/*
 *
 */

#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>

#include <zstd.h>

#include <nxt_http_compression.h>

static void nxt_zstd_free(const nxt_http_comp_compressor_ctx_t *ctx)
{
    ZSTD_CStream *zstd = ctx->zstd_ctx;

    ZSTD_freeCStream(zstd);
}

static void nxt_zstd_init(nxt_http_comp_compressor_ctx_t *ctx)
{
    ZSTD_CStream **zstd = &ctx->zstd_ctx;

    *zstd = ZSTD_createCStream();
    ZSTD_initCStream(*zstd, ctx->level);

    printf("%s: zstd compression level [%d]\n", __func__, ctx->level);
}

static size_t nxt_zstd_compressed_size(const nxt_http_comp_compressor_ctx_t *ctx,
                                       size_t in_len)
{
    return ZSTD_compressBound(in_len);
}

static ssize_t nxt_zstd_compress(nxt_http_comp_compressor_ctx_t *ctx,
                                 const uint8_t *in_buf, size_t in_len,
                                 uint8_t *out_buf, size_t out_len, bool last)
{
    size_t ret;
    ZSTD_CStream *zstd = ctx->zstd_ctx;
    ZSTD_inBuffer zinb = { .src = in_buf, .size = in_len };
    ZSTD_outBuffer zoutb = { .dst = out_buf, .size = out_len };

    printf("%s: in_len [%lu] out_len [%lu]\n", __func__, in_len, out_len);

    ret = ZSTD_compressStream(zstd, &zoutb, &zinb);

    if (zinb.pos < zinb.size) {
        printf("%s: short by [%d]\n", __func__, zinb.pos < zinb.size);
        ret = ZSTD_flushStream(zstd, &zoutb);
    }

    if (last) {
        ret = ZSTD_endStream(zstd, &zoutb);
        nxt_zstd_free(ctx);
    }

    printf("%s: ret [%lu]\n", __func__, ret);
    if (ZSTD_isError(ret)) {
        printf("%s: [%s]\n", __func__, ZSTD_getErrorName(ret));
        return -1;
    }

    return zoutb.pos;
}

const nxt_http_comp_operations_t  nxt_comp_zstd_ops = {
    .init               = nxt_zstd_init,
    .compressed_size    = nxt_zstd_compressed_size,
    .deflate            = nxt_zstd_compress,
    .free_ctx           = nxt_zstd_free,
};