Sindbad~EG File Manager

module.exports = {
    failure: function(errors, remaining) {
        if (errors.length < 1) {
            throw new Error("Failure must have errors");
        }
        return new Result({
            status: "failure",
            remaining: remaining,
            errors: errors
        });
    },
    error: function(errors, remaining) {
        if (errors.length < 1) {
            throw new Error("Failure must have errors");
        }
        return new Result({
            status: "error",
            remaining: remaining,
            errors: errors
        });
    },
    success: function(value, remaining, source) {
        return new Result({
            status: "success",
            value: value,
            source: source,
            remaining: remaining,
            errors: []
        });
    },
    cut: function(remaining) {
        return new Result({
            status: "cut",
            remaining: remaining,
            errors: []
        });
    }
};

var Result = function(options) {
    this._value = options.value;
    this._status = options.status;
    this._hasValue = options.value !== undefined;
    this._remaining = options.remaining;
    this._source = options.source;
    this._errors = options.errors;
};

Result.prototype.map = function(func) {
    if (this._hasValue) {
        return new Result({
            value: func(this._value, this._source),
            status: this._status,
            remaining: this._remaining,
            source: this._source,
            errors: this._errors
        });
    } else {
        return this;
    }
};

Result.prototype.changeRemaining = function(remaining) {
    return new Result({
        value: this._value,
        status: this._status,
        remaining: remaining,
        source: this._source,
        errors: this._errors
    });
};

Result.prototype.isSuccess = function() {
    return this._status === "success" || this._status === "cut";
};

Result.prototype.isFailure = function() {
    return this._status === "failure";
};

Result.prototype.isError = function() {
    return this._status === "error";
};

Result.prototype.isCut = function() {
    return this._status === "cut";
};

Result.prototype.value = function() {
    return this._value;
};

Result.prototype.remaining = function() {
    return this._remaining;
};

Result.prototype.source = function() {
    return this._source;
};

Result.prototype.errors = function() {
    return this._errors;
};