#include <time.h>
#include <string.h>

#include "impl-select.h"
#include "3rdparty/argon2.h"


extern uint64_t uv_hrtime(void);


#define BENCH_SAMPLES 1024U
#define BENCH_MEM_BLOCKS 512


#ifdef _MSC_VER
#   define strcasecmp  _stricmp
#endif


static argon2_impl selected_argon_impl = { "default", NULL, fill_segment_default };


/* the benchmark routine is not thread-safe, so we can use a global var here: */
static block memory[BENCH_MEM_BLOCKS];


static uint64_t benchmark_impl(const argon2_impl *impl) {
    memset(memory, 0, sizeof(memory));

    argon2_instance_t instance;
    instance.version        = ARGON2_VERSION_NUMBER;
    instance.memory         = memory;
    instance.passes         = 1;
    instance.memory_blocks  = BENCH_MEM_BLOCKS;
    instance.segment_length = BENCH_MEM_BLOCKS / ARGON2_SYNC_POINTS;
    instance.lane_length    = instance.segment_length * ARGON2_SYNC_POINTS;
    instance.lanes          = 1;
    instance.threads        = 1;
    instance.type           = Argon2_id;

    argon2_position_t pos;
    pos.lane    = 0;
    pos.pass    = 0;
    pos.slice   = 0;
    pos.index   = 0;

    /* warm-up cache: */
    impl->fill_segment(&instance, pos);

    /* OK, now measure: */
    const uint64_t time = uv_hrtime();

    for (uint32_t i = 0; i < BENCH_SAMPLES; i++) {
        impl->fill_segment(&instance, pos);
    }

    return uv_hrtime() - time;
}


void argon2_select_impl()
{
    argon2_impl_list impls;
    const argon2_impl *best_impl = NULL;
    uint64_t best_bench = UINT_MAX;

    argon2_get_impl_list(&impls);

    for (uint32_t i = 0; i < impls.count; i++) {
        const argon2_impl *impl = &impls.entries[i];

        if (impl->check != NULL && !impl->check()) {
            continue;
        }

        const uint64_t bench = benchmark_impl(impl);
        if (bench < best_bench) {
            best_bench = bench;
            best_impl  = impl;
        }
    }

    if (best_impl != NULL) {
        selected_argon_impl = *best_impl;
    }
}


void xmrig_ar2_fill_segment(const argon2_instance_t *instance, argon2_position_t position)
{
    selected_argon_impl.fill_segment(instance, position);
}


const char *argon2_get_impl_name()
{
    return selected_argon_impl.name;
}


int argon2_select_impl_by_name(const char *name)
{
    argon2_impl_list impls;
    argon2_get_impl_list(&impls);

    for (uint32_t i = 0; i < impls.count; i++) {
        const argon2_impl *impl = &impls.entries[i];

        if (strcasecmp(impl->name, name) == 0) {
            selected_argon_impl = *impl;

            return 1;
        }
    }

    return 0;
}