/* luatools.c
 *
 * Lua Tools
 *
 *
 */

#include <lauxlib.h>
#include <lualib.h>
#include <stdio.h>
#include <string.h>
#include "luatools.h"

const char *luaGetFieldString(lua_State *L, const char *key)
{
    if (!L || !key)
        return NULL;

    const char *ret = NULL;

    /* push the key string onto stack */
    lua_pushstring(L, key);

    lua_gettable(L, -2);
    if (!lua_isstring(L, -1))
    {
        fprintf(stderr, "Lua: \"%s\" field within the table is not a string\n", key);
        lua_pop(L, 1);

        return ret;
    }

    ret = lua_tostring(L, -1); /* should this be freed at some point? */
    lua_pop(L, 1);

    return ret;
}

double luaGetFieldNumber(lua_State *L, const char *key)
{
    if (!L || !key)
        return -1.0;

    double ret = -1.0;

    /* push the key string onto stack */
    lua_pushstring(L, key);

    /* remember, -1 points to top of the stack, our table should a second
     * item from the top, this call effectively accesses t[key] and
     * pushes that value on the stack */
    lua_gettable(L, -2);
    if (!lua_isnumber(L, -1))
    {
        fprintf(stderr, "Lua: \"%s\" field within the table is NaN\n", key);
        lua_pop(L, 1);

        return ret;
    }

    /* finally retrieve our value */
    ret = lua_tonumber(L, -1);

    /* value is no longer needed, pop it */
    lua_pop(L, 1);

    return ret;
}

int luaLoadConfig(lua_State *L, const char *fname)
{
    if (!L || !fname)
        return -1;

    int status;

    /* load the file containing the config */
    /* call a function, what function? dry run the script? */
    status = (luaL_loadfile(L, fname) || lua_pcall(L, 0, 0, 0));
    if (status)
    {
        fprintf(stderr, "Lua: %s\n", lua_tostring(L, -1));
        return -1;
    }

    return 0;
}

int luaFillTablePlatform(lua_State *L, struct luat_table_platform *p)
{
    if (!L || !p)
        return -1;

    double ret;
    const char *ret_str = NULL;

    /* pushes the table on the stack */
    lua_getglobal(L, "platform");

    if (!lua_istable(L, -1))
    {
        fprintf(stderr, "Lua: failed to parse \"platform\" table\n");
        lua_pop(L, 1);
        return -1;
    }

    if ((ret_str = luaGetFieldString(L, "name")) != NULL)
        p->name  = ret_str;

    if ((ret_str = luaGetFieldString(L, "icon")) != NULL)
        p->icon  = ret_str;

    if ((ret = luaGetFieldNumber(L, "xres")) != -1.0)
        p->xres  = (unsigned int) ret;

    if ((ret = luaGetFieldNumber(L, "yres")) != -1.0)
        p->yres  = (unsigned int) ret;

    if ((ret = luaGetFieldNumber(L, "bpp")) != -1.0)
        p->bpp   = (unsigned int) ret;

    if ((ret = luaGetFieldNumber(L, "af")) != -1.0)
        p->af   = (unsigned int) ret;

    if ((ret = luaGetFieldNumber(L, "fovy")) != -1.0)
        p->fovy  = (float) ret;

    if ((ret = luaGetFieldNumber(L, "znear")) != -1.0)
        p->znear = (float) ret;

    if ((ret = luaGetFieldNumber(L, "zfar")) != -1.0)
        p->zfar  = (float) ret;

    if ((ret = luaGetFieldNumber(L, "maxfps")) != -1.0)
        p->maxfps   = (unsigned int) ret;

    /* pop the table */
    lua_pop(L, 1);

    return 0;
}

void luaPrintTablePlatform(struct luat_table_platform *p)
{
    if (!p)
        return;

    printf("-- Lua platform config file --\n"
           "  name  : %s\n"
           "  icon  : %s\n"
           "  xres  : %u\n"
           "  yres  : %u\n"
           "  bpp   : %u\n"
           "  af    : %u\n"
           "  fovy  : %f\n"
           "  znear : %f\n"
           "  zfar  : %f\n"
           "  maxfps: %u\n",
           p->name, p->icon, p->xres, p->yres, p->bpp, p->af,
           p->fovy, p->znear, p->zfar, p->maxfps);
    puts("");
}