//
// Created by 猎人猪 on 2023/2/26.
//

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#include "common.h"
#include "gateway.h"
#include "sponge.h"

GW_store gw_store;
GW_temp_store gw_temp_store;
int ecu_count=0;

// 注册阶段-分配密钥
void gw_reg(unsigned char ID[2],unsigned char key[KEY_LENGTH_BYTES])
{
    for(int i=0;i<2;++i)
    {
        gw_store.ecu_material[ecu_count].ID[i]=ID[i];
    }
    for(int i=0;i<KEY_LENGTH_BYTES;++i)
    {
        gw_store.ecu_material[ecu_count].kk[0][i]=key[i];
    }

}

// 认证阶段-发送请求
AUTH_request gw_auth_req()
{
    srand((unsigned) time(NULL));
    AUTH_request request;
    request.r1=rand();

    gw_temp_store.r1=request.r1;

    return request;
}

// 认证阶段-验证/更新密钥
AUTH_verify gw_auth_verify(AUTH_response response)
{
    unsigned char hash_plain[SIZE_INT*2+KEY_LENGTH_BYTES];
    unsigned char hash_result[SHA3_RESULT_LENGTH_BYTES];
    unsigned char *p_temp;

    memcpy(hash_plain,&gw_temp_store.r1,SIZE_INT);
    memcpy(hash_plain+SIZE_INT,&response.r2,SIZE_INT);
    memcpy(hash_plain+SIZE_INT*2, &gw_store.ecu_material[ecu_count].kk[response.f], KEY_LENGTH_BYTES);

    p_temp= sponge(hash_plain, sizeof(hash_plain));
    memcpy(hash_result,p_temp,SHA3_RESULT_LENGTH_BYTES);

    if(memcmp(hash_result+KEY_LENGTH_BYTES,response.c2,KEY_LENGTH_BYTES))
    {
        cclPrintf("gateway: authentication failed!");
        exit(-1);
    }
    else
    {
        cclPrintf("gateway: authentication passed!");
    }

    unsigned char new_f=(response.f+1)%2;
    memcpy(gw_store.ecu_material[ecu_count].kk[new_f], hash_result, KEY_LENGTH_BYTES);

    unsigned char sk[KEY_LENGTH_BYTES];
    calculate_sk(hash_result+KEY_LENGTH_BYTES*2,hash_result+KEY_LENGTH_BYTES*3,sk);

    cclPrintf("sk on gateway side is:");
    char print_buf[KEY_LENGTH_BYTES * 2 + 1];
    arrayToStr(sk, KEY_LENGTH_BYTES, print_buf);
    print_buf[KEY_LENGTH_BYTES * 2] = '\0';
    cclPrintf("%s", print_buf);

    AUTH_verify verify;
    memcpy(verify.c3,hash_result+KEY_LENGTH_BYTES*2,KEY_LENGTH_BYTES);

    return verify;
}