/* A JavaScript implementation of the Secure Hash Standard
 * Version 0.3 Copyright Angel Marin 2003-2004 - http://anmar.eu.org/
 * Distributed under the BSD License
 * Some bits taken from Paul Johnston's SHA-1 implementation
 */
var chrsz   = 8;   /* bits per input character. 8 - ASCII; 16 - Unicode      */
var hexcase = 0;    /* hex output format. 0 - lowercase; 1 - uppercase        */
var b64pad  = "=";  /* base-64 pad character. "=" for strict RFC compliance   */

function safe_add (x, y) {
  var lsw = (x & 0xFFFF) + (y & 0xFFFF);
  var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
  return (msw << 16) | (lsw & 0xFFFF);
}

function S (X, n) {return ( X >>> n ) | (X << (32 - n));}

function R (X, n) {return ( X >>> n );}

function Ch(x, y, z) {return ((x & y) ^ ((~x) & z));}

function Maj(x, y, z) {return ((x & y) ^ (x & z) ^ (y & z));}

function Sigma0256(x) {return (S(x, 2) ^ S(x, 13) ^ S(x, 22));}

function Sigma1256(x) {return (S(x, 6) ^ S(x, 11) ^ S(x, 25));}

function Gamma0256(x) {return (S(x, 7) ^ S(x, 18) ^ R(x, 3));}

function Gamma1256(x) {return (S(x, 17) ^ S(x, 19) ^ R(x, 10));}

function Sigma0512(x) {return (S(x, 28) ^ S(x, 34) ^ S(x, 39));}

function Sigma1512(x) {return (S(x, 14) ^ S(x, 18) ^ S(x, 41));}

function Gamma0512(x) {return (S(x, 1) ^ S(x, 8) ^ R(x, 7));}

function Gamma1512(x) {return (S(x, 19) ^ S(x, 61) ^ R(x, 6));}

function core_sha256 (m, l) {
    var K = new Array(0x428A2F98,0x71374491,0xB5C0FBCF,0xE9B5DBA5,0x3956C25B,0x59F111F1,0x923F82A4,0xAB1C5ED5,0xD807AA98,0x12835B01,0x243185BE,0x550C7DC3,0x72BE5D74,0x80DEB1FE,0x9BDC06A7,0xC19BF174,0xE49B69C1,0xEFBE4786,0xFC19DC6,0x240CA1CC,0x2DE92C6F,0x4A7484AA,0x5CB0A9DC,0x76F988DA,0x983E5152,0xA831C66D,0xB00327C8,0xBF597FC7,0xC6E00BF3,0xD5A79147,0x6CA6351,0x14292967,0x27B70A85,0x2E1B2138,0x4D2C6DFC,0x53380D13,0x650A7354,0x766A0ABB,0x81C2C92E,0x92722C85,0xA2BFE8A1,0xA81A664B,0xC24B8B70,0xC76C51A3,0xD192E819,0xD6990624,0xF40E3585,0x106AA070,0x19A4C116,0x1E376C08,0x2748774C,0x34B0BCB5,0x391C0CB3,0x4ED8AA4A,0x5B9CCA4F,0x682E6FF3,0x748F82EE,0x78A5636F,0x84C87814,0x8CC70208,0x90BEFFFA,0xA4506CEB,0xBEF9A3F7,0xC67178F2);
    var HASH = new Array(0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19);
    var W = new Array(64);
    var a, b, c, d, e, f, g, h, i, j;
    var T1, T2;

    /* append padding */
    m[l >> 5] |= 0x80 << (24 - l % 32);
    m[((l + 64 >> 9) << 4) + 15] = l;

    for ( var i = 0; i<m.length; i+=16 ) {
        a = HASH[0];
        b = HASH[1];
        c = HASH[2];
        d = HASH[3];
        e = HASH[4];
        f = HASH[5];
        g = HASH[6];
        h = HASH[7];

        for ( var j = 0; j<64; j++) {
            if (j < 16) W[j] = m[j + i];
            else W[j] = safe_add(safe_add(safe_add(Gamma1256(W[j - 2]), W[j - 7]), Gamma0256(W[j - 15])), W[j - 16]);

            T1 = safe_add(safe_add(safe_add(safe_add(h, Sigma1256(e)), Ch(e, f, g)), K[j]), W[j]);
            T2 = safe_add(Sigma0256(a), Maj(a, b, c));

            h = g;
            g = f;
            f = e;
            e = safe_add(d, T1);
            d = c;
            c = b;
            b = a;
            a = safe_add(T1, T2);
        }
        
        HASH[0] = safe_add(a, HASH[0]);
        HASH[1] = safe_add(b, HASH[1]);
        HASH[2] = safe_add(c, HASH[2]);
        HASH[3] = safe_add(d, HASH[3]);
        HASH[4] = safe_add(e, HASH[4]);
        HASH[5] = safe_add(f, HASH[5]);
        HASH[6] = safe_add(g, HASH[6]);
        HASH[7] = safe_add(h, HASH[7]);
    }
    return HASH;
}

function core_sha512 (m, l) {
    var K = new Array(0x428a2f98d728ae22, 0x7137449123ef65cd, 0xb5c0fbcfec4d3b2f, 0xe9b5dba58189dbbc, 0x3956c25bf348b538, 0x59f111f1b605d019, 0x923f82a4af194f9b, 0xab1c5ed5da6d8118, 0xd807aa98a3030242, 0x12835b0145706fbe, 0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2, 0x72be5d74f27b896f, 0x80deb1fe3b1696b1, 0x9bdc06a725c71235, 0xc19bf174cf692694, 0xe49b69c19ef14ad2, 0xefbe4786384f25e3, 0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65, 0x2de92c6f592b0275, 0x4a7484aa6ea6e483, 0x5cb0a9dcbd41fbd4, 0x76f988da831153b5, 0x983e5152ee66dfab, 0xa831c66d2db43210, 0xb00327c898fb213f, 0xbf597fc7beef0ee4, 0xc6e00bf33da88fc2, 0xd5a79147930aa725, 0x06ca6351e003826f, 0x142929670a0e6e70, 0x27b70a8546d22ffc, 0x2e1b21385c26c926, 0x4d2c6dfc5ac42aed, 0x53380d139d95b3df, 0x650a73548baf63de, 0x766a0abb3c77b2a8, 0x81c2c92e47edaee6, 0x92722c851482353b, 0xa2bfe8a14cf10364, 0xa81a664bbc423001, 0xc24b8b70d0f89791, 0xc76c51a30654be30, 0xd192e819d6ef5218, 0xd69906245565a910, 0xf40e35855771202a, 0x106aa07032bbd1b8, 0x19a4c116b8d2d0c8, 0x1e376c085141ab53, 0x2748774cdf8eeb99, 0x34b0bcb5e19b48a8, 0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb, 0x5b9cca4f7763e373, 0x682e6ff3d6b2b8a3, 0x748f82ee5defb2fc, 0x78a5636f43172f60, 0x84c87814a1f0ab72, 0x8cc702081a6439ec, 0x90befffa23631e28, 0xa4506cebde82bde9, 0xbef9a3f7b2c67915, 0xc67178f2e372532b, 0xca273eceea26619c, 0xd186b8c721c0c207, 0xeada7dd6cde0eb1e, 0xf57d4f7fee6ed178, 0x06f067aa72176fba, 0x0a637dc5a2c898a6, 0x113f9804bef90dae, 0x1b710b35131c471b, 0x28db77f523047d84, 0x32caab7b40c72493, 0x3c9ebe0a15c9bebc, 0x431d67c49c100d4c, 0x4cc5d4becb3e42b6, 0x597f299cfc657e2a, 0x5fcb6fab3ad6faec, 0x6c44198c4a475817);
    var HASH = new Array(0x6a09e667f3bcc908, 0xbb67ae8584caa73b, 0x3c6ef372fe94f82b, 0xa54ff53a5f1d36f1, 0x510e527fade682d1, 0x9b05688c2b3e6c1f, 0x1f83d9abfb41bd6b, 0x5be0cd19137e2179);
    var W = new Array(80);
    var a, b, c, d, e, f, g, h, i, j;
    var T1, T2;

}

function str2binb (str) {
  var bin = Array();
  var mask = (1 << chrsz) - 1;
  for(var i = 0; i < str.length * chrsz; i += chrsz)
    bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (24 - i%32);
  return bin;
}

function binb2str (bin) {
  var str = "";
  var mask = (1 << chrsz) - 1;
  for(var i = 0; i < bin.length * 32; i += chrsz)
    str += String.fromCharCode((bin[i>>5] >>> (24 - i%32)) & mask);
  return str;
}

function binb2hex (binarray) {
  var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
  var str = "";
  for(var i = 0; i < binarray.length * 4; i++)
  {
    str += hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8+4)) & 0xF) +
           hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8  )) & 0xF);
  }
  return str;
}

function binb2b64 (binarray) {
  var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var str = "";
  for(var i = 0; i < binarray.length * 4; i += 3)
  {
    var triplet = (((binarray[i   >> 2] >> 8 * (3 -  i   %4)) & 0xFF) << 16)
                | (((binarray[i+1 >> 2] >> 8 * (3 - (i+1)%4)) & 0xFF) << 8 )
                |  ((binarray[i+2 >> 2] >> 8 * (3 - (i+2)%4)) & 0xFF);
    for(var j = 0; j < 4; j++)
    {
      if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;
      else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);
    }
  }
  return str;
}

function hex_sha256(s){return binb2hex(core_sha256(str2binb(s),s.length * chrsz));}
function b64_sha256(s){return binb2b64(core_sha256(str2binb(s),s.length * chrsz));}
function str_sha256(s){return binb2str(core_sha256(str2binb(s),s.length * chrsz));}

/*********************************

 
*/      
function sign(secret, message) {
	var messageBytes = str2binb(message);
	var secretBytes = str2binb(secret);
	if (secretBytes.length > 16) {
    	secretBytes = core_sha256(secretBytes, secret.length * chrsz);
	}
	var ipad = Array(16), opad = Array(16);
	for (var i = 0; i < 16; i++) { 
	ipad[i] = secretBytes[i] ^ 0x36363636;
	opad[i] = secretBytes[i] ^ 0x5C5C5C5C;
	}
	var imsg = ipad.concat(messageBytes);
	var ihash = core_sha256(imsg, 512 + message.length * chrsz);
	var omsg = opad.concat(ihash);
	var ohash = core_sha256(omsg, 512 + 256);
	var b64hash = binb2b64(ohash);
	var urlhash = encodeURIComponent(b64hash);
    return urlhash;
}
      
      Date.prototype.toISODate =
	      new Function("with (this)\n    return " +
		 "getFullYear()+'-'+addZero(getMonth()+1)+'-'" +
		 "+addZero(getDate())+'T'+addZero(getHours())+'%3A'" +
		 "+addZero(getMinutes())+'%3A'+addZero(getSeconds())+'.000Z'");
 
function addZero(n) {
	return ( n < 0 || n > 9 ? "" : "0" ) + n;
}

function getNowTimeStamp() {
	var time = new Date();
	var gmtTime = new Date(time.getTime() + (time.getTimezoneOffset() * 60000));
	return gmtTime.toISODate() ;
}
 
function showAmazon(itemASIN){

	var ajaxRequest;  // The variable that makes Ajax possible!

	try{
		// Opera 8.0+, Firefox, Safari
		ajaxRequest = new XMLHttpRequest();
	} catch (e){
		// Internet Explorer Browsers
		try{
			ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try{
				ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e){
				// Something went wrong
				//alert("Your browser broke!");
				return false;
			}
		}
	}
	// Create a function that will receive data sent from the server
	ajaxRequest.onreadystatechange = function(){
		if(ajaxRequest.readyState == 4){
			var ajaxDisplay = document.getElementById('itemamazon');
			ajaxDisplay.innerHTML = ajaxRequest.responseText;
		}
	}
	var timestamp = getNowTimeStamp();
	var queryString = "asin=" + itemASIN + "&timestamp=" + timestamp + "&signature=" + sign("fSuEEfExM7D93YAiZBRnIhU99SOMG9aSWNkx6pSw", "GET\nwebservices.amazon.com\n/onca/xml\nAWSAccessKeyId=1TRH4A7DG6V1VY7DPV02&AssociateTag=thetoptens08-20&ItemId="+itemASIN+"&Operation=ItemLookup&ResponseGroup=Medium%2CTracks%2CItemAttributes&Service=AWSECommerceService&Timestamp="+timestamp);
	ajaxRequest.open("POST", "/item-amazon.asp", true);
	ajaxRequest.setRequestHeader("Content-Type","application/x-www-form-urlencoded; charset=UTF-8");
	ajaxRequest.send(queryString); 
}