#include <curve.h>
#include <sha256.h>

char hexdigits[] = "0123456789ABCDEF";


void sha256(char *message, int len, char *hash)
{
    SHA256_CTX sha;
    sha256_init( &sha );
    sha256_update( &sha, message, len );
    sha256_final( &sha, hash );
}

void sha256_curve_points(ec_point_t* points, int points_length, curve_t curve, char *hash)
{
    SHA256_CTX sha;
    int blen = curve->bitwidth >> 3;
    char b[blen];

    sha256_init( &sha );

    for (int i=0;i<points_length;i++)
    {
        memset( b, 0x00, blen );
        mpz_export( b, NULL, -1, 1, -1, 0, points[i]->x );
        sha256_update( &sha, b, blen );
        
        memset( b, 0x00, blen );
        mpz_export( b, NULL, -1, 1, -1, 0, points[i]->y );
        sha256_update( &sha, b, blen );
    }

    sha256_final( &sha, hash);
}

char *print_hex(char *p, int len)
{
    static char *s = NULL;
    static int slen = 0;
    int minsize = (len<<1)+1;

    if (slen < minsize)
    {
        if (s)
            free(s);
        s = malloc(minsize);
        slen = minsize;
    }

    for (int i=0; i<len; i++)
    {
        s[ (i<<1)     ] = hexdigits[ (p[i]>>4) & 0x0f ];
        s[ (i<<1) +1  ]= hexdigits[ (p[i])    & 0x0f ];
    }
    s[minsize-1] = 0x00;
    
    return s;

}