/**
 * @file alias.c
 * @author Ambroz Bizjak <ambrop7@gmail.com>
 * 
 * @section LICENSE
 * 
 * This file is part of BadVPN.
 * 
 * BadVPN is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 * 
 * BadVPN 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.
 * 
 * @section DESCRIPTION
 * 
 * Synopsis:
 *   alias(string target)
 * 
 * Variables and objects:
 *   - empty name - resolves target
 *   - nonempty name N - resolves target.N
 */

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

#include <misc/concat_strings.h>
#include <ncd/NCDModule.h>

#include <generated/blog_channel_ncd_alias.h>

#define ModuleLog(i, ...) NCDModuleInst_Backend_Log((i), BLOG_CURRENT_CHANNEL, __VA_ARGS__)

struct instance {
    NCDModuleInst *i;
    char *target;
};

static void func_new (NCDModuleInst *i)
{
    // allocate instance
    struct instance *o = malloc(sizeof(*o));
    if (!o) {
        ModuleLog(i, BLOG_ERROR, "failed to allocate instance");
        goto fail0;
    }
    NCDModuleInst_Backend_SetUser(i, o);
    
    // init arguments
    o->i = i;
    
    // read arguments
    NCDValue *target_arg;
    if (!NCDValue_ListRead(o->i->args, 1, &target_arg)) {
        ModuleLog(o->i, BLOG_ERROR, "wrong arity");
        goto fail1;
    }
    if (NCDValue_Type(target_arg) != NCDVALUE_STRING) {
        ModuleLog(o->i, BLOG_ERROR, "wrong type");
        goto fail1;
    }
    o->target = NCDValue_StringValue(target_arg);
    
    // signal up
    NCDModuleInst_Backend_Up(o->i);
    return;
    
fail1:
    free(o);
fail0:
    NCDModuleInst_Backend_SetError(i);
    NCDModuleInst_Backend_Dead(i);
}

static void func_die (void *vo)
{
    struct instance *o = vo;
    NCDModuleInst *i = o->i;
    
    // free instance
    free(o);
    
    NCDModuleInst_Backend_Dead(i);
}

static int func_getvar (void *vo, const char *name, NCDValue *out)
{
    struct instance *o = vo;
    
    if (!strcmp(name, "")) {
        return NCDModuleInst_Backend_GetVar(o->i, o->target, out);
    }
    
    char *target_name = concat_strings(3, o->target, ".", name);
    if (!target_name) {
        ModuleLog(o->i, BLOG_ERROR, "concat_strings failed");
        return 0;
    }
    
    int res = NCDModuleInst_Backend_GetVar(o->i, target_name, out);
    
    free(target_name);
    
    return res;
}

static NCDModuleInst * func_getobj (void *vo, const char *name)
{
    struct instance *o = vo;
    
    if (!strcmp(name, "")) {
        return NCDModuleInst_Backend_GetObj(o->i, o->target);
    }
    
    char *target_name = concat_strings(3, o->target, ".", name);
    if (!target_name) {
        ModuleLog(o->i, BLOG_ERROR, "concat_strings failed");
        return NULL;
    }
    
    NCDModuleInst *res = NCDModuleInst_Backend_GetObj(o->i, target_name);
    
    free(target_name);
    
    return res;
}

static const struct NCDModule modules[] = {
    {
        .type = "alias",
        .func_new = func_new,
        .func_die = func_die,
        .func_getvar = func_getvar,
        .func_getobj = func_getobj
    }, {
        .type = NULL
    }
};

const struct NCDModuleGroup ncdmodule_alias = {
    .modules = modules
};