/*
 * 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 <nw/log.h>
#include <nw/ops.h>
#include <nanowasm/nw.h>
#include <nw/interp.h>
#include <nw/types.h>
#include <errno.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>

static int push(struct nw_interp *const i, FILE *const f)
{
    const long pc = ftell(f);

    if (pc < 0)
    {
        LOG("%s: ftell(3): %s\n", __func__, strerror(errno));
        i->exception = "I/O error";
        return -1;
    }

    struct nw_frame *const fp = i->fp;
    struct nw_block *const p = interp_stackptr(i);
    const struct nw_block b =
    {
        .pc = pc,
        .prev = fp->last_block
    };

    if (interp_stack_push(i, &b, sizeof b))
    {
        LOG("%s: interp_stack_push failed\n", __func__);
        return -1;
    }

    fp->last_block = p;
    return 0;
}

static int op(struct nw_interp *const i, FILE *const f)
{
    varint7 sig;

    if (varint7_read(f, &sig))
    {
        LOG("%s: varint7_read failed\n", __func__);
        return -1;
    }
    else if (i && push(i, f))
    {
        LOG("%s: push failed\n", __func__);
        return -1;
    }

    return 0;
}

int op_block(struct nw_interp *const i)
{
    return op(i, i->f);
}

int check_block(FILE *const f)
{
    return op(NULL, f);
}