/*
 * 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/sections.h>
#include <nw/types.h>
#include <errno.h>
#include <stddef.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>

int check_resizable_limits(FILE *const f, struct resizable_limits *const r)
{
    varuint1 flags;
    varuint32 initial;

    *r = (const struct resizable_limits){0};

    if (varuint1_read(f, &flags))
    {
        LOG("%s: varuint1_read failed\n", __func__);
        return -1;
    }
    else if (varuint32_read(f, &initial))
    {
        LOG("%s: varuint32_read failed\n", __func__);
        return -1;
    }

    if (flags)
    {
        varuint32 maximum;

        if (varuint32_read(f, &maximum))
        {
            LOG("%s: varuint32_read failed\n", __func__);
            return -1;
        }

        r->max = maximum;
        r->max_available = true;
    }

    static const unsigned long page_size = 64lu * 1024lu;

    if (initial > UINT32_MAX / page_size)
    {
        LOG("%s: initial size (%lu) overflow \n", __func__,
            (unsigned long)initial);
        return 1;
    }

    r->sz = initial * page_size;
    return 0;
}

size_t get_type_size(const enum value_type type)
{
    static const size_t list[] =
    {
        [VALUE_TYPE_I32] = sizeof (int32_t),
        [VALUE_TYPE_I64] = sizeof (int64_t),
        [VALUE_TYPE_F32] = sizeof (float),
        [VALUE_TYPE_F64] = sizeof (double)
    };

    return list[type];
}

enum
{
    I32 = 0x7f,
    I64 = 0x7e,
    F32 = 0x7d,
    F64 = 0x7c,
    ANYFUNC = 0x70,
    FUNC = 0x60,
    BLOCK_TYPE = 0x40
};

int get_value_type(const varint7 type, enum value_type *const vtype)
{
    static const struct size
    {
        varint7 type;
        enum value_type vtype;
    } sizes[] =
    {
        {.type = I32, .vtype = VALUE_TYPE_I32},
        {.type = I64, .vtype = VALUE_TYPE_I64},
        {.type = F32, .vtype = VALUE_TYPE_F32},
        {.type = F64, .vtype = VALUE_TYPE_F64},
        /* TODO: check this. */
        {.type = ANYFUNC, .vtype = VALUE_TYPE_I32},
        /* TODO: check this. */
        {.type = FUNC, .vtype = VALUE_TYPE_I32},
        /* TODO: check this. */
        {.type = BLOCK_TYPE, .vtype = VALUE_TYPE_I32}
    };

    for (size_t i = 0; i < sizeof sizes / sizeof *sizes; i++)
    {
        const struct size *const s = &sizes[i];

        if (type == s->type)
        {
            *vtype = s->vtype;
            return 0;
        }
    }

    LOG("%s: unknown type %#hhx\n", __func__, (char)type);
    return -1;
}

static int32_t swap_i32(const int32_t in)
{
    const int8_t *const p = (const int8_t *)&in;

    return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
}

int32_t htoni32(const int32_t in)
{
    return swap_i32(in);
}

int32_t ntohi32(const int32_t in)
{
    return swap_i32(in);
}

const char *value_type_tostr(const enum value_type v)
{
    static const char *const s[] =
    {
#define X(x) [x] = #x,
        VALUE_TYPES
#undef X
    };

    return s[v];
}