/* 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 invokeRequest( exurl ) {
 
	if (getAccessKeyId() == "AWS Access Key ID") {
	  alert("Please provide an AWS Access Key ID");
	  return "";
	}
 
	if (getSecretAccessKey() == "AWS Secret Access Key") {
	  alert("Please provide an AWS Secret Access Key");
	  return "";
	}
 
        var unsignedUrl = exurl; //document.forms[0].elements["UnsignedURL"].value;
        if (unsignedUrl == "") {
	  alert("Please provide a URL");
	  return "";
	}
 
	var lines = unsignedUrl.split("\n");
	unsignedUrl = "";
	for (var i in lines) { unsignedUrl += lines[i]; }
 
        // find host and query portions
        var urlregex = new RegExp("^http:\\/\\/(.*)\\/onca\\/xml\\?(.*)$");
        var matches = urlregex.exec(unsignedUrl);
 
	if (matches == null) {
	  alert("Could not find PA-API end-point in the URL. Please ensure the URL looks like the example provided.");
	  return "";
	}
 
        var host = matches[1].toLowerCase();
        var query = matches[2];
 
        // split the query into its constituent parts
        var pairs = query.split("&");
 
        // remove signature if already there
        // remove access key id if already present 
        //  and replace with the one user provided above
        // add timestamp if not already present
        pairs = cleanupRequest(pairs);
 
        // show it
//        document.forms[0].elements["NameValuePairs"].value = pairs.join("\n");
        
        // encode the name and value in each pair
        pairs = encodeNameValuePairs(pairs);
        
        // sort them and put them back together to get the canonical query string
        pairs.sort();
//        document.forms[0].elements["OrderedPairs"].value = pairs.join("\n");
 
        var canonicalQuery = pairs.join("&");
        var stringToSign = "GET\n" + host + "\n/onca/xml\n" + canonicalQuery;
 
        // calculate the signature
        var secret = getSecretAccessKey();
        var signature = sign(secret, stringToSign);
        
        // assemble the signed url
        var signedUrl = "http://" + host + "/onca/xml?" + canonicalQuery + "&Signature=" + signature;
/*        
        // update the UI
        var stringToSignArea = document.forms[0].elements["StringToSign"];
        stringToSignArea.value = stringToSign;
        
        var signedURLArea = document.forms[0].elements["SignedURL"];
        signedURLArea.value = signedUrl;
*/
		return signedUrl;
      }
 
      function encodeNameValuePairs(pairs) {
        for (var i = 0; i < pairs.length; i++) {
          var name = "";
          var value = "";
          
          var pair = pairs[i];
          var index = pair.indexOf("=");
 
          // take care of special cases like "&foo&", "&foo=&" and "&=foo&" 
          if (index == -1) {
            name = pair;
          } else if (index == 0) {
            value = pair;
          } else {
            name = pair.substring(0, index);
            if (index < pair.length - 1) {
              value = pair.substring(index + 1);
            }
          }
          
	  // decode and encode to make sure we undo any incorrect encoding
          name = encodeURIComponent(decodeURIComponent(name));
 
	  value = value.replace(/\+/g, "%20");
          value = encodeURIComponent(decodeURIComponent(value));
 
          pairs[i] = name + "=" + value;
        }
        
        return pairs;
      }
      
      function cleanupRequest(pairs) {
        var haveTimestamp = false;
	var haveAwsId = false;
        var accessKeyId =  getAccessKeyId();
        
        var nPairs = pairs.length;
        var i = 0;
        while (i < nPairs) {
          var p = pairs[i];
          if (p.search(/^Timestamp=/) != -1) {
            haveTimestamp = true;
          } else if (p.search(/^(AWSAccessKeyId|SubscriptionId)=/) != -1) {
            pairs.splice(i, 1, "AWSAccessKeyId=" + accessKeyId);
	    haveAwsId = true;
          } else if (p.search(/^Signature=/) != -1) {
            pairs.splice(i, 1);
            i--;
            nPairs--;
          }
          i++;
        }
 
        if (!haveTimestamp) {
          pairs.push("Timestamp=" + getNowTimeStamp());
        }
 
	if (!haveAwsId) {
	  pairs.push("AWSAccessKeyId=" + accessKeyId);
	}
        return pairs;
      }
      
      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())+':'" +
		 "+addZero(getMinutes())+':'+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 getAccessKeyId() {
          return document.forms[0].elements['AWSAccessKeyId'].value;
      }
      
      function getSecretAccessKey() {
          return document.forms[0].elements['AWSSecretAccessKey'].value;        
      }