#include <stdio.h>
#include "gcrypt.h"
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <strings.h>
#include <omp.h>
#include <time.h>
#include <inttypes.h>
#include "cryptwrapper.h"
#include "rainbowvalue.h"
#include "readBulk.h"





int main(int argc, char const *argv[]) {
    if (argc < 3){
        printf("please select rainbow table and encrypted file\n");
        return 1;
    }
    FILE * fptr_rainbow = fopen(argv[1],"rb");
    FILE * fptr_encry = fopen(argv[2],"rb");

    if (fptr_encry==NULL){
        printf("could not open encrypted file %s\n",argv[1]);
        return 1;
    }
    if (fptr_rainbow==NULL){
        printf("could not open rainbow table  file %s\n",argv[2]);
        return 1;
    }

    mycryptwrapper_init();

    // to calculate hash without trailing 256 bits of decrypted file
    size_t mens = gcry_md_get_algo_dlen(algo);
    void * digest=malloc(mens);

    // initialization vector for decryption and encryption
    size_t len = 8;


    size_t file_len;
    if (fseek(fptr_encry,0,SEEK_END)){
        perror("could not ssek end of file\n"); return 1;
    }
    file_len = ftell(fptr_encry);
    if (file_len==0){
        perror("file length is 0\n");
        return 1;
    }
    rewind(fptr_encry); // go to beginning of file
    uint8_t * buf = malloc(file_len);
    if (fread(buf, sizeof(uint8_t),file_len,fptr_encry)!= file_len){
        perror("could not read complete file\n");
        return 1;
    }
    //encrypted file is stored in buf and can now be decrypted




    struct s_rainbowvalue256 * rs = malloc(sizeof(struct s_rainbowvalue256)*BULKSIZE);
    size_t num_rainbow_values;
    clock_t old_clock;
    // read a block of rainbow values
    int success = 0;
    while ((num_rainbow_values=fread(rs, sizeof(struct s_rainbowvalue256),BULKSIZE,fptr_rainbow ))!=0){
        if (success==1){break;}
        //printf("read %d rainbow values\n", (int) num_rainbow_values);
        // iterate through rainbow values and decrypt
        old_clock=clock();
    #pragma omp parallel for
        for (size_t i = 0 ; i < num_rainbow_values ; i++){
            if (success==1){
                #pragma omp exitregion
            }
            uint8_t * decrypted_buf = malloc(file_len);//allocate mem for decrypted buffer
            gcry_cipher_hd_t dhd;
            if (gcry_cipher_open(&dhd,cipher,GCRY_CIPHER_MODE_CFB,0)){perror("could not open cypher\n");}
            if (gcry_cipher_setkey(dhd,rs[i].hash,8)){perror("could not set key\n");};
            void * iv = malloc(len);
            memset(iv,0,len);
            if (gcry_cipher_setiv(dhd, iv , len)){perror("could not set init vector\n");}
            if (gcry_cipher_decrypt(dhd,decrypted_buf,file_len,buf,file_len)){perror("could not decrypt\n");}
            //mycryptwrapper_print(decrypted_buf,file_len);
            //printf("pw: %s\nfile:%s\n",rs[i].pw,decrypted_buf);
            if (check_sha256_tag(decrypted_buf,file_len)){
                printf("pw: %s\n", rs[i].pw);

                char * enc_fname = malloc(strlen(argv[2])+5);
                strcpy(enc_fname, argv[2]);
                strcat(enc_fname,".decr");
                FILE * encrypted_fptr = fopen(enc_fname,"wb");
                if (fwrite(decrypted_buf,1,file_len-32,encrypted_fptr)!=file_len-32){
                    perror("couln not write all data to decrypted file");
                    //return 1;
                #pragma omp exitregion
                };

                printf("successfully saved decrypted data in %s\n", enc_fname);
                //return 0;
                success=1;
                #pragma omp exitregion
                }// decryption succesfull end
            free(iv);
            free(decrypted_buf);
            gcry_cipher_close(dhd);
        }// end parallel
        float sec = (float)((clock()-old_clock))/(float)CLOCKS_PER_SEC;
        printf("\rcalc/sec: %4.0f", num_rainbow_values/sec);

    }
    if(success==0){
        printf("\nnothing found\n");
    }
    return 0;
}