function _array(length, elementFunction, args) {
    var array = [];
    if (length != null) {
        for (var i = 0; i < length; ++i) {
            array[i] = elementFunction.apply(this, args);
        }
    } else {
        throw "length is required.";
    }
    return array;
}

function boolean() {
    return Math.random() < 0.5;
}

function booleanArray(length) {
    return _array(length, boolean);
}

function float(limit, min) {
    if (limit != null) {
        if (min != null) {
            return Math.random() * (limit - min) + min;
        } else {
            return Math.random() * limit;
        }
    } else {
        throw "max is required.";
    }
}

function floatArray(length, limit, min) {
    return _array(length, float, [limit, min]);
}

function integer(max, min) {
    if (max != null) {
        if (min != null) {
            if (max < min) {
                throw "max [" + max + "] is less than min [" + min + "]";
            }
            return Math.floor(Math.random() * (max - min + 1)) + min;
        } else {
            return Math.floor(Math.random() * (max + 1));
        }
    } else {
        throw "max is required.";
    }
}

function integerArray(length, max, min) {
    return _array(length, integer, [max, min]);
}

function _normalizeRanges(ranges) {
    if (randomExt.DEBUG) {
        console.log("Normalizing ranges:", ranges);
    }
    ranges.sort(function (a, b) {
        return a[0] - b[0];
    });
    if (randomExt.DEBUG) {
        console.log("sorted ranges:", ranges);
    }
    for (var i = 0; i < ranges.length - 1; ++i) {
        for (var j = i + 1; j < ranges.length; ++j) {
            // remove right contained
            if (ranges[i][1] >= ranges[j][1]) {
                ranges.splice(j, 1);
                j--;
            }
            // fix overlap
            else if (ranges[i][1] >= ranges[j][0]) {
                ranges[j][0] = ranges[i][1] + 1;
            }
            if (randomExt.DEBUG) {
                console.log("iteration (" + i + "," + j + "):", ranges);
            }
        }
    }
    if (randomExt.DEBUG) {
        console.log("Normalized ranges:", ranges);
    }
}

function _integerFromRanges(ranges) {
    _normalizeRanges(ranges);
    if (ranges != null) {
        var span = 0;
        for (var i = 0; i < ranges.length; ++i) {
            span += ranges[i][1] - ranges[i][0] + 1;
        }
        var randomNumber = Math.floor(Math.random() * span);
        for (var i = 0; i < ranges.length; ++i) {
            randomNumber += ranges[i][0];
            if (randomNumber <= ranges[i][1]) {
                break;
            } else {
                randomNumber -= ranges[i][1] + 1;
            }
        }
        return randomNumber;
    } else {
        throw "ranges is required.";
    }
}

function _integerArrayFromRanges(length, ranges) {
    var numberArray = [];
    if (length != null && ranges != null) {
        for (var i = 0; i < length; ++i) {
            numberArray[i] = _integerFromRanges(ranges);
        }
    } else {
        throw "length and ranges is required.";
    }
    return numberArray;
}

function _stringFromRanges(maxLength, minLength, ranges) {
    var dString = "";
    var length = integer(maxLength, minLength);
    var unicodeNumbers = _integerArrayFromRanges(length, ranges);
    dString = String.fromCharCode.apply(this, unicodeNumbers);
    return dString;
}

function date(endDate, startDate) {
    if (endDate == null) {
        throw "end date is required.";
    }
    var endDateTime = endDate.getTime();
    var startDateTime = startDate != null ? startDate.getTime() : 0;
    return new Date(integer(endDateTime, startDateTime));
}

function dateArray(length, endDate, startDate) {
    return _array(length, date, [endDate, startDate]);
}

function string(maxLength, minLength) {
    if (randomExt.DEBUG) {
        console.log("string maxLength:", maxLength, " minLength:", minLength);
    }
    return _stringFromRanges(maxLength, minLength, [[32, 126]]);
}

function uString(maxLength, minLength) {
    if (randomExt.DEBUG) {
        console.log("string maxLength:", maxLength, " minLength:", minLength);
    }
    return _stringFromRanges(maxLength, minLength, [[1, 9999]]);
}

function stringArray(arrayLength, stringMaxLength, stringMinLength) {
    return _array(arrayLength, string, [stringMaxLength, stringMinLength]);
}

function restrictedString(content, maxLength, minLength) {
    var ranges = [];
    for (var i = 0; i < content.length; ++i) {
        var contentType = content[i];
        switch (contentType) {
            case randomExt.CHAR_TYPE.SPECIAL:
                ranges = ranges.concat([
                    [33, 47],
                    [58, 64],
                    [91, 96],
                    [123, 126],
                ]);
                break;
            case randomExt.CHAR_TYPE.SPACE:
                ranges = ranges.concat([[32, 32]]);
                break;
            case randomExt.CHAR_TYPE.NUMERIC:
                ranges = ranges.concat([[48, 57]]);
                break;
            case randomExt.CHAR_TYPE.UPPERCASE:
                ranges = ranges.concat([[65, 90]]);
                break;
            case randomExt.CHAR_TYPE.LOWERCASE:
                ranges = ranges.concat([[97, 122]]);
                break;
            case randomExt.CHAR_TYPE.HEX:
                ranges = ranges.concat([
                    [48, 57],
                    [97, 102],
                ]);
                break;
            default:
                if (typeof contentType === "string") {
                    for (var j = 0; j < contentType.length; ++j) {
                        ranges = ranges.concat([
                            [contentType.charCodeAt(j), contentType.charCodeAt(j)],
                        ]);
                    }
                }
        }
    }
    return _stringFromRanges(maxLength, minLength, ranges);
}

function restrictedStringArray(arrayLength, content, stringMaxLength, stringMinLength) {
    return _array(arrayLength, restrictedString, [content, stringMaxLength, stringMinLength]);
}

function _fromDescriptor(randomDescriptor) {
    var randomValue = null;
    if (
        randomDescriptor == null ||
        !randomDescriptor.shift ||
        randomDescriptor.length <= 0 ||
        typeof randomDescriptor[0] !== "function"
    ) {
        randomValue = randomDescriptor;
    } else {
        var randomFunction = randomDescriptor[0];
        if (randomDescriptor.length > 1) {
            var propertyValueArgs = randomDescriptor.slice(1, randomDescriptor.length);
            randomValue = randomFunction.apply(this, propertyValueArgs);
        } else {
            randomValue = randomFunction();
        }
    }
    return randomValue;
}

function object(template) {
    if (randomExt.DEBUG) {
        console.log("object template:", template);
    }
    var newObject = {};
    var properties = Object.getOwnPropertyNames(template);
    for (var i = 0; i < properties.length; ++i) {
        var property = properties[i];
        var randomDescriptor = template[property];
        newObject[property] = _fromDescriptor(randomDescriptor);
    }
    return newObject;
}

function objectArray(length, template) {
    return _array(length, object, [template]);
}

function stringPattern(pattern, variableDefinition) {
    var stringPattern = pattern;
    var properties = Object.getOwnPropertyNames(variableDefinition);
    var replacedStringArray = new Array();
    for (var i = 0; i < stringPattern.length; ++i) {
        if (variableDefinition.hasOwnProperty(stringPattern[i])) {
            replacedStringArray[i] = _fromDescriptor(variableDefinition[stringPattern[i]]);
        } else {
            replacedStringArray[i] = stringPattern[i];
        }
    }
    return replacedStringArray.join("");
}

function stringPatternArray(length, pattern, variableDefinition) {
    return _array(length, stringPattern, [pattern, variableDefinition]);
}

function pick(array) {
    if (array == null) {
        throw "input array is null or undefined.";
    }
    return array[integer(array.length - 1)];
}

function shuffle(array) {
    if (array == null) {
        throw "input array is null or undefined.";
    }
    for (var i = 0; i < array.length; ++i) {
        var randomIndex = integer(array.length - 1);
        var temp = array[randomIndex];
        array[randomIndex] = array[i];
        array[i] = temp;
    }
}

function subArray(array, length) {
    // validation
    if (array == null) {
        throw "input array is null or undefined.";
    } else if (length == null) {
        throw "input length is null or undefined.";
    } else if (array.length < length) {
        throw "input length [" + length + "] must not exceed array length [" + array.length + "]";
    }
    // logic
    var copiedArray = array.slice();
    shuffle(copiedArray);
    return copiedArray.slice(0, length);
}

function splitArray(array, count, ensureEqualSize) {
    if (array == null || count == null) {
        throw "array and count is required.";
    }
    if (array.length < count) {
        throw "input array length is not sufficient for the split.";
    }
    var arrayCopy = [...array];
    shuffle(arrayCopy);
    var outputArrays = [];
    for (var i = count, start = 0, remaining = arrayCopy.length; i > 0; --i) {
        var nextLength = ensureEqualSize
            ? Math.ceil(remaining / i)
            : i === 1
            ? remaining
            : integer(remaining - i, 1);
        var slicedArray = arrayCopy.slice(start, start + nextLength);
        remaining -= slicedArray.length;
        start += slicedArray.length;
        outputArrays.push(slicedArray);
    }
    return outputArrays;
}

function color() {
    return "#".concat(((Math.random() * 0xffffff) << 0).toString(16));
}

function guid() {
    return randomExt.stringPattern("xxxxxxxx-xxxx-yxxx-zxxx-xxxxxxxxxxxx", {
        x: [randomExt.restrictedString, [randomExt.CHAR_TYPE.HEX], 1, 1],
        y: [randomExt.restrictedString, ["12345"], 1, 1],
        z: [randomExt.restrictedString, ["89ab"], 1, 1],
    });
}

var randomExt = {
    boolean: boolean,
    booleanArray: booleanArray,
    integer: integer,
    integerArray: integerArray,
    float: float,
    floatArray: floatArray,
    date: date,
    dateArray: dateArray,
    string: string,
    uString: uString,
    stringArray: stringArray,
    restrictedString: restrictedString,
    restrictedStringArray: restrictedStringArray,
    object: object,
    objectArray: objectArray,
    stringPattern: stringPattern,
    stringPatternArray: stringPatternArray,
    pick: pick,
    shuffle: shuffle,
    subArray: subArray,
    splitArray: splitArray,
    color: color,
    guid: guid,
    CHAR_TYPE: {
        LOWERCASE: 0,
        UPPERCASE: 1,
        NUMERIC: 2,
        SPECIAL: 3,
        SPACE: 4,
        HEX: 5,
    },
    DEBUG: false,
};

module.exports = randomExt;