/*
 * nanowasm, a tiny WebAssembly/Wasm interpreter
 * Copyright (C) 2023-2024  Xavier Del Campo Romero
 *
 * 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 https://mozilla.org/MPL/2.0/.
 */

#include <nanowasm/nw.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static int proc_exit(const struct nw_args *const params,
    union nw_value *const ret, void *const user)
{
    return -1;
}

int main(int argc, char *argv[])
{
    static const struct nw_import imports[] =
    {
        {
            .kind = NW_KIND_FUNCTION,
            .module = "wasi_snapshot_preview1",
            .field = "proc_exit",
            .u.function =
            {
                .signature = "i32()",
                .fn = proc_exit
            }
        }
    };

    static const struct nw_mod_cfg cfg =
    {
        .path = "example.wasm",
        .imports = imports,
        .n_imports = sizeof imports / sizeof *imports
    };

    struct nw_mod m;

    if (nw_load(&cfg, &m))
    {
        fprintf(stderr, "%s: nw_load failed\n", __func__);
        return EXIT_FAILURE;
    }

    const struct nw_inst_cfg icfg =
    {
        .interp =
        {
            .stack = NW_BUF(256),
            .heap = NW_BUF(2048),
            .global = NW_BUF(24),
            .m = &m
        }
    };

    struct nw_inst inst;

    if (nw_start(&icfg, &inst))
    {
        fprintf(stderr, "%s: nw_start failed\n", __func__);
        return EXIT_FAILURE;
    }

    const union nw_inst_state *s = &inst.state;
    int ret = EXIT_FAILURE;

again:

    switch (nw_run(&inst))
    {
        case NW_STATE_AGAIN:
            goto again;

        case NW_STATE_RETURNED:
            fprintf(stderr, "instance returned %ld\n", s->retval);
            break;

        case NW_STATE_EXCEPTION:
            fprintf(stderr, "exception: %s\n", s->exception);
            goto end;

        case NW_STATE_FATAL:
            goto end;
    }

    ret = EXIT_SUCCESS;

end:

    if (nw_stop(&inst))
    {
        fprintf(stderr, "%s: nw_stop failed\n", __func__);
        ret = EXIT_FAILURE;
    }

    return ret;
}