/*
 * 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/types.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>

static int set_i32(struct nw_interp *const i, void *const data,
    const varuint32 idx)
{
    const void *const stackptr = (const char *)i->cfg.stack.buf + i->stack_i;
    const int32_t *const src = (const int32_t *)stackptr - 1;
    int32_t *const dst = (int32_t *)data + idx;

    *dst = *src;
    return 0;
}

static int set_i64(struct nw_interp *const i, void *const data,
    const varuint32 idx)
{
    const void *const stackptr = (const char *)i->cfg.stack.buf + i->stack_i;
    const int64_t *const src = (const int64_t *)stackptr - 1;
    int64_t *const dst = (int64_t *)data + idx;

    *dst = *src;
    return 0;
}

static int set_f32(struct nw_interp *const i, void *const data,
    const varuint32 idx)
{
    const void *const stackptr = (const char *)i->cfg.stack.buf + i->stack_i;
    const float *const src = (const float *)stackptr - 1;
    float *const dst = (float *)data + idx;

    *dst = *src;
    return 0;
}

static int set_f64(struct nw_interp *const i, void *const data,
    const varuint32 idx)
{
    const void *const stackptr = (const char *)i->cfg.stack.buf + i->stack_i;
    const double *const src = (const double *)stackptr - 1;
    double *const dst = (double *)data + idx;

    *dst = *src;
    return 0;
}

static int set_local(const varuint32 local_index, struct nw_interp *const i)
{
    struct nw_frame *fr;
    varuint32 idx;

    for (idx = local_index, fr = i->fp; fr; fr = fr->next)
        if (idx < fr->n_locals)
            break;

    if (!fr)
    {
        LOG("%s: cannot access local variable %lu\n", __func__,
            (unsigned long)local_index);
        i->exception = "local variable index out of bounds";
        return -1;
    }

    static int (*const set[])(struct nw_interp *, void *, varuint32) =
    {
        [VALUE_TYPE_I32] = set_i32,
        [VALUE_TYPE_I64] = set_i64,
        [VALUE_TYPE_F32] = set_f32,
        [VALUE_TYPE_F64] = set_f64,
    };

    if (set[fr->local_type](i, fr + 1, idx))
    {
        LOG("%s: set type %d failed\n", __func__, fr->local_type);
        return -1;
    }

    return 0;
}

static int op(struct nw_interp *const i, FILE *const f)
{
    varuint32 local_index;

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

    return 0;
}

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

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