid_time();

    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);
}

#setup the database connection and other things FS::SelfService::XMLRPC
#expects to be in place.  aka "kid time" in freeside-selfservice-server
sub freeside_kid_time {

  #if we need a db connection in the parent
  ##get new db handle
  #$FS::UID::dbh->{InactiveDestroy} = 1;
  #forksuidsetup($user);

  adminsuidsetup($user);

  #i guess that was it
}

### 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;