/*
 * 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/io.h>
#include <nw/log.h>
#include <nw/routines.h>

static enum nw_state get_maximum(struct nw_mod *const m)
{
    const struct nw_io_cfg *const cfg = &m->cfg.io;
    struct nw_sm_mem *const mem = &m->sm.memory;
    struct nw_mod_out_mem *const lin = &m->out.linear;
    struct nw_sm_leb128 *const l = &mem->leb128;
    const enum nw_state n = nwp_varuint32(cfg, l, &lin->max, cfg->user);

    if (n)
        return n;

    m->next = nwp_section_exit;
    return NW_AGAIN;
}

static enum nw_state get_initial(struct nw_mod *const m)
{
    const struct nw_io_cfg *const cfg = &m->cfg.io;
    struct nw_sm_mem *const mem = &m->sm.memory;
    struct nw_mod_out_mem *const lin = &m->out.linear;
    struct nw_sm_leb128 *const l = &mem->leb128;
    const enum nw_state n = nwp_varuint32(cfg, l, &lin->initial, cfg->user);

    if (n)
        return n;

    m->next = mem->flags ? get_maximum : nwp_section_exit;
    return NW_AGAIN;
}

static enum nw_state get_flags(struct nw_mod *const m)
{
    const struct nw_io_cfg *const cfg = &m->cfg.io;
    struct nw_sm_mem *const mem = &m->sm.memory;
    struct nw_sm_leb128 *const l = &mem->leb128;
    const enum nw_state n = nwp_varuint1(cfg, l, &mem->flags, cfg->user);

    if (n)
        return n;

    m->next = get_initial;
    return NW_AGAIN;
}

static enum nw_state get_count(struct nw_mod *const m)
{
    const struct nw_io_cfg *const cfg = &m->cfg.io;
    struct nw_sm_mem *const mem = &m->sm.memory;
    struct nw_sm_leb128 *const l = &mem->leb128;
    const enum nw_state n = nwp_varuint32(cfg, l, &mem->count, cfg->user);

    if (n)
        return n;
    else if (mem->count > 1)
    {
#ifdef NW_LOG
        nwp_log("MVP WebAssembly supports no more than 1 memory\n");
#endif
        return NW_FATAL;
    }

    m->next = mem->count ? get_flags : nwp_section_exit;
    return NW_AGAIN;
}

void nwp_section_memory(struct nw_mod *const m)
{
    const struct nw_sm_mem mem = {0};

    m->next = get_count;
    m->sm.memory = mem;
}