#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <time.h>
#include <fcntl.h>
#include "sha1.h"
#include "base64.h"

#include "lua/lualib.h"

#define LEFTROTATE(x, c) (((x) << (c)) | ((x) >> (32 - (c))))

static unsigned simple_hash(const char* key)
{
	unsigned hashval;
    for (hashval = 0; *key != '\0'; key++)
      hashval = *key + 31 * hashval;
	return hashval;
}

static void md5(uint8_t *initial_msg, size_t initial_len, char* buff) {
	uint32_t h0, h1, h2, h3;
	char tmp[80];
    uint8_t *msg = NULL;
    uint32_t r[] = {7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22,
                    5,  9, 14, 20, 5,  9, 14, 20, 5,  9, 14, 20, 5,  9, 14, 20,
                    4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23,
                    6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21};
    // Use binary integer part of the sines of integers (in radians) as constants// Initialize variables:
    uint32_t k[] = {
        0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
        0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
        0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
        0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
        0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
        0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
        0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
        0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
        0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
        0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
        0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05,
        0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
        0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
        0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
        0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
        0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391};
 
    h0 = 0x67452301;
    h1 = 0xefcdab89;
    h2 = 0x98badcfe;
    h3 = 0x10325476;
 
    // Pre-processing: adding a single 1 bit
    //append "1" bit to message    
    /* Notice: the input bytes are considered as bits strings,
       where the first bit is the most significant bit of the byte.[37] */
 
    // Pre-processing: padding with zeros
    //append "0" bit until message length in bit ≡ 448 (mod 512)
    //append length mod (2 pow 64) to message
 
    int new_len;
    for(new_len = initial_len*8 + 1; new_len%512!=448; new_len++);
    new_len /= 8;
 
    msg = calloc(new_len + 64, 1); // also appends "0" bits 
                                   // (we alloc also 64 extra bytes...)
    memcpy(msg, initial_msg, initial_len);
    msg[initial_len] = 128; // write the "1" bit
 
    uint32_t bits_len = 8*initial_len; // note, we append the len
    memcpy(msg + new_len, &bits_len, 4);           // in bits at the end of the buffer
 
    // Process the message in successive 512-bit chunks:
    //for each 512-bit chunk of message:
    int offset;
    for(offset=0; offset<new_len; offset += (512/8)) {
 
        // break chunk into sixteen 32-bit words w[j], 0 ≤ j ≤ 15
        uint32_t *w = (uint32_t *) (msg + offset);
 
        // Initialize hash value for this chunk:
        uint32_t a = h0;
        uint32_t b = h1;
        uint32_t c = h2;
        uint32_t d = h3;
 
        // Main loop:
        uint32_t i;
        for(i = 0; i<64; i++) {
 
            uint32_t f, g;
 
             if (i < 16) {
                f = (b & c) | ((~b) & d);
                g = i;
            } else if (i < 32) {
                f = (d & b) | ((~d) & c);
                g = (5*i + 1) % 16;
            } else if (i < 48) {
                f = b ^ c ^ d;
                g = (3*i + 5) % 16;          
            } else {
                f = c ^ (b | (~d));
                g = (7*i) % 16;
            }

            uint32_t temp = d;
            d = c;
            c = b;
            //printf("rotateLeft(%x + %x + %x + %x, %d)\n", a, f, k[i], w[g], r[i]);
            b = b + LEFTROTATE((a + f + k[i] + w[g]), r[i]);
            a = temp;
 
        }
 
        // Add this chunk's hash to result so far:
 	   
        h0 += a;
        h1 += b;
        h2 += c;
        h3 += d;
		
    }
	uint8_t *p;
	p=(uint8_t *)&h0;
	sprintf(tmp,"%02x%02x%02x%02x", p[0], p[1], p[2], p[3]);//, h0
	strcpy(buff, tmp);
	p=(uint8_t *)&h1;
	sprintf(tmp,"%02x%02x%02x%02x", p[0], p[1], p[2], p[3]); //, h1)
	strcat(buff,tmp);
	p=(uint8_t *)&h2;
	sprintf(tmp,"%02x%02x%02x%02x", p[0], p[1], p[2], p[3]); // , h2
    strcat(buff,tmp);
	p=(uint8_t *)&h3;
	sprintf(tmp,"%02x%02x%02x%02x", p[0], p[1], p[2], p[3]); // , h3
	strcat(buff,tmp);
    // cleanup
    free(msg);
 
}
void sha1(const char* text, char* out)
{	
	uint8_t d [20];
    SHA1_CTX context;
    SHA1_Init(&context);
    SHA1_Update(&context, text, strlen(text));
    SHA1_Final(d, &context);
    digest_to_hex(d,out);
}

static int l_simple_hash(lua_State *L)
{
    const char *s = luaL_checkstring(L, 1);
    lua_pushnumber(L, simple_hash(s));
    return 1;
}
static int l_md5(lua_State *L)
{
    const char *s = luaL_checkstring(L, 1);
    int len = strlen(s);
    char buff[256];
    md5((uint8_t *)s, len, buff);
    lua_pushstring(L, buff);
    return 1;
}
static int l_sha1(lua_State *L)
{
    const char *s = luaL_checkstring(L, 1);
    char buff[80];
    sha1(s, buff);
    lua_pushstring(L, buff);
    return 1;
}
static int l_base64_encode(lua_State *L)
{
    char *s;
    int len;
    char *dst;
    slice_t *vec = NULL;
    if (lua_isstring(L, 1))
    {
        s = (char *)luaL_checkstring(L, 1);
        len = strlen(s);
    }
    else
    {
        // this may be an bytearray
        vec = lua_check_slice(L, 1);
        s = (char *)vec->data;
        len = vec->len;
    }
    if (len == 0)
    {
        lua_pushstring(L, "");
        return 1;
    }
    dst = (char *)malloc(((len * 4) / 3) + (len / 96) + 6); //(((4 * len / 3) + 3) & ~3)+1
    Base64encode(dst, s, len);
    lua_pushstring(L, dst);
    free(dst);
    return 1;
}
static int l_base64_decode(lua_State *L)
{
    const char *s = luaL_checkstring(L, 1);
    int len = Base64decode_len(s);
    // decode data to a byte array
    lua_new_slice(L, len);
    slice_t *vec = NULL;
    vec = lua_check_slice(L, -1);
    len = Base64decode((char *)vec->data, s);
    vec->len = len;
    // lua_pushstring(L,dst);
    // free(dst);
    return 1;
}

static const struct luaL_Reg enc[] = {
    {"b64encode", l_base64_encode},
    {"b64decode", l_base64_decode},
    {"hash", l_simple_hash},
    {"md5", l_md5},
    {"sha1", l_sha1},
    {NULL, NULL}};

int luaopen_enc(lua_State *L)
{
    luaL_newlib(L, enc);
    return 1;
}