/*
  LibRCC - plugin's abstraction

  Copyright (C) 2005-2018 Suren A. Chilingaryan <csa@suren.me>

  This library is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License version 2.1 or later
  as published by the Free Software Foundation.

  This library 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 Lesser General Public License 
  for more details.

  You should have received a copy of the GNU Lesser 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.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "internal.h"
#include "rcchome.h"
#include "plugin.h"

#ifdef RCC_PLUGINS
# include <dlfcn.h>
# ifndef RTLD_NOW
#  define RTLD_NOW 0
# endif
#endif /* RCC_PLUGINS */


rcc_library_handle rccLibraryOpen(char *filename)
{
#ifdef RCC_PLUGINS
    if (filename) return (rcc_library_handle)dlopen(filename, RTLD_NOW);
#endif /* RCC_PLUGINS */

    return NULL;
}

void rccLibraryClose(rcc_library_handle handle)
{
#ifdef RCC_PLUGINS
    if (handle) dlclose(handle);
#endif /* RCC_PLUGINS */
}

void* rccLibraryFind(rcc_library_handle handle, const char *symbol)
{
#ifdef RCC_PLUGINS
    if ((handle)||(symbol)) return dlsym(handle, symbol);
#endif /* RCC_PLUGINS */

    return NULL;
}


static rcc_plugin_handle_s rcc_engine_handles[RCC_MAX_PLUGINS];

int rccPluginInit() {
    unsigned int i;
    
    for (i=0;i<RCC_MAX_PLUGINS;i++)
	rcc_engine_handles[i].sn = NULL;
    
    return 0;
}

void rccPluginFree() {
    unsigned int i;
    
    for (i=0;i<RCC_MAX_PLUGINS;i++)
	if (rcc_engine_handles[i].sn) {
	    rccLibraryClose(rcc_engine_handles[i].handle);
	    free(rcc_engine_handles[i].sn);
	    rcc_engine_handles[i].sn = NULL;
	}
}


rcc_plugin_handle rccPluginGetHandleByName(rcc_plugin_type type, const char *name) {
    unsigned int i;

    rcc_plugin_handle handles;
    
    if (!name) return NULL;
    
    switch(type) {
	case RCC_PLUGIN_TYPE_ENGINE:
	    handles = rcc_engine_handles;
	break;
	default:
	    return NULL;
    }
    
    for (i=0;i<RCC_MAX_PLUGINS;i++)
	if ((handles[i].sn)&&(!strcasecmp(handles[i].sn, name))) return handles+i;
    
    return NULL;
}

rcc_plugin_handle rccPluginGetFreeHandle(rcc_plugin_type type) {
    unsigned int i;

    rcc_plugin_handle handles;
    
    switch(type) {
	case RCC_PLUGIN_TYPE_ENGINE:
	    handles = rcc_engine_handles;
	break;
	default:
	    return NULL;
    }
    
    for (i=0;i<RCC_MAX_PLUGINS;i++)
	if (!handles[i].sn) return handles+i;
    
    return NULL;
}

rcc_plugin_handle rccPluginLoad(rcc_plugin_type type, const char *name) {
#ifdef RCC_PLUGINS
    void *res;
    void *infofunc;
    char *pluginfn;

    rcc_plugin_handle plugin;
    
    if (!name) return NULL;
    
    plugin = rccPluginGetHandleByName(type, name);
    if (plugin) return plugin;
    
    plugin = rccPluginGetFreeHandle(type);
    if (!plugin) return plugin;
    
    switch (type) {
	case RCC_PLUGIN_TYPE_ENGINE:
	    pluginfn = (char*)malloc((48 + strlen(rcc_home_dir) + strlen(name))*sizeof(char));
	    if (!pluginfn) return NULL;
	
	    sprintf(pluginfn, "%s/.rcc/engines/%s_engine.so", rcc_home_dir, name);
	    res = rccLibraryOpen(pluginfn);
	    if (!res) {
		sprintf(pluginfn, LIBRCC_DATA_DIR "/engines/%s_engine.so", name);
		res = rccLibraryOpen(pluginfn);
	    }
	    free(pluginfn);
	    
	    if (res) {
		infofunc = rccLibraryFind(res, "rccGetInfo");
		if (infofunc) {
		    plugin->sn = strdup(name);
		    if (plugin->sn) {
			plugin->handle = (rcc_library_handle)res;
			plugin->info_function = infofunc;
			return plugin;
		    } else rccLibraryClose(res);
		} else rccLibraryClose(res);
	    }
	break;
	default:
	    return NULL;
    }
#endif /* RCC_PLUGINS */

    return NULL;
}


rcc_engine *rccPluginEngineGetInfo(const char *name, const char *language) {
    rcc_plugin_handle handle;
    rcc_plugin_engine_info_function infofunc;

    handle = rccPluginLoad(RCC_PLUGIN_TYPE_ENGINE, name);
    if (!handle) return NULL;
    
    infofunc = (rcc_plugin_engine_info_function)(handle->info_function);
    if (!infofunc) return NULL;
    
    return infofunc(language);
}