/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */

#include "osl/module.h"
#include "osl/process.h"

#include "rtl/bootstrap.hxx"
#include "rtl/process.h"

#include "salinst.hxx"
#include "unx/gensys.h"
#include "unx/gendata.hxx"
#include "headless/svpinst.hxx"
#include "unx/desktops.hxx"
#include <vcl/printerinfomanager.hxx>
#include <config_vclplug.h>

#include <cstdio>
#include <unistd.h>

extern "C" {
typedef SalInstance*(*salFactoryProc)();
}

namespace {

// HACK to obtain Application::IsHeadlessModeEnabled early on, before
// Application::EnableHeadlessMode has potentially been called:
bool IsHeadlessModeRequested()
{
    if (Application::IsHeadlessModeEnabled()) {
        return true;
    }
    sal_uInt32 n = rtl_getAppCommandArgCount();
    for (sal_uInt32 i = 0; i < n; ++i) {
        OUString arg;
        rtl_getAppCommandArg(i, &arg.pData);
        if ( arg == "--headless" || arg == "-headless" ) {
            return true;
        }
    }
    return false;
}

}

static oslModule pCloseModule = nullptr;

static SalInstance* tryInstance( const OUString& rModuleBase, bool bForce = false )
{
    if (rModuleBase == "svp")
        return svp_create_SalInstance();

    SalInstance* pInst = nullptr;
    OUString aModule(
#ifdef SAL_DLLPREFIX
            SAL_DLLPREFIX
#endif
            "vclplug_" + rModuleBase + "lo" SAL_DLLEXTENSION );

    oslModule aMod = osl_loadModuleRelative(
        reinterpret_cast< oslGenericFunction >( &tryInstance ), aModule.pData,
        SAL_LOADMODULE_GLOBAL );
    if( aMod )
    {
        salFactoryProc aProc = reinterpret_cast<salFactoryProc>(osl_getAsciiFunctionSymbol( aMod, "create_SalInstance" ));
        if( aProc )
        {
            pInst = aProc();
            SAL_INFO(
                "vcl.plugadapt",
                "sal plugin " << aModule << " produced instance " << pInst);
            if( pInst )
            {
                pCloseModule = aMod;

#ifndef ANDROID
                /*
                 * Recent GTK+ versions load their modules with RTLD_LOCAL, so we can
                 * not access the 'gnome_accessibility_module_shutdown' anymore.
                 * So make sure libgtk+ & co are still mapped into memory when
                 * atk-bridge's atexit handler gets called.
                 * #i109007# KDE3 seems to have the same problem.
                 * And same applies for KDE4.
                 */
                if( rModuleBase == "gtk" || rModuleBase == "gtk3" || rModuleBase == "tde" || rModuleBase == "kde" || rModuleBase == "kde4" )
                {
                    pCloseModule = nullptr;
                }
#endif
                GetSalData()->m_pPlugin = aMod;
            }
            else
                osl_unloadModule( aMod );
        }
        else
        {
            SAL_WARN(
                "vcl.plugadapt",
                "could not load symbol create_SalInstance from shared object "
                    << aModule);
            osl_unloadModule( aMod );
        }
    }
    else if (bForce)
    {
        SAL_WARN("vcl.plugadapt", "could not load shared object " << aModule);
    }
    else
    {
        SAL_INFO("vcl.plugadapt", "could not load shared object " << aModule);
    }

    return pInst;
}

#if !defined(ANDROID)

namespace {

extern "C" typedef DesktopType Fn_get_desktop_environment();

}

static DesktopType get_desktop_environment()
{
    OUString aModule(DESKTOP_DETECTOR_DLL_NAME);
    oslModule aMod = osl_loadModuleRelative(
        reinterpret_cast< oslGenericFunction >( &tryInstance ), aModule.pData,
        SAL_LOADMODULE_DEFAULT );
    DesktopType ret = DESKTOP_UNKNOWN;
    if( aMod )
    {
        Fn_get_desktop_environment * pSym
            = reinterpret_cast<Fn_get_desktop_environment *>(
                osl_getAsciiFunctionSymbol(aMod, "get_desktop_environment"));
        if( pSym )
            ret = pSym();
    }
    osl_unloadModule( aMod );
    return ret;
}

#else

#define get_desktop_environment() DESKTOP_NONE // For now...

#endif

static SalInstance* autodetect_plugin()
{
    static const char* const pTDEFallbackList[] =
    {
        "tde",
#if ENABLE_KDE4
        "kde4",
#endif
        "gtk3", "gtk", "gen", nullptr
    };

    static const char* const pKDEFallbackList[] =
    {
#if ENABLE_KDE4
        "kde4",
#endif
        "gtk3", "gtk", "gen", nullptr
    };

    static const char* const pStandardFallbackList[] =
    {
        "gtk3", "gtk", "gen", nullptr
    };

    static const char* const pHeadlessFallbackList[] =
    {
        "svp", nullptr
    };

    DesktopType desktop = get_desktop_environment();
    const char * const * pList = pStandardFallbackList;
    int nListEntry = 0;

    // no server at all: dummy plugin
    if ( desktop == DESKTOP_NONE )
        pList = pHeadlessFallbackList;
    else if ( desktop == DESKTOP_GNOME ||
              desktop == DESKTOP_UNITY ||
              desktop == DESKTOP_XFCE  ||
              desktop == DESKTOP_KDE3 ||
              desktop == DESKTOP_MATE )
        pList = pStandardFallbackList;
    else if( desktop == DESKTOP_TDE )
        pList = pTDEFallbackList;
    else if( desktop == DESKTOP_KDE4 || desktop == DESKTOP_KDE5 )
        pList = pKDEFallbackList;

    SalInstance* pInst = nullptr;
    while( pList[nListEntry] && pInst == nullptr )
    {
        OUString aTry( OUString::createFromAscii( pList[nListEntry] ) );
        pInst = tryInstance( aTry );
        SAL_INFO_IF(
            pInst, "vcl.plugadapt",
            "plugin autodetection: " << pList[nListEntry]);
        nListEntry++;
    }

    return pInst;
}

SalInstance *CreateSalInstance()
{
    SalInstance *pInst = nullptr;

    OUString aUsePlugin;
    if( IsHeadlessModeRequested() )
        aUsePlugin = "svp";
    else
    {
        rtl::Bootstrap::get( "SAL_USE_VCLPLUGIN", aUsePlugin );
    }

    if( !aUsePlugin.isEmpty() )
        pInst = tryInstance( aUsePlugin, true );

    if( ! pInst )
        pInst = autodetect_plugin();

    // fallback, try everything
    static const char* const pPlugin[] = {
        "gtk3", "gtk", "kde4", "kde", "tde", "gen" };

    for ( int i = 0; !pInst && i != SAL_N_ELEMENTS(pPlugin); ++i )
        pInst = tryInstance( OUString::createFromAscii( pPlugin[ i ] ) );

    if( ! pInst )
    {
        std::fprintf( stderr, "no suitable windowing system found, exiting.\n" );
        _exit( 1 );
    }

    // acquire SolarMutex
    pInst->AcquireYieldMutex( 1 );

    return pInst;
}

void DestroySalInstance( SalInstance *pInst )
{
    // release SolarMutex
    pInst->ReleaseYieldMutex();

    delete pInst;
    if( pCloseModule )
        osl_unloadModule( pCloseModule );
}

void InitSalData()
{
}

void DeInitSalData()
{
}

void InitSalMain()
{
}

void SalAbort( const OUString& rErrorText, bool bDumpCore )
{
    if( rErrorText.isEmpty() )
        std::fprintf( stderr, "Application Error\n" );
    else
        std::fprintf( stderr, "%s\n", OUStringToOString(rErrorText, osl_getThreadTextEncoding()).getStr() );
    if( bDumpCore )
        abort();
    else
        _exit(1);
}

const OUString& SalGetDesktopEnvironment()
{
    // Order to match desktops.hxx' DesktopType
    static const char * const desktop_strings[] = {
        "none", "unknown", "GNOME", "UNITY",
        "XFCE", "MATE", "TDE",
        "KDE", "KDE4", "KDE5" };
    static OUString aRet;
    if( aRet.isEmpty())
    {
        aRet = OUString::createFromAscii(
            desktop_strings[get_desktop_environment()]);
    }
    return aRet;
}

SalData::SalData() :
    m_pInstance(nullptr),
    m_pPlugin(nullptr),
    m_pPIManager(nullptr)
{
}

SalData::~SalData()
{
    psp::PrinterInfoManager::release();
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */