var bigInt = (function () {
    var base = 10000000, logBase = 7;
    var sign = {
        positive: false,
        negative: true
    };

    var normalize = function (first, second) {
        var a = first.value, b = second.value;
        var length = a.length > b.length ? a.length : b.length;
        for (var i = 0; i < length; i++) {
            a[i] = a[i] || 0;
            b[i] = b[i] || 0;
        }
        for (var i = length - 1; i >= 0; i--) {
            if (a[i] === 0 && b[i] === 0) {
                a.pop();
                b.pop();
            } else break;
        }
        if (!a.length) a = [0], b = [0];
        first.value = a;
        second.value = b;
    };

    var parse = function (text, first) {
        if (typeof text === "object") return text;
        text += "";
        var s = sign.positive, value = [];
        if (text[0] === "-") {
            s = sign.negative;
            text = text.slice(1);
        }
	var base = 10;
        if (text.slice(0, 2) == "0x") {
            base = 16;
            text = text.slice(2);
        }
	else {
	        var texts = text.split("e");
		if (texts.length > 2) throw new Error("Invalid integer");
		if (texts[1]) {
		    var exp = texts[1];
		    if (exp[0] === "+") exp = exp.slice(1);
		    exp = parse(exp);
		    if (exp.lesser(0)) throw new Error("Cannot include negative exponent part for integers");
		    while (exp.notEquals(0)) {
		        texts[0] += "0";
		        exp = exp.prev();
		    }
		}
	        text = texts[0];
	}
        if (text === "-0") text = "0";
	text = text.toUpperCase();
        var isValid = (base == 16 ? /^[0-9A-F]*$/ : /^[0-9]+$/).test(text);
        if (!isValid) throw new Error("Invalid integer");
	if (base == 16) {
		var val = bigInt(0);
		while (text.length) {
			v = text.charCodeAt(0) - 48;
			if (v > 9)
				v -= 7;
			text = text.slice(1);
			val = val.times(16).plus(v);
		}
		return val;
	}
	else {
		while (text.length) {
		    var divider = text.length > logBase ? text.length - logBase : 0;
		    value.push(+text.slice(divider));
		    text = text.slice(0, divider);
		}
	        var val = bigInt(value, s);
	        if (first) normalize(first, val);
        	return val;
	}
    };

    var goesInto = function (a, b) {
        var a = bigInt(a, sign.positive), b = bigInt(b, sign.positive);
        if (a.equals(0)) throw new Error("Cannot divide by 0");
        var n = 0;
        do {
            var inc = 1;
            var c = bigInt(a.value, sign.positive), t = c.times(10);
            while (t.lesser(b)) {
                c = t;
                inc *= 10;
                t = t.times(10);
            }
            while (c.lesserOrEquals(b)) {
                b = b.minus(c);
                n += inc;
            }
        } while (a.lesserOrEquals(b));

        return {
            remainder: b.value,
            result: n
        };
    };

    var bigInt = function (value, s) {
        var self = {
            value: value,
            sign: s
        };
        var o = {
            value: value,
            sign: s,
            negate: function (m) {
                var first = m || self;
                return bigInt(first.value, !first.sign);
            },
            abs: function (m) {
                var first = m || self;
                return bigInt(first.value, sign.positive);
            },
            add: function (n, m) {
                var s, first = self, second;
                if (m) (first = parse(n)) && (second = parse(m));
                else second = parse(n, first);
                s = first.sign;
                if (first.sign !== second.sign) {
                    first = bigInt(first.value, sign.positive);
                    second = bigInt(second.value, sign.positive);
                    return s === sign.positive ?
						o.subtract(first, second) :
						o.subtract(second, first);
                }
                normalize(first, second);
                var a = first.value, b = second.value;
                var result = [],
					carry = 0;
                for (var i = 0; i < a.length || carry > 0; i++) {
                    var sum = (a[i] || 0) + (b[i] || 0) + carry;
                    carry = sum >= base ? 1 : 0;
                    sum -= carry * base;
                    result.push(sum);
                }
                return bigInt(result, s);
            },
            plus: function (n, m) {
                return o.add(n, m);
            },
            subtract: function (n, m) {
                var first = self, second;
                if (m) (first = parse(n)) && (second = parse(m));
                else second = parse(n, first);
                if (first.sign !== second.sign) return o.add(first, o.negate(second));
                if (first.sign === sign.negative) return o.subtract(o.negate(second), o.negate(first));
                if (o.compare(first, second) === -1) return o.negate(o.subtract(second, first));
                var a = first.value, b = second.value;
                var result = [],
					borrow = 0;
                for (var i = 0; i < a.length; i++) {
                    var tmp = a[i] - borrow;
                    borrow = tmp < b[i] ? 1 : 0;
                    var minuend = (borrow * base) + tmp - b[i];
                    result.push(minuend);
                }
                return bigInt(result, sign.positive);
            },
            minus: function (n, m) {
                return o.subtract(n, m);
            },
            multiply: function (n, m) {
                var s, first = self, second;
                if (m) (first = parse(n)) && (second = parse(m));
                else second = parse(n, first);
                s = first.sign !== second.sign;
                var a = first.value, b = second.value;
                var resultSum = [];
                for (var i = 0; i < a.length; i++) {
                    resultSum[i] = [];
                    var j = i;
                    while (j--) {
                        resultSum[i].push(0);
                    }
                }
                var carry = 0;
                for (var i = 0; i < a.length; i++) {
                    var x = a[i];
                    for (var j = 0; j < b.length || carry > 0; j++) {
                        var y = b[j];
                        var product = y ? (x * y) + carry : carry;
                        carry = product > base ? Math.floor(product / base) : 0;
                        product -= carry * base;
                        resultSum[i].push(product);
                    }
                }
                var max = -1;
                for (var i = 0; i < resultSum.length; i++) {
                    var len = resultSum[i].length;
                    if (len > max) max = len;
                }
                var result = [], carry = 0;
                for (var i = 0; i < max || carry > 0; i++) {
                    var sum = carry;
                    for (var j = 0; j < resultSum.length; j++) {
                        sum += resultSum[j][i] || 0;
                    }
                    carry = sum > base ? Math.floor(sum / base) : 0;
                    sum -= carry * base;
                    result.push(sum);
                }
                return bigInt(result, s);
            },
            times: function (n, m) {
                return o.multiply(n, m);
            },
            divmod: function (n, m) {
                var s, first = self, second;
                if (m) (first = parse(n)) && (second = parse(m));
                else second = parse(n, first);
                s = first.sign !== second.sign;
                if (bigInt(first.value, first.sign).equals(0)) return {
                    quotient: bigInt([0], sign.positive),
                    remainder: bigInt([0], sign.positive)
                };
                if (second.equals(0)) throw new Error("Cannot divide by zero");
                var a = first.value, b = second.value;
                var result = [], remainder = [];
                for (var i = a.length - 1; i >= 0; i--) {
                    var n = [a[i]].concat(remainder);
                    var quotient = goesInto(b, n);
                    result.push(quotient.result);
                    remainder = quotient.remainder;
                }
                result.reverse();
                return {
                    quotient: bigInt(result, s),
                    remainder: bigInt(remainder, first.sign)
                };
            },
            divide: function (n, m) {
                return o.divmod(n, m).quotient;
            },
            over: function (n, m) {
                return o.divide(n, m);
            },
            mod: function (n, m) {
                return o.divmod(n, m).remainder;
            },
            pow: function (n, m) {
                var first = self, second;
                if (m) (first = parse(n)) && (second = parse(m));
                else second = parse(n, first);
                var a = first, b = second;
                if (b.lesser(0)) return ZERO;
                if (b.equals(0)) return ONE;
                var result = bigInt(a.value, a.sign);

                if (b.mod(2).equals(0)) {
                    var c = result.pow(b.over(2));
                    return c.times(c);
                } else {
                    return result.times(result.pow(b.minus(1)));
                }
            },
            next: function (m) {
                var first = m || self;
                return o.add(first, 1);
            },
            prev: function (m) {
                var first = m || self;
                return o.subtract(first, 1);
            },
            compare: function (n, m) {
                var first = self, second;
                if (m) (first = parse(n)) && (second = parse(m, first));
                else second = parse(n, first);
                normalize(first, second);
                if (first.value.length === 1 && second.value.length === 1 && first.value[0] === 0 && second.value[0] === 0) return 0;
                if (second.sign !== first.sign) return first.sign === sign.positive ? 1 : -1;
                var multiplier = first.sign === sign.positive ? 1 : -1;
                var a = first.value, b = second.value;
                for (var i = a.length - 1; i >= 0; i--) {
                    if (a[i] > b[i]) return 1 * multiplier;
                    if (b[i] > a[i]) return -1 * multiplier;
                }
                return 0;
            },
            compareAbs: function (n, m) {
                var first = self, second;
                if (m) (first = parse(n)) && (second = parse(m, first));
                else second = parse(n, first);
                first.sign = second.sign = sign.positive;
                return o.compare(first, second);
            },
            equals: function (n, m) {
                return o.compare(n, m) === 0;
            },
            notEquals: function (n, m) {
                return !o.equals(n, m);
            },
            lesser: function (n, m) {
                return o.compare(n, m) < 0;
            },
            greater: function (n, m) {
                return o.compare(n, m) > 0;
            },
            greaterOrEquals: function (n, m) {
                return o.compare(n, m) >= 0;
            },
            lesserOrEquals: function (n, m) {
                return o.compare(n, m) <= 0;
            },
            isPositive: function (m) {
                var first = m || self;
                return first.sign === sign.positive;
            },
            isNegative: function (m) {
                var first = m || self;
                return first.sign === sign.negative;
            },
            isEven: function (m) {
                var first = m || self;
                return first.value[0] % 2 === 0;
            },
            isOdd: function (m) {
                var first = m || self;
                return first.value[0] % 2 === 1;
            },
            toString: function (m) {
                var first = m || self;
                var str = "", len = first.value.length;
                while (len--) {
                    if (first.value[len].toString().length === 8) str += first.value[len];
                    else str += (base.toString() + first.value[len]).slice(-logBase);
                }
                while (str[0] === "0") {
                    str = str.slice(1);
                }
                if (!str.length) str = "0";
                var s = (first.sign === sign.positive || str == "0") ? "" : "-";
                return s + str;
            },
            toHex: function (m) {
                var first = m || self;
                var str = "";
				var l = this.abs();
                while (l > 0) {
					var qr = l.divmod(256);
					var b = qr.remainder.toJSNumber();
					str = (b >> 4).toString(16) + (b & 15).toString(16) + str;
                    l = qr.quotient;
                }
                return (this.isNegative() ? "-" : "") + "0x" + str;
            },
            toJSNumber: function (m) {
                return +o.toString(m);
            },
            valueOf: function (m) {
                return o.toJSNumber(m);
            }
        };
        return o;
    };

    var ZERO = bigInt([0], sign.positive);
    var ONE = bigInt([1], sign.positive);
    var MINUS_ONE = bigInt([1], sign.negative);

    var fnReturn = function (a) {
        if (typeof a === "undefined") return ZERO;
        return parse(a);
    };
    fnReturn.zero = ZERO;
    fnReturn.one = ONE;
    fnReturn.minusOne = MINUS_ONE;
    return fnReturn;
})();

if (typeof module !== "undefined") {
    module.exports = bigInt;
}