/*
 * 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 <nw/interp.h>
#include <nw/log.h>
#include <nw/search.h>
#include <nw/sections.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>

int nw_start(const struct nw_inst_cfg *const icfg, struct nw_inst *const i)
{
    int ret = -1;
    const struct nw_mod *const m = icfg->interp.m;
    const struct nw_mod_cfg *const mcfg = &m->cfg;
    FILE *const f = fopen(mcfg->path, "rb");
    struct search_fn fn;
    struct nw_frame fr = {0};

    *i = (const struct nw_inst){0};

    if (!f)
    {
        LOG("%s: fopen(3) %s: %s\n", __func__, mcfg->path, strerror(errno));
        goto end;
    }
    else if (m->sections.start)
    {
        /* TODO. */
    }
    else if (interp_start(&icfg->interp, f, &i->interp))
    {
        LOG("%s: interp_start failed\n", __func__);
        goto end;
    }
    else if (search_exported_fn("_start", m, f, &fn))
    {
        LOG("%s: search_exported_fn failed\n", __func__);
        goto end;
    }
    else if (section_global_push(f, m, &i->interp))
    {
        LOG("%s: section_global_push failed\n", __func__);
        goto end;
    }
    else if (section_type_push(f, m, fn.index, &fr))
    {
        LOG("%s: section_type_push failed\n", __func__);
        goto end;
    }
    else if (fseek(f, fn.start, SEEK_SET))
    {
        LOG("%s: fseek(3): %s\n", __func__, strerror(errno));
        return -1;
    }
    else if (section_code_push(f, &fr))
    {
        LOG("%s: section_code_push failed\n", __func__);
        goto end;
    }
#if 0
    else if (interp_push(&i->interp, &fr))
    {
        LOG("%s: interp_push failed\n", __func__);
        goto end;
    }
#endif

    ret = 0;

end:

    if (ret && f && fclose(f))
    {
        LOG("%s: fclose(3) %s: %s\n", __func__, mcfg->path, strerror(errno));
        ret = -1;
    }

    return ret;
}