/*****************************************************************************
 * ntservice.c: Windows NT/2K/XP service interface
 *****************************************************************************
 * Copyright (C) 2004 the VideoLAN team
 *
 * Authors: Gildas Bazin <gbazin@videolan.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#define VLC_MODULE_LICENSE VLC_LICENSE_GPL_2_PLUS
#include <vlc_common.h>
#include <vlc_threads.h>
#include <vlc_plugin.h>
#include <vlc_interface.h>
#include <vlc_charset.h>
#include <vlc_memstream.h>

#define VLCSERVICENAME "VLC media player"

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
static int  Activate( vlc_object_t * );
static void Close   ( vlc_object_t * );

#define INSTALL_TEXT N_( "Install Windows Service" )
#define INSTALL_LONGTEXT N_( \
    "Install the Service and exit." )
#define UNINSTALL_TEXT N_( "Uninstall Windows Service" )
#define UNINSTALL_LONGTEXT N_( \
    "Uninstall the Service and exit." )
#define NAME_TEXT N_( "Display name of the Service" )
#define NAME_LONGTEXT N_( \
    "Change the display name of the Service." )
#define OPTIONS_TEXT N_("Configuration options")
#define OPTIONS_LONGTEXT N_( \
    "Configuration options that will be " \
    "used by the Service (eg. --foo=bar --no-foobar). It should be specified "\
    "at install time so the Service is properly configured.")
#define EXTRAINTF_TEXT N_("Extra interface modules")
#define EXTRAINTF_LONGTEXT N_( \
    "Additional interfaces spawned by the " \
    "Service. It should be specified at install time so the Service is " \
    "properly configured. Use a comma separated list of interface modules. " \
    "(common values are: logger, sap, rc, http)")

vlc_module_begin ()
    set_shortname( N_("NT Service"))
    set_description( N_("Windows Service interface") )
    set_subcategory( SUBCAT_INTERFACE_CONTROL )
    add_bool( "ntservice-install", false,
              INSTALL_TEXT, INSTALL_LONGTEXT )
    add_bool( "ntservice-uninstall", false,
              UNINSTALL_TEXT, UNINSTALL_LONGTEXT )
    add_string ( "ntservice-name", VLCSERVICENAME,
                 NAME_TEXT, NAME_LONGTEXT )
    add_string ( "ntservice-options", NULL,
                 OPTIONS_TEXT, OPTIONS_LONGTEXT )
    add_string ( "ntservice-extraintf", NULL,
                 EXTRAINTF_TEXT, EXTRAINTF_LONGTEXT )

    set_capability( "interface", 0 )
    set_callbacks( Activate, Close )
vlc_module_end ()

struct intf_sys_t
{
    SERVICE_STATUS_HANDLE hStatus;
    SERVICE_STATUS status;
    char *psz_service;
    vlc_thread_t thread;
};

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static void *Run( void * );
static int NTServiceInstall( intf_thread_t *p_intf );
static int NTServiceUninstall( intf_thread_t *p_intf );
static void WINAPI ServiceDispatch( DWORD numArgs, char **args );
static void WINAPI ServiceCtrlHandler( DWORD control );

/* We need this global */
static intf_thread_t *p_global_intf;

/*****************************************************************************
 * Activate: initialize and create stuff
 *****************************************************************************/
static int Activate( vlc_object_t *p_this )
{
    intf_thread_t *p_intf = (intf_thread_t*)p_this;
    intf_sys_t *p_sys = malloc( sizeof( *p_sys ) );
    if( unlikely(p_sys == NULL) )
        return VLC_ENOMEM;

    p_intf->p_sys = p_sys;

    if( vlc_clone( &p_sys->thread, Run, p_intf ) )
        return VLC_ENOMEM;

    return VLC_SUCCESS;
}

/*****************************************************************************
 * Close: destroy interface
 *****************************************************************************/
void Close( vlc_object_t *p_this )
{
    intf_thread_t *p_intf = (intf_thread_t*)p_this;
    intf_sys_t *p_sys = p_intf->p_sys;

    vlc_join( p_sys->thread, NULL );
    free( p_sys );
}

/*****************************************************************************
 * Run: interface thread
 *****************************************************************************/
static void *Run( void *data )
{
    intf_thread_t *p_intf = data;
    SERVICE_TABLE_ENTRY dispatchTable[] =
    {
        { (WCHAR*) TEXT(VLCSERVICENAME), (LPSERVICE_MAIN_FUNCTION) &ServiceDispatch },
        { NULL, NULL }
    };

    vlc_thread_set_name("vlc-ntservice");

    p_global_intf = p_intf;
    p_intf->p_sys->psz_service = var_InheritString( p_intf, "ntservice-name" );
    p_intf->p_sys->psz_service = p_intf->p_sys->psz_service ?
        p_intf->p_sys->psz_service : strdup(VLCSERVICENAME);

    if( var_InheritBool( p_intf, "ntservice-install" ) )
    {
        NTServiceInstall( p_intf );
        return NULL;
    }

    if( var_InheritBool( p_intf, "ntservice-uninstall" ) )
    {
        NTServiceUninstall( p_intf );
        return NULL;
    }

    if( StartServiceCtrlDispatcher( dispatchTable ) == 0 )
    {
        msg_Err( p_intf, "StartServiceCtrlDispatcher failed" ); /* str review */
    }

    free( p_intf->p_sys->psz_service );

    /* Make sure we exit (In case other interfaces have been spawned) */
    libvlc_Quit( vlc_object_instance(p_intf) );
    return NULL;
}

/*****************************************************************************
 * NT Service utility functions
 *****************************************************************************/
static int NTServiceInstall( intf_thread_t *p_intf )
{
    intf_sys_t *p_sys  = p_intf->p_sys;
    char *psz_extra;
    struct vlc_memstream path_stream;
    WCHAR psz_pathtmp[MAX_PATH];

    SC_HANDLE handle = OpenSCManager( NULL, NULL, SC_MANAGER_ALL_ACCESS );
    if( handle == NULL )
    {
        msg_Err( p_intf,
                 "could not connect to Services Control Manager database" );
        return VLC_EGENERIC;
    }

    if( vlc_memstream_open(&path_stream) != 0 )
    {
        CloseServiceHandle( handle );
        return VLC_ENOMEM;
    }

    /* Find out the filename of ourselves so we can install it to the
     * service control manager */
    GetModuleFileName( NULL, psz_pathtmp, MAX_PATH );
    vlc_memstream_printf( &path_stream, "\"%ls\" -I ntservice", psz_pathtmp );

    psz_extra = var_InheritString( p_intf, "ntservice-extraintf" );
    if( psz_extra && *psz_extra )
        vlc_memstream_printf( &path_stream, " --ntservice-extraintf %s", psz_extra );
    free( psz_extra );

    psz_extra = var_InheritString( p_intf, "ntservice-options" );
    if( psz_extra && *psz_extra )
        vlc_memstream_printf( &path_stream, " %s", psz_extra );
    free( psz_extra );

    if ( vlc_memstream_close( &path_stream ) != 0 )
    {
        CloseServiceHandle( handle );
        return VLC_ENOMEM;
    }

    SC_HANDLE service =
        CreateServiceA( handle, p_sys->psz_service, p_sys->psz_service,
                       GENERIC_READ | GENERIC_EXECUTE,
                       SERVICE_WIN32_OWN_PROCESS,
                       SERVICE_AUTO_START, SERVICE_ERROR_IGNORE,
                       path_stream.ptr, NULL, NULL, NULL, NULL, NULL );
    if( service == NULL )
    {
        if( GetLastError() != ERROR_SERVICE_EXISTS )
        {
            msg_Err( p_intf, "could not create new service: \"%s\" (%s)",
                     p_sys->psz_service, path_stream.ptr );
            free( path_stream.ptr );
            CloseServiceHandle( handle );
            return VLC_EGENERIC;
        }
        else
        {
            msg_Warn( p_intf, "service \"%s\" already exists",
                      p_sys->psz_service );
        }
    }
    else
    {
        msg_Warn( p_intf, "service successfully created" );
    }

    free( path_stream.ptr );

    if( service ) CloseServiceHandle( service );
    CloseServiceHandle( handle );

    return VLC_SUCCESS;
}

static int NTServiceUninstall( intf_thread_t *p_intf )
{
    intf_sys_t *p_sys  = p_intf->p_sys;

    SC_HANDLE handle = OpenSCManager( NULL, NULL, SC_MANAGER_ALL_ACCESS );
    if( handle == NULL )
    {
        msg_Err( p_intf,
                 "could not connect to Services Control Manager database" );
        return VLC_EGENERIC;
    }

    /* First, open a handle to the service */
    SC_HANDLE service = OpenServiceA( handle, p_sys->psz_service, DELETE );
    if( service == NULL )
    {
        msg_Err( p_intf, "could not open service" );
        CloseServiceHandle( handle );
        return VLC_EGENERIC;
    }

    /* Remove the service */
    if( !DeleteService( service ) )
    {
        msg_Err( p_intf, "could not delete service \"%s\"",
                 p_sys->psz_service );
    }
    else
    {
        msg_Dbg( p_intf, "service deleted successfully" );
    }

    CloseServiceHandle( service );
    CloseServiceHandle( handle );

    return VLC_SUCCESS;
}

static void WINAPI ServiceDispatch( DWORD numArgs, char **args )
{
    (void)numArgs;
    (void)args;
    intf_thread_t *p_intf = (intf_thread_t *)p_global_intf;
    intf_sys_t    *p_sys  = p_intf->p_sys;
    char *psz_modules, *psz_parser;

    /* We have to initialize the service-specific stuff */
    memset( &p_sys->status, 0, sizeof(SERVICE_STATUS) );
    p_sys->status.dwServiceType = SERVICE_WIN32;
    p_sys->status.dwCurrentState = SERVICE_START_PENDING;
    p_sys->status.dwControlsAccepted = SERVICE_ACCEPT_STOP;

    p_sys->hStatus =
        RegisterServiceCtrlHandlerA( p_sys->psz_service, &ServiceCtrlHandler );
    if( p_sys->hStatus == (SERVICE_STATUS_HANDLE)0 )
    {
        msg_Err( p_intf, "failed to register service control handler" );
        return;
    }

    /*
     * Load background interfaces
     */
    psz_modules = var_InheritString( p_intf, "ntservice-extraintf" );
    psz_parser = psz_modules;
    while( psz_parser && *psz_parser )
    {
        char *psz_module, *psz_temp;
        psz_module = psz_parser;
        psz_parser = strchr( psz_module, ',' );
        if( psz_parser )
        {
            *psz_parser = '\0';
            psz_parser++;
        }

        if( asprintf( &psz_temp, "%s,none", psz_module ) != -1 )
        {
            /* Try to create the interface */
            if( intf_Create( vlc_object_instance(p_intf), psz_temp ) )
            {
                msg_Err( p_intf, "interface \"%s\" initialization failed",
                         psz_temp );
                free( psz_temp );
                continue;
            }
            free( psz_temp );
        }
    }
    free( psz_modules );

    /* Initialization complete - report running status */
    p_sys->status.dwCurrentState = SERVICE_RUNNING;
    p_sys->status.dwCheckPoint   = 0;
    p_sys->status.dwWaitHint     = 0;

    SetServiceStatus( p_sys->hStatus, &p_sys->status );
}

static void WINAPI ServiceCtrlHandler( DWORD control )
{
    intf_thread_t *p_intf = (intf_thread_t *)p_global_intf;
    intf_sys_t    *p_sys  = p_intf->p_sys;

    switch( control )
    {
    case SERVICE_CONTROL_SHUTDOWN:
    case SERVICE_CONTROL_STOP:
        p_sys->status.dwCurrentState = SERVICE_STOPPED;
        p_sys->status.dwWin32ExitCode = 0;
        p_sys->status.dwCheckPoint = 0;
        p_sys->status.dwWaitHint = 0;
        break;
    case SERVICE_CONTROL_INTERROGATE:
        /* just set the current state to whatever it is... */
        break;
    }

    SetServiceStatus( p_sys->hStatus, &p_sys->status );
}
