/*
 uniduk.c, integrate a Javascript engine in Unicon
 tectonics: gcc -std=c99 -o uniduk.so -shared -fpic uniduk.c duktape.c -lm
*/

#include <stdio.h>
#include "duktape.h"
#include "icall.h"

/*
 dukeval, evaluate a Javascript string or from file
*/
static duk_context *unictx;
static int duk_loaded = 0;

int
dukeval(int argc, descriptor *argv, int fromfile)
{
    /* Need a string argument */
    if (argc < 1) Error(103); 

    if (!duk_loaded) {
        unictx = duk_create_heap_default();
        /* if bad init, report program malfunction */
        if (!unictx)  Error(500);
        duk_loaded = 1;
    }

    /* argument is either a filename or code string */
    ArgString(1);

    if (fromfile) {
        duk_eval_file(unictx, StringVal(argv[1]));
    } else {
        duk_eval_string(unictx, StringVal(argv[1]));
    }
    duk_int_t typ = duk_get_type(unictx, -1);
    switch (typ) {
        case DUK_TYPE_NONE:
        case DUK_TYPE_UNDEFINED:
            RetNull();
            break;
        case DUK_TYPE_NULL:
            duk_pop(unictx);
            RetNull();
            break;
        case DUK_TYPE_NUMBER:
        case DUK_TYPE_BOOLEAN:
            RetReal(duk_get_number(unictx, -1));
            break;
        case DUK_TYPE_STRING:
            RetConstString((char *)duk_get_string(unictx, -1));
            break;
        default:
            fprintf(stderr, "Unsupported Duk type: %d\n", typ);
            Error(178);
            break;
    }
    return 0;
}

/*
 uniduk, a Unicon loadfunc function
 Usage from Unicon
    uniduk := loadfunc("./uniduk.so", "uniduk")
    result := uniduk("print('Hello'); var r = 7 * 6;")
*/
int
uniduk(int argc, descriptor *argv)
{
    int result;
    result = dukeval(argc, argv, 0);
    return result;
}

/*
 unidukFile, load Duktape code from file
 Usage from Unicon
    unidukfile := loadfunc("./uniduk.so", "unidukFile")
    result := unidukfile("uniduk.js")
*/
int
unidukFile(int argc, descriptor *argv)
{
    int result;
    result = dukeval(argc, argv, 1);
    return result;
}

/*
 unidukDone, a Unicon loadfunc function for Duktape rundown
 Usage from Unicon
    unidukdone := loadfunc("./uniduk.so", "unidukDone")
    result := unidukDone()
 Unicon result is &null, by nature of not being set
*/
int
unidukDone(int argc, descriptor *argv)
{
    duk_destroy_heap(unictx);
    duk_loaded = 0;
    return 0;
}