// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "prf_defs.h"
#if (WX_AIRSYNC_CFG)


#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "gki.h"
#include "app_airsync_md5.h"

const uint32_t X[4][2] = {{0, 1}, {1, 5}, {5, 3}, {0, 7}};
const uint32_t S[4][4] = {{ 7, 12, 17, 22 },{ 5, 9 , 14, 20 },{ 4, 11, 16, 23 },{ 6, 10, 15, 21 }};
uint32_t F( uint32_t X, uint32_t Y, uint32_t Z )
{
	return ( X & Y ) | ( ~X & Z );
}
uint32_t G( uint32_t X, uint32_t Y, uint32_t Z )
 {
	return ( X & Z ) | ( Y & ~Z );
 }
uint32_t H( uint32_t X, uint32_t Y, uint32_t Z )
{
	return X ^ Y ^ Z;
}
uint32_t I( uint32_t X, uint32_t Y, uint32_t Z )
{
	return Y ^ ( X | ~Z );
}
  // rotates x left s bits.
uint32_t rotate_left( uint32_t x, uint32_t s )
{
	return ( x << s ) | ( x >> ( 32 - s ) );
}

 // Pre-processin
uint32_t count_padding_bits ( uint32_t length )
{
//	uint32_t div = length * BITS / BLOCK_SIZE;
	uint32_t mod = length * BITS % BLOCK_SIZE;
	uint32_t c_bits;
	if ( mod == 0 )
	{
			c_bits = MOD_SIZE;
	}
	else
	{
		c_bits = ( MOD_SIZE + BLOCK_SIZE - mod ) % BLOCK_SIZE;
	}
	return c_bits / BITS;
}

MD5String append_padding_bits ( char * argv )
{
	uint32_t msg_length = strlen ( argv );
	uint32_t bit_length = count_padding_bits ( msg_length );
	uint64_t app_length = msg_length * BITS;
	MD5String string;
	string.str = (char *)GKI_getbuf(msg_length + bit_length + APP_SIZE / BITS);
	strncpy ( string.str, argv, msg_length );
	memset ( string.str + msg_length, 0, bit_length );
	string.str [ msg_length ] = SINGLE_ONE_BIT;
	memmove ( string.str + msg_length + bit_length, (char *)&app_length, sizeof( uint64_t ) );
	string.len = msg_length + bit_length + sizeof( uint64_t );
	return string;
}

int32_t wechat_md5 (char *argv, uint8_t *md5_32)
{
	MD5String string;
	uint32_t w[16];
	uint32_t chain[4];
	uint32_t state[4];

	uint32_t ( *auxi[ 4 ])( uint32_t, uint32_t, uint32_t ) = { F, G, H, I };
	int sIdx;
	int wIdx;
	string = append_padding_bits ( argv );
	chain[0] = A;
	chain[1] = B;
	chain[2] = C;
	chain[3] = D;
	for (uint32_t j = 0; j < string.len; j += BLOCK_SIZE / BITS)
	{
		memmove ( (char *)w, string.str + j, BLOCK_SIZE / BITS );
		memmove ( state, chain, sizeof(chain) );
		for ( uint8_t roundIdx = 0; roundIdx < 4; roundIdx++ )
		{
			wIdx = X[ roundIdx ][ 0 ];
			sIdx = 0;
			for (uint8_t i = 0; i < 16; i++ )
			{	
				state[sIdx] = state [(sIdx + 1)%4] + rotate_left( state[sIdx] +(*auxi[ roundIdx])( state[(sIdx+1) % 4],
				state[(sIdx+2) % 4], 
				state[(sIdx+3) % 4]) + w[ wIdx ] + (uint32_t)floor((1ULL << 32) * fabs(sin( roundIdx * 16 + i + 1 )) ),
				S[ roundIdx ][ i % 4 ]);
				sIdx = ( sIdx + 3 ) % 4;
				wIdx = ( wIdx + X[ roundIdx ][ 1 ] ) & 0xF;
			}
		}
		chain[ 0 ] += state[ 0 ];
		chain[ 1 ] += state[ 1 ];
		chain[ 2 ] += state[ 2 ];
		chain[ 3 ] += state[ 3 ];
	}
	memmove ( md5_32 + 0, (char *)&chain[0], sizeof(uint32_t) );
	memmove ( md5_32 + 4, (char *)&chain[1], sizeof(uint32_t) );
	memmove ( md5_32 + 8, (char *)&chain[2], sizeof(uint32_t) );
	memmove ( md5_32 + 12, (char *)&chain[3], sizeof(uint32_t) );
	free(string.str);
	string.str = NULL;
  return EXIT_SUCCESS;

}


#endif	///WX_AIRSYNC_CFG