/*
 * nanowasm, a tiny WebAssembly/Wasm interpreter
 * Copyright (C) 2023-2025  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/ops.h>
#include <nw/routines.h>

static enum nw_state run(struct nw_interp *const i)
{
    const struct nw_i_sm_end *const e = &i->sm.end;
    struct nw_frame *const f = &i->fr;

    if (i->set)
        return NW_OK;
    else if (f->block_i)
    {
        f->block_i--;
        nwp_interp_resume(i);
    }
    else
    {
        const long expected = f->start + f->body_size;

        if (e->offset != expected)
        {
            static const char *const exc = "unexpected end";

#ifdef NW_LOG
            nwp_log("%s\n", exc);
#endif
            i->exception = exc;
            return NW_FATAL;
        }
        else if (f->child)
            nwp_unwind(i);
    }

    return NW_AGAIN;
}

static enum nw_state get_offset(struct nw_interp *const i)
{
    struct nw_i_sm_end *const e = &i->sm.end;
    const struct nw_io_cfg *const cfg = &i->cfg.io;
    const enum nw_state n = cfg->tell(&e->offset, cfg->user);

    if (n)
        return n;

    return run(i);
}

void nwp_op_end(struct nw_interp *const i)
{
    static const struct nw_i_sm_end e;

    i->sm.end = e;
    i->next = get_offset;
}