/*
 * A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined
 * in FIPS PUB 180-1
 * Version 2.1a Copyright Paul Johnston 2000 - 2002.
 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
 * Distributed under the BSD License
 * See http://pajhome.org.uk/crypt/md5 for details.
 */

/* Change Log
 *
 * 2011-04-22 Ryan Li <ryan@ryanium.com>
 *   * Wrap functions in Foxtrick.SHA1 and remove unneeded ones to prevent
 *     namespace conflicts in Firefox.
 */

if (!Foxtrick)
	var Foxtrick = {};

Foxtrick.SHA1 = {
	/*
	 * Configurable variables. You may need to tweak these to be compatible with
	 * the server-side, but the defaults work in most cases.
	 */

	/* FIXME - should make Foxtrick.SHA1 as a function receiving these
	 * as parameters.
	 */
	b64pad : "", /* base-64 pad character. "=" for strict RFC compliance   */
	chrsz : 8,  /* bits per input character. 8 - ASCII; 16 - Unicode      */

	/*
	 * These are the functions you'll usually want to call
	 * They take string arguments and return either hex or base-64 encoded strings
	 */
	b64_hmac_sha1 : function(key, data) {
		var b64pad = Foxtrick.SHA1.b64pad;
		/*
		 * Convert an array of big-endian words to a base-64 string
		 */
		var binb2b64 = function(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;
		};
		return binb2b64(this.core_hmac_sha1(key, data));
	},

	/*
	 * Calculate the SHA-1 of an array of big-endian words, and a bit length
	 */
	core_sha1 : function(x, len) {
		/*
		 * Add integers, wrapping at 2^32. This uses 16-bit operations internally
		 * to work around bugs in some JS interpreters.
		 */
		var safe_add = function(x, y) {
			var lsw = (x & 0xFFFF) + (y & 0xFFFF);
			var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
			return (msw << 16) | (lsw & 0xFFFF);
		};
		/*
		 * Perform the appropriate triplet combination function for the current
		 * iteration
		 */
		var sha1_ft = function(t, b, c, d) {
			if(t < 20) return (b & c) | ((~b) & d);
			if(t < 40) return b ^ c ^ d;
			if(t < 60) return (b & c) | (b & d) | (c & d);
			return b ^ c ^ d;
		};
		/*
		 * Determine the appropriate additive constant for the current iteration
		 */
		var sha1_kt = function(t) {
			return (t < 20) ?  1518500249 : (t < 40) ?  1859775393 :
				(t < 60) ? -1894007588 : -899497514;
		};
		/*
		 * Bitwise rotate a 32-bit number to the left.
		 */
		var rol = function(num, cnt) {
			return (num << cnt) | (num >>> (32 - cnt));
		};

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

		var w = Array(80);
		var a =  1732584193;
		var b = -271733879;
		var c = -1732584194;
		var d =  271733878;
		var e = -1009589776;

		for (var i = 0; i < x.length; i += 16) {
			var olda = a;
			var oldb = b;
			var oldc = c;
			var oldd = d;
			var olde = e;

			for (var j = 0; j < 80; j++) {
				if (j < 16)
					w[j] = x[i + j];
				else
					w[j] = rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);
				var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)),
					safe_add(safe_add(e, w[j]), sha1_kt(j)));
				e = d;
				d = c;
				c = rol(b, 30);
				b = a;
				a = t;
			}

			a = safe_add(a, olda);
			b = safe_add(b, oldb);
			c = safe_add(c, oldc);
			d = safe_add(d, oldd);
			e = safe_add(e, olde);
		}
		return Array(a, b, c, d, e);
	},

	/*
	 * Calculate the HMAC-SHA1 of a key and some data
	 */
	core_hmac_sha1 : function(key, data) {
		var chrsz = this.chrsz;
		/*
		 * Convert an 8-bit or 16-bit string to an array of big-endian words
		 * In 8-bit function, characters >255 have their hi-byte silently ignored.
		 */
		var str2binb = function(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) << (32 - chrsz - i%32);
			return bin;
		};

		var bkey = str2binb(key);
		if (bkey.length > 16)
			bkey = this.core_sha1(bkey, key.length * chrsz);

		var ipad = Array(16), opad = Array(16);
		for (var i = 0; i < 16; i++) {
			ipad[i] = bkey[i] ^ 0x36363636;
			opad[i] = bkey[i] ^ 0x5C5C5C5C;
		}

		var hash = this.core_sha1(ipad.concat(str2binb(data)), 512 + data.length * chrsz);
		return this.core_sha1(opad.concat(hash), 512 + 160);
	}
};
