/*
 * 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/leb128.h>
#include <nw/log.h>
#include <nw/types.h>
#include <stdio.h>

int varuint1_read(FILE *const f, varuint1 *const out)
{
    unsigned long long value;

    if (leb128_read_unsigned(f, 1, &value))
        return -1;

    *out = value;
    return 0;
}

int varint7_read(FILE *const f, varint7 *const out)
{
    long long value;

    if (leb128_read_signed(f, 7, &value))
        return -1;

    *out = value;
    return 0;
}

int varuint7_read(FILE *const f, varuint7 *const out)
{
    unsigned long long value;

    if (leb128_read_unsigned(f, 7, &value))
        return -1;

    *out = value;
    return 0;
}

int varuint32_read(FILE *const f, varuint32 *out)
{
    unsigned long long value;

    if (leb128_read_unsigned(f, 32, &value))
        return -1;

    *out = value;
    return 0;
}

int varint32_read(FILE *const f, varint32 *const out)
{
    long long value;

    if (leb128_read_signed(f, 32, &value))
        return -1;

    *out = value;
    return 0;
}

int varuint64_read(FILE *const f, varuint64 *const out)
{
    unsigned long long value;

    if (leb128_read_unsigned(f, 64, &value))
        return -1;

    *out = value;
    return 0;
}

int varint64_read(FILE *const f, varint64 *const out)
{
    long long value;

    if (leb128_read_signed(f, 64, &value))
        return -1;

    *out = value;
    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 little_endian_i32(const int32_t in)
{
    const union
    {
        uint8_t a[4];
        uint32_t b;
    } v =
    {
        .b = in
    };

    return v.a[0] | (v.a[1] << 8l) | (v.a[2] << 16l) | (v.a[3] << 24l);
}

int32_t htoni32(const int32_t in)
{
    return little_endian_i32(in);
}

int32_t ntohi32(const int32_t in)
{
    return little_endian_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];
}